WO2005125039A1

WO2005125039A1 - Method for determining the position of an rf transceiver in a known area

Info

Publication number: WO2005125039A1
Application number: PCT/CA2005/000982
Authority: WO
Inventors: Martin Pellerin; René LANDRY
Original assignee: École De Technologie Supérieure
Priority date: 2004-06-22
Filing date: 2005-06-22
Publication date: 2005-12-29

Abstract

A method and apparatus are disclosed for determining the position of an RF transceiver in a known area. A plurality of fixed beacons is provided in the area. An electromagnetic environment is then dynamically mapped to the area; a communication link with the transceiver is then established and the position is computed using the established communication link and the mapping.

Description

METHOD FOR DETERMINING THE POSITION OF AN RF TRANSCEIVER IN A KNOWN AREA

TECHNICAL FIELD

This invention relates to the field of telecommunications. More precisely, this invention pertains to a method for positioning an RF transceiver in a known area.

BACKGROUND OF THE INVENTION

It is known to locate a mobile unit using a plurality of wireless transceivers.

However many drawbacks have been contemplated by the skilled addressee.

For instance, while it may be possible to precisely locate a mobile unit in a first given area, it may not be possible to precisely locate the mobile unit in a second given area for various reasons, such as an influence of an electromagnetic environment, an influence of existing or coming obstacles, a limited transmitting power of the plurality of wireless transceivers, etc.

It is an object of the invention to overcome at least one of the above-identified drawbacks.

SUMMARY OF THE INVENTION

It is an object of the invention to provide a method for positioning an RF transceiver in a known area.

Yet another object of the invention is to provide a method for positioning an RF transceiver in a known area. According to a first aspect of the invention, there is provided a method for positioning an RF transceiver in a known area, the method comprising providing a plurality of beacons fixed for a predetermined time in the area, dynamically mapping an electromagnetic environment to the area, establishing a communication link with the transceiver and calculating a position for the transceiver using the established communication link and the mapping.

According to another aspect of the invention, there is provided a method for positioning an RF transceiver in a known area, the method comprising receiving a dynamic map of an electronic environment comprising a plurality of beacons fixed for a predetermined time in the known area, receiving information concerning an established communication link with the RF transceiver and calculating a position for the transceiver using the established communication link and the dynamic map.

According to another aspect of the invention, there is provided a method for positioning an RF transceiver in a known area, the method comprising providing a plurality of fixed beacons fixed for a predetermined time in the area, dynamically mapping an electromagnetic environment to the area, establishing a communication link with the transceiver, receiving inertial data from a sensor located in the RF transceiver and calculating a position for the transceiver using the established communication link, the mapping and the received inertial data.

In this specification, the term "known area" is intended to mean "an evolving map". BRIEF DESCRIPTION OF THE DRAWINGS

Further features and advantages of the present invention will become apparent from the following detailed description, taken in combination with the appended drawings, in which:

Fig. 1 is a block diagram showing a plurality of wireless transmitting units, a wireless mobile unit and a wireless mobile unit positioning server;

Fig. 2a is a block diagram showing a first embodiment of a wireless mobile unit;

Fig. 2b is a block diagram showing a second embodiment of a wireless mobile unit which comprises an inertial sensor unit ;

Fig. 3 is a block diagram showing an embodiment of the wireless mobile unit positioning server;

Fig. 4 is a block diagram showing an embodiment of a position detection unit comprised in the wireless mobile unit positioning server;

Fig. 5 is a flowchart showing how an estimated position of a wireless mobile unit is computed in one embodiment of the invention;

Fig. 6 is a flowchart showing how an estimated position of a wireless mobile unit is computed in one embodiment of the invention where inertial data provided by a sensor is used;

Fig. 7 is a flowchart showing how dynamical mapping of an environment is performed; and

Fig. 8 is a flowchart showing how an estimated position of a wireless mobile unit is computed. It will be noted that throughout the appended drawings, like features are identified by like reference numerals.

DETAILED DESCRIPTION OF AN EMBODIMENT

Now referring to Fig. 1, there is shown a system comprising a wireless mobile unit 10, a plurality of wireless transmitting units 12, 14, and 16 and a wireless mobile positioning server 18.

The wireless mobile unit 10 is a wireless transceiver capable of wirelessly communicating with at least one of the plurality of wireless transmitting units (beacons) 12, 14, and 16 and the wireless mobile positioning server 18 according to a communication standard.

It will be appreciated that a wireless transmitting unit may be fixed for a predetermined time in an area, useful for determining the position of the wireless mobile unit. It should be further appreciated that at least one wireless transmitting unit be further added/subtracted to/from the area.

In an embodiment the communication standard is IEEE802.11x. Alternatively, the communication standard is Bluetooth'™¹ or any other wireless communication standard.

Now referring to Fig. 2a, there is shown an embodiment of the wireless mobile unit 10.

The wireless mobile unit 10 comprises a wireless port 20, a processing unit 24 and an optional memory unit 26. The skilled addressee will appreciate that the wireless mobile unit 10 may further comprise various units, not shown here for clarity purposes, such a display unit, a speaker unit, etc. The wireless port 20 is adapted for transceiving a wireless signal according to the communication standard. It should be understood that while in one embodiment, the wireless port 20 may receive and transmit a wireless signal; in an alternative embodiment, the wireless port 20 may only transmit a wireless signal.

The processing unit 24 is used for processing the received signal and for providing a signal to transmit to using the wireless port 20.

The wireless ^' mobile unit 10 further comprises the optional memory unit 26 which is used to store data provided by the processing unit 24. In an embodiment, the optional memory unit 26 is a volatile-type memory.

Now referring to Fig. 2b, there is shown another embodiment of the wireless mobile unit 10. In this embodiment, the wireless mobile unit 10 further comprises an inertial sensor unit 28. The inertial sensor unit 28 provides an inertial sensor signal to the processing unit 24. In an embodiment of the invention, the inertial sensor unit 28 is preferably a Micro-Electro-Mechanical Systems (MEMS) selected from the group consisting of accelerometers, gyroscopes, altimeters, magnetic compass, barometer, etc. Alternatively, the inertial sensor unit 28 may comprise an apparatus which uses a Voltage Controlled Oscillator (VCO) or a Numerically Controlled Oscillator (NCO) . As further explained below, the inertial sensor unit 28 is used to further enhance the provision of the estimated position of the wireless mobile unit 10 comprising the inertial sensor unit 28.

Now referring back to Fig. 1, the plurality of wireless transmitting units 12, 14 and 16 may or not be adapted for communication with the wireless mobile unit 10. The plurality of wireless transmitting units 12, 14 and 16 may therefore comprise base stations for communicating with the wireless mobile unit 10 as well as any devices transmitting/radiating a wireless signal.

The skilled addressee will appreciate that such devices transmitting/radiating a wireless signal may be selected from the group consisting of mobile phones, computers, TV, satellite-transmitted signals, current/voltage transformers, rotating machines, or the like.

Now referring to Fig. 3, there is shown an embodiment of the wireless mobile unit positioning server 18.

The wireless mobile unit positioning server 18 comprises a physical layout providing unit 30, an electromagnetic simulation unit 32, a beacon data manipulation unit, an electromagnetic data acquisition unit 34, an electromagnetic environment data manipulation unit 35, an. electromagnetic environment data storing unit 36, a position detection unit 38, a position providing unit 39 and a wireless receiving unit 40.

The physical layout providing unit 30 provides a physical layout data signal to the electromagnetic simulation unit 32.

The physical layout data relates to a given environment. It should be understood that the environment is not limited solely to closed or interior spaces.

The physical layout data signal comprises a physical location indication as well as pertinent data for each element which may affect radio wave transmission in the given environment. The skilled addressee will appreciate that the elements may comprise physical structures, walls, obstacles, objects, floor, ceiling, apparatus, or the like.

The physical location indication is preferably given according to a 3-dimensional coordinate system while the pertinent data comprises information such as porosity, attenuation, loss, reflection, distortion, corruption, angular effect and a squared providing of these values with respect to a material and space as well as proximity or distance effect with respect to a transmitter. It will be appreciated that a squared value is used in order to obtain more reliable information about the influence caused by a material on an electromagnetic wave. In fact, the skilled addressee will appreciate that for instance an incoming electromagnetic wave hitting perpendicularly a given material will propagate less in the material than in the case where the incoming electromagnetic wave hits the material with an angle smaller than 90 degrees.

In an embodiment, the physical layout providing unit 30 is implemented in the wireless mobile unit positioning server 18. Alternatively, the physical layout data signal is provided to the electromagnetic simulation unit 32 via a network, which is a Wide Area Network (WAN) such as the Internet. In another embodiment, the physical layout is provided by the wireless mobile unit 10.

The beacon data manipulation unit 33 provides a beacon data signal to the electromagnetic simulation unit 32. The beacon data manipulation unit 33 may be operated manually by a user which selects a desired position or by using an algorithm.

The beacon data signal comprises an indication of a position of a beacon communicating with the wireless mobile unit 10 in the environment. In an embodiment of the invention, the position of the beacon is a 3-dimensional position with respect to a given reference. The beacon data signal further comprises information pertinent to wireless transmission such as frequency of the beacon, transmission power of the beacon, an antenna radiation pattern, etc.

The electromagnetic data acquisition unit 34 is used for performing an electromagnetic data acquisition at selected places in the real environment. The selected places may be chosen according to various criteria. The criteria may be anyone of a signal stability, a signal quality, a signal availability, an absence or a small movement of the wireless mobile unit and a tuning of a reading according to predetermined delays .

The acquired data signal comprises -an indication of a physical location in the environment as well as an electromagnetic measure. The electromagnetic measure comprises for a given frequency band at least one of a signal/noise value and a power value.

The electromagnetic environment data manipulation unit 35 receives the acquired data signal and provides a manipulated acquired data signal to the electromagnetic simulation unit 32.

The wireless receiving unit 40 receives a wireless signal. It should be appreciated that the wireless signal may comprise data related to a wireless transmission of a plurality of devices, if applicable, and is not limited to data related to the wireless transmission of the wireless mobile unit 10 or to the wireless transmission of the wireless transmitting unit communicating with the wireless mobile unit 10 if applicable. Therefore and more precisely, the wireless receiving unit 40 provides a detected electromagnetic source signal to ^• the electromagnetic simulation unit 32. The detected electromagnetic source signal comprises at least one of a signal/noise value and a power value for a given frequency band.

The electromagnetic simulation unit 32 receives the physical layout data signal provided by the physical layout providing unit 30, the beacon data signal provided by the beacon data manipulation unit 33, the manipulated acquired data signal provided by the electromagnetic environment data manipulation unit 35 and the detected electromagnetic sources signal provided by the wireless receiving unit. The electromagnetic simulation unit 32 may further receive a simulated data signal provided by the electromagnetic environment data storing unit 36. The electromagnetic simulation unit 32 performs a simulation of the electromagnetic environment using the physical layout data signal, the beacon data signal, the manipulated acquired data signal and the detected electromagnetic sources and provides a simulated data signal to the electromagnetic environment data storing unit 36. The electromagnetic simulation unit 32 is therefore used for building the electromagnetic environment data storing unit 36. The skilled addressee should understand that a mapping of the electromagnetic environment is dynamically performed by the electromagnetic simulation unit 32 and that the electromagnetic environment data storing unit 36 is continuously updated. Only selected parts of the electromagnetic environment data storing unit 36 are preferably updated which avoid unnecessary computations. The selected part are selected according to various criteria such as a frequency band, a knowledge of a former position of the wireless mobile unit 10, a level of activity in a given part of the electromagnetic environment, a client need, etc.

The electromagnetic environment data storing unit 36 stores data preferably in a matrix form and comprises electromagnetic data for the environment.

It will be appreciated that the electromagnetic environment data manipulation unit 35 may also provide at least one part of the acquired data signal to the electromagnetic environment data storing unit 36.

The position detection unit 38 receives a measured data signal provided by .the wireless receiving unit 40 and uses the electromagnetic environment data storing unit 36 to create an estimated position signal as explained below.

The estimated position signal is provided to the position providing unit 39. The position providing unit 39 may provide the estimated position - signal of the wireless mobile unit 10 to a plurality of destinations depending on an application sought. For instance, the wireless mobile positioning server 18 may performs a tracking of the wireless mobile unit 10 without submitting any information to the wireless mobile unit 10. Alternatively, it may be desirable to provide the estimated position signal to the wireless mobile unit 10.

Now referring to Fig. ^'4, there is shown an embodiment of a position detection unit 38 comprised in the wireless mobile unit positioning server 18.

The position detection unit 38 comprises a position processing unit 42 and a plurality of position estimation units. In this embodiment, the plurality of position estimation units comprises a first position estimation unit 44, a second position estimation unit 46 and a third position estimation unit 48.

The position processing unit 42 receives a wireless received signal provided by the wireless receiving unit 40 and data provided' from the electromagnetic environment data storing unit 36.

Each of the plurality of position estimation units estimates a position and provides a corresponding estimated position signal to the position processing unit 42. It should be understood that such a corresponding estimated position signal is generated according to an algorithm. The skilled addressee will appreciate that this is of great advantage as a given algorithm may provide a corresponding given result which is better that another result provided by another algorithm depending on a specific situation.

The position processing unit 42 receives a plurality of corresponding estimated position signals and selects one which is believed to be suitable. It should be understood that the selected one is chosen according to at least one criterion. For instance the criterion may be a time- preceding position signal. Alternatively, the criterion may be based on a position of the wireless mobile unit and/or its derivative, a comparison with another wireless mobile unit 10, etc.

In the embodiment disclosed in Fig. 4, the first position estimation unit 44 receives at least one part of the wireless received signal provided by the position processing unit 42, -performs a first access to the electromagnetic environment data storing unit 36 according to a first algorithm and receives a first set of data. The first position estimation unit 44 computes a first estimated position signal according to the first algorithm. The first position estimation unit 44 provides the first estimated position signal to the position processing unit 42.

Similarly, the second position estimation unit 46 receives at least one part of the wireless received signal provided by the position processing unit 42, performs a second access to the electromagnetic environment data storing unit 36 according to a second algorithm and receives a second set of data. The second position estimation unit 46 computes a second estimated position signal according to the second algorithm. The second position estimation unit 46 provides the second estimated position signal to the position processing unit 42.

The third position estimation unit 48 receives at least one part of the wireless received signal provided by the position processing unit 42, performs a third access to the electromagnetic environment data storing unit 36 according to a third algorithm and receives a third set of data. The third position estimation unit 48 computes a third estimated position signal according to the third algorithm.

The third position estimation unit 48 provides the third estimated position signal to the position processing unit42.

The position processing unit 42 selects a suitable estimated position signal using the first estimated position signal, the second estimated position signal and the third estimated position signal.

The position processing unit 42 updates the electromagnetic environment data storing unit 36 using the estimated position signal and the corresponding wireless received signal .

The estimated position signal is provided to the position providing unit 39 by the position processing unit 42. Now referring to Fig.5, there is shown how an estimated position of a wireless mobile unit is computed according to a first embodiment of the invention.

According to step 50, a plurality of beacons is provided. The plurality of beacons is provided using the beacon data manipulation unit 33. In one embodiment, the plurality of beacons is provided manually by a user. Alternatively, the plurality of beacons is automatically provided. Preferably, the user provides the plurality of beacons through a user interface displaying at least one part of the physical layout.

According to step 52, the electromagnetic environment is dynamically mapped. Now referring to Fig. 7, there is shown •how the electromagnetic environment is dynamically mapped.

According to step 70, a plurality of wireless bands' (frequency ranges) is detected using the wireless receiving unit 40.

According to step 72, an electromagnetic environment is dynamically mapped for each of the plurality of wireless bands. It should be understood that it is desirable to use a plurality of wireless bands in order to enable an. accurate positioning. Using only a single frequency band limits the accuracy of the positioning.

Now referring back to Fig. 3, the electromagnetic environment is dynamically mapped using the electromagnetic simulation unit 32 and the electromagnetic environment data manipulation unit 35.

The resulting electromagnetic environment data is stored in the electromagnetic environment data storing unit 36.

In an embodiment, the electromagnetic environment is dynamically mapped in response to various events such as detection of a new wireless transmitting unit, a dynamic modification of the electromagnetic environment, etc.

It should be further understood that preferably a limited part of the electromagnetic environment data storing unit 36 is updated each time.

According to step 54, a communication link is established between the wireless mobile unit 10 and the wireless mobile unit positioning server 18. Alternatively, the communication link may be established between the wireless mobile unit 10 and a wireless transmitting unit of the plurality of wireless transmitting units.

According to step 56, the estimated position of the wireless mobile unit 10 is computed.

Referring to Fig. 8, there is shown how the estimated position of the wireless mobile unit 10 is computed.

According to step 80, a signal indicative of a power signal is provided. Alternatively, a signal indicative of a signal/noise ratio is provided.

In the case where the wireless mobile unit 10 has a communication established with one of the plurality of wireless transmitting units, the signal indicative of a power signal/SNR may be provided by one of the wireless mobile unit 10 and the wireless transmitting unit. In the case where the wireless mobile unit 10 has a communication link established with the wireless mobile unit positioning server 18, the signal indicative of a power signal/SNR may be provided by one of the wireless mobile unit 10 and the wireless mobile unit positioning server 18. It should be understood that the signal indicative of a power signal/SNR may or not be related to a frequency band used to communicate with the wireless mobile unit 10. In the case where the power signal/SNR is not related to the frequency band used to communicate with the wireless mobile unit 10, the power signal/SNR should be provided by the wireless mobile unit 10.

According to step 82, the signal indicative of a power signal/SNR is transmitted to the wireless mobile unit positioning server 18. Alternatively, time information may be used. In such case, the positioning server 18 provides the signal in a data packet having a high priority. By measuring the amount of time required for transmitting and retransmitting back the data packet to the wireless mobile unit positioning server 18, and by estimating the time for processing the data packet, it is possible to determine the time information and therefore position the wireless mobile unit 10.

The signal indicative of the power signal/SNR is received by the wireless receiving unit 40 and transmitted to the position processing unit 42.

According to step 84, the signal indicative of the power signal/SNR is discriminated. It should be understood that discrimination is performed in order to avoid providing a distorted signal for instance or a prima facie wrong/useless signal. The purpose of the discrimination is to avoid merging a good value with a bad value. The discrimination may be performed according to a plurality of strategies .

A first discrimination strategy is to compare the value of a given signal to discriminate with a more probable value. The more probable value has been identified as reliable, known. Such signal may be provided by a fixed beacon. The first strategy would be to filter the given signal according to the more probable value.

A second discrimination strategy is to compare the value of a given signal to discriminate based on a frequency. As explained previously a plurality of signals having various frequencies may be collected in order to compute the estimated position of the wireless mobile unit 10. A measured wireless signal of a particular frequency may be more reliable than another measured wireless signal of another frequency. Large variations in the value of a signal of a given frequency band may be indicative of an unreliable frequency band for estimating the position of the wireless mobile unit 10.

A third discrimination strategy is to use a further wireless receiver which discriminates the values of a given signal and records negative variations and provides an indication of whether a value of the given signal should be or not taken.

A fourth discrimination strategy would be to have an indication of a value to expect and to^' discriminate according to this value.

A further discrimination strategy may be an empirical strategy in which the wireless mobile unit 10 may recognize that it must use a given wireless signal for a second, time. The empiric discrimination strategy is based upon providing a value on the basis of a long observation period and discriminating values directly upon receipt.

A further discrimination strategy may be based upon simulating a value of a wireless signal depending upon alterations that the signal should have encountered on its propagation path. In such case, the surrounding environment is used in order to simulate the value of the wireless signal.

A further discrimination strategy may be based upon applying filters on the signal.

A further discrimination strategy may be based upon a type of material used.

Α further discrimination strategy may be based on the environment surrounding the wireless mobile unit 10. The skilled addressee' will for instance appreciate that the wireless mobile unit 10 may not go through walls for instance. It will be also appreciated that a direct path between a wireless transmitting unit 10 and the wireless mobile unit positioning server 18 may be preferred.

According to step 86, a correction may be applied in order to correct the discriminated signal. The correction may comprise at least one of merging at least two discriminated signals, modifying at least one part of the discriminated signal according to a statistical analysis or the like.

According to step 88, the corrected signal is processed in order to provide an estimated position signal for the wireless mobile unit 10. The step of processing the corrected signal comprises providing at least one part of the corrected signal to each of the plurality of position estimation units, for each of the position estimation units 44, 46, 48, accessing the electromagnetic environment data storing unit 36, processing received data using the corrected signal to provide a corresponding estimated position signal and providing an estimation signal by selecting one of the corresponding estimated position signals provided by the plurality of position estimation units.

In an embodiment, the processing of the corrected signal may first comprise an analysis of at least one part of the corrected signal. The analysis is based on the value of the corrected signal either using by comparing the corrected signal with a standard signal or by comparing the value of the corrected signal with a former measured value.

Now referring to Fig. 6, there is shown how an estimated position of a wireless mobile unit 10 is computed according to a second embodiment of the invention. In this embodiment, the wireless mobile unit 10 is of the type shown in Fig. 2b.

According to step 60, a plurality of beacons is provided. The plurality of beacons is provided using the beacons data manipulation unit 33. In one embodiment, the plurality of beacons is provided manually by a user. Alternatively, the plurality of beacons is automatically provided.

According to step 62, the electromagnetic environment is dynamically mapped. Such mapping is performed similarly to the mapping performed in step 52. According to step 64, a communication link is established with the wireless mobile unit 10.

According to step 66, inertial data is received from a sensor. The inertial data may be received from the inertial sensor unit 28.

According to step 68, a position of the wireless mobile unit 10 is computed. In this embodiment, the received inertial data is used in order to compute the estimated position of the wireless mobile unit 10.

While it has been disclosed that the computing of the estimated position signal is performed by the position processing unit 42, it should be understood that at least one part of the computing of the estimated position signal may be alternatively performed by the wireless mobile unit 10. In such case, the optional memory unit 26 may comprise a position estimation unit and at least one part of the electromagnetic environment data storing unit 36. Still in the embodiment, the processing unit 24 of the wireless mobile unit 10 may be used to compute the estimated position signal.

It will further be appreciated that the estimated position signal may be used in order to update the electromagnetic environment data storing unit 36.

It should be further appreciated that the method for positioning a RF transceiver may be used even if the transceiver is only transmitting. In such case, the RF transceiver is used to transmit a signal to at least one beacon and the at least one beacon receiving the signal uses the information to position the RF transceiver. In such case, the positioning is not computed in the transceiver per se. Alternatively, the transceiver may be used to only receive a signal.

It will be appreciated that the method disclosed for positioning a RF transceiver may be advantageously used in an environment which is not known at the beginning. For example, in the case of fire in a building, a plurality of fire trucks may be placed around the building, each fire truck acting as a beacon fixed for a predetermined time in the area. A mapping of the electromagnetic environment of the building may then be dynamically performed using the plurality of beacons . Firemen may then enter the building and operate inside the building. Each fireman may have a transceiver and a communication link may be established with a beacon or with another transceiver. The method disclosed may then be advantageously used to locate the firemen inside the building. Also it will be appreciated that the mapping may be used to determine properties of- the building.

While illustrated in the block diagrams as groups of discrete components communicating with each other via distinct data signal connections, it will be understood by those skilled in the art that the preferred embodiments are provided by a combination of hardware and software components, with some components being implemented by a given function or operation of a hardware or software system, and many of the data paths illustrated being implemented by data communication within a computer application or operating system. The structure illustrated is thus provided for efficiency of teaching the present preferred embodiment.

It should be noted that the present invention can be carried out as a method, can be embodied in a system, a computer readable medium or an electrical or electro- magnetical signal.

The embodiments of the invention described above are intended to be exemplary only. The scope of the invention is therefore intended to be limited solely by the scope of the appended claims .

Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A method for positioning an RF transceiver in a known area, said method comprising: providing a plurality of beacons fixed for a predetermined time in said area; dynamically mapping an electromagnetic environment to said area; establishing a communication link with said transceiver; and calculating a position for said transceiver using said established communication link and said mapping.

2. The method as claimed in claim 1, wherein said communication link is established using at least one of said plurality of beacons.

3. The method as claimed in claim 1, wherein said plurality of beacons comprises a device radiating an RF signal.

4. The method as claimed in claim 3, wherein said device radiating said RF signal is selected from a group consisting of mobile phones, computers, TV, current- voltage transformers, rotating machines.

5. The method as claimed in claim 1, wherein said providing of said plurality of beacons fixed for a predetermined time in said area is performed manually.

6. The method as claimed in claim 1, wherein said providing of said plurality of beacons fixed for a predetermined time in said area is performed automatically.

7. The method as claimed in any one of claims 1 to 6, wherein said dynamically mapping of said electromagnetic environment to said area is performed in response to an event.

8. The method as claimed in claim 7, wherein said event comprises at least one of a detection of a wireless transmitting unit and a change in said electromagnetic environment.

9. The method as claimed in any one of claims 1 to 8, wherein said dynamically mapping of said electromagnetic environment to said area comprises detecting a plurality of wireless frequency ranges and mapping an electromagnetic environment for each of said plurality of wireless frequency ranges.

10. The method as claimed in any one of claims 1 to 9, wherein said calculating of a position for said transceiver using said established communication link and said mapping comprises providing at least one of a power signal of said established communication link and a signal/noise ratio of said established communication link; discriminating the at. least one of a power signal of said established communication link and a signal/noise ratio of said established communication link according to at least one discrimination strategy.

11. The method as claimed in claim 10, wherein said at least one discrimination strategy comprises comparing said provided at least one of a power signal of said established communication link and a signal/noise ratio of said established communication link with a known value.

12. The method as claimed in claim 10, wherein said at least one discrimination strategy comprises comparing said provided at least one of a power signal of said established communication link and a signal/noise ratio of said established communication link based on a frequency.

13. The method as claimed in claim 10, wherein said at least one discrimination strategy comprises using an indication of a value to expect for said provided at least one of a power signal of said established communication link and a signal/noise ratio of said established communication link.

14. The method as claimed in claim 10, wherein said at least one discrimination strategy comprises using an empirical discrimination strategy.

15. The method as claimed in claim 10, wherein said at least one discrimination strategy comprises using results from an expected simulation for said provided at least one of a power signal of said established communication link and a signal/noise ratio of said established communication link.

16. The method as claimed in claim 10, wherein said at least one discrimination strategy comprises filtering said provided at least one of a power signal of said established communication link and a signal/noise ratio of said established communication link.

17. The method as claimed in claim 10, wherein said discrimination strategy is based on at least one of a type of material used and an environment surrounding said RF transceiver.

18. The method as claimed in claim 10, where when a plurality of signals are discriminated, the method further comprises correcting the plurality of discriminated signals.

19. The method as claimed in claim 18, wherein said correcting comprises at least one of merging at least two discriminated signals and modifying at ₍ least one part of the plurality of the discriminated signals according to a statistical analysis.

20. The method as claimed in any one of claims 18-19, wherein said calculating of said position for said transceiver comprises processing the corrected plurality of discriminated signals.

21. The method as claimed in claim 20, wherein said processing comprises using said mapping with said corrected plurality of discriminated signals to provide a plurality of estimated positions and selecting one of said plurality of estimated positions to provide said position for said transceiver.

22. The method as claimed in any one of claims 1-21, further comprising receiving inertial data from a sensor located in said RF transceiver and using the received inertial data from said sensor for said calculating a position for said transceiver.

23. The method as claimed in any one of claims 1-22, wherein said establishing a communication with said transceiver . comprises at least one of transmission and reception of a signal.

24. A method for positioning an RF transceiver in a known area, said method comprising:, receiving a dynamic map of an electronic environment comprising a plurality of beacons fixed for a predetermined time in said known area; receiving information concerning an established communication link with said RF transceiver; and calculating a position for said transceiver using said established communication link and said dynamic map.

25. A computer program embodied in an electrical or an electromechanical carrier signal having codes adapted to performed the method as claimed in claim 24.

26. A method for positioning an RF transceiver in a known area, said method comprising: providing a plurality of fixed beacons fixed for a predetermined time in said area; dynamically mapping an electromagnetic environment to said area; establishing a communication link with said transceiver; receiving inertial data from a sensor located in said RF transceiver; and calculating a position for said transceiver using said established communication link, said mapping and said received inertial data.