CN103180751B - Arrival angle calculation device - Google Patents

Abstract

The purpose of the present invention is to provide an arrival angle calculation device that can calculate an arrival angle to a high degree of accuracy. This arrival angle calculation device (1) comprises a plurality of antennae, a plurality of received signal processing units, and an arrival angle calculation unit. Each of the received signal processing units comprise reception units (12a, 12b), correlation processing units (21a, 21b), peak detection units (22a, 22b), and timing control units (23a, 23b). The timing control units (23a, 23b) are characterised in that when the ratio between the power of the peak period in a period corresponding to an information unit and the power of a period excluding the peak period is larger than a threshold value, signals from the correlation processing units (21a, 21b) are output to an arrival angle calculation unit (24).

Description

Angle of arrival calculation element

Technical field

The present invention relates to the phase place of electric wave and the angle of arrival calculation element of the calculating for angle of arrival degree that detect and arrive.

Background technology

In arrival direction estimation unit in the past, use the computing that the operand such as calculating, inverse matrix operation of cross-correlation coefficient is large, need the computing of hundreds of symbol weight.Therefore, the arrival direction estimation unit obtaining being estimated arrival direction by easy computing is wished.

The arrival direction estimation unit reducing computing scale is proposed in patent documentation 1.In the arrival direction estimation unit described in patent documentation 1, to the Received signal strength received by two antennas, the coefficient of arrival direction is calculated by complex conjugation circuit and mlultiplying circuit, by carrying out arctangent cp cp operation and arc cosine computing in arrival direction testing circuit, and have estimated the arrival direction receiving ripple.

Prior art document

Patent documentation

Patent documentation 1: Japanese Unexamined Patent Publication 10-177064 publication

Summary of the invention

The problem that invention will solve

But, in patent documentation 1, the power that have employed the arrival direction vector compared between 1 slot is with threshold value and when larger than threshold value, upgrade the formation of arrival direction, therefore, likely can not detect exactly and receive expectation ripple in ripple to upgrade arrival direction.Such as, when receiving the background value of ripple and being high, and expect the signal level of ripple independently, the power receiving ripple is often large than threshold value.In this case, under background value, arrival direction is also calculated, is upgraded, and therefore correctly can not estimate arrival direction.

The present invention carries out in view of such point, its object is to provide a kind of and can suppress the impact of the background value receiving ripple and can with the angle of arrival calculation element of high precision computation angle of arrival.

For solving the means of problem

The feature of angle of arrival calculation element of the present invention is to possess: multiple antenna, receives the electric wave sent from certain position, multiple Received signal strength handling part, is arranged accordingly with described each antenna, and angle of arrival calculating part, be taken into from the output signal exported by described multiple Received signal strength handling part the component of signal that becomes identical information unit between Received signal strength handling part thus calculate the angle of arrival of described electric wave, described each Received signal strength handling part possesses: acceptance division, and the electric wave that the described antenna by correspondence receives is transformed to the Received signal strength of the phase information with this electric wave and exports, correlation processing unit, carries out relevant treatment by the Received signal strength exported from described acceptance division, peakvalue's checking portion, detects the peak value having carried out the Received signal strength of described relevant treatment, and timing control part, to cut out the mode becoming the component of signal of identical information unit between described Received signal strength handling part from the output signal of described correlation processing unit, match with the timing of the peak value detected by described peakvalue's checking portion, thus control the output signal exported from described correlation processing unit be taken into timing, when the power between the peak period during described information unit is suitable and except between this peak period during the ratio of power be greater than threshold value, signal from described correlation processing unit exports to described angle of arrival calculating part by described timing control part.

According to this formation, by the ratio of the power between the peak period and the power during beyond it compared with threshold value, when calculating angle of arrival than when being greater than threshold value, even if the signal level therefore beyond the expectation ripple receiving ripple is high, also can detect the peak value expecting ripple exactly, and calculate angle of arrival.That is, do not calculate angle of arrival according to the part expected beyond ripple, therefore can improve the computational accuracy of angle of arrival.

In angle of arrival calculation element of the present invention, also can be, by ∑ P ₁with ∑ P ₂than ∑ P ₁/ ∑ P ₂compare with threshold value, described than ∑ P ₁/ ∑ P ₂when being greater than described threshold value, the signal from described correlation processing unit exports to described angle of arrival calculating part by described timing control part, wherein above-mentioned ∑ P ₁be suitable with described information unit during peak period between power sum, above-mentioned ∑ P ₂be suitable with described information unit during except between the described peak period during power sum.

In angle of arrival calculation element of the present invention, also can be, described angle of arrival calculating part possesses: complex conjugate portion, fetches the complex conjugate of the signal of the timing control part of the Received signal strength handling part of My World, and the Received signal strength handling part of this side is corresponding with the antenna of a side; Complex multiplication portion, by the signal multiplication of the output in described complex conjugate portion and the timing control part from the Received signal strength handling part of the opposing party, the Received signal strength handling part of this opposing party is corresponding with the antenna of the opposing party; Arc tangent portion, uses the output in described complex multiplication portion to carry out arctangent cp cp operation, calculates the phase differential of the described reception electric wave between described antenna; Equalization part, averages the output in described arc tangent portion; And angle of arrival transformation component, use the output of described equalization part to carry out inverse trigonometric function computing, thus be transformed to angle of arrival.According to this formation, the calculating of cross-correlation coefficient, inverse matrix operation etc. can not be used and calculate angle of arrival, therefore can reduce the scale arriving angle calculation device.

In angle of arrival calculation element of the present invention, also can be, near in I-Q plane+180 ° and/or-180 ° of the described phase distribution calculated, described angle of arrival calculating part averages after making each phase differential rotate predetermined angular, after this mean value deducts described predetermined angular, carry out inverse trigonometric function computing, thus be transformed to angle of arrival.According to this formation, when phase distribution is in the phase differential region of the tendency of reduction in the computational accuracy of angle of arrival, make phase differential only rotate predetermined angular and carry out arriving the computing of angle calculation, therefore the computational accuracy of angle of arrival does not just reduce.As a result, the computational accuracy of angle of arrival can fully be improved.

In angle of arrival calculation element of the present invention, also can be, in described I-Q plane, when be greater than+90 ° or the number ratio of phase differential that is less than-90 ° and be less than+90 ° and be greater than the quantity of the phase differential of-90 ° many, be judged as being distributed near+180 ° and/or-180 ° in described I-Q plane.

In angle of arrival calculation element of the present invention, also can be make described predetermined angular be any one angles of+90 ° ,-90 ° ,+180 ° or-180 °.

In angle of arrival calculation element of the present invention, also can be, when the I component of the output in described complex multiplication portion be bear and the absolute value of the I component of the output in described complex multiplication portion is fully large compared with the absolute value of Q component, by carrying out the arctangent cp cp operation of the relation of having exchanged I component and Q component after the symbol reversing described Q component, calculate the phase differential after correction, phase differential after described correction is averaged, after this mean value deducts 90 °, carry out inverse trigonometric function computing, thus be transformed to angle of arrival.According to this formation, when phase distribution is in the phase differential region of the tendency of reduction in the computational accuracy of angle of arrival, make phase differential rotate the amount of predetermined angular and carry out arriving the computing of angle calculation, therefore the computational accuracy of angle of arrival does not just reduce.As a result, the computational accuracy of angle of arrival can fully be improved.

In angle of arrival calculation element of the present invention, also can be, when the I component of the output in described complex multiplication portion be bear and the absolute value of the I component of the output in described complex multiplication portion is fully large compared with the absolute value of Q component, by carrying out the arctangent cp cp operation of the relation of having exchanged I component and Q component after the symbol reversing described I component, calculate the phase differential after correction, phase differential after described correction is averaged, carry out inverse trigonometric function computing after 90 ° are added to this mean value, thus be transformed to angle of arrival.According to this formation, when phase distribution is in the phase differential region of the tendency of reduction in the computational accuracy of angle of arrival, make phase differential rotate the amount of predetermined angular and carry out arriving the computing of angle calculation, therefore the computational accuracy of angle of arrival does not just reduce.As a result, the computational accuracy of angle of arrival can fully be improved.

In angle of arrival calculation element of the present invention, also can be, when the I component of the output in described complex multiplication portion be bear and the absolute value of the I component of the output in described complex multiplication portion is fully large compared with the absolute value of Q component, by the phase differential after carrying out arctangent cp cp operation calculate correction after the reversed symbol of described I component and the symbol of Q component, phase differential after described correction is averaged, after this mean value deducts 180 °, carry out inverse trigonometric function computing, thus be transformed to angle of arrival.According to this formation, when phase distribution is in the phase differential region of the tendency of reduction in the computational accuracy of angle of arrival, make phase differential rotate the amount of predetermined angular and carry out arriving the computing of angle calculation, therefore the computational accuracy of angle of arrival does not just reduce.As a result, the computational accuracy of angle of arrival can fully be improved.

Invention effect

According to angle of arrival calculation element of the present invention, obtain power between the peak period and between the peak period beyond remaining period in the ratio of power, the ratio obtain this and threshold value compare, when calculating angle of arrival than when being greater than threshold value, even if the signal level therefore beyond the expectation ripple receiving ripple is high, also can detect the peak value expecting ripple exactly, and calculate angle of arrival.That is, do not calculate angle of arrival according to the part expected beyond ripple, therefore can improve the computational accuracy of angle of arrival.

Accompanying drawing explanation

Fig. 1 is the block diagram of the configuration example representing the angle of arrival calculation element that embodiment relates to.

Fig. 2 is the block diagram of the concrete formation (DSSS) representing the angle of arrival calculation element that embodiment relates to.

Fig. 3 is the figure of the example of the output waveform representing totalizer.

Fig. 4 (a) is the figure of the example of the output waveform representing arc tangent portion, and (b) is the figure of the example of the output waveform representing power calculation portion.

Fig. 5 is the schematic diagram of the geometry relation representing the electric wave arriving antenna.

Fig. 6 is the schematic diagram representing the example comprising the position detecting system arriving angle calculation device.

Fig. 7 is the process flow diagram that the angle of arrival in angle of arrival calculation element calculates.

Fig. 8 is the schematic diagram of the signal to the input of peakvalue's checking portion.

Fig. 9 represents the schematic diagram to the example of the signal of peakvalue's checking portion input when to use DSSS as modulation system.

Figure 10 is the schematic diagram of the example of the signal of the peakvalue's checking portion input represented when being taken into Received signal strength to using AD transducer.

Figure 11 is the block diagram of other example representing angle of arrival calculating part.

Figure 12 is the schematic diagram of the computer capacity representing phase differential.

Figure 13 is the schematic diagram of the example of the phase data representing calculating.

Figure 14 is the schematic diagram of the outline that angle of arrival when representing that phase differential becomes near+180 ° or-180 ° calculates.

Figure 15 is the process flow diagram that the angle of arrival of phase differential when becoming near+180 ° or-180 ° calculates.

Figure 16 is the block diagram of other example representing angle of arrival calculating part.

Figure 17 is the block diagram of the concrete formation (OFDM) representing the angle of arrival calculation element that embodiment relates to.

Figure 18 (a) is the schematic diagram of the formation of the symbol represented in OFDM, and (b) is the schematic diagram of the situation of the relevant treatment representing OFDM symbol string.

Figure 19 (a) (b) is the figure of the example of the output waveform represented from power calculation portion, c () is the figure of the example of the output waveform represented from adder, (d) is the figure of the example of the output waveform of each several part represented from arc tangent portion.

Figure 20 is the schematic diagram of the configuration example representing the capsule endoscope system employing angle of arrival calculation element.

Embodiment

Fig. 1 is the block diagram of the configuration example representing the angle of arrival calculation element that one embodiment of the present invention relates to.Angle of arrival calculation element 1 of the present embodiment possesses: reference signal generating unit 10, can with the oscillation frequency reference signal of regulation; Antenna for receiving 11a, 11b, configure with separating predetermined distance; Acceptance division 12a, 12b, use the reference signal from reference signal generating unit 10 output and the electric wave accepted by antenna for receiving 11a, 11b be transformed to Received signal strength and export; And operational part 13, the various calculation process calculated for angle of arrival are carried out according to the Received signal strength exported from acceptance division 12a, 12b.In addition, angle of arrival calculation element 1, calculates angle of arrival according to the delayed phase that the propagation delay by electric wave causes, and therefore needs to receive the electric wave with identical information at two points separating predetermined distance (or point of more than two).Therefore, antenna and the receiving system of two (or more than them) corresponding with receiving electric wave is needed to possess.In addition, as long as can receive identical arrival electric wave (identical information unit) the position of more than two that separate predetermined distance, angle of arrival calculation element 1 is not limited to the formation of the receiving system possessing more than two.

Acceptance division 12a, 12b are configured to comprise low noise amplifier, frequency mixer, bandpass filter etc., and are configured to the electric wave that can receive assigned frequency.Operational part 13 is configured to comprise: correlation processing unit 21a, 21b, carries out the relevant treatment of Received signal strength; Peakvalue's checking portion 22a, 22b, detect the peak value having carried out the Received signal strength of relevant treatment; Timing control part 23a, 23b, coordinate the timing of the peak value detected by peakvalue's checking portion 22a, 22b and the signal exported from correlation processing unit 21a, 21b; And angle of arrival calculating part 24, according to the signal from timing control part 23a, 23b, carry out the calculating of angle of arrival.In addition, the formation of operational part 13, function can by hardware implementing, also can by software simulating.

Correlation processing unit 21a, 21b will export from the Received signal strength of acceptance division 12a, 12b and high signal multiplication relevant to this Received signal strength.By the relevant height of the signal taken advantage of and Received signal strength in correlation processing unit 21a, 21b, the signal therefore exported from correlation processing unit 21a, 21b becomes peak value at related interval.Peakvalue's checking portion 22a, 22b calculate the power from the output signal of correlation processing unit 21a, 21b, and detect the power peak of output signal.Timing control part 23a, 23b are engaged in the peak value timing detected in peakvalue's checking portion 22a, 22b, and the output signal of auto-correlation processing portion 21a, 21b exports to angle of arrival calculating part 24 in the future.Particularly, based on the information calculated according to the power between the detected peak period, determine whether that the output signal of auto-correlation processing portion 21a, 21b in the future exports to angle of arrival calculating part 24.

Fig. 2 represents the block diagram of the concrete configuration example of angle of arrival calculation element when to use direct spread spectrum (DSSS) as modulation system.In addition, illustrate only the formation suitable with the operational part 13 in Fig. 1 in fig. 2.

In fig. 2, correlation processing unit 21a possesses: the diffuse code generator 31 that diffuse code occurs; Multiplier 32a and 32b that Received signal strength is multiplied with diffuse code; And the output of multiplier 32a and 32b added up to 1 (bit) period amount the totalizer 33a exported to peakvalue's checking portion 22a and timing control part 23a and 33b.Peakvalue's checking portion 22a possesses: the power calculation portion 34a calculating the power of the signal exported from totalizer 33a and 33b; And detect its power peak and the peak power detection portion 35a exported to timing control part 23a.Timing control part 23a possesses buffer unit 36a, controls to export to angle of arrival calculating part 24 from the signal of totalizer 33a and 33b based on the signal from peak power detection portion 35a.Equally, correlation processing unit 21b possesses diffuse code generator 31, multiplier 32c and 32d, totalizer 33c and 33d, and peakvalue's checking portion 22b possesses power calculation portion 34b, peak power detection portion 35b, and timing control part 23b possesses buffer unit 36b.Angle of arrival calculating part 24 possesses: the complex conjugate complex conjugate portion 41 of getting the output of buffer unit 36a; By the complex multiplication portion 42 of the output complex multiplication of the output in complex conjugate portion 41 and buffer unit 36b; The output in complex multiplication portion 42 is used to carry out the arc tangent portion 43 of arctangent cp cp operation; The power calculation portion 44 of the interval power of each chip (chip) is calculated according to the output signal in complex multiplication portion 42; According to the information from power calculation portion 44 by the equalization part 45 of the output equalization in arc tangent portion 43; And use the output of equalization part 45 to be transformed to the angle of arrival transformation component 46 of angle of arrival.

There is the diffuse code for the signal despreading that will be expanded to by DSSS on frequency axis in diffuse code generator 31.This diffuse code is corresponding with the diffuse code used when transmitter side code modulates (expansion).Received signal strength is multiplied by above-mentioned diffuse code and carries out despreading by multiplier 32a and 32b.Input from the in-phase component I1 in the Received signal strength of acceptance division 12a to multiplier 32a.In addition, input from the quadrature component Q1 in the Received signal strength of acceptance division 12a to multiplier 32b.Totalizer 33a and 33b is added the output of each chip interval of multiplier 32a and 32b in (position is interval) during suitable with 1 and exports.Fig. 3 (a) represents the example from the output waveform of totalizer 33a.Fig. 3 (b) is the magnified partial view of the output waveform shown in Fig. 3 (a).In addition, Fig. 3 (c) represents the example from the output waveform of totalizer 33b.Fig. 3 (d) is the magnified partial view of the output waveform shown in Fig. 3 (c).

The power calculation portion 34a to peakvalue's checking portion 22a and the buffer unit 36a input of timing control part 23a by the output signal of totalizer 33a and the output signal of totalizer 33b.Power calculation portion 34a calculates the power of each chip interval according to the output signal of totalizer 33a and 33b.Particularly, the absolute value of the output signal of the absolute value of the output signal of the totalizer 33a suitable with in-phase component and the totalizer 33b suitable with quadrature component is added by power calculation portion 34a, as each chip interval power information and export to peak power detection portion 35a.Peak power detection portion 35a, when accepting the power information of each chip interval, detect the power peak in Received signal strength, the buffer unit 36a as power peak information to timing control part 23a exports.In addition, also the square value of the output signal of the square value of the output signal of totalizer 33a and totalizer 33b can be added and export to peak power detection portion 35a.

The power peak information exported from peakvalue's checking portion 22a (peak power detection portion 35a) is, information with presence or absence of the peak value of judgement Received signal strength.Particularly, power peak information is, the power sum ∑ P during near the peak point of expression Received signal strength in (between the peak period) ₁and from the power sum ∑ P during eliminating beyond between the peak period during 1 of the information unit become DSSS ₂ratio R (=∑ P ₁/ ∑ P ₂) whether be greater than threshold value R _thinformation.In power peak information, be greater than R at R _thwhen, timing control part 23a (buffer unit 36a) thinks to have peak value at this timing receipt signal, and is exported to angle of arrival calculating part 24 by 1 signal Ia1 measured and signal Qa1.On the other hand, R is less than at R _thwhen, timing control part 23a (buffer unit 36a) thinks not have peak value at this timing receipt signal, and stops the output to angle of arrival calculating part 24.In addition, herein, peakvalue's checking portion 22a has carried out the calculation process information-related with power peak, but also can carry out the calculation process information-related with power peak in timing control part 23a.

Correlation processing unit 21b (diffuse code generator 31, multiplier 32c and 32d, totalizer 33c and 33d), peakvalue's checking portion 22b (power calculation portion 34b, peak power detection portion 35b), the action of timing control part 23b (buffer unit 36b), function, same with above-mentioned correlation processing unit 21a (diffuse code generator 31, multiplier 32a and 32b, totalizer 33a and 33b), peakvalue's checking portion 22a (power calculation portion 34a, peak power detection portion 35a), the action of timing control part 23a (buffer unit 36a), function.Just, to Received signal strength and the Received signal strength inputted to correlation processing unit 21a of correlation processing unit 21b input, owing to receiving identical electric wave at 2 that separate predetermined distance, therefore phase place is slightly different.Therefore, slightly different with the phase place of the signal exported from timing control part 23a from the signal of timing control part 23b output.When using the signal suitable with in-phase component as real part, the output O signal suitable with quadrature component being showed timing control part 23a as imaginary part by plural number _a1, and the output O of timing control part 23b _a2time, become following formula (1), (2) are such.In addition, and represent the phase place of each signal.

[formula 1]

$O_{a1}=\mathrm{Ia}1+\mathrm{iQa}1={\mathrm{Ae}}^{{\mathrm{i\φ}}_1}=A{\cos \mathrm{\φ}}_1+\mathrm{iA}{\sin \mathrm{\φ}}_1\·\·\·\left(1\right)$

[formula 2]

$O_{a2}=\mathrm{Ia}2+\mathrm{iQa}2={\mathrm{Ae}}^{{\mathrm{i\φ}}_2}=A{\cos \mathrm{\φ}}_2+\mathrm{iA}{\sin \mathrm{\φ}}_2\·\·\·\left(2\right)$

The output O of timing control part 23a _a1be transfused to the complex conjugate portion 41 arriving angle calculation portion 24.Complex conjugate portion 41 is by the output O of timing control part 23a _a1complex conjugate export to complex multiplication portion 42.That is, Ia1 is outputed signal from complex conjugate portion 41 and signal by the sign-inverted of signal Qa1.As the output O with complex representation complex conjugate portion 41 _{a1 '}time, become following formula (3) such.

[formula 3]

$O_{{a1}^{\′}}=\mathrm{Ia}1-\mathrm{iQa}1={\mathrm{Ae}}^{{-\mathrm{i\φ}}_1}={A\cos \mathrm{\φ}}_1-i{A\sin \mathrm{\φ}}_1\·\·\·\left(3\right)$

Complex multiplication portion 42 is by the output O in complex conjugate portion 41 _{a1 '}with the output O of timing control part 23b _a2complex multiplication, and export as the signal Ib of multiplied result and signal Qb to arc tangent portion 43 and power calculation portion 44.The output O in complex multiplication portion 42 _b, export O _bin-phase component Ib and quadrature component Qb to be expressed as the formula of stating (4) ~ (6) such.

[formula 4]

$\begin{array}{c}{O}_b={\mathrm{Ae}}^{-i{\mathrm{\φ}}_1}\·{\mathrm{Ae}}^{i{\mathrm{\φ}}_2}(={\mathrm{Be}}^{i({\mathrm{\φ}}_2-{\mathrm{\φ}}_1)})\\ =(\mathrm{Ia}1\×\mathrm{Ia}2+\mathrm{Qa}1\×\mathrm{Qa}2)+i(\mathrm{Qa}1\×\mathrm{Ia}2-\mathrm{Ia}1\×\mathrm{Qa}2)\end{array}\·\·\·\left(4\right)$

[formula 5]

Ib＝Ia1×Ia2+Qa1×Qa2···(5)

[formula 6]

Qb＝Qa1×Ia2-Ia1×Qa2···(6)

Arc tangent portion 43 uses the output in complex multiplication portion 42 to carry out arctangent cp cp operation.Particularly, carry out with the output signal Ib in complex multiplication portion 42 be denominator, to output signal the arctangent cp cp operation of the value that Qb is molecule.Fig. 4 (a) represents the example from the output waveform in arc tangent portion 43.The output O in arc tangent portion 43 _arctanwith phase differential quite, represented by following formula (7).

[formula 7]

$O_{\arctan }={\tan }^{-1}\frac{\mathrm{Qb}}{\mathrm{Ib}}={\mathrm{\φ}}_2-{\mathrm{\φ}}_1\·\·\·\left(7\right)$

Power calculation portion 44 calculates the power of each chip interval according to the output signal in complex multiplication portion 42.Particularly, the absolute value of the absolute value of Ib and Qb is added by power calculation portion 44, and as each chip interval power information and export to equalization part 45.In addition, also the square value of the square value of Ib and Qb can be added and export to equalization part 45.Fig. 4 (b) represents the example from the output waveform in power calculation portion 44.Equalization part 45, when accepting the power information of each chip interval, according to the output O of this information by arc tangent portion 43 _arctanequalization and exporting to angle of arrival transformation component 46.In addition, power calculation portion 44 and equalization part 45 also can suitably be omitted.

Angle of arrival transformation component 46 uses the output of equalization part 45 (when not having equalization part 45, using the output in arc tangent portion 43) and is transformed to angle of arrival by inverse trigonometric function computing.As inverse trigonometric function computing, such as, inverse sine computing can be applied.The output of the value obtained by this computing, i.e. angle of arrival transformation component 46 is suitable with angle of arrival θ (rad).The output O of angle of arrival transformation component 46 _arcsinrepresented by following formula (8).In addition, in following formula, λ (m) is the wavelength receiving ripple, and d (m) is the distance between antenna for receiving.

[formula 8]

$O_{\arcsin }={\sin }^{-1}\frac{O_{43}}{2\mathrm{\π}}\·\frac{\mathrm{\λ}}{d}=\mathrm{\θ}\·\·\·\left(8\right)$

Obtaining angle of arrival by above-mentioned process, is because geometry relation is as shown in Figure 5 set up.Be set to the direction that reaches to specify for benchmark and the electric wave angulation of two antenna for receiving 11a, 11b that d (m) spaced apart configures is θ (rad).Arrive the propagation distance of the electric wave of antenna for receiving 11b, long Δ (m) compared with the propagation distance of the electric wave of arrival antenna for receiving 11a, produces phase delay (phase differential (rad)).When representing difference delta and the phase differential of the propagation distance produced in the model by the wavelength X (m) receiving ripple relation time, become following formula (9) such.In addition, in following formula, Δ < λ.

[formula 9]

$\mathrm{\&Delta;}=\mathrm{\&lambda;}\&CenterDot;\frac{{\mathrm{\&phi;}}_2-{\mathrm{\&phi;}}_1}{2\mathrm{\&pi;}}\&CenterDot;\&CenterDot;\&CenterDot;\left(9\right)$

In addition, according to the geometry relation of the difference delta of the propagation distance in above-mentioned model, antenna spacing d, angle of arrival θ, following formula (10) is set up.

[formula 10]

Δ＝d?sin?θ···(10)

That is, angle of arrival θ will be expressed as following formula (11) like that.In addition, formula (11) is suitable with the process in angle of arrival transformation component 46.Known like this, angle of arrival can be calculated by the angle of arrival calculation element of present embodiment.

[formula 11]

$\mathrm{\&theta;}={\sin }^{-1}\frac{{\mathrm{\&phi;}}_2-{\mathrm{\&phi;}}_1}{2\mathrm{\&pi;}}\&CenterDot;\frac{\mathrm{\&lambda;}}{d}\&CenterDot;\&CenterDot;\&CenterDot;\left(11\right)$

Then, the example of the position detecting system employing angle of arrival calculation element is described.Position detecting system 101 shown in Fig. 6 is configured to comprise and arrives angle calculation device 1a, separates predetermined distance D with angle of arrival calculation element 1a and other angle of arrival calculation element 1b, access point 2 or the user terminal 3 that configure.Access point 2 and user terminal 3 are configured to, and possess transmitting system and receiving system (not shown) respectively, can carry out two-way information transmission (communication).In addition, access point 2 and user terminal 3 are configured to, and can send the electric wave arriving angle calculation by the transmitting system possessed separately to angle of arrival calculation element 1a and angle of arrival calculation element 1b.The object that position is detected is any one of access point 2 or user terminal 3.

Angle of arrival calculation element 1a receives the electric wave sent from the transmission antenna of access point 2 by antenna for receiving 11aa and 11ab, thus calculates the angle of arrival being benchmark with angle of arrival calculation element 1a.In addition, angle of arrival calculation element 1b receives the electric wave sent from the transmission antenna of access point 2 by antenna for receiving 11ba and 11bb, thus calculates the angle of arrival being benchmark with angle of arrival calculation element 1b.If the position relationship of angle of arrival calculation element 1a and angle of arrival calculation element 1b is known, then can decide the position of access point 2 according to the angle of arrival with respective being benchmark.

In addition, when the position of user terminal 3 is detected, angle of arrival calculation element 1a and angle of arrival calculation element 1b calculates the angle of arrival of the electric wave sent from user terminal 3.

Fig. 7 is the process flow diagram that the angle of arrival in angle of arrival calculation element 1 of the present embodiment calculates.When angle of arrival calculation element 1 receives the electric wave arriving angle calculation object, acceptance division 12a, 12b export Received signal strength to correlation processing unit 21a, 21b.After this, correlation processing unit 21a, 21b carry out relevant treatment and the addition process of Received signal strength in step 201.

After this, peakvalue's checking portion 22a, 22b carrys out the peak value P of detection power in step 202. according to the output signal of correlation processing unit 21a, 21b _peak.After this, the power sum ∑ P during calculating near peak point in (between the peak period) ₁and from the power sum ∑ P during (during information unit) during 1 eliminates beyond between the peak period ₂, and calculate their ratio R (=∑ P ₁/ ∑ P ₂).Fig. 8 (a) schematically represents the signal to peakvalue's checking portion 22a, 22b input.Peak power P _peakfor the power on the peak point P in Fig. 8 (a), ∑ P ₁for t between the peak period ₁in power sum, ∑ P ₂for eliminating t between the peak period during 1 ₁during t ₂in power sum.Herein, t between the peak period ₁during being the lifting interval comprising peak value.Such as, as shown in Figure 9, when using DSSS as modulation system, the lifting that can form 2 times of the cycle tc of diffuse code is interval.Therefore, as t between the peak period during this 2tc can being set ₁.In addition, in fig .9, period t ₂use 1 period tb and be expressed as tb-2tc.

Figure 10 represents the example of the signal of peakvalue's checking portion 22a, 22b input when being taken into Received signal strength to using AD transducer.The transverse axis t of Figure 10 represents encoding samples, and t gets discrete value.Such as, when using DSSS as modulation system, if diffuse code is 11 chips, is 1 μ s during 1, be then 0.091 μ s during 1 chip of diffuse code.If establish AD to be transformed to the over-sampling of 4 times during 1 chip, be then elevated interval extension 1 chip amount, become ips=ip-3, ipe=ip+3.In this case, R is expressed as following formula (12) like that.

[several 12]

$R=\frac{{\mathrm{\&Sigma;}}_{\mathrm{ip}-3}^{\mathrm{ip}+3}{P}_i}{{\mathrm{\&Sigma;}}_{i1}^{i2}{P}_i-{\mathrm{\&Sigma;}}_{\mathrm{ip}-3}^{\mathrm{ip}+3}{P}_i}\&CenterDot;\&CenterDot;\&CenterDot;\left(12\right)$

In step 203, peakvalue's checking portion 22a, 22b is by calculated ratio R (=∑ P ₁/ ∑ P ₂) with regulation threshold value R _thcompare.R is compared at R _thwhen large, the signal of this content exports to timing control part 23a, 23b by peakvalue's checking portion 22a, 22b.Timing control part 23a, compares R when accepting R _thduring the signal of large content, think that Received signal strength exists peak value, and the signal needed for the calculating of angle of arrival is exported to angle of arrival calculating part 24.After this, in step 204, angle of arrival calculating part 24 calculates angle of arrival.On the other hand, be R at R _thwhen following, the signal of this content exports to timing control part 23a, 23b by peakvalue's checking portion 22a, 22b, and timing control part 23a, thinks that Received signal strength does not exist peak value, and stops the output to angle of arrival calculating part 24.After this, angle of arrival calculation element 1 performs the flow process from step 201 again.R _thfor arbitrary value.Such as, can by by judging that with presence or absence of peak value, the value of degree is set as R with comparing of R _th.

Like this, by by the index (R) relevant with detected peak value and threshold value (R _th) compare the presence or absence judging peak value, the presence or absence of peak value can be judged exactly.

Herein, judge that compared with the threshold value of power with presence or absence of peak value, method is investigated to by power (power) merely.Fig. 8 (b) schematically represents signal (solid line) that background value is high and the low signal (dotted line) of background value.In Fig. 8 (b), when such background value shown in dotted line is low, can pass through the peak value of power and the threshold value P of power _thcompare, carry out detection peak.But, in Fig. 8 (b), when background value is as shown by the solid line high to more than P _thdegree time, even if by the peak value of power and P _thcomparing can not detection peak.This is because, in the peak value of power and the threshold value of power simple is compared, can not background value be considered.So, as shown in the embodiment, by using the index considering background value in the detection of peak value, the presence or absence of peak value can be judged exactly.

As shown above, angle of arrival calculation element of the present embodiment, by obtain power between the peak period with between the peak period beyond remaining period in power ratio and compare the presence or absence that this ratio obtained and threshold value judge peak value, even if the peak value of expecting ripple also can be detected exactly when the background value receiving ripple is high and for the calculating of angle of arrival.That is, do not calculate angle of arrival according to the component of signal expected beyond ripple, therefore can improve the computational accuracy of angle of arrival.

Figure 11 is the block diagram of another form of the angle of arrival calculating part 24 illustrated in angle of arrival calculation element 1.Angle of arrival calculating part 24 shown in Figure 11 possesses: the output O getting timing control part 23a _a1complex conjugate complex conjugate portion 51; By the output O in complex conjugate portion 51 _{a1 '}with the output O of timing control part 23b _a2the complex multiplication portion 52 of complex multiplication; And use the output in complex multiplication portion 52 to carry out the arc tangent portion 53 of arctangent cp cp operation.Complex conjugate portion 51, complex multiplication portion 52, the action in arc tangent portion 53, function, same with above-mentioned complex conjugate portion 41, complex multiplication portion 42, the action in arc tangent portion 43, function.In addition possess: the operation result (phase differential) based on arc tangent portion 53 comes the phase difference correction portion 54 of correction calculation result; By the equalization part 55 of the output equalization in phase difference correction portion 54; The phase differential correction unit 56 again correcting the operation result (mean value) of equalization part 55 when correcting has been carried out in phase difference correction portion 54; And use phase differential again correction unit 56 output and be transformed to the angle of arrival transformation component 57 of angle of arrival.The action of angle of arrival transformation component 57, function, same with the action of above-mentioned angle of arrival transformation component 46, function.

Phase difference correction portion 54, when the phase differential of the operation result as arc tangent portion 53 becomes the value near+180 ° (+π), near-180 ° (-π), carry out the process of the angle (phase differential) adding regulation in the operation result in arc tangent portion.As shown in the I-Q plane of Figure 12, phase differential projects on the coordinate of the phase range of-180 ° ~+180 ° (-π ~+π) by the angle of arrival calculating part 24 of present embodiment.Therefore, such as, as shown in Figure 13 (a), when the phase differential calculated by arc tangent portion 53 does not become the value near+180 ° and-180 °, by by its equalization, and suitably angle of arrival can be calculated.But as shown in Figure 13 (b), when the phase differential calculated by arc tangent portion 53 becomes the value near+180 and-180, a little error of the phase differential calculated will apply large impact to angle calculation., being assumed to two values obtaining-178 ° and+178 ° as phase data herein, is become+178 ° after producing the error of-4 ° as-178 ° of original value as+178 ° of value of a side.In fact their difference is only 4 °.But in handling averagely, when conduct-178 ° and+178 ° during equalization, mean value becomes 0 °.Although in fact there is the phase differential of about 180 °, can be processed as 0 ° by handling averagely.Like this, when the phase differential of institute's equalization significantly departs from from original phase differential, suitable angle of arrival calculates and becomes difficulty.

So, angle of arrival calculating part 24 shown in Figure 11, when the phase differential calculated by arc tangent portion 53 becomes the value near+180 ° and-180 °, phase difference correction portion 54 carries out the correction process of the angle (phase differential) adding regulation in the operation result in arc tangent portion 53, and carries out suitable equalization.The operation result in arc tangent portion 53 whether be+180 ° or-180 ° near value, the distribution of multiple phase differential that can obtain based on the operation result as arc tangent portion 53 judges.Such as, when be greater than+90 ° (+pi/2s) or be less than-90 ° (-pi/2s) phase differential quantity, than be less than+90 ° and be greater than the quantity of the phase differential of-90 ° many, can be judged to be the operation result in arc tangent portion 53 be+180 ° and-180 ° near value.The angle (phase differential) that phase difference correction portion 54 can be made to add such as+90 °, as long as but the angle of suitable handling averagely can be carried out, be not defined in this.Preferably, also can be any one of-90 ° ,+180 ° or-180 °.

Equalization part 55 is by the output equalization in phase difference correction portion 54.The angle of arrival calculating part 24 of present embodiment, carries out adding the correction of phase differential, therefore, it is possible to carry out suitable handling averagely in equalization part 55 when calculating and being unsuitable for the phase differential of equalization.Phase differential is correction unit 56 again, when having carried out the correction of phase differential in phase difference correction portion 54, corrects the output of equalization part 55.Particularly, the correction deducting the angle (phase differential) added as corrected value in phase difference correction portion 54 is carried out.

The outline that angle of arrival when Figure 14 schematically represents that phase differential becomes near+180 ° and-180 ° calculates.When the phase differential calculated by arc tangent portion 53 in I-Q plane near+180 ° and-180 °, phase difference correction portion 54 adds corrected value (+90 °) and makes X-axis rotate in phase differential, and is transformed to the coordinate axis of mean value calculation.Equalization part 55 carrys out calculating mean value (-92 °) based on these data.Phase differential again correction unit 56 carries out the correction deducting corrected value (+90 °) from the output data in phase difference correction portion 54, and to inverse sine portion 57 export correct after data (+178 °).

Figure 15 is the processing flow chart in above-mentioned angle of arrival calculating part 24.The complex conjugate portion 51 of angle of arrival calculating part 24 calculates the output O of timing control part 23a in step 301 _a1complex conjugate.In addition, complex multiplication portion 52 is in step 302 by the output O of timing control part 23b _a2with the output O in complex conjugate portion 51 _{a1 '}be multiplied.After this, arc tangent portion 53 uses the output in complex multiplication portion 52 to carry out arctangent cp cp operation in step 303, calculates the phase differential between Received signal strength.

In step 304, phase difference correction portion 54 judge the phase differential that calculates in I-Q plane whether as+180 ° and-180 ° near value.When value near calculated phase differential not+180 ° and-180 °, enter step 305, angle of arrival calculating part 24 not phase calibration difference and calculate angle of arrival.When the value near calculated phase differential is+180 ° or near-180 °, enter step 306.This judgement, as described above, can be greater than+90 ° or be less than-90 ° the quantity of phase differential whether than being less than+90 ° and the quantity being greater than the phase differential of-90 ° mostly is benchmark to carry out.

Within step 306, phase difference correction portion 54 carries out the process adding 90 ° in the phase differential of the operation result as arc tangent portion 53.In step 307, equalization part 55 is by the output equalization in phase difference correction portion 54.After this, in step 308, phase differential again correction unit 56 carry out the process deducting 90 ° from the mean value of the operation result as equalization part 55.After this, in a step 309, angle of arrival transformation component 57 calculates angle of arrival according to the output of phase differential correction unit 56 again.Like this, in the angle of arrival calculating part 24 shown in Figure 11, by adding the phase differential of regulation and deduct a series of process of the phase differential of regulation after equalization and calculate suitable mean value, therefore the computational accuracy of angle of arrival does not just reduce.As a result, the computational accuracy of angle of arrival can fully be improved.

In addition, herein, phase difference correction portion 54 carries out the process of the angle adding regulation in the operation result in arc tangent portion 53, as long as but suitable handling averagely can be realized, be not defined in this.Such as, the angle of arrival calculating part 24 of formation as shown in Figure 16 can also be used.Angle of arrival calculating part 24 shown in Figure 16 possesses: the output O getting timing control part 23a _a1complex conjugate complex conjugate portion 61; And by the output O in complex conjugate portion 61 _{a1 '}with the output O of timing control part 23b _a2the complex multiplication portion 62 of complex multiplication.Complex conjugate portion 61, the action in complex multiplication portion 62, function, same with above-mentioned complex conjugate portion 41, the action in complex multiplication portion 42, function.In addition possess: by the IQ comparing section 63 of absolute value compared with the absolute value of quadrature component (Q component) of the in-phase component (I component) of the output in complex multiplication portion 62; And using the output in complex multiplication portion 62, the output according to IQ comparing section 63 is selected, is changed operational method, and carries out the arc tangent portion 64 of arctangent cp cp operation.In addition possess: using the equalization part 65 of the phase differential equalization of the operation result as arc tangent portion 64; The phase differential correction unit 66 again of the mean value of the operation result as equalization part 65 is corrected according to the operational method in arc tangent portion 64; And use phase differential again correction unit 66 output and be transformed to the angle of arrival transformation component 67 of angle of arrival.The action of angle of arrival transformation component 67, function, same with the action of above-mentioned angle of arrival transformation component 46, function.

IQ comparing section 63 judges that whether the in-phase component (I component) of the output in complex multiplication portion is as negative, and compares the absolute value of the in-phase component (I component) of the output in complex multiplication portion 62 and the absolute value of quadrature component (Q component).Particularly, whether fully large (whether the absolute value ︱ Qb ︱ of quadrature component is fully little compared with the absolute value ︱ Ib ︱ of in-phase component) IQ comparing section 63 judges the symbol of in-phase component Ib, and judge the absolute value ︱ Ib ︱ of in-phase component compared with the absolute value ︱ Qb ︱ of quadrature component.When the phase differential of Received signal strength gets the value near+180 ° and-180 ° in I-Q plane, in-phase component Ib is negative (Ib < 0), and the absolute value ︱ Ib ︱ of in-phase component is fully large compared with the absolute value ︱ Qb ︱ of quadrature component.Therefore, by judging the symbol of in-phase component Ib and judging whether the absolute value ︱ Ib ︱ of in-phase component is fully large compared with the absolute value ︱ Qb ︱ of quadrature component, can judge whether phase differential gets the value near+180 ° and-180 °.

Arc tangent portion 64 uses the output in complex multiplication portion 62, carrys out Selecting operation method and carry out arctangent cp cp operation according to the output of IQ comparing section 63.When in-phase component is positive, in-phase component be negative and the absolute value ︱ Ib ︱ of in-phase component and the absolute value ︱ Qb ︱ of quadrature component be same degree or less than it when, carry out with the output Ib in complex multiplication portion 62 be denominator, to export the arctangent cp cp operation of the value that Qb is molecule.When in-phase component is negative and the absolute value ︱ Ib ︱ of in-phase component is fully large compared with the absolute value ︱ Qb ︱ of quadrature component, such as, carry out making-the Qb of the sign-inverted of the output Qb in complex multiplication portion 62 be denominator, to export the arctangent cp cp operation of the value that Ib is molecule.In addition, the above-mentioned process when the absolute value ︱ Ib ︱ of in-phase component is fully large compared with the absolute value ︱ Qb ︱ of quadrature component, and makes X-axis rotate+90 ° and to carry out the process of arctangent cp cp operation suitable.That is, the phase differential obtained by this process is in original phase differential, add the value of+90 °.

In addition, the process when the absolute value ︱ Ib ︱ of in-phase component is fully large compared with the absolute value ︱ Qb ︱ of quadrature component, is not defined in above-mentioned process.Such as, also can carry out with the output Qb in complex multiplication portion 62 be denominator, to make the arctangent cp cp operation of the value that-Ib of the sign-inverted of output Ib is molecule.This process, and makes X-axis rotate-90 ° and to carry out the process of arctangent cp cp operation suitable.That is, the phase differential obtained by this process is in original phase differential, add the value (having deducted the value of+90 °) of-90 °.In addition, such as also can make the symbol of the output Ib in complex multiplication portion 62 and export the sign-inverted of Qb and carry out arctangent cp cp operation.This process, and makes X-axis rotate+180 ° (or-180 °) and to carry out the process of arctangent cp cp operation suitable.That is, the phase differential obtained by this process is the value adding+180 ° (or-180 °) in original phase differential.By this process, also suitable mean value can be calculated.

Equalization part 65 is by the output equalization in arc tangent portion 64.The angle of arrival calculating part 24 of present embodiment adds in fact the correction of (or deducting) phase differential when calculating and being unsuitable for the phase differential of equalization, therefore, it is possible to carry out suitable handling averagely in equalization part 65.Phase differential again correction unit 66, when arc tangent portion 64 has carried out the process making X-axis rotate+90 °, corrects the output of equalization part 65.Particularly, the correction deducting+90 ° is carried out.In addition, when arc tangent portion 64 has carried out the process making X-axis rotate-90 °, carry out the correction (namely adding the correction of+90 °) deducting-90 °.Equally, when arc tangent portion 64 has carried out the process making X-axis rotate+180 ° (or-180 °), the correction deducting+180 ° (or-180 °) has been carried out.

Like this, the angle of arrival calculating part 24 shown in Figure 16 also can calculate suitable mean value in the same manner as the angle of arrival calculating part 24 shown in Figure 11, and therefore the computational accuracy of angle of arrival does not just reduce.As a result, the computational accuracy of angle of arrival can fully be improved.

Figure 17 is the block diagram of the concrete configuration example of the angle of arrival calculation element represented when to use OFDM (OFDM) as modulation system.In addition, in fig. 17, illustrate only the formation suitable with the operational part 13 in Fig. 1.

In fig. 17, correlation processing unit 21a possesses: the complex conjugate complex conjugate portion 71a getting the output of acceptance division 12a; Make the amount that the output of acceptance division 12a postpones specified time limit and the delay portion 72a exported; By the complex multiplication portion 73a of the output complex multiplication of the output of complex conjugate portion 71a and delay portion 72a; And be only added the output of complex multiplication portion 73a and totalizer 74a, the 74b of output in GI (protection interval) period.Peakvalue's checking portion 22a possesses: the power calculation portion 75a calculating the power of the signal exported from totalizer 74a, 74b; And detect its power peak and the peak power detection portion 76a exported to timing control part 23a.Timing control part 23a possess based on the signal from peak power detection portion 76a control from acceptance division 12a output from signal to angle of arrival calculating part 24 timing delay portion 77a.Equally, correlation processing unit 21b possesses complex conjugate portion 71b, delay portion 72b, complex multiplication portion 73b, totalizer 74c, 74d, and peakvalue's checking portion 22b possesses power calculation portion 75b, peak power detection portion 76b, timing control part 23b possess delay portion 77b.Angle of arrival calculating part 24 possesses: the complex conjugate complex conjugate portion 81 of getting the output of delay portion 77a; By the complex multiplication portion 82 of the output complex multiplication of the output in complex conjugate portion 81 and delay portion 77b; Only be added the output in complex multiplication portion 42 and adder 83a, the 83b of output in GI (protection interval) period; The arc tangent portion 84 of arctangent cp cp operation is carried out in the output of use adder 83a, 83b; By the equalization part 85 of the output equalization in arc tangent portion 84; And use the output of equalization part 85 to be transformed to the angle of arrival transformation component 86 of angle of arrival.

Delay portion 72a, 72b get the auto-correlation of OFDM symbol string, therefore make the output of acceptance division 12a postpone the amount of specified time limit and export.Particularly; delay portion 72a, 72b; the GI (protection interval) exported in order to the afterbody of OFDM symbol that exported by complex conjugate portion 71a and delay portion 72a, 72b inputs to complex multiplication portion 73a in identical timing, and makes the output of acceptance division 12a postpone the amount of specified time limit and export.Complex multiplication portion 73a is by the output complex multiplication of the output of complex conjugate portion 71a and delay portion 72a.Totalizer 74a and 74b is only added the output of each chip interval of complex multiplication portion 73a and exports during GI.

Figure 18 (a) is the schematic diagram of the formation representing OFDM symbol string.As shown in Figure 18 (a), OFDM symbol string is made up of with the initial GI being configured in OFDM symbol the OFDM symbol as data portion.GI is the data having copied OFDM symbol afterbody, is inserted into prevent the interference between OFDM symbol.Figure 18 (b) is the schematic diagram of the situation of the relevant treatment (auto-correlation processing) of the OFDM symbol string represented in correlation processing unit 21a.As shown in Figure 18 (a), the output of the output relative complex conjugate portion 71a of delay portion 72a is delayed the amount of OFDM symbol length.Therefore, in complex multiplication portion 73a, can be multiplied with the output of delay portion 72a by the output of complex conjugate portion 71a and take from relevant.Autocorrelation value (GI correlation) illustrates peak value when there are the data identical with GI in the output of complex conjugate portion 71a and the output of delay portion 72a, therefore by using this point, and can detect OFDM symbol initial as data portion.

The output signal of totalizer 74a and 74b is transfused to the power calculation portion 75a of peakvalue's checking portion 22a.Power calculation portion 75a calculates the power of each chip interval according to the output signal of totalizer 74a and 74b.Particularly, the absolute value of the absolute value of the output signal suitable with in-phase component and the output signal suitable with quadrature component is added by power calculation portion 34a, as each chip interval power information and export to peak power detection portion 76a.In addition, also the square value phase adduction of the square value of the output signal suitable with in-phase component and the output signal suitable with quadrature component can be exported to peak power detection portion 76a.Figure 19 (a) represents the example from the output waveform of power calculation portion 75a.Figure 19 (b) is the magnified partial view of the output waveform shown in Figure 19 (a).Peak power detection portion 76a is when accepting the power information of each chip interval, and detect the power peak in Received signal strength, the delay portion 77a as power peak information to timing control part 23a exports.

From power peak information information with presence or absence of the peak value of judgement Received signal strength that peakvalue's checking portion 22a (peak power detection portion 35a) exports.Particularly, power peak information is, the power sum ∑ P during near the peak point of expression Received signal strength in (between the peak period) ₁and from the power sum ∑ P during eliminating beyond between the peak period during 1 symbol of the information unit become OFDM ₂ratio R (=∑ P ₁/ ∑ P ₂) whether be greater than threshold value R _thlarge information.When using OFDM as modulation system, equal with during GI between the peak period.In addition, during so-called 1 symbol, with added up to GI during and suitable during (during OFDM symbol) during data.In power peak information, be greater than R at R _thwhen, timing control part 23a (delay portion 77a) thinks to have peak value at this timing receipt signal, and by the Received signal strength from acceptance division 12a to angle of arrival calculating part 24.On the other hand, R is less than at R _thwhen, timing control part 23a (delay portion 77a) thinks not have peak value at this timing receipt signal, and stops the output to angle of arrival calculating part 24.In addition, herein, peakvalue's checking portion 22a has carried out the calculation process information-related with power peak, but also can carry out the calculation process information-related with power peak in timing control part 23a.

Correlation processing unit 21b (complex conjugate portion 71b, delay portion 72b, complex multiplication portion 73b, totalizer 74c, 74d), peakvalue's checking portion 22b (power calculation portion 75b, peak power detection portion 76b), the action of timing control part 23b (delay portion 77b), function, same with correlation processing unit 21a (complex conjugate portion 71a, delay portion 72a, complex multiplication portion 73a, totalizer 74a, 74b), peakvalue's checking portion 22a (power calculation portion 75a, peak power detection portion 76a), the action of timing control part 23a (delay portion 77a), function.Just, to the Received signal strength of correlation processing unit 21b input and the Received signal strength to correlation processing unit 21a input, owing to have received identical electric wave at 2 that separate predetermined distance, therefore phase place is slightly different.Therefore, at the signal exported from timing control part 23b and from the signal that timing control part 23a exports, phase place is slightly different.

The output of timing control part 23a is transfused to the complex conjugate portion 81 arriving angle calculation portion 24.The complex conjugate of the output of timing control part 23a exports to complex multiplication portion 82 by complex conjugate portion 81.Operation result by the output complex multiplication of the output in complex conjugate portion 81 and timing control part 23b, and exports to adder 83a and 83b by complex multiplication portion 82.Adder 83a and 83b is added the output of each chip interval in complex multiplication portion 82 and exports to arc tangent portion 84 during GI.Figure 19 (c) represents the example from the output waveform of adder 83a and 83b.In the drawings, the output waveform of adder 83a is represented by I, and the output waveform of adder 83b is represented by Q.

Arc tangent portion 84 uses the output of adder 83a and 83b to carry out arctangent cp cp operation, calculates the phase differential of Received signal strength.Figure 19 (d) represents the example from the output waveform in arc tangent portion 84.Equalization part 85 is by the output equalization in arc tangent portion 84 and export to angle of arrival transformation component 86.In addition, equalization part 85 also can suitably be omitted.Angle of arrival transformation component 86 uses the output of equalization part 85 (when not having equalization part 85, the output in arc tangent portion 84) and is transformed to angle of arrival by inverse trigonometric function computing.The output of the value obtained by this computing, i.e. angle of arrival transformation component 86 is suitable with angle of arrival.

Like this, in the angle of arrival calculation element 1 of operational part 13 with Figure 17, also by obtain power between the peak period with between the peak period beyond remaining period in power ratio and compare the presence or absence that this ratio obtained and threshold value judge peak value, even if the peak value of expecting ripple also can be detected exactly when the background value receiving ripple is high and for the calculating of angle of arrival.That is, do not calculate angle of arrival according to the component of signal expected beyond ripple, therefore can improve the computational accuracy of angle of arrival.

Figure 20 is the schematic diagram representing location-specific capsule endoscope system angle of arrival calculation element 1 being applied to capsule endoscope.Capsule endoscope system shown in Figure 20 possesses multiple sensor array 401, record data recorder 402 from the data of sensor array 401.Sensor array 401 possesses the antenna suitable with the antenna for receiving of angle of arrival calculation element 1, and is configured to the electric wave that can receive the capsule endoscope swallowed from patient.The phase information that data recorder 402 has according to the electric wave received in sensor array 401, determines the position of the capsule endoscope that patient swallows.

The capsule endoscope that patient swallows is moved by gastral vermicular movement.The position of capsule endoscope is monitored, and can be confirmed whether to reach examination position.When capsule endoscope arrives examination position, the situation at examination position is photographed and sends to data recorder 402, data recorder 402 recording image information by capsule endoscope.Like this, by monitoring the position of capsule endoscope, and position can not be examined and photographs by over sight (OS).In addition, the power supply of the timing connection camera at examination position etc. can be reached at capsule endoscope, and cut off the power supply of camera etc. when having departed from examination position, therefore can reduce battery capacity.In addition, the quantity of sensor (antenna) can be cut down.In addition, if battery capacity is identical, a large amount of images can be sent compared with the capsule endoscope of type in the past, distinct image can be obtained.

Like this, determined by position angle of arrival calculation element 1 being applied to capsule endoscope, excellent capsule endoscope system can be constructed.

As described above, according to angle of arrival calculation element of the present invention, obtain power between the peak period and between the peak period beyond remaining period in the ratio of power, and compare this ratio obtained and threshold value, when calculating angle of arrival than when being greater than threshold value, even if the signal level therefore beyond the expectation ripple receiving ripple is high, also can detects the peak value expecting ripple exactly, and calculate angle of arrival.That is, do not calculate angle of arrival according to the part expected beyond ripple, therefore can improve the computational accuracy of angle of arrival.

In addition, the present invention is not defined in the record of above-mentioned embodiment, suitably can change in the mode playing its effect.Such as, in the above-described embodiment, by the power sum between the peak period with the ratio of the power sum during except between the peak period, compared with threshold value, as long as but the angle of arrival can carrying out considering the level of the signal expected beyond ripple calculate, be not limited thereto.Such as, also can use between the peak period certain timing power and except between the peak period during certain timing power as parameter.

In addition, in the above-described embodiment, formation shown in the drawings etc. is not defined in this, suitably can change in the scope playing effect of the present invention.

Utilizability in industry

Angle of arrival calculation element of the present invention may be used for system and other various uses of the position determining object.

The application is No. 2010-254011, the Japanese Patent Application based on proposing on November 12nd, 2010, and contains its full content.

Claims (9)

1. an angle of arrival calculation element, is characterized in that,

Possess: multiple antenna, receive the electric wave sent from certain position; Multiple Received signal strength handling part, is arranged accordingly with described each antenna; And angle of arrival calculating part, be taken into from the output signal exported by described multiple Received signal strength handling part the component of signal that becomes identical information unit between Received signal strength handling part thus calculate the angle of arrival of described electric wave,

Described each Received signal strength handling part possesses: acceptance division, and the electric wave that the described antenna by correspondence receives is transformed to the Received signal strength of the phase information with this electric wave and exports; Correlation processing unit, carries out relevant treatment by the Received signal strength exported from described acceptance division; Peakvalue's checking portion, detects the peak value having carried out the Received signal strength of described relevant treatment; And timing control part, to cut out the mode becoming the component of signal of identical information unit between described Received signal strength handling part from the output signal of described correlation processing unit, match with the timing of the peak value detected by described peakvalue's checking portion, thus control being taken into regularly of the output signal exported from described correlation processing unit

When the power between the peak period during described information unit is suitable and except between this peak period during the ratio of power be greater than threshold value, the signal from described correlation processing unit exports to described angle of arrival calculating part by described timing control part.

2. angle of arrival calculation element as claimed in claim 1, is characterized in that,

By ∑ P ₁with ∑ P ₂than ∑ P ₁/ ∑ P ₂compare with threshold value, described than ∑ P ₁/ ∑ P ₂when being greater than described threshold value, the signal from described correlation processing unit exports to described angle of arrival calculating part by described timing control part, wherein above-mentioned ∑ P ₁be suitable with described information unit during peak period between power sum, above-mentioned ∑ P ₂be suitable with described information unit during except between the described peak period during power sum.

3. angle of arrival calculation element as claimed in claim 1 or 2, is characterized in that,

Described angle of arrival calculating part possesses:

Complex conjugate portion, fetches the complex conjugate of the signal of the timing control part of the Received signal strength handling part of My World, and the Received signal strength handling part of this side is corresponding with the antenna of a side;

Complex multiplication portion, by the signal multiplication of the output in described complex conjugate portion and the timing control part from the Received signal strength handling part of the opposing party, the Received signal strength handling part of this opposing party is corresponding with the antenna of the opposing party;

Arc tangent portion, uses the output in described complex multiplication portion to carry out arctangent cp cp operation, calculates the phase differential of the described reception electric wave between described antenna;

Equalization part, averages the output in described arc tangent portion; And

Angle of arrival transformation component, uses the output of described equalization part to carry out inverse trigonometric function computing, thus is transformed to angle of arrival.

4. angle of arrival calculation element as claimed in claim 3, is characterized in that,

Near in I-Q plane+180 ° and/or-180 ° of the described phase distribution calculated, described angle of arrival calculating part averages after making each phase differential rotate predetermined angular, after this mean value deducts described predetermined angular, carry out inverse trigonometric function computing, thus be transformed to angle of arrival.

5. angle of arrival calculation element as claimed in claim 4, is characterized in that,

In described I-Q plane, when be greater than+90 ° or the number ratio of phase differential that is less than-90 ° and be less than+90 ° and be greater than the quantity of the phase differential of-90 ° many, be judged as being distributed near+180 ° and/or-180 ° in described I-Q plane.

6. angle of arrival calculation element as claimed in claim 4, is characterized in that,

Described predetermined angular is any one angle of+90 ° ,-90 ° ,+180 ° or-180 °.

7. angle of arrival calculation element as claimed in claim 3, is characterized in that,

When the I component of the output in described complex multiplication portion be bear and the absolute value of the I component of the output in described complex multiplication portion is fully large compared with the absolute value of Q component, by carrying out the arctangent cp cp operation of the relation of having exchanged I component and Q component after the symbol reversing described Q component, calculate the phase differential after correction, phase differential after described correction is averaged, after this mean value deducts 90 °, carry out inverse trigonometric function computing, thus be transformed to angle of arrival.

8. angle of arrival calculation element as claimed in claim 3, is characterized in that,

When the I component of the output in described complex multiplication portion be bear and the absolute value of the I component of the output in described complex multiplication portion is fully large compared with the absolute value of Q component, by carrying out the arctangent cp cp operation of the relation of having exchanged I component and Q component after the symbol reversing described I component, calculate the phase differential after correction, phase differential after described correction is averaged, carry out inverse trigonometric function computing after 90 ° are added to this mean value, thus be transformed to angle of arrival.

9. angle of arrival calculation element as claimed in claim 3, is characterized in that,

When the I component of the output in described complex multiplication portion be bear and the absolute value of the I component of the output in described complex multiplication portion is fully large compared with the absolute value of Q component, by the phase differential after carrying out arctangent cp cp operation calculate correction after the reversed symbol of described I component and the symbol of Q component, phase differential after described correction is averaged, after this mean value deducts 180 °, carry out inverse trigonometric function computing, thus be transformed to angle of arrival.