CA2238949A1 - Mobile position determination - Google Patents
Mobile position determination Download PDFInfo
- Publication number
- CA2238949A1 CA2238949A1 CA002238949A CA2238949A CA2238949A1 CA 2238949 A1 CA2238949 A1 CA 2238949A1 CA 002238949 A CA002238949 A CA 002238949A CA 2238949 A CA2238949 A CA 2238949A CA 2238949 A1 CA2238949 A1 CA 2238949A1
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- CA
- Canada
- Prior art keywords
- base station
- satellite
- data
- station
- cellular
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S19/00—Satellite radio beacon positioning systems; Determining position, velocity or attitude using signals transmitted by such systems
- G01S19/01—Satellite radio beacon positioning systems transmitting time-stamped messages, e.g. GPS [Global Positioning System], GLONASS [Global Orbiting Navigation Satellite System] or GALILEO
- G01S19/03—Cooperating elements; Interaction or communication between different cooperating elements or between cooperating elements and receivers
- G01S19/07—Cooperating elements; Interaction or communication between different cooperating elements or between cooperating elements and receivers providing data for correcting measured positioning data, e.g. DGPS [differential GPS] or ionosphere corrections
- G01S19/071—DGPS corrections
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S19/00—Satellite radio beacon positioning systems; Determining position, velocity or attitude using signals transmitted by such systems
- G01S19/01—Satellite radio beacon positioning systems transmitting time-stamped messages, e.g. GPS [Global Positioning System], GLONASS [Global Orbiting Navigation Satellite System] or GALILEO
- G01S19/03—Cooperating elements; Interaction or communication between different cooperating elements or between cooperating elements and receivers
- G01S19/04—Cooperating elements; Interaction or communication between different cooperating elements or between cooperating elements and receivers providing carrier phase data
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W64/00—Locating users or terminals or network equipment for network management purposes, e.g. mobility management
Abstract
Position determining apparatus comprises a cellular radio system including at least one base station having a base station satellite receiver (6) and position determination means including a cellular mobile station (50) coupled to a local satellite receiver (58), the base station being arranged to transmit base station satellite data including data representing a carrier phase measurement derived from a satellite signal (70) received by the base station satellite receiver (6) to the mobile station (50) via a cellular radio link and the position determination means being arranged to determine its position relative to the base station using local satellite data received by the local satellite receiver (58) and to correct errors in this position determination using base station satellite data. The relative positions of the base stations may be determined automatically with reference to an external positional reference. The external positional reference may be a satellite-based position determining system.
Description
CA 02238949 1998-0~-28 ~RTT-~ POSTTTON DET~MTN~TTON
The present lnvention relates to position-determ;n;ng apparatus particularly but not exclusively for mobile use and has particular application in land surveying.
The in~rastructure currently available to surveyors, map makers, GIS data collectors and navigators, ~or example, ~or high precision positioning is historically based on a national triangulation scheme. The in~rastructure includes a networ~ o~ markers such as triangulation pillars, whose coordinates are known and are usually sold to interested parties through the country's national mapping agency.
Historically, geodetic surveying was per~ormed optically using a device such as a theodolite in con3unction with the markers. For this reason, many of the markers are located at the tops o~ hills to ensure that they are readily inter-visible. This historical system has several drawbacks.
Firstly, although the positions o~ the markers have been measured over many years and have been computed with additional data such as that provided by satellite positioning systems e.g. Global Positioning System (GPS), the network of markers and their coordinates ~requently include significant errors. For example, in the UK the ordnance survey ~apping is based on a triangulation per~ormed in 1936 (the so-called OSGB36 triangulation).
This is known to represent the United Kingdom as having a north-south length 20 metres di~erent ~rom its true length. Various more recent, more accurate and there~ore CA 02238949 1998-0~-28 di~erent triangulations (such as OSGB72 and OS(SN)80) are used in dif~erent fields such as engineering. The use of dif~erent triangulation networks causes confusion.
Secondly, the above prob}em is exacerbated by the respective existence of two independent triangulation networks for the determination of horizontal and vertical positions. To make matters worse, the markers ~or the two independent networks are not necessarily co-located.
In most countries, the national mapping organisation maintains the triangulation network. Income is generated from the network by one-off payments ~or the sale of the computed coordinates of the markers. Thus the revenue is limited and arises in significant amounts only sporadically e.g. when the positions o~ the markers have been recalculated. It is not uncommon, however, ~or markers to be destroyed or to move due to ground movement. With inadequate maintenance, ~urther inaccuracies are thereby introduced into the triangulation networks.
It is known to per~orm accurate position determinations using a dif~erential GPS-type measurement in which two satellite receivers are used, one being placed at a known position and the other being placed at a position to be determineA. It is possible to use a triangulation marker as the known position. ~owever, this has at least two disadvantages. Firstly the coordinates o~ the marker may be inaccurate ~or the reasons given above and secondly the markers are ~requently positioned in inaccessible areas such as hilltops, as described above. In some countries, such as the United Kingdom, new markers suitable ~or the use o~ GPS
CA 02238949 1998-0~-28 W O 97/21109 PCT/GB~G~'~ 986 equipment are being placed in more accessible areas so that the satellite receiver o~ known position (the so-called master station~ can more conveniently be set up. For example, in the United Kingdom the new GPS control markers can all be accessed with a 2-wheel drive vehicle. However, for a party to take advantage of this it is necessary ~or the party to provide both satellite receivers at each respective site and to set them up itsel~; this being relatively expensive and inconvenient.
Currently there exists a worldwide network o~ several hundred tracking stations incorporating permanently recording dual-~requency geodetic GPS receivers. This network is called the IGS ~International GPS Service for Geodynamics) network.
Further features of IGS are summarised in document JPL 400-5S2 6/95 published by the Jet Propulsion Laboratory of the California Institute o~ Technology and entitled "Monitoring Global Change ~y Satellite Tracking". In particular, the IGS network provides online access to IGS tracking station coordinates and velocities, GPS satellite to IGS tracking station measurement information, and very accurate GPS
satellite ephemerides.
The co-called Precise Ephemerides, precise GPS satellite orbit and clock data are available in near real-time (approximately a day late~. The tracking station coordinates are regularly computed and published and have a relative accuracy of between 3mm and lcm between any two sites around the world.
CA 02238949 1998-0~-28 W O 97/21109 PCT/GB96/~2986 These publlshed "control" coordinates can be regarded as absolute reference positions to which differential GPS
measurements can be referred in order to define actual coordinates for the newly surveyed points. Any position obtained using a differential GPS techni~ue is in fact only a relative position with respect to the stations providing the measurement and/or measurement correction data.
Whilst sufficient information exists to use one of these receivers for dif~erential GPS measurements, it should be appreciated that due to differences in propagation conditions existing between the satellites and the master station and the satellites and the position to be determined, that the accuracy of differential GPS is 1~ diminished as the distance between the master station and the position to be determined increases (typically at a rate of 0.5 to 1 mm per kilometre separation). Thus it is not possible to use an IGS or e~uivalent receiver for high accuracy real-time position determination in all areas.
Attempts have been made to use the base station of a cellular radio network as the reference station in a differential GPS arrangement. Two such attempts are described in GB 2264837-A and W094/12892 respectively.
However, both o~ these attempts have been made in order to provide vehicle location facilities ~or vehicle fleet managers. Since the descri~ed systems do not seek to solve the problem of providing high accuracy measurements for surveying, these systems do not provide su~icient positioning accuracy for surveying.
CA 02238949 1998-0~-28 According to a first aspect of the present invention, position determining apparatus comprises a cellular radio system including at least one base station having a base station satellite receiver, and position determination means including a cellular mobile station coupled to a local satellite receiver, the base station being arranged to transmit base station satellite data including data representing a carrier phase measurement derived ~rom a satellite signal received by the base station satellite receiver to the mobile station via a cellular radio link and the position determination means being arranged to determine its position relative to the base station using local satellite data received by the local satellite receiver and to correct errors in this position determination using the base station satellite data.
In this application the term "base station" means a cellular radio base station forming part of a cellular radio communication infrastructure having a plurality of such base stations which are capable of ~x~h~nging rad~o signals with a plurality of cellular mobile stations such as mobile cellular telephones over cellular radio links.
Most digital cellular telephone ~ase stations (e.g. GSM base stations) need to have access to a precise timing system to ensure the accuracy of the TDMA modulation techniques used.
A common and cost-effective method of providing the necessary accuracy of timing is to use the accurate timing built into the GPS system. Each of the GPS satellites has a plurality of atomic clocks which are monitored and adjusted from stations on the ground Thus, using CA 02238949 1998-0~-28 W O 97/21109 PCT/GB~6~'~29~6 conventional techniques it is possible to derive an extremely accurate (down to nanosecond accuracies) timing signal from received GPS signals. For this reason, many base stations already include a base station satellite receiver which is used to steer a high quality oscillator for the TDMA timing. This means that the cost of the present invention in terms of adapting the cellular radio system hardware can be m; n; m~ 1 . The base station satellite data transmitted to the mobile station may be raw GPS data (typically pseudorange and carrier phase measurements in a standard format such as RINEX-Receiver Independent Exchange) and in~ormation concerning the precise position of the base station. From this information, the position determination means may calculate its own measurement corrections. Using this information, the determination means may correct for errors such as satellite clock and orbit errors and atmospheric propagation ef~ects to improve the accuracy of a position determined using the local satellite data. The use of carrier phase measurements provides the accuracy required o~ surveyiny apparatus. Correction data based on a code phase measurement does not provide sufficient accuracy.
The mobile station may be a conventional mobile station having a data communication facility. Data comm-lntcation is built into most digital cellular radio specifications (including GSM) and is already used for mobile modem connections for laptop computers.
The relative position determination may be performed in real-time using the local and base station satellite data CA 02238949 1998-0~-28 to per~orm a di~erential GPS measurement or alternatively both signals may be logged to a data recorder and the calculations performed later. Data-logging may be per~ormed in addition to a real-time calculation so that the position solutions may be double-checked later, or the raw data may be archived ~or QA (quality assurance) purposes.
The accuracy of the relative position determination achieved using apparatus according to the invention will depend in part on the quantity, or more importantly the duration, o~
data received from the base station. By providing billing means arranged to measure the duration o~ a transmission to the mobile station, the user may be charged for the length of time for which data is transmitted to the mobile station which relates directly to the quality o~ the relative position determination.
The quality of the position determination may further be l~nh~nced by m;lk;ng additional relative determinations using base station satellite data received ~rom alternative adjacent base stations. This allows independently determined position solutions to be compared.
Each base station may include a local database including information relating to its own location, the location of adjacent base stations, the telephone number ~or the service for the adjacent base stations, and/or predetermined GPS
measurements. The base stations are pre~erably interconnected using existing land lines to permit the interchange of at least in~ormation related to the relative locations o~ adjacent base stations. Pre~erably the CA 02238949 1998-0~-28 location information held in the local databases is coordinated by at least one central computing centre (CCC), which is connected to each base station.
According to a second aspect of the invention, a cellular radio system includes at least one base station satellite receiver and is operable to transmit base station satellite data including data representative of a carrier phase measurement derived ~rom a satellite signal received by the ~ase station satellite receiver ~or reception by remote position determination means comprising a mobile station coupled to a remote satellite receiver, for use in computing the position of the remote determination means relative to the base station based on the base station satellite data lS received by the remote satellite receiver.
According to a third aspect o~ the invention, a method o~
position determination using a cellular radio in~rastructure having a plurality of base stations are of known position and include a respective satellite receiver, wherein the method comprises transmitting from at least one of the base stations via a cellular radio link, base station satellite data derived from a satellite signal received by the base station satellite receiver, wherein the data includes data representative of a carrier phase measurement and is transmitted to a cellular mobile station coupled to a local satellite receiver, and wherein the method further comprises using the base station satellite data received via the cellular radio link to determine the position of the mobile station relative to the said base station based on local satellite data received by the local satellite receiver.
CA 02238949 1998-0~-28 W O 97~1109 PCT/GBS''~29~6 According to a f~ourth aspect o:~ the invention a method of operating a cellular radio in~rastructure having a~ least one base station including a base station satellite receiver comprises transmitting base station sa~e}lite data including data representative of carrier phase measurement derived ~rom satellite signals received by the ba8e station satellite receiver ~or reception by a cellular mo~ile station and ~or computation of the position o~ the mobile station relative to the base station based on data received by a satellite receiver associated with the mobile station.
According to a ~ifth aspect o~ the invention a method o~
operating a mobile position-determ; n i ng unit which includes a cellular mobile station coupled to a local satellite receiver, receiving at least a carrier phase measurement ~rom a cellular base station of known position and forming part o~ a cellular radio infrastructure and computing the position of the mobile unit relative to the base station position based on the local satellite data and the remote satellite data.
According to a sixth aspect of the invention, there is provided a method o~ determi n; ng the position o~ a plurality of cellular base stations forming part o~ a cellular radio system, each base station having a base station satellite position fixing system, wherein the method comprises determin~g the position of at least one base station relative to the position of a re~erence satellite position-~ixing system located at a known position by passing correction information derived from the reference position ~ixing system to the said at least one base station to CA 02238949 1998-0~-28 W O 97/21~09 PCT/GBg6/~2986 permit correction of the base station position determ~ n~ by the respective base station position fixing system thereby to determine the position of the base station more accurately, and using the more accurately determined position of the said base station to permit the said base station to replace the reference satellite position-fixing system as a reference for the more accurate determination of the position of another of the base stations.
The external re~erence satellite position fixing system may be one of the above mentioned IGS receivers. Starting with this known reference, the accurate position of each o~ the base stations may be determined using relative GPS carrier phase measurements initially between the external re~erence system and base stations and then between adjacent base stations throughout the whole cellular system. Preferably, as many base station positional measurements as possible are taken directly from one or more external reference satellite position fixing systems to min;m; ze the cumulative effect of errors as the base station position determinations propagate through the cellular system.
Each base station may undertake the abovementioned measurement of its own position relative to adjacent base stations as a background task over many hours or days. It may do this using a differential G~S measurement using an adjacent base station as the master station. It will be appreciated that since in a di~erential GPS measurement the position of the master station is assumed to be known, any errors in the position of the master station will translate directly into an equivalent error in any measurement taken using that master station. Thus, in e~fect, the measurement i5 always made relative to the master station.
Relative position data (typically in the form of position s vectors of a base station relative to the external reference system) are pre~erably communicated ~ack to the CCC which can monitor trends in luo~ ents of a particular base station and can determine the correct ~unctioning of the satellite receiving equipment o~ each base station by checking the lo relative positions o~ adjacent base stations against their expected and/or previous ~ixes. The check will also highlight movement of the base station such as may be caused by mining su~sidence. The CCC pre~erably also operates to scale, orient and adjust the determined relative positions of the base stations to ensure that their determined absolute position ~ixes fit plausibly within the network o~
external reference satellite position fixing systems. It will be noted that a sel~-determined relative base station position measurement can be cross-re~erenced with a measurement based on any available adjacent base station.
Thus the CCC has a margin of re~l-n~nt data with which to determine where errors or movements seem to be occurring.
The CCC adjustment may be per~ormed using "least squares"
optimisation algorithms.
Similarly, when a new base station is installed, its position may be determined with re~erence to adjacent base stations. In this way, the system can be expanded and made sel~-calibrating. Periodically, the network-wide and local databases may be updated with revised position calculations CA 02238949 1998-0~-28 W O 97~1109 PCT/GB96/02986 ~or each of the base stations. ~t the same time, the updated positions may be published to the surveying community.
Thus, in summary, the invention provides accurate, reliable and convenient positioning in~ormation requiring the user to have only a cellular ~obile station such as a mobile telephone and a satellite receiver (typically a GPS
receiver). ~ several base stations are equipped to make their satellite data available to mobile cellular stations, the user can roam between the coverage areas o~ the dif~erent ~ase stations without having to set up di~~erential position determination equipment at di~erent locations of known positions. Existing cellular radio system hardware may be used in particular the GPS receivers in the base station. Mobile GPS receivers and cellular stations having data transmission capabilities are already available.
The GPS unit installed at the cellular base station is pre~erably of a type that can provide both the timing outputs required to time-synchronise the cellular co~lln; cations, and the raw measurements required ~or the di~erential positioning applications. This arrangement has signi~icant cost bene~its since the ~PS receiver is required ~or time synchronisation o~ the cellular network and the ability to o~~er a surveying service may there~ore be offered by adding ~eatures to the GPS receiver at relatively small cost. An alternative implementation is to have separate GPS timing and position determining units to produce the time synchronisation and the above-mentioned data.
Given the built-in call duration measurement and billing means ~ound in a cellular telephone network, and the good correlation between length of availability of base station satellite data and accuracy of measurement, the presently available infrastructure is well suited to position-determination-accuracy related billing. This contlnuous flow of revenue is better suited to a position determination network which inevitably requires continuous maintenance rather than the historical system in which income was generated sporadically.
The invention is readily able to monitor its o~n performance and to calibrate new base stations as described above. Thus maintenance and expansion can be partly automated.
Due to the nature of cellular mobile transmissions, it is already necessary to have a relatively dense network of base stations in urban areas. Denser base station distribution can provide greater accuracy since the distance between the base station and position to be determined is less (therefore enhancing the effect of differential measurements) and furthermore such a dense distribution allows an increased number of adjacent base stations to be used for independent accuracy checks to be made.
A connection to a base station may be made using a conventional dial-up connection. This may be automated by the provision ~y the base station of the numbers of suitable adjacent base stations for additional checks on the accuracy of the data.
CA 02238949 1998-0~-28 A mobile unit, regardless o~ its location within the cellular infrastructure, can be arranged to call a uni~ue number corresponding to the type of service required (eg raw measurements or measurement corrections required) which would then automatically route its call to the nearest cellular base station satellite data source. A separate set of unique numbers may then be used automatically to route the call to the second, third or more closest cellular base stations if independent check measurements are required.
The cellular infrastructure already stores information indicating which cell the mobile unit is in and can therefore be automatically arranged to locate adjacent cells.
An alternative technique is automatically to c~mlln;cate data between ad~acent sites and store the adjacent base station coordinates and/or raw satellite measurements locally in the adjacent cell data base so that only one base 6tation need be accessed by the user to obtain a ~irst 2Q measurement and one or more independent check measurements.
It will be appreciated that the IGS network is cited as one example of a highly accurate external positional reference network. Other such networks may be used to tie the base 2s station positions into an external frame of reference, it being necessary only that the positions of the reference network nodes be known to an accuracy at least as good as that required of the position-deter~ n; ng apparatus.
Furthermore, GPS-related terms (including measurement types) should be construed to indicate their equivalent in other satellite-based navigation systems such as the former Soviet CA 02238949 1998-0~-28 W O 97t21109 PCT/GB96/02986 Union's GLONASS system. Additionally, the apparatus is not limited to use with a GSM cellular radio system.
The invention will now be described by way of example with reference to the drawings in which:
Figure ~ is a schematic block diagram of a cellular radio system in accordance with the invention; and Figure 2 is a schematic block diagram of mobile parts a position determination means in accordance with the invention; and Figure 3 is a schematic diagram of position determination means in accordance with the invention.
With reference to Figure 1, which shows the fixed parts of the system in accordance with the invention, a plurality of cellular base stations 2 comprise a cellular transceiver 4 for controlling and communicating with a cellular mobile station, a GPS receiver 6, a local cell database 8 and an ad~acent cell data~ase 10.
The GPS receiver 6 is conventionally used to provide a timing and fre~uency reference to the cellular transceiver 4. As part of the derivation of a timing solution, the receiver 6 generates time-tagged pseudo-range and carrier phase data deri~ed from received GPS satellite signals, given the accurate coordinates for the position of the receiver 6 su~ficient in~ormation is then available to compute accurate differential GPS corrections for both CA 02238949 1998-0~-28 carrier phase and pseudo-range measurements. The recei~er 6 preferably has the capability of tracking all satellites above the horizon in order to provide high accuracy measurements. Typically the measurements are pseudoranges, allowing accuracy to within plur or minus 10 to 20 cm, and carrier phase, allowing accuracy to within plus or minus 1 mm or less.
Computed corrections ~or the carrier phase and pseudo-range measurements are ~ed into the local cell database 8. When a user wishes to make a position determination, the base station is called and its position and correction data are relayed from the local cell database 8 to the transceiver 4 for onward transmission to the user's mobile station.
Alternatively, raw GPS measurements and the base station coordinates may be transmitted to the mobile station for local measurement correction calculations to be performed.
The GPS receiver 6 also operates, as a background task, to compute its position relative to an adjacent base station site, typically to an accuracy o~ between 1 and 3 cm. This computation is performed as a check of the correct functioning of the base station systems and there~ore can be performed over several hours. The computation is performed by receiving measurement correction information from adjacent cell base stations via the adjacent cell database 10. These corrections are then used to estimate a correction for the base station's own position determination and thereby to derive a position determination relative to the adjacent base ~tation. This relative position vector once calculated is passed via an intercell co~m-ln~cations CA 02238949 1998-0~-28 land line 12 to a network-wide database 14. The GPS
receiver 6 may then select an alternative adjacent base station and perform an identical computation. The network-wide database 14 then holds a series of relative position vector measurements ~or each adjacent base station pair which may be used to calibrate the network as described below.
Having performed a position determination using satellite data (i.e. measurement corrections or raw GPS data and coordinate data) ~rom one cellular base station 2, a user may wish to repeat the determination using an alternative base station 2 as a quality or con~idence assessment. To ~acilitate this, the ad~acent cell database 10 holds details of ad~acent cell base stations such as a telephone number and any other necessary access information. This information is passed back to the user via the transceiver 4. The user may then transfer his call to another base station 2 using this information and may then perform a ~urther position determination.
It may be desired to provide the determ; n~ n5 means with measurement data and/or correction data from several cellular base stations simultaneously thus allowing the computation of its position relative to the same several base stations using either of the known GPS multi-baseline or GPS network computation techniques.
Information related to usage of the base station and in particular the duration of any calls made to the base CA 02238949 1998-0~-28 W O 97/21109 PCT/GB~61'02986 station, are passed to the network-wide database 14 and then onto a customer charging system 16.
A central computing centre (CCC) 18 is connected to the network-wide database 14 (typically using an integrated services digital network (ISDN) connection). Amongst other functions, the CCC periodically reads the computed inter-cell relative positions computed by each base station 2, from the network-wide database 14. The CCC uses these relative positions and solution quality information to calculate new solutions for the network base station coordinates. The solutions for these coordinates are automatically positioned, orientated and scaled to ~it within accurately known base station position coordinates derived directly from an accurate external re~erence framework such as the positions of the IGS recording stations. Periodically (typically every six or twelve months) the CCC-computed base station coordinates are published and entered into the network-wide database for use by each base station in its own GPS measurements. The coordinates are typically derived using least squares optimisation techniques.
The CCC 18 also computes position solutions for those base
The present lnvention relates to position-determ;n;ng apparatus particularly but not exclusively for mobile use and has particular application in land surveying.
The in~rastructure currently available to surveyors, map makers, GIS data collectors and navigators, ~or example, ~or high precision positioning is historically based on a national triangulation scheme. The in~rastructure includes a networ~ o~ markers such as triangulation pillars, whose coordinates are known and are usually sold to interested parties through the country's national mapping agency.
Historically, geodetic surveying was per~ormed optically using a device such as a theodolite in con3unction with the markers. For this reason, many of the markers are located at the tops o~ hills to ensure that they are readily inter-visible. This historical system has several drawbacks.
Firstly, although the positions o~ the markers have been measured over many years and have been computed with additional data such as that provided by satellite positioning systems e.g. Global Positioning System (GPS), the network of markers and their coordinates ~requently include significant errors. For example, in the UK the ordnance survey ~apping is based on a triangulation per~ormed in 1936 (the so-called OSGB36 triangulation).
This is known to represent the United Kingdom as having a north-south length 20 metres di~erent ~rom its true length. Various more recent, more accurate and there~ore CA 02238949 1998-0~-28 di~erent triangulations (such as OSGB72 and OS(SN)80) are used in dif~erent fields such as engineering. The use of dif~erent triangulation networks causes confusion.
Secondly, the above prob}em is exacerbated by the respective existence of two independent triangulation networks for the determination of horizontal and vertical positions. To make matters worse, the markers ~or the two independent networks are not necessarily co-located.
In most countries, the national mapping organisation maintains the triangulation network. Income is generated from the network by one-off payments ~or the sale of the computed coordinates of the markers. Thus the revenue is limited and arises in significant amounts only sporadically e.g. when the positions o~ the markers have been recalculated. It is not uncommon, however, ~or markers to be destroyed or to move due to ground movement. With inadequate maintenance, ~urther inaccuracies are thereby introduced into the triangulation networks.
It is known to per~orm accurate position determinations using a dif~erential GPS-type measurement in which two satellite receivers are used, one being placed at a known position and the other being placed at a position to be determineA. It is possible to use a triangulation marker as the known position. ~owever, this has at least two disadvantages. Firstly the coordinates o~ the marker may be inaccurate ~or the reasons given above and secondly the markers are ~requently positioned in inaccessible areas such as hilltops, as described above. In some countries, such as the United Kingdom, new markers suitable ~or the use o~ GPS
CA 02238949 1998-0~-28 W O 97/21109 PCT/GB~G~'~ 986 equipment are being placed in more accessible areas so that the satellite receiver o~ known position (the so-called master station~ can more conveniently be set up. For example, in the United Kingdom the new GPS control markers can all be accessed with a 2-wheel drive vehicle. However, for a party to take advantage of this it is necessary ~or the party to provide both satellite receivers at each respective site and to set them up itsel~; this being relatively expensive and inconvenient.
Currently there exists a worldwide network o~ several hundred tracking stations incorporating permanently recording dual-~requency geodetic GPS receivers. This network is called the IGS ~International GPS Service for Geodynamics) network.
Further features of IGS are summarised in document JPL 400-5S2 6/95 published by the Jet Propulsion Laboratory of the California Institute o~ Technology and entitled "Monitoring Global Change ~y Satellite Tracking". In particular, the IGS network provides online access to IGS tracking station coordinates and velocities, GPS satellite to IGS tracking station measurement information, and very accurate GPS
satellite ephemerides.
The co-called Precise Ephemerides, precise GPS satellite orbit and clock data are available in near real-time (approximately a day late~. The tracking station coordinates are regularly computed and published and have a relative accuracy of between 3mm and lcm between any two sites around the world.
CA 02238949 1998-0~-28 W O 97/21109 PCT/GB96/~2986 These publlshed "control" coordinates can be regarded as absolute reference positions to which differential GPS
measurements can be referred in order to define actual coordinates for the newly surveyed points. Any position obtained using a differential GPS techni~ue is in fact only a relative position with respect to the stations providing the measurement and/or measurement correction data.
Whilst sufficient information exists to use one of these receivers for dif~erential GPS measurements, it should be appreciated that due to differences in propagation conditions existing between the satellites and the master station and the satellites and the position to be determined, that the accuracy of differential GPS is 1~ diminished as the distance between the master station and the position to be determined increases (typically at a rate of 0.5 to 1 mm per kilometre separation). Thus it is not possible to use an IGS or e~uivalent receiver for high accuracy real-time position determination in all areas.
Attempts have been made to use the base station of a cellular radio network as the reference station in a differential GPS arrangement. Two such attempts are described in GB 2264837-A and W094/12892 respectively.
However, both o~ these attempts have been made in order to provide vehicle location facilities ~or vehicle fleet managers. Since the descri~ed systems do not seek to solve the problem of providing high accuracy measurements for surveying, these systems do not provide su~icient positioning accuracy for surveying.
CA 02238949 1998-0~-28 According to a first aspect of the present invention, position determining apparatus comprises a cellular radio system including at least one base station having a base station satellite receiver, and position determination means including a cellular mobile station coupled to a local satellite receiver, the base station being arranged to transmit base station satellite data including data representing a carrier phase measurement derived ~rom a satellite signal received by the base station satellite receiver to the mobile station via a cellular radio link and the position determination means being arranged to determine its position relative to the base station using local satellite data received by the local satellite receiver and to correct errors in this position determination using the base station satellite data.
In this application the term "base station" means a cellular radio base station forming part of a cellular radio communication infrastructure having a plurality of such base stations which are capable of ~x~h~nging rad~o signals with a plurality of cellular mobile stations such as mobile cellular telephones over cellular radio links.
Most digital cellular telephone ~ase stations (e.g. GSM base stations) need to have access to a precise timing system to ensure the accuracy of the TDMA modulation techniques used.
A common and cost-effective method of providing the necessary accuracy of timing is to use the accurate timing built into the GPS system. Each of the GPS satellites has a plurality of atomic clocks which are monitored and adjusted from stations on the ground Thus, using CA 02238949 1998-0~-28 W O 97/21109 PCT/GB~6~'~29~6 conventional techniques it is possible to derive an extremely accurate (down to nanosecond accuracies) timing signal from received GPS signals. For this reason, many base stations already include a base station satellite receiver which is used to steer a high quality oscillator for the TDMA timing. This means that the cost of the present invention in terms of adapting the cellular radio system hardware can be m; n; m~ 1 . The base station satellite data transmitted to the mobile station may be raw GPS data (typically pseudorange and carrier phase measurements in a standard format such as RINEX-Receiver Independent Exchange) and in~ormation concerning the precise position of the base station. From this information, the position determination means may calculate its own measurement corrections. Using this information, the determination means may correct for errors such as satellite clock and orbit errors and atmospheric propagation ef~ects to improve the accuracy of a position determined using the local satellite data. The use of carrier phase measurements provides the accuracy required o~ surveyiny apparatus. Correction data based on a code phase measurement does not provide sufficient accuracy.
The mobile station may be a conventional mobile station having a data communication facility. Data comm-lntcation is built into most digital cellular radio specifications (including GSM) and is already used for mobile modem connections for laptop computers.
The relative position determination may be performed in real-time using the local and base station satellite data CA 02238949 1998-0~-28 to per~orm a di~erential GPS measurement or alternatively both signals may be logged to a data recorder and the calculations performed later. Data-logging may be per~ormed in addition to a real-time calculation so that the position solutions may be double-checked later, or the raw data may be archived ~or QA (quality assurance) purposes.
The accuracy of the relative position determination achieved using apparatus according to the invention will depend in part on the quantity, or more importantly the duration, o~
data received from the base station. By providing billing means arranged to measure the duration o~ a transmission to the mobile station, the user may be charged for the length of time for which data is transmitted to the mobile station which relates directly to the quality o~ the relative position determination.
The quality of the position determination may further be l~nh~nced by m;lk;ng additional relative determinations using base station satellite data received ~rom alternative adjacent base stations. This allows independently determined position solutions to be compared.
Each base station may include a local database including information relating to its own location, the location of adjacent base stations, the telephone number ~or the service for the adjacent base stations, and/or predetermined GPS
measurements. The base stations are pre~erably interconnected using existing land lines to permit the interchange of at least in~ormation related to the relative locations o~ adjacent base stations. Pre~erably the CA 02238949 1998-0~-28 location information held in the local databases is coordinated by at least one central computing centre (CCC), which is connected to each base station.
According to a second aspect of the invention, a cellular radio system includes at least one base station satellite receiver and is operable to transmit base station satellite data including data representative of a carrier phase measurement derived ~rom a satellite signal received by the ~ase station satellite receiver ~or reception by remote position determination means comprising a mobile station coupled to a remote satellite receiver, for use in computing the position of the remote determination means relative to the base station based on the base station satellite data lS received by the remote satellite receiver.
According to a third aspect o~ the invention, a method o~
position determination using a cellular radio in~rastructure having a plurality of base stations are of known position and include a respective satellite receiver, wherein the method comprises transmitting from at least one of the base stations via a cellular radio link, base station satellite data derived from a satellite signal received by the base station satellite receiver, wherein the data includes data representative of a carrier phase measurement and is transmitted to a cellular mobile station coupled to a local satellite receiver, and wherein the method further comprises using the base station satellite data received via the cellular radio link to determine the position of the mobile station relative to the said base station based on local satellite data received by the local satellite receiver.
CA 02238949 1998-0~-28 W O 97~1109 PCT/GBS''~29~6 According to a f~ourth aspect o:~ the invention a method of operating a cellular radio in~rastructure having a~ least one base station including a base station satellite receiver comprises transmitting base station sa~e}lite data including data representative of carrier phase measurement derived ~rom satellite signals received by the ba8e station satellite receiver ~or reception by a cellular mo~ile station and ~or computation of the position o~ the mobile station relative to the base station based on data received by a satellite receiver associated with the mobile station.
According to a ~ifth aspect o~ the invention a method o~
operating a mobile position-determ; n i ng unit which includes a cellular mobile station coupled to a local satellite receiver, receiving at least a carrier phase measurement ~rom a cellular base station of known position and forming part o~ a cellular radio infrastructure and computing the position of the mobile unit relative to the base station position based on the local satellite data and the remote satellite data.
According to a sixth aspect of the invention, there is provided a method o~ determi n; ng the position o~ a plurality of cellular base stations forming part o~ a cellular radio system, each base station having a base station satellite position fixing system, wherein the method comprises determin~g the position of at least one base station relative to the position of a re~erence satellite position-~ixing system located at a known position by passing correction information derived from the reference position ~ixing system to the said at least one base station to CA 02238949 1998-0~-28 W O 97/21~09 PCT/GBg6/~2986 permit correction of the base station position determ~ n~ by the respective base station position fixing system thereby to determine the position of the base station more accurately, and using the more accurately determined position of the said base station to permit the said base station to replace the reference satellite position-fixing system as a reference for the more accurate determination of the position of another of the base stations.
The external re~erence satellite position fixing system may be one of the above mentioned IGS receivers. Starting with this known reference, the accurate position of each o~ the base stations may be determined using relative GPS carrier phase measurements initially between the external re~erence system and base stations and then between adjacent base stations throughout the whole cellular system. Preferably, as many base station positional measurements as possible are taken directly from one or more external reference satellite position fixing systems to min;m; ze the cumulative effect of errors as the base station position determinations propagate through the cellular system.
Each base station may undertake the abovementioned measurement of its own position relative to adjacent base stations as a background task over many hours or days. It may do this using a differential G~S measurement using an adjacent base station as the master station. It will be appreciated that since in a di~erential GPS measurement the position of the master station is assumed to be known, any errors in the position of the master station will translate directly into an equivalent error in any measurement taken using that master station. Thus, in e~fect, the measurement i5 always made relative to the master station.
Relative position data (typically in the form of position s vectors of a base station relative to the external reference system) are pre~erably communicated ~ack to the CCC which can monitor trends in luo~ ents of a particular base station and can determine the correct ~unctioning of the satellite receiving equipment o~ each base station by checking the lo relative positions o~ adjacent base stations against their expected and/or previous ~ixes. The check will also highlight movement of the base station such as may be caused by mining su~sidence. The CCC pre~erably also operates to scale, orient and adjust the determined relative positions of the base stations to ensure that their determined absolute position ~ixes fit plausibly within the network o~
external reference satellite position fixing systems. It will be noted that a sel~-determined relative base station position measurement can be cross-re~erenced with a measurement based on any available adjacent base station.
Thus the CCC has a margin of re~l-n~nt data with which to determine where errors or movements seem to be occurring.
The CCC adjustment may be per~ormed using "least squares"
optimisation algorithms.
Similarly, when a new base station is installed, its position may be determined with re~erence to adjacent base stations. In this way, the system can be expanded and made sel~-calibrating. Periodically, the network-wide and local databases may be updated with revised position calculations CA 02238949 1998-0~-28 W O 97~1109 PCT/GB96/02986 ~or each of the base stations. ~t the same time, the updated positions may be published to the surveying community.
Thus, in summary, the invention provides accurate, reliable and convenient positioning in~ormation requiring the user to have only a cellular ~obile station such as a mobile telephone and a satellite receiver (typically a GPS
receiver). ~ several base stations are equipped to make their satellite data available to mobile cellular stations, the user can roam between the coverage areas o~ the dif~erent ~ase stations without having to set up di~~erential position determination equipment at di~erent locations of known positions. Existing cellular radio system hardware may be used in particular the GPS receivers in the base station. Mobile GPS receivers and cellular stations having data transmission capabilities are already available.
The GPS unit installed at the cellular base station is pre~erably of a type that can provide both the timing outputs required to time-synchronise the cellular co~lln; cations, and the raw measurements required ~or the di~erential positioning applications. This arrangement has signi~icant cost bene~its since the ~PS receiver is required ~or time synchronisation o~ the cellular network and the ability to o~~er a surveying service may there~ore be offered by adding ~eatures to the GPS receiver at relatively small cost. An alternative implementation is to have separate GPS timing and position determining units to produce the time synchronisation and the above-mentioned data.
Given the built-in call duration measurement and billing means ~ound in a cellular telephone network, and the good correlation between length of availability of base station satellite data and accuracy of measurement, the presently available infrastructure is well suited to position-determination-accuracy related billing. This contlnuous flow of revenue is better suited to a position determination network which inevitably requires continuous maintenance rather than the historical system in which income was generated sporadically.
The invention is readily able to monitor its o~n performance and to calibrate new base stations as described above. Thus maintenance and expansion can be partly automated.
Due to the nature of cellular mobile transmissions, it is already necessary to have a relatively dense network of base stations in urban areas. Denser base station distribution can provide greater accuracy since the distance between the base station and position to be determined is less (therefore enhancing the effect of differential measurements) and furthermore such a dense distribution allows an increased number of adjacent base stations to be used for independent accuracy checks to be made.
A connection to a base station may be made using a conventional dial-up connection. This may be automated by the provision ~y the base station of the numbers of suitable adjacent base stations for additional checks on the accuracy of the data.
CA 02238949 1998-0~-28 A mobile unit, regardless o~ its location within the cellular infrastructure, can be arranged to call a uni~ue number corresponding to the type of service required (eg raw measurements or measurement corrections required) which would then automatically route its call to the nearest cellular base station satellite data source. A separate set of unique numbers may then be used automatically to route the call to the second, third or more closest cellular base stations if independent check measurements are required.
The cellular infrastructure already stores information indicating which cell the mobile unit is in and can therefore be automatically arranged to locate adjacent cells.
An alternative technique is automatically to c~mlln;cate data between ad~acent sites and store the adjacent base station coordinates and/or raw satellite measurements locally in the adjacent cell data base so that only one base 6tation need be accessed by the user to obtain a ~irst 2Q measurement and one or more independent check measurements.
It will be appreciated that the IGS network is cited as one example of a highly accurate external positional reference network. Other such networks may be used to tie the base 2s station positions into an external frame of reference, it being necessary only that the positions of the reference network nodes be known to an accuracy at least as good as that required of the position-deter~ n; ng apparatus.
Furthermore, GPS-related terms (including measurement types) should be construed to indicate their equivalent in other satellite-based navigation systems such as the former Soviet CA 02238949 1998-0~-28 W O 97t21109 PCT/GB96/02986 Union's GLONASS system. Additionally, the apparatus is not limited to use with a GSM cellular radio system.
The invention will now be described by way of example with reference to the drawings in which:
Figure ~ is a schematic block diagram of a cellular radio system in accordance with the invention; and Figure 2 is a schematic block diagram of mobile parts a position determination means in accordance with the invention; and Figure 3 is a schematic diagram of position determination means in accordance with the invention.
With reference to Figure 1, which shows the fixed parts of the system in accordance with the invention, a plurality of cellular base stations 2 comprise a cellular transceiver 4 for controlling and communicating with a cellular mobile station, a GPS receiver 6, a local cell database 8 and an ad~acent cell data~ase 10.
The GPS receiver 6 is conventionally used to provide a timing and fre~uency reference to the cellular transceiver 4. As part of the derivation of a timing solution, the receiver 6 generates time-tagged pseudo-range and carrier phase data deri~ed from received GPS satellite signals, given the accurate coordinates for the position of the receiver 6 su~ficient in~ormation is then available to compute accurate differential GPS corrections for both CA 02238949 1998-0~-28 carrier phase and pseudo-range measurements. The recei~er 6 preferably has the capability of tracking all satellites above the horizon in order to provide high accuracy measurements. Typically the measurements are pseudoranges, allowing accuracy to within plur or minus 10 to 20 cm, and carrier phase, allowing accuracy to within plus or minus 1 mm or less.
Computed corrections ~or the carrier phase and pseudo-range measurements are ~ed into the local cell database 8. When a user wishes to make a position determination, the base station is called and its position and correction data are relayed from the local cell database 8 to the transceiver 4 for onward transmission to the user's mobile station.
Alternatively, raw GPS measurements and the base station coordinates may be transmitted to the mobile station for local measurement correction calculations to be performed.
The GPS receiver 6 also operates, as a background task, to compute its position relative to an adjacent base station site, typically to an accuracy o~ between 1 and 3 cm. This computation is performed as a check of the correct functioning of the base station systems and there~ore can be performed over several hours. The computation is performed by receiving measurement correction information from adjacent cell base stations via the adjacent cell database 10. These corrections are then used to estimate a correction for the base station's own position determination and thereby to derive a position determination relative to the adjacent base ~tation. This relative position vector once calculated is passed via an intercell co~m-ln~cations CA 02238949 1998-0~-28 land line 12 to a network-wide database 14. The GPS
receiver 6 may then select an alternative adjacent base station and perform an identical computation. The network-wide database 14 then holds a series of relative position vector measurements ~or each adjacent base station pair which may be used to calibrate the network as described below.
Having performed a position determination using satellite data (i.e. measurement corrections or raw GPS data and coordinate data) ~rom one cellular base station 2, a user may wish to repeat the determination using an alternative base station 2 as a quality or con~idence assessment. To ~acilitate this, the ad~acent cell database 10 holds details of ad~acent cell base stations such as a telephone number and any other necessary access information. This information is passed back to the user via the transceiver 4. The user may then transfer his call to another base station 2 using this information and may then perform a ~urther position determination.
It may be desired to provide the determ; n~ n5 means with measurement data and/or correction data from several cellular base stations simultaneously thus allowing the computation of its position relative to the same several base stations using either of the known GPS multi-baseline or GPS network computation techniques.
Information related to usage of the base station and in particular the duration of any calls made to the base CA 02238949 1998-0~-28 W O 97/21109 PCT/GB~61'02986 station, are passed to the network-wide database 14 and then onto a customer charging system 16.
A central computing centre (CCC) 18 is connected to the network-wide database 14 (typically using an integrated services digital network (ISDN) connection). Amongst other functions, the CCC periodically reads the computed inter-cell relative positions computed by each base station 2, from the network-wide database 14. The CCC uses these relative positions and solution quality information to calculate new solutions for the network base station coordinates. The solutions for these coordinates are automatically positioned, orientated and scaled to ~it within accurately known base station position coordinates derived directly from an accurate external re~erence framework such as the positions of the IGS recording stations. Periodically (typically every six or twelve months) the CCC-computed base station coordinates are published and entered into the network-wide database for use by each base station in its own GPS measurements. The coordinates are typically derived using least squares optimisation techniques.
The CCC 18 also computes position solutions for those base
2~ stations 2 which can be computed relative to an IGS tracking station. This is per~ormed by downloading IGS tracking data, site coordinates and precise ephemerides from the IGS
database 20 via an Internet connection. Typically this data is available in the RINEX format (see above).
CA 02238949 1998-0~-28 The CCC 18 may when it is reading the relative position measurements computed by the base stations monitor the performance o~ each base station. Since the network-wide database 14 contains many interrelated relative pOSition measurements and in particular will usually have a relative measurement between two base stations performed by each respective base station, it is a relatively trivial task ~or the CCC to determine which base station is in error if unlikely relative measurement results are produced. This permits the system to continuously monitor its own performance and highlight problems automatically.
Furthermore, a similar technique may be used by the CCC to calibrate a new base station site by updating the new stations adjacent cell database 10 to cause it to perform repeated relative measurements with its adjacent base stations thereby providing a set of data from which the new base station's position can be determined. Once such a position has been determined it can be published on the network-wide database 14 and the relevant adjacent cell databases 10 can be updated. It is expected that each base station may have its position determined to a confidence level of between 1 and 2 cm.
With reference to Figure 2, a uQer's mobile position determination means includes a cellular telephone 50 which may be of a digital type operable directly to transmit digital data to the transceiver 4 or may be of the analogue type having a connection via a modem 52 to the base station 2.
CA 02238949 1998-0~-28 W O 97/21109 PC~1~5G/~2986 Satellite data received from the base station transceiver 4 is communicated to a GPS data processor 54.
The data processor 54 is connected to a GPS measurement sensor 56 which passes locally measured pseudoranges and carrier phase measurements to the data processor 54.
Depending on the ~uality of the GPS sensor 56 and the quantity of the GPS base station measurement and/or correction data received via the cellular telephone 50, a position solution ~or the determination means may vary in accuracy from 10 metres down to a ~ew millimetres. The accuracy produced may be tailored to a user's particular requirements. Typically the GPS sensor 56 and data processor 54 will be in a single GPS positioning system 58.
User command inputs and outputs such as position and quality may be issued and viewed via a control display unit (CDU) interface 60.
The computed positions and/or the raw GPS data (both local and from the base station) may be log~ed to a data storage device 62 or fed out to an external device via a connection 64. This permits additional checks and measurements to be made at a later time, or data may be archived ~or QA
(quality assurance) purposes.
The GPS sensor 56, the data processor 54, the CDU interface 60, the data storage device 62 and the position output connection 64 may conveniently be packaged into a single unit. This may then be connected directly by a wire link to a digital cellular tel~rhon~ for co~mlln;cation with the base station. Alternatively, the cellular telephone may be packaged with the above-mentioned components to provide a single device capable of determining position. This may be packaged in the form of a cellular mobile telephone with an integral GPS and cellular radio antenna.
Figure 3 shows a schematic diagram of the complete system.
A satellite signal 70 is received by GPS receiver 6.
Measurement corrections are passed to cellular transceiver 4 for onward transmission to cellular telephone 50. The measurement corrections are communicated to the GPS
positioning system 58 which uses these corrections to determine a position relative to the base station 6 based on satellite signals 72 received locally by the mobile station from GPS satellites 74.
database 20 via an Internet connection. Typically this data is available in the RINEX format (see above).
CA 02238949 1998-0~-28 The CCC 18 may when it is reading the relative position measurements computed by the base stations monitor the performance o~ each base station. Since the network-wide database 14 contains many interrelated relative pOSition measurements and in particular will usually have a relative measurement between two base stations performed by each respective base station, it is a relatively trivial task ~or the CCC to determine which base station is in error if unlikely relative measurement results are produced. This permits the system to continuously monitor its own performance and highlight problems automatically.
Furthermore, a similar technique may be used by the CCC to calibrate a new base station site by updating the new stations adjacent cell database 10 to cause it to perform repeated relative measurements with its adjacent base stations thereby providing a set of data from which the new base station's position can be determined. Once such a position has been determined it can be published on the network-wide database 14 and the relevant adjacent cell databases 10 can be updated. It is expected that each base station may have its position determined to a confidence level of between 1 and 2 cm.
With reference to Figure 2, a uQer's mobile position determination means includes a cellular telephone 50 which may be of a digital type operable directly to transmit digital data to the transceiver 4 or may be of the analogue type having a connection via a modem 52 to the base station 2.
CA 02238949 1998-0~-28 W O 97/21109 PC~1~5G/~2986 Satellite data received from the base station transceiver 4 is communicated to a GPS data processor 54.
The data processor 54 is connected to a GPS measurement sensor 56 which passes locally measured pseudoranges and carrier phase measurements to the data processor 54.
Depending on the ~uality of the GPS sensor 56 and the quantity of the GPS base station measurement and/or correction data received via the cellular telephone 50, a position solution ~or the determination means may vary in accuracy from 10 metres down to a ~ew millimetres. The accuracy produced may be tailored to a user's particular requirements. Typically the GPS sensor 56 and data processor 54 will be in a single GPS positioning system 58.
User command inputs and outputs such as position and quality may be issued and viewed via a control display unit (CDU) interface 60.
The computed positions and/or the raw GPS data (both local and from the base station) may be log~ed to a data storage device 62 or fed out to an external device via a connection 64. This permits additional checks and measurements to be made at a later time, or data may be archived ~or QA
(quality assurance) purposes.
The GPS sensor 56, the data processor 54, the CDU interface 60, the data storage device 62 and the position output connection 64 may conveniently be packaged into a single unit. This may then be connected directly by a wire link to a digital cellular tel~rhon~ for co~mlln;cation with the base station. Alternatively, the cellular telephone may be packaged with the above-mentioned components to provide a single device capable of determining position. This may be packaged in the form of a cellular mobile telephone with an integral GPS and cellular radio antenna.
Figure 3 shows a schematic diagram of the complete system.
A satellite signal 70 is received by GPS receiver 6.
Measurement corrections are passed to cellular transceiver 4 for onward transmission to cellular telephone 50. The measurement corrections are communicated to the GPS
positioning system 58 which uses these corrections to determine a position relative to the base station 6 based on satellite signals 72 received locally by the mobile station from GPS satellites 74.
Claims
1. Position-determining apparatus comprising a cellular radio system including at least one base station having a base station satellite receiver, and position determination means including a cellular mobile station coupled to a local satellite receiver, the base station being arranged to transmit base station satellite data including data representing a carrier phase measurement derived from a satellite signal received by the base station satellite receiver to the mobile station via a cellular radio link and the position determination means being arranged to determine its position relative to the base station using local satellite data received by the local satellite receiver and to correct errors in this position determination using the base station satellite data, the application further including an adjacent cell database associated with a first base station for storing the base station coordinate data of at least one adjacent cell base station. and/or base station satellite data generated by the adjacent cell base station or base stations.
2. Apparatus according to claim 1, wherein the base station satellite receiver is arranged to provide satellite-derived timing signals for synchronisation of the cellular radio system.
3. Apparatus according to claim 1 or claim 2 including billing means operable to measure the duration of the cellular radio link.
4. Apparatus according to any preceding claim, including a network-wide database for holding base station coordinate data related to the location of each base station.
5. Apparatus according to any preceding claim. including a local cell database associated with a base station for storing predetermined base station coordinate data and/or base station satellite data.
6. A cellular radio system including at least one base station satellite receiver and operable to transmit base station satellite data including data representative of a carrier phase measurement derived from a satellite signal received by the base station satellite receiver for reception by remote position determination means comprising a mobile station coupled to a remote satellite receiver, for use in computing the position of the remote position determination means relative to the base station based on the base station satellite data received by the remote satellite receiver, the system further including an adjacent cell database associated with a first base station for storing the base station coordinate data of at least one adjacent cell base station, and/or base station satellite data generated by the adjacent cell base station or base stations.
7. A method of position determination using a cellular radio infrastructure having a plurality of base stations which are of known position and include a respective satellite receiver, wherein the method comprises transmitting from at least one of the base stations via a cellular radio link, base station satellite data derived from a satellite signal received by the base station satellite receiver, wherein the data includes data representative of a carrier phase measurement and is transmitted to a cellular mobile station coupled to a local satellite receiver, and wherein the method further comprises using the base station satellite data received via the cellular radio link to determine the position of the mobile station relative to the said base station based on local satellite data received by the local satellite receiver, the method further comprising storing the base station coordinate data of at least one adjacent cell base station, and/or base station satellite data generated by the adjacent cell base station or base stations in an adjacent cell database associated with a first base station.
8. A method according to claim 7 using a cellular radio infrastructure having a plurality of said base stations each of known position and each having a satellite receiver, whereby base station data can be transmitted to the mobile station from any of the base stations depending on their proximity to the mobile stations.
9. A method according to claim 7 or claim 8, including the steps of storing in the mobile station an address code unique to a position determining function, which address code automatically gives the mobile station access to a database within a base station, which database contains base station satellite data, and automatically routing via the cellular radio infrastructure a call containing the said code from the mobile station to the database.
10. A method according to claim 9, including the steps of storing in the mobile station a plurality of address codes relating to a plurality of respective databases containing base station satellite data stored in a plurality of respective base stations, whereby transmission of a selected one of the said address codes automatically gives the mobile station access to a selected one of the databases.
11. A method according to claim 9 or claim 10, including storing in the mobile station an address code relating to a base station having a plurality of databases containing satellite data from a plurality of satellite receivers located in different base stations, whereby transmission of the address code gives the mobile station access to the said databases to permit an independent check measurement to be made.
12. A method according to any of claims 7 to 11, wherein the cellular mobile stations includes logging means for recording the base station satellite data and the local satellite data.
13. A method according to any of claims 7 to 12, wherein the positions of the base stations are calibrated by determining the position of at least one base station relative to the position of an external reference satellite position-fixing system located at a known position by passing reference satellite data derived from the external reference position fixing system to the said at least one base station to permit correction of the base station position determined by the respective base station position fixing system thereby to determine the position of the base station more accurately, and using the more accurately determined position of the said base station to permit the said base station to replace the external reference satellite position-fixing system as a reference for the more accurate determination of the position of another of the base stations.
15. A method of operating a mobile position-determining unit which includes a cellular mobile station coupled to a local satellite receiver, wherein the method comprises receiving local satellite data from the local satellite receiver, receiving at least a carrier phase measurement from a cellular base station of known position and forming part of a cellular radio infrastructure and computing the position of the mobile unit relative to the base station position based on the local satellite data and the remote satellite data.
16. A method of determining the position of a plurality of cellular base stations forming part of a cellular radio system, each base station having a base station satellite position fixing system, wherein the method comprises determining the position of at least one of the base stations relative to the position of an external reference satellite position fixing system located at a known position by passing reference satellite data derived from the external reference position fixing system to the said at least one base station to permit correction of the base station position determined by the respective base station position fixing system thereby to determine the position of the base station more accurately, and using the more accurately determined position of the said base station to permit the said base station to replace the reference satellite position fixing system as a reference for the more accurate determination of the position of another of the base stations.
17. A method according to claim 16, including monitoring the performance of a first base station by comparing relative position measurements of the same position performed using different combinations of base stations including the first base station and determining which base station is in error if relative measurement results falling outside expected parameters are produced.
2. Apparatus according to claim 1, wherein the base station satellite receiver is arranged to provide satellite-derived timing signals for synchronisation of the cellular radio system.
3. Apparatus according to claim 1 or claim 2 including billing means operable to measure the duration of the cellular radio link.
4. Apparatus according to any preceding claim, including a network-wide database for holding base station coordinate data related to the location of each base station.
5. Apparatus according to any preceding claim. including a local cell database associated with a base station for storing predetermined base station coordinate data and/or base station satellite data.
6. A cellular radio system including at least one base station satellite receiver and operable to transmit base station satellite data including data representative of a carrier phase measurement derived from a satellite signal received by the base station satellite receiver for reception by remote position determination means comprising a mobile station coupled to a remote satellite receiver, for use in computing the position of the remote position determination means relative to the base station based on the base station satellite data received by the remote satellite receiver, the system further including an adjacent cell database associated with a first base station for storing the base station coordinate data of at least one adjacent cell base station, and/or base station satellite data generated by the adjacent cell base station or base stations.
7. A method of position determination using a cellular radio infrastructure having a plurality of base stations which are of known position and include a respective satellite receiver, wherein the method comprises transmitting from at least one of the base stations via a cellular radio link, base station satellite data derived from a satellite signal received by the base station satellite receiver, wherein the data includes data representative of a carrier phase measurement and is transmitted to a cellular mobile station coupled to a local satellite receiver, and wherein the method further comprises using the base station satellite data received via the cellular radio link to determine the position of the mobile station relative to the said base station based on local satellite data received by the local satellite receiver, the method further comprising storing the base station coordinate data of at least one adjacent cell base station, and/or base station satellite data generated by the adjacent cell base station or base stations in an adjacent cell database associated with a first base station.
8. A method according to claim 7 using a cellular radio infrastructure having a plurality of said base stations each of known position and each having a satellite receiver, whereby base station data can be transmitted to the mobile station from any of the base stations depending on their proximity to the mobile stations.
9. A method according to claim 7 or claim 8, including the steps of storing in the mobile station an address code unique to a position determining function, which address code automatically gives the mobile station access to a database within a base station, which database contains base station satellite data, and automatically routing via the cellular radio infrastructure a call containing the said code from the mobile station to the database.
10. A method according to claim 9, including the steps of storing in the mobile station a plurality of address codes relating to a plurality of respective databases containing base station satellite data stored in a plurality of respective base stations, whereby transmission of a selected one of the said address codes automatically gives the mobile station access to a selected one of the databases.
11. A method according to claim 9 or claim 10, including storing in the mobile station an address code relating to a base station having a plurality of databases containing satellite data from a plurality of satellite receivers located in different base stations, whereby transmission of the address code gives the mobile station access to the said databases to permit an independent check measurement to be made.
12. A method according to any of claims 7 to 11, wherein the cellular mobile stations includes logging means for recording the base station satellite data and the local satellite data.
13. A method according to any of claims 7 to 12, wherein the positions of the base stations are calibrated by determining the position of at least one base station relative to the position of an external reference satellite position-fixing system located at a known position by passing reference satellite data derived from the external reference position fixing system to the said at least one base station to permit correction of the base station position determined by the respective base station position fixing system thereby to determine the position of the base station more accurately, and using the more accurately determined position of the said base station to permit the said base station to replace the external reference satellite position-fixing system as a reference for the more accurate determination of the position of another of the base stations.
15. A method of operating a mobile position-determining unit which includes a cellular mobile station coupled to a local satellite receiver, wherein the method comprises receiving local satellite data from the local satellite receiver, receiving at least a carrier phase measurement from a cellular base station of known position and forming part of a cellular radio infrastructure and computing the position of the mobile unit relative to the base station position based on the local satellite data and the remote satellite data.
16. A method of determining the position of a plurality of cellular base stations forming part of a cellular radio system, each base station having a base station satellite position fixing system, wherein the method comprises determining the position of at least one of the base stations relative to the position of an external reference satellite position fixing system located at a known position by passing reference satellite data derived from the external reference position fixing system to the said at least one base station to permit correction of the base station position determined by the respective base station position fixing system thereby to determine the position of the base station more accurately, and using the more accurately determined position of the said base station to permit the said base station to replace the reference satellite position fixing system as a reference for the more accurate determination of the position of another of the base stations.
17. A method according to claim 16, including monitoring the performance of a first base station by comparing relative position measurements of the same position performed using different combinations of base stations including the first base station and determining which base station is in error if relative measurement results falling outside expected parameters are produced.
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| GBGB9524754.0A GB9524754D0 (en) | 1995-12-04 | 1995-12-04 | Mobile position determination |
| GB9524754.0 | 1995-12-04 |
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| EP (1) | EP0866983B1 (en) |
| JP (1) | JP2000501504A (en) |
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Families Citing this family (88)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8352400B2 (en) | 1991-12-23 | 2013-01-08 | Hoffberg Steven M | Adaptive pattern recognition based controller apparatus and method and human-factored interface therefore |
| US10361802B1 (en) | 1999-02-01 | 2019-07-23 | Blanding Hovenweep, Llc | Adaptive pattern recognition based control system and method |
| US5884214A (en) | 1996-09-06 | 1999-03-16 | Snaptrack, Inc. | GPS receiver and method for processing GPS signals |
| US5663734A (en) * | 1995-10-09 | 1997-09-02 | Precision Tracking, Inc. | GPS receiver and method for processing GPS signals |
| US5841396A (en) * | 1996-03-08 | 1998-11-24 | Snaptrack, Inc. | GPS receiver utilizing a communication link |
| US6208290B1 (en) * | 1996-03-08 | 2001-03-27 | Snaptrack, Inc. | GPS receiver utilizing a communication link |
| US5945944A (en) * | 1996-03-08 | 1999-08-31 | Snaptrack, Inc. | Method and apparatus for determining time for GPS receivers |
| US6236365B1 (en) | 1996-09-09 | 2001-05-22 | Tracbeam, Llc | Location of a mobile station using a plurality of commercial wireless infrastructures |
| US9134398B2 (en) | 1996-09-09 | 2015-09-15 | Tracbeam Llc | Wireless location using network centric location estimators |
| US7764231B1 (en) | 1996-09-09 | 2010-07-27 | Tracbeam Llc | Wireless location using multiple mobile station location techniques |
| FI973386A (en) * | 1997-07-25 | 1999-01-26 | Vaeaenaenen Mikko Kalervo | A method for analyzing and communicating health information |
| US6529159B1 (en) * | 1997-08-28 | 2003-03-04 | At Road, Inc. | Method for distributing location-relevant information using a network |
| DE19741216C2 (en) * | 1997-09-18 | 1999-10-14 | Siemens Ag | Method and arrangement for eavesdropping on communication connections in a satellite-based mobile radio system |
| US6070078A (en) * | 1997-10-15 | 2000-05-30 | Ericsson Inc. | Reduced global positioning system receiver code shift search space for a cellular telephone system |
| US6081229A (en) * | 1998-03-17 | 2000-06-27 | Qualcomm Incorporated | System and method for determining the position of a wireless CDMA transceiver |
| US6411811B2 (en) * | 1998-04-20 | 2002-06-25 | Ericsson Inc. | System and method for provisioning assistance global positioning system information to a mobile station |
| US5999124A (en) * | 1998-04-22 | 1999-12-07 | Snaptrack, Inc, | Satellite positioning system augmentation with wireless communication signals |
| US6061018A (en) * | 1998-05-05 | 2000-05-09 | Snaptrack, Inc. | Method and system for using altitude information in a satellite positioning system |
| US6252543B1 (en) * | 1998-05-28 | 2001-06-26 | Ericsson Inc. | Location system combining ranging measurements from GPS and cellular networks |
| US6415154B1 (en) | 1998-10-06 | 2002-07-02 | Ericsson Inc. | Method and apparatus for communicating auxilliary information and location information between a cellular telephone network and a global positioning system receiver for reducing code shift search time of the receiver |
| JP2000155163A (en) * | 1998-11-20 | 2000-06-06 | Sony Computer Entertainment Inc | Positioning system, method, and device |
| AU2022100A (en) * | 1998-12-08 | 2000-06-26 | Ericsson Inc. | Provisioning of gps assistance data in a wcdma network |
| US7966078B2 (en) | 1999-02-01 | 2011-06-21 | Steven Hoffberg | Network media appliance system and method |
| GB2347035B (en) | 1999-02-16 | 2003-10-08 | Symmetricom Inc | Positioning system |
| GB2347571A (en) | 1999-03-03 | 2000-09-06 | Secr Defence | Locating system |
| US6275707B1 (en) * | 1999-10-08 | 2001-08-14 | Motorola, Inc. | Method and apparatus for assigning location estimates from a first transceiver to a second transceiver |
| US7797448B1 (en) * | 1999-10-28 | 2010-09-14 | Ernest G Szoke | GPS-internet linkage |
| US7142878B1 (en) | 1999-11-12 | 2006-11-28 | Lucent Technologies Inc. | Method of timing calibration |
| CA2326292A1 (en) * | 1999-12-03 | 2001-06-03 | Lucent Technologies Inc. | Method of timing calibration |
| US6680919B1 (en) * | 2000-02-04 | 2004-01-20 | Nokia Corporation | Downloading of maps and location specific configuration information to GPS-capable mobile communication terminal |
| WO2001084862A2 (en) * | 2000-05-03 | 2001-11-08 | Telefonaktiebolaget Lm Ericsson (Publ) | Calibration of positioning systems |
| US9875492B2 (en) | 2001-05-22 | 2018-01-23 | Dennis J. Dupray | Real estate transaction system |
| US10684350B2 (en) | 2000-06-02 | 2020-06-16 | Tracbeam Llc | Services and applications for a communications network |
| US10641861B2 (en) | 2000-06-02 | 2020-05-05 | Dennis J. Dupray | Services and applications for a communications network |
| US6331836B1 (en) | 2000-08-24 | 2001-12-18 | Fast Location.Net, Llc | Method and apparatus for rapidly estimating the doppler-error and other receiver frequency errors of global positioning system satellite signals weakened by obstructions in the signal path |
| US6405127B1 (en) * | 2000-09-15 | 2002-06-11 | General Electric Company | Method for determining stationary locomotive location in a railyard |
| WO2002025309A1 (en) | 2000-09-20 | 2002-03-28 | Koninklijke Philips Electronics N.V. | A method of determining the position of a mobile unit |
| JP2002168734A (en) * | 2000-11-30 | 2002-06-14 | Fuji Heavy Ind Ltd | Vehicle management system |
| JP2002311123A (en) * | 2001-04-11 | 2002-10-23 | Mitsui & Co Ltd | Satellite position measuring system |
| US6882309B2 (en) | 2001-07-18 | 2005-04-19 | Fast Location. Net, Llc | Method and system for processing positioning signals based on predetermined message data segment |
| US6529160B2 (en) | 2001-07-18 | 2003-03-04 | Fast Location.Net, Llc | Method and system for determining carrier frequency offsets for positioning signals |
| US6515620B1 (en) | 2001-07-18 | 2003-02-04 | Fast Location.Net, Llc | Method and system for processing positioning signals in a geometric mode |
| US9052374B2 (en) | 2001-07-18 | 2015-06-09 | Fast Location.Net, Llc | Method and system for processing positioning signals based on predetermined message data segment |
| US6628234B2 (en) | 2001-07-18 | 2003-09-30 | Fast Location.Net, Llc | Method and system for processing positioning signals in a stand-alone mode |
| JP4049558B2 (en) * | 2001-08-06 | 2008-02-20 | 株式会社デンソー | Wireless communication terminal, computer program, and position-related information transmission method |
| US7068704B1 (en) | 2001-09-26 | 2006-06-27 | Itt Manufacturing Enterpprises, Inc. | Embedded chirp signal for position determination in cellular communication systems |
| US6983160B2 (en) * | 2001-10-25 | 2006-01-03 | Motorola, Inc. | Base site and method for GPS-based regional time synchronization |
| US7127257B2 (en) * | 2001-12-27 | 2006-10-24 | Qualcomm Incorporated | Use of mobile stations for determination of base station location parameters in a wireless mobile communication system |
| WO2003069941A1 (en) * | 2002-02-15 | 2003-08-21 | Nokia Corporation | Positioning in a telecommunications system |
| US6975939B2 (en) * | 2002-07-29 | 2005-12-13 | The United States Of America As Represented By The Secretary Of The Army | Mapping patterns of movement based on the aggregation of spatial information contained in wireless transmissions |
| US8010124B2 (en) | 2003-03-24 | 2011-08-30 | Sony Ericsson Mobile Communications Ab | Methods, systems and computer program products for providing location determination information to an assisted location service |
| US8483717B2 (en) | 2003-06-27 | 2013-07-09 | Qualcomm Incorporated | Local area network assisted positioning |
| US8971913B2 (en) | 2003-06-27 | 2015-03-03 | Qualcomm Incorporated | Method and apparatus for wireless network hybrid positioning |
| US7123928B2 (en) * | 2003-07-21 | 2006-10-17 | Qualcomm Incorporated | Method and apparatus for creating and using a base station almanac for position determination |
| US7321776B2 (en) | 2003-09-25 | 2008-01-22 | Sony Ericsson Mobile Communications Ab | Estimating GPS time at cellular terminals based on timing of information from base stations and satellites |
| WO2005060669A2 (en) * | 2003-12-19 | 2005-07-07 | Kennedy Joseph P | E-otd augmentation to u-tdoa location system |
| US20050143090A1 (en) * | 2003-12-29 | 2005-06-30 | Interdigital Technology Corporation | Location aided wireless signal characteristic adjustment |
| GB2410849B (en) * | 2003-12-30 | 2007-03-14 | Nokia Corp | A GPS device |
| BRPI0418696A (en) | 2004-04-02 | 2007-06-12 | Qualcomm Inc | methods and equipment for signaling assisted position determination systems |
| KR100560389B1 (en) * | 2004-07-05 | 2006-03-13 | 한국전자통신연구원 | Optimal Base Station Selecting Method in Wireless Network |
| US7358897B2 (en) | 2004-08-16 | 2008-04-15 | Sony Ericsson Mobile Communicatios Ab | Apparatus, methods and computer program products for GPS signal acquisition using an adaptive search engine |
| US7453956B2 (en) | 2004-08-16 | 2008-11-18 | Sony Ericsson Mobile Communications Ab | Apparatus, methods and computer program products for signal acquisition using common demodulation templates |
| PL2026085T3 (en) * | 2004-10-21 | 2012-08-31 | Nokia Technologies Oy | Providing carrier-phase measurements upon request for satellite based positioning |
| US7548200B2 (en) | 2006-04-24 | 2009-06-16 | Nemerix Sa | Ephemeris extension method for GNSS applications |
| EP1873546A1 (en) * | 2006-06-23 | 2008-01-02 | Nemerix SA | Method and system for ephemeris extension for GNSS applications |
| US8497801B2 (en) * | 2007-02-05 | 2013-07-30 | Qualcomm Incorporated | Prediction refresh method for ephemeris extensions |
| JP5118894B2 (en) * | 2007-06-05 | 2013-01-16 | 株式会社Ｋｄｄｉ研究所 | Wireless base station |
| US20090043435A1 (en) * | 2007-08-07 | 2009-02-12 | Quantum Engineering, Inc. | Methods and systems for making a gps signal vital |
| US20090312036A1 (en) | 2008-06-16 | 2009-12-17 | Skyhook Wireless, Inc. | Methods and systems for improving the accuracy of expected error estimation in location determinations using a hybrid cellular and wlan positioning system |
| US8478228B2 (en) | 2008-10-20 | 2013-07-02 | Qualcomm Incorporated | Mobile receiver with location services capability |
| US8306726B2 (en) * | 2009-04-28 | 2012-11-06 | Caterpillar Inc. | Position monitoring system for a mobile machine |
| US8509970B2 (en) | 2009-06-30 | 2013-08-13 | Invensys Rail Corporation | Vital speed profile to control a train moving along a track |
| FR2948188B1 (en) * | 2009-07-20 | 2011-09-09 | Soletanche Freyssinet | METHOD FOR MONITORING THE MOVEMENTS OF A FIELD |
| US8600297B2 (en) * | 2009-07-28 | 2013-12-03 | Qualcomm Incorporated | Method and system for femto cell self-timing and self-locating |
| US9651674B2 (en) * | 2009-12-11 | 2017-05-16 | At&T Mobility Ii Llc | Devices, systems and methods for providing location information over a cellular network |
| US20110181465A1 (en) * | 2010-01-26 | 2011-07-28 | Rongsheng Li | Multi-constellation global navigation satellite system augmentation and assistance |
| WO2011128722A1 (en) * | 2010-04-12 | 2011-10-20 | Nokia Corporation | Selection of a relative positioning method |
| US9538493B2 (en) | 2010-08-23 | 2017-01-03 | Finetrak, Llc | Locating a mobile station and applications therefor |
| RU2470261C1 (en) * | 2011-12-07 | 2012-12-20 | Открытое акционерное общество "Завод им. В.А. Дегтярева" | Method to solve special geodetic tasks |
| US9405010B2 (en) | 2012-05-02 | 2016-08-02 | Raven Industries, Inc. | Geospatial positioning using correction information provided over cellular control channels |
| US9671501B2 (en) * | 2012-09-26 | 2017-06-06 | Trimble Inc. | Global navigation satellite systems (GNSS) positioning using precise satellite data |
| US9743373B2 (en) | 2012-12-28 | 2017-08-22 | Trimble Inc. | Concurrent dual processing of pseudoranges with corrections |
| US9612341B2 (en) * | 2012-12-28 | 2017-04-04 | Trimble Inc. | GNSS receiver positioning system |
| US9880286B2 (en) | 2012-12-28 | 2018-01-30 | Trimble Inc. | Locally measured movement smoothing of position fixes based on extracted pseudoranges |
| CN106285627A (en) * | 2016-08-31 | 2017-01-04 | 西部黄金克拉玛依哈图金矿有限责任公司 | The Contact triangle measurement method that a kind of down-hole adjacent wires is obstructed |
| JP7113178B2 (en) * | 2016-12-27 | 2022-08-05 | パナソニックＩｐマネジメント株式会社 | Positioning system, base station and positioning method |
| EP3708000A1 (en) * | 2019-03-13 | 2020-09-16 | Swiss Timing Ltd. | Measuring system for horse race or training |
| WO2023209927A1 (en) * | 2022-04-28 | 2023-11-02 | 三菱電機株式会社 | Position orientation device |
Family Cites Families (26)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4812991A (en) * | 1986-05-01 | 1989-03-14 | Magnavox Govt. And Industrial Electronics Company | Method for precision dynamic differential positioning |
| JPH0820499B2 (en) * | 1987-01-30 | 1996-03-04 | 日本無線株式会社 | Combined positioning system |
| US4928106A (en) * | 1988-07-14 | 1990-05-22 | Ashtech Telesis, Inc. | Global positioning system receiver with improved radio frequency and digital processing |
| GB2241623A (en) * | 1990-02-28 | 1991-09-04 | Philips Electronic Associated | Vehicle location system |
| US5043736B1 (en) * | 1990-07-27 | 1994-09-06 | Cae Link Corp | Cellular position location system |
| JPH04266228A (en) * | 1991-02-21 | 1992-09-22 | Sony Corp | Telephone system for mobile body |
| JPH04315076A (en) * | 1991-04-12 | 1992-11-06 | Sharp Corp | Gps local position measuring apparatus |
| JPH04369492A (en) * | 1991-06-18 | 1992-12-22 | Pioneer Electron Corp | Gps position measurement device |
| US5148179A (en) * | 1991-06-27 | 1992-09-15 | Trimble Navigation | Differential position determination using satellites |
| US5303297A (en) * | 1991-07-25 | 1994-04-12 | Motorola, Inc. | Dynamic pricing method and apparatus for communication systems |
| DE4136136C1 (en) * | 1991-11-02 | 1993-03-04 | Westdeutscher Rundfunk, Anstalt Des Oeffentlichen Rechts, 5000 Koeln, De | |
| JP3349510B2 (en) * | 1991-12-16 | 2002-11-25 | ピンレインジャー（オーストラリア）プロプライエタリー リミテッド | Distance measurement method |
| JPH05232210A (en) * | 1992-02-20 | 1993-09-07 | Kokusai Denshin Denwa Co Ltd <Kdd> | Positioning method and control method of moving body utilizing gas satellite |
| US5311194A (en) * | 1992-09-15 | 1994-05-10 | Navsys Corporation | GPS precision approach and landing system for aircraft |
| US5390124A (en) * | 1992-12-01 | 1995-02-14 | Caterpillar Inc. | Method and apparatus for improving the accuracy of position estimates in a satellite based navigation system |
| MY110677A (en) * | 1992-12-02 | 1999-01-30 | Voxson Pty Ltd | Improvements in positioning systems |
| US5422813A (en) * | 1992-12-17 | 1995-06-06 | Stanford Telecommunications, Inc. | No-outage GPS/commercial RF positioning system |
| TW279864B (en) * | 1993-02-19 | 1996-07-01 | Janssen Pharmaceutica Nv | |
| US5548293A (en) * | 1993-03-24 | 1996-08-20 | Leland Stanford Junior University | System and method for generating attitude determinations using GPS |
| US5477458A (en) * | 1994-01-03 | 1995-12-19 | Trimble Navigation Limited | Network for carrier phase differential GPS corrections |
| FR2715230B1 (en) * | 1994-01-19 | 1996-04-05 | Sercel Rech Const Elect | Real-time radio location system and method. |
| US5617100A (en) * | 1994-04-07 | 1997-04-01 | Matsushita Electric Industrial Co., Ltd. | Accurate position measuring system |
| JPH09511829A (en) * | 1994-04-12 | 1997-11-25 | エヌエフエス ナヴィガツィオーンス− ウント フルークフュールングス−ジステーメ ゲゼルシャフト ミット ベシュレンクテル ハフツング | Satellite navigation method |
| ZA952853B (en) * | 1994-04-18 | 1995-12-21 | Caterpillar Inc | Method and apparatus for real time monitoring and co-ordination of multiple geography altering machines on a work site |
| US6732077B1 (en) * | 1995-05-12 | 2004-05-04 | Trimble Navigation Limited | Speech recognizing GIS/GPS/AVL system |
| US5727034A (en) * | 1995-07-26 | 1998-03-10 | Nokia Telecommunications Oy | Apparatus and method for synchronizing base sites individually in a communication system |
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1995
- 1995-12-04 GB GBGB9524754.0A patent/GB9524754D0/en active Pending
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1996
- 1996-12-02 GB GB9625049A patent/GB2308033B/en not_active Expired - Lifetime
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- 1996-12-03 AU AU10367/97A patent/AU722293B2/en not_active Ceased
- 1996-12-03 US US08/758,728 patent/US6128501A/en not_active Expired - Lifetime
- 1996-12-03 AT AT96941117T patent/ATE201933T1/en not_active IP Right Cessation
- 1996-12-03 JP JP9521077A patent/JP2000501504A/en active Pending
- 1996-12-03 CA CA002238949A patent/CA2238949A1/en not_active Abandoned
- 1996-12-03 EP EP96941117A patent/EP0866983B1/en not_active Expired - Lifetime
- 1996-12-03 ES ES96941117T patent/ES2160263T3/en not_active Expired - Lifetime
- 1996-12-03 DE DE69613235T patent/DE69613235T2/en not_active Expired - Fee Related
- 1996-12-03 DK DK96941117T patent/DK0866983T3/en active
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| ATE201933T1 (en) | 2001-06-15 |
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| AU1036797A (en) | 1997-06-27 |
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| GB2308033B (en) | 2000-04-12 |
| EP0866983A1 (en) | 1998-09-30 |
| ES2160263T3 (en) | 2001-11-01 |
| WO1997021109A1 (en) | 1997-06-12 |
| GB9625049D0 (en) | 1997-01-22 |
| DE69613235D1 (en) | 2001-07-12 |
| GB2308033A (en) | 1997-06-11 |
| JP2000501504A (en) | 2000-02-08 |
| DE69613235T2 (en) | 2002-05-02 |
| GB9524754D0 (en) | 1996-04-24 |
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