JP6592912B2 - Communication system, receiving device, server, signal processing method, wave source position calculating method, and program - Google Patents

Description

  The present invention relates to a server for calculating a position of a wave source.

  In recent years, effective use of frequency bands (white space) that are not used spatially and temporally as one of the means to improve frequency utilization efficiency to cope with the tightness of frequency resources and the explosive increase in mobile traffic. Is mentioned. As described above, in order to efficiently use the vacant frequency band, it is necessary to appropriately grasp the spatial and temporal vacancy conditions for each frequency.

As such a white space detection method, for example, there is a method in which a radio wave reachable range due to propagation loss in free space is specified from the position of a pre-registered transmission wave source, and the outside of the range is set as white space.
For example, a device described in Patent Document 1 is known as a device for detecting an unused frequency spectrum.

Special table 2012-529196 gazette

Note that the white space detection method using the position of a transmission wave source with pre-registration has a problem that a white space cannot be detected for a transmission wave source that is not pre-registered. Accordingly, there is a demand for specifying the position of a wave source that is not pre-registered.
In addition to the detection of the white space, there has been a demand for specifying the position of the transmission wave source for the purpose of specifying the transmission source of illegal radio waves.

As a method for specifying the position of such a wave source, a calculation method using TDoA (Time Difference of Arrival) is known. In calculating the position of the wave source using the TDoA, using the cross-correlation of data received by three or more receiving devices, the arrival time difference (TDoA) at which the same radio wave transmitted from the wave source has reached each receiving device. ) Is calculated. For details of the position calculation method by TDoA, refer to the following document, for example.
Literature: K. Ho, Y. Chan, “Solution and performance analysis of geolocation by tdoa”, IEEE Transactions on Aerospace and Electronic Systems, vol. 29, no. 4, p. 1311-1322, October 1993

  In the calculation of the position of the wave source by such TDoA, the cross-correlation of the received signal is used. Therefore, if the signal used in the calculation of the cross-correlation is lengthened, the noise included in the data is theoretically uncorrelated. Thus, the calculation accuracy of the arrival time difference is improved, and as a result, the calculation accuracy of the position of the wave source is also improved.

  However, a wave source that is a target for detecting a white space, an illegal radio wave source, or the like does not always transmit radio waves. If the signal sample used in the calculation of the cross-correlation when calculating the arrival time difference includes such a non-transmission period, the calculation accuracy of the arrival time difference decreases, and as a result, the wave source The position calculation accuracy also decreases. Therefore, there is a problem that it is difficult to increase the number of samples of the signal for calculating the arrival time difference.

  The present invention has been made in response to the above problems, and in the case of calculating the position of a wave source by TDoA, a communication system that can improve the calculation accuracy of the arrival time difference even if fewer signal samples are used. The purpose is to provide.

In order to achieve the above object, a communication system according to the present invention is a communication system including three or more receiving devices that receive radio waves from a wave source and a server, and the receiving device receives radio waves from the wave source. Antenna, a distributor that divides the received signal received by the antenna, a plurality of RF circuits that convert the plurality of received signals divided by the distributor into baseband signals, and a plurality of RF circuits respectively. A transmission unit that transmits the plurality of baseband signals transmitted to the server, and the server includes a plurality of baseband signals for a pair of the reception unit that receives the plurality of baseband signals from the reception device and the reception device. An arrival time difference calculation unit that calculates a difference in arrival time of radio waves from a wave source using a cross-correlation with respect to a combination of By using the arrival time difference calculated by the arrival time difference calculating unit for each of the plurality of pairs of the wave source position calculation unit for calculating the position of the wave source, with a, but.
With such a configuration, when calculating the cross-correlation for calculating the arrival time difference for a certain pair of receiving apparatuses, the cross-correlation according to the plurality of combinations of the plurality of baseband signals converted by the plurality of RF circuits is obtained. Can be calculated. Therefore, it is possible to increase the number of signal samples for calculating the cross-correlation within a certain reception time and to calculate the arrival time difference, compared with the case where one baseband signal sequence converted by one RF circuit is used. The accuracy can be improved, and as a result, the calculation accuracy of the position of the wave source can also be improved.

In addition, a receiving device according to the present invention includes a communication device including three or more receiving devices that receive radio waves from a wave source, and a server that calculates the position of the wave source using the arrival time difference of radio waves from the wave source to the receiving device. A receiving device in a system, which receives an electric wave from a wave source, a distributor that divides a reception signal received by the antenna, and a plurality of reception signals that are divided by the distributor, respectively, into baseband signals And a transmission unit that transmits a plurality of baseband signals respectively converted by the plurality of RF circuits to a server.
With such a configuration, a plurality of baseband signals converted by a plurality of RF circuits can be transmitted to a server that calculates the position of the wave source. As a result, in the server, when calculating the cross-correlation for calculating the arrival time difference for a certain pair of receiving devices, the cross-correlation corresponding to the plurality of combinations of the plurality of baseband signals converted by the plurality of RF circuits is performed. Thus, the calculation accuracy of the arrival time difference can be improved.

The receiving apparatus according to the present invention further includes a received power calculating unit that calculates received power using two or more baseband signals converted by different RF circuits, and the transmitting unit is calculated by the received power calculating unit. Received power may also be transmitted to the server.
With such a configuration, the received power is calculated using two or more baseband signals converted by different RF circuits, so that the noise is decorrelated and the received power is accurate even when the received power is low. You will be able to calculate well. Further, in the server, for example, the position of the wave source can be calculated with higher accuracy by calculating the position of the wave source using the arrival time difference regarding three or more receiving devices having higher received power.

The receiving apparatus according to the present invention further includes a multipath information calculation unit that calculates multipath information that is information related to the power of the delayed wave, using two or more baseband signals converted by different RF circuits. The transmission unit may also transmit the multipath information calculated by the multipath information calculation unit to the server.
With such a configuration, by calculating the power of the delayed wave using two or more baseband signals converted by different RF circuits, the noise is decorrelated and even in a situation where the power of the delayed wave is low, The power can be calculated accurately. Further, in the server, for example, by using the multipath information, the position of the wave source is calculated by using the arrival time difference regarding three or more receiving apparatuses having a smaller influence of the delayed wave, thereby providing a more accurate wave source position. Can be calculated.

Also, the server according to the present invention divides a plurality of received signals that have received radio waves from a wave source by a distributor and converts the plurality of received signals into a plurality of baseband signals by a plurality of RF circuits, respectively. And a server in a communication system comprising a server, wherein a cross-correlation for a plurality of combinations of a plurality of baseband signals is used for a pair of a receiving unit that receives a plurality of baseband signals from a receiving device and a pair of the receiving devices The position of the wave source is calculated using the arrival time difference calculation unit for calculating the arrival time difference of the radio wave from the wave source, the position of the reception device, and the arrival time difference calculated by the arrival time difference calculation unit for each of a plurality of pairs of the reception devices. And a wave source position calculation unit for calculating.
With such a configuration, when calculating the cross-correlation for calculating the arrival time difference for a certain pair of receiving apparatuses, the cross-correlation according to the plurality of combinations of the plurality of baseband signals converted by the plurality of RF circuits is obtained. The calculation accuracy of the arrival time difference can be improved.

In the server according to the present invention, the communication system includes four or more receiving devices, and each of the four or more receiving devices is calculated using two or more baseband signals converted by different RF circuits. A reception power acquisition unit that acquires received power, and a selection unit that selects three or more reception devices with a large reception power acquired by the reception power acquisition unit, and the wave source position calculation unit includes: The position of the wave source may be calculated using the arrival time difference calculated for each of a plurality of pairs of three or more receiving devices selected by.
With such a configuration, it is possible to calculate the position of the wave source with higher accuracy by calculating the position of the wave source using the arrival time difference regarding the receiving device having a higher reception power.

In the server according to the present invention, the communication system includes four or more receiving devices, and each of the four or more receiving devices is calculated using two or more baseband signals converted by different RF circuits. A multipath information acquisition unit that acquires multipath information, which is information related to the power of the delayed wave, and three or more receivers that are less affected by the delay wave indicated by the multipath information acquired by the multipath information acquisition unit And a wave source position calculation unit that calculates the position of the wave source using arrival time differences calculated for each of a plurality of pairs of three or more receiving devices selected by the selection unit. Also good.
With such a configuration, it is possible to calculate the position of the wave source with higher accuracy by using the multipath information and calculating the position of the wave source using the arrival time difference for the receiving apparatus that is less affected by the delayed wave. .

The server according to the present invention further includes a reception power acquisition unit that acquires reception power calculated using two or more baseband signals converted by different RF circuits for each of the three or more reception devices. The wave source position calculation unit may calculate the position of the wave source by using the arrival time difference between the pair of receiving apparatuses together with a weight corresponding to two received powers corresponding to the pair of receiving apparatuses.
With such a configuration, the position of the wave source can be calculated so as to increase the influence of the arrival time difference that is considered to be more accurate, and the calculation accuracy of the position of the wave source is improved.

  According to the communication system and the like according to the present invention, when calculating the position of the wave source by TDoA, it is possible to improve the calculation accuracy of the arrival time difference even if a baseband signal having a shorter reception time is used.

The block diagram which shows the structure of the communication system by embodiment of this invention The block diagram which shows the structure of the receiver by the same embodiment The block diagram which shows the structure of the server by the embodiment The flowchart which shows operation | movement of the receiver by the same embodiment The flowchart which shows operation | movement of the server by the embodiment The flowchart which shows operation | movement of the server by the embodiment The flowchart which shows operation | movement of the server by the embodiment The flowchart which shows operation | movement of the server by the embodiment The figure which shows an example of the delay profile in the embodiment Schematic diagram showing an example of the appearance of the computer system in the embodiment The figure which shows an example of a structure of the computer system in the embodiment

  Hereinafter, a communication system according to the present invention will be described using embodiments. In the following embodiments, components and steps denoted by the same reference numerals are the same or equivalent, and repetitive description may be omitted. The communication system according to the present embodiment includes a receiving device having two or more RF circuits, and a server that calculates the position of the wave source using a plurality of baseband signals converted by the two or more RF circuits. It is a thing.

  FIG. 1 is a block diagram showing a configuration of a communication system 10 according to the present embodiment. The communication system 10 according to the present embodiment includes three or more receiving devices 1 and a server 2. The plurality of receiving apparatuses 1 and the server 2 are connected via a wired or wireless communication line 100. The communication line 100 may be, for example, the Internet, an intranet, a public telephone line network, or the like. 1 shows a case where the communication system 10 includes four receiving apparatuses 1, the number of the receiving apparatuses 1 included in the communication system 10 may be three or more. Is not limited. As will be described later, when the server 2 selects the receiving device 1 used for calculating the position of the wave source 3, it is preferable that the communication system 10 includes four or more receiving devices 1. It is. The wave source 3 may be anything as long as it transmits radio waves. For example, the wave source 3 may be a radio base station such as a mobile phone or a base station of a radio system such as a taxi. Alternatively, other radio waves may be transmitted. The position of the receiving device 1 is assumed to be known.

  FIG. 2 is a block diagram showing a configuration of receiving apparatus 1 according to the present embodiment. The receiving device 1 receives radio waves from the wave source 3, and includes an antenna 11, a distributor 12, a plurality of RF circuits 13-1 to 13-N, a received power calculation unit 14, and multipath information calculation. Unit 15 and transmission unit 16.

The antenna 11 receives radio waves from the wave source 3. The received reception signal is input from the antenna 11 to the distributor 12.
The distributor 12 divides the received signal received by the antenna 11 into a plurality of parts, and inputs the divided plurality of received signals to the plurality of RF circuits 13-1 to 13 -N, respectively.

  The N RF circuits 13-1 to 13-N convert the plurality of reception signals divided by the distributor 12 into baseband signals, respectively. The conversion is performed by performing high-frequency signal processing of a corresponding frequency on the received signal. Note that the baseband signal here is strictly a baseband signal obtained by digitizing an analog baseband signal by AD conversion. N is an integer of 2 or more. The value of N may be the same for each receiving apparatus 1 or may be different. When the RF circuits 13-1 to 13-N are not particularly distinguished, they are referred to as RF circuits 13.

上式において、Ｅ［ｒ_i ^(u)(n)ｒ_i ^(v)*(n)］は、次式の通りである。

The received power calculation unit 14 calculates received power using two or more baseband signals converted by different RF circuits 13. Specifically, the received power calculation unit 14 may calculate the received power P _i as in the following equation.

In the above ^{_{equation, E [r i (u)}} (n) r i (v) * (n)] are as follows.

As described above, N is the number of RF circuits 13 included in the reception apparatus 1, and N _a is the number of samples for which the reception apparatus 1 calculates a correlation. In r _i ^(u) (n), i is an integer index for identifying the receiving device 1, u is an integer index for identifying the RF circuit 13, and n is a sample in the baseband signal. An integer index that identifies Also, r _i ^(u) (n) is the value of the n th sample (IQ data or complex amplitude value) in the baseband signal converted by the u th RF circuit 13 in the i th receiving device 1. The sample is a sample when an analog baseband signal is digitized. In the above equation, when N = 2, received power is calculated using two baseband signals converted by different RF circuits 13. On the other hand, when N ≧ 3, two baseband signals converted by different RF circuits 13 are used, and the received power corresponding to the two baseband signals (the above E [r _i ^(u) ( n) r _i ^{(v) *} (n)]) is calculated and added to the different pairs of the RF circuits 13, whereby the final received power is calculated.

なお、上式右辺のＥ［ｒ_i ^(u)(n)ｒ_i ^(v)*(n−τ)］は、受信電力を算出する際に用いたＥ［ｒ_i ^(u)(n)ｒ_i ^(v)*(n)］の式において、ｒ_i ^(v)*(n)、ｒ_i ^(v)*(n−k)のｎをｎ−τとしたものである。また、Ｄ_i（０）は、次式で示されるものであり、ある時点の受信電力に対応する値である。

また、Ｄ_i（τ）は、その時点のベースバンド信号と、τ×δだけ後の時点におけるベースバンド信号との相互相関に応じた値である。そのため、Ｄ_i（τ）が大きい値である時点τには、電力の大きい遅延波が存在することになる。したがって、このＤ_i（τ）は、遅延プロファイルに準ずる評価量となる。例えば、Ｄ_i（τ）は、図７で示されるようになる。なお、上式において、Ｎ＝２の場合には、異なるＲＦ回路１３によって変換された２個のベースバンド信号を用いてマルチパス情報が算出されることになる。一方、Ｎ≧３の場合には、異なるＲＦ回路１３によって変換された２個のベースバンド信号を用いて、その２個のベースバンド信号に応じた相互相関（上記Ｅ［ｒ_i ^(u)(n)ｒ_i ^(v)*(n−τ)］）が算出され、それをＲＦ回路１３の異なるペアについて足しあわせて絶対値をとることによって、最終的なマルチパス情報が算出されることになる。 The multipath information calculation unit 15 uses the two or more baseband signals converted by the different RF circuits 13 to calculate multipath information that is information regarding the power of the delayed wave. Specifically, the multipath information calculation unit 15 calculates the evaluation amount D _i (τ) according to the delay profile as in the following equation, and acquires the multipath information using the evaluation amount. Good. Note that τ is an integer satisfying 1 ≦ τ ≦ L ₁ and is an index indicating a sample delay amount in AD conversion. The delay time is τ × δ obtained by multiplying τ by the sampling period δ. L ₁ is a predetermined integer greater than 1. The multipath information calculation unit 15 calculates D _i (τ) for each τ of 1 ≦ τ ≦ L ₁ .

Incidentally, the above equation right side ^{_{E [r i (u) (}} n) r i (v) * (n-τ)] is, E was used to calculate the received power ^{_{[r i (u) (n}} ) r in the formula of ^{_{i (v) * (n)}} ], in which ^{_{r i (v) * (n}} ), the n of ^{_{r i (v) * (n}} -k) and the n-τ. D _i (0) is represented by the following equation, and is a value corresponding to the received power at a certain time.

D _i (τ) is a value corresponding to the cross-correlation between the baseband signal at that time point and the baseband signal at a time point later by τ × δ. Therefore, there is a delayed wave with a large power at a time τ where D _i (τ) is a large value. Therefore, this D _i (τ) is an evaluation amount according to the delay profile. For example, D _i (τ) is as shown in FIG. In the above equation, when N = 2, multipath information is calculated using two baseband signals converted by different RF circuits 13. On the other hand, in the case of N ≧ 3, two baseband signals converted by different RF circuits 13 are used, and a cross-correlation (the above E [r _i ^(u) ( n) r _i ^{(v) *} (n−τ)]) is calculated and added to the different pairs of the RF circuit 13 to obtain an absolute value, whereby the final multipath information is calculated. Become.

また、マルチパス情報算出部１５は、電力の大きい遅延波があるかどうかや、短い遅延時間の遅延波があるかどうかを知ることができる、上述した以外の値を、マルチパス情報としてもよいことは言うまでもない。 The multipath information calculation unit 15 may use the D _i (τ) (1 ≦ τ ≦ L ₁ ) as multipath information. As will be described later, what is necessary in the server 2 is whether or not there is a delayed wave with a large power and whether or not there is a delayed wave with a short delay time. Therefore, the multipath information calculation unit 15 uses, for example, a value of D _i (τ) exceeding a predetermined threshold as information indicating the power of the delayed wave having a large power and the delay time of the delayed wave, τ may be multipath information. Note that the multipath information may be information indicating the power of a delayed wave with high power, or may be information indicating the delay time of a delayed wave with high power. In addition, whether there is a delayed wave with a large power can be determined by whether the value of the following equation is large. Therefore, the multipath information calculation unit 15 may calculate multipath information that is a value of the following equation. The value of the following equation is the total power ratio of the delayed wave to the first wave power (normalized delayed wave total power). Hereinafter, the PD _i may be referred to as delay wave total power.

In addition, the multipath information calculation unit 15 may determine whether there is a delayed wave with a large power or whether there is a delayed wave with a short delay time as a value other than those described above as multipath information. Needless to say.

Here, the merit of calculating received power and multipath information as described above will be described. When calculating the reception power and multi-path information as described above, for ^{_{example, E [r i (u)}} (n) r i (v) * (n)] in the ^{_{r i (u) (n)}} r i ^{(v) * As shown in} (n), two baseband signals which are outputs of different RF circuits 13 are used. As such, by calculating the correlation of the output of another RF circuit 13, the noise is decorrelated, and the received power and multipath information are calculated in a situation where the received power is low (SNR <0). Even in such a case, calculation with high accuracy can be performed. In particular, since the noise included in the baseband signal is the largest due to the RF circuit 13, the ability to decorrelate the noise related to the RF circuit 13 greatly contributes to noise reduction. When there are three or more RF circuits 13, as described above, the cross-correlation using the two baseband signals that are the outputs of the different RF circuits 13 is summed for the pair of RF circuits 13. Thus, the result is substantially the same as increasing the number of samples. Therefore, it is possible to calculate received power and multipath information with high accuracy. When calculating the reception power or the like by using only one RF circuit, as can be seen from the above equation, but only N _a number of addition is performed, the two, which is the output of the different RF circuit 13 When the cross-correlation using the baseband signal is summed for all the pairs of the RF circuits 13, the number of combinations according to the number obtained by multiplying N _a by the number of combinations _N C ₂ for selecting 2 from N is added. Will be performed, and the accuracy will increase accordingly. If the number of additions exceeds N _a , it is considered that the accuracy is higher than when only at least one RF circuit is used. Therefore, when the receiving apparatus 1 has N RF circuits 13, RF It is not necessary to sum the cross-correlation for all pairs of circuits 13. For example, reception power and multipath information may be calculated by adding cross-correlation for two or more pairs of RF circuits 13.

  The transmission unit 16 transmits a plurality of baseband signals respectively converted by the plurality of RF circuits 13 to the server 2. Note that the plurality of baseband signals are usually baseband signals corresponding to the same period. In addition, the transmission unit 16 transmits the reception power calculated by the reception power calculation unit 14 to the server 2. Further, the transmission unit 16 transmits the multipath information calculated by the multipath information calculation unit 15 to the server 2. The transmission unit 16 may transmit the N baseband signals, the reception power, and the multipath information together to the server 2 or may transmit them separately. In the present embodiment, the former case will be mainly described. In the former case, the baseband signal to be transmitted and the baseband signal used for calculating received power and multipath information may or may not be the same. . Further, when the baseband signal, the received power, etc. are separately transmitted to the server 2, for example, the transmission unit 16 first transmits the received power and the multipath information to the server 2, and according to the transmission, The baseband signal may be transmitted to the server 2 when a baseband signal transmission request is received by a receiving unit (not shown). In such a case, the baseband signal to be transmitted is usually different from the baseband signal used for calculating received power and multipath information.

  The transmission unit 16 may directly transmit a plurality of baseband signals or the like to the server 2 or may indirectly transmit them via another server or the like. Further, the transmission unit 16 may perform transmission by using an address held by a recording medium (not shown) as a transmission destination. Further, the transmission unit 16 may or may not include a transmission device (for example, a modem or a network card) for performing transmission. The transmission unit 16 may be realized by hardware, or may be realized by software such as a driver that drives the transmission device.

  In addition, since the baseband signals transmitted from the plurality of receiving apparatuses 1 to the server 2 are used to calculate the arrival time difference of radio waves as described later, it is preferable that they are synchronized. That is, it is preferable that a plurality of baseband signals corresponding to radio waves at the same time are transmitted from three or more receiving apparatuses 1 to the server 2. Therefore, for example, each receiving device 1 may synchronize timing using GPS (Global Positioning System) time, or may synchronize timing using an optical fiber or the like connecting a plurality of receiving devices 1.

  In FIG. 2, only the characteristic components of the receiving apparatus 1 according to the present embodiment are shown, but it goes without saying that the receiving apparatus 1 may include other components. For example, a baseband unit or a processing unit that performs processing related to a received signal may exist after the RF circuit 13.

  FIG. 3 is a block diagram showing a configuration of the server 2 according to the present embodiment. The server 2 calculates the position of the wave source 3 using the arrival time difference of radio waves from the wave source 3 to the receiving device 1. The server 2 receives the reception unit 21, the received power acquisition unit 22, and the multipath information acquisition unit 23. , A selection unit 24, an arrival time difference calculation unit 25, a wave source position calculation unit 26, and an output unit 27.

  The receiving unit 21 receives a plurality of baseband signals transmitted from the receiving device 1. The receiving unit 21 receives a plurality of baseband signals from three or more receiving devices 1. The receiving unit 21 may or may not receive baseband signals from all the receiving devices 1 included in the communication system 10. In the latter case, for example, the baseband signal may be received only from the reception device 1 selected by the selection unit 24 described later. In that case, the transmission amount of information can be reduced as compared with the case where all the receiving apparatuses 1 transmit baseband signals.

  The receiving unit 21 may or may not include a wired or wireless receiving device (for example, a modem or a network card) for receiving. The receiving unit 21 may be realized by hardware, or may be realized by software such as a driver that drives the receiving device.

  The reception power acquisition unit 22 acquires reception power calculated using two or more baseband signals converted by different RF circuits 13 for each of the four or more reception devices 1. The reception power may be obtained by receiving the reception power calculated in the reception device 1 from the reception device 1 or by using a plurality of baseband signals transmitted from the reception device 1. The power may be calculated. In the latter case, the reception power acquisition unit 22 calculates reception power corresponding to each reception device 1 using a plurality of baseband signals respectively received by the reception unit 21 from four or more reception devices 1. Also good. The reception power calculation method is the same as the reception power calculation method performed by the reception power calculation unit 14, and a description thereof will be omitted. In the present embodiment, the case where the reception power acquisition unit 22 receives reception power from each of four or more reception devices 1 will be mainly described.

  When receiving received power, the received power acquiring unit 22 may or may not include a wired or wireless receiving device (for example, a modem or a network card) for receiving. The reception power acquisition unit 22 may be realized by hardware, or may be realized by software such as a driver that drives the reception device.

  The multipath information acquisition unit 23 is information on delay wave power calculated using two or more baseband signals converted by different RF circuits 13 for each of the four or more receiving apparatuses 1. Get path information. The acquisition of the multipath information may be to receive the multipath information calculated in the receiving device 1 from the receiving device 1 or using a plurality of baseband signals transmitted from the receiving device 1. Multipath information may be calculated. In the latter case, the multipath information acquisition unit 23 calculates multipath information corresponding to each receiving device 1 using a plurality of baseband signals received by the receiving unit 21 from four or more receiving devices 1, respectively. May be. The method of calculating the multipath information is the same as the method of calculating the multipath information by the multipath information calculation unit 15, and the description thereof is omitted. In the present embodiment, the case where the multipath information acquisition unit 23 receives multipath information from each of four or more receiving apparatuses 1 will be mainly described.

  When receiving multipath information, the multipath information acquisition unit 23 may or may not include a wired or wireless receiving device (for example, a modem or a network card) for reception. Good. Further, the multipath information acquisition unit 23 may be realized by hardware, or may be realized by software such as a driver that drives the receiving device.

  In addition, when the received power acquisition unit 22 and the multipath information acquisition unit 23 receive received power and receive multipath information, for example, the server 2 includes a plurality of baseband signals, received power, and multipath. When information including information is received from the receiving device 1, among the information, a plurality of baseband signals are received by the receiving unit 21, received power is received by the received power acquiring unit 22, and multipath information is It may be considered that the path information acquisition unit 23 receives the information. In that case, for example, the three components may be considered to be physically configured as one receiving means.

  The selection unit 24 selects three or more receiving apparatuses 1 from the four or more receiving apparatuses 1 by using at least one of reception power and multipath information regarding each of the four or more receiving apparatuses 1. A plurality of baseband signals corresponding to the received signals received by the three or more selected receiving apparatuses 1 are used for calculating the position of the wave source 3.

  The selection unit 24 may select, for example, three or more reception devices 1 with large reception power acquired by the reception power acquisition unit 22, and the delay indicated by the multipath information acquired by the multipath information acquisition unit 23. Three or more receiving apparatuses 1 that are less affected by waves may be selected, or three or more receiving apparatuses 1 that have higher received power and are less affected by delayed waves indicated by multipath information may be selected. .

  Selecting three or more receiving devices 1 with large received power may be, for example, selecting a predetermined number (usually three or more) of receiving devices 1 from the one with larger received power. Of course, the receiving device 1 may be selected in a predetermined ratio from the one having the larger received power, or the receiving device 1 having the received power larger than the threshold may be selected. The threshold value may be determined according to the maximum value of the received power. For example, the threshold value may be a value obtained by multiplying the maximum value of the received power by a value smaller than 1, or a value obtained by subtracting a predetermined positive value from the maximum value of the received power. In addition, when less than three receiving apparatuses 1 are selected by the selection, the selection unit 24, for example, in order from the largest reception power so that the number of the selected receiving apparatuses 1 is at least three. In addition, additional selections may be made.

To select three or more receiving apparatuses 1 that are less affected by the delayed wave indicated by the multipath information, for example, the maximum power of the delayed wave (for example, the maximum value of D _i (τ)) is set for each receiving apparatus 1. It is also possible to specify and select a predetermined number of receiving apparatuses 1 from the one with the smallest maximum power of the delayed wave, and receive a predetermined ratio from the one with the smallest maximum power of the delayed wave. The device 1 may be selected, or the receiving device 1 may be selected such that the maximum power of the delayed wave is smaller than the threshold value regarding the maximum power of the delayed wave. This is because, when the maximum power of the delay wave is small in the delay profile, it can be considered that the influence of the delay wave included in the delay profile is small. The threshold value may be determined according to the minimum value of the maximum power of the delayed wave. For example, the threshold value may be a value obtained by multiplying the minimum value of the maximum power of the delayed wave by a value greater than 1, and a predetermined positive value is added to the minimum value of the maximum power of the delayed wave. There may be. Further, when less than three receiving apparatuses 1 are selected by the selection, the selection unit 24 sets the maximum power of the delayed wave so that, for example, at least three receiving apparatuses 1 are selected. Additional selections may be made in order from the smallest.

The selection of three or more receivers 1 that are less affected by the delayed wave indicated by the multipath information means that, for example, a predetermined number of receivers 1 having a smaller delay wave total power (for example, PD _i ) are determined in advance. The receiving device 1 may be selected, or a predetermined proportion of the receiving devices 1 may be selected from the smaller delayed wave total power, and the delayed wave total power may be selected as the delayed wave total power. It is also possible to select a receiving device 1 that is smaller than the threshold for This is because if the delay wave total power is small in the delay profile, it can be considered that the influence of the delay wave included in the delay profile is small. Note that the threshold may be determined according to the minimum value of the total delay wave power. In addition, when less than three receiving apparatuses 1 are selected by the selection, the selection unit 24, for example, has a smaller delay wave total power so that at least three receiving apparatuses 1 are selected. In order, additional selections may be made.

In addition, the selection of three or more receiving apparatuses 1 that are less affected by the delayed wave indicated by the multipath information means that, for example, for each receiving apparatus 1, the minimum delay time of the delayed wave (for example, D _i (exceeding a predetermined threshold) The minimum value of τ) according to τ) is specified, and a predetermined number of receiving devices 1 may be selected from the one with the smallest minimum delay time, or may be decided in advance from the one with the smallest minimum delay time. It is possible to select a certain percentage of the receiving apparatuses 1, or to select the receiving apparatuses 1 whose minimum delay time is smaller than a threshold for the minimum delay time. This is because, in the delay profile, when the minimum delay time of a delayed wave with large power is small, it can be considered that the error of the estimated arrival time difference caused by the influence of the delayed wave is small. The threshold value may be determined according to the minimum value of the minimum delay time. Further, when less than three receiving apparatuses 1 are selected by the selection, the selecting unit 24 starts from the one with the smallest minimum delay time so that, for example, at least three receiving apparatuses 1 are selected. In order, additional selections may be made.

  The selection of three or more receiving apparatuses 1 that are less affected by the delayed wave indicated by the multipath information means that, for example, the delayed wave is used by using both the maximum power of the delayed wave and the minimum delay time of the delayed wave. It is also possible to select the receiving apparatus 1 having a small maximum power and a minimum delay time of the delayed wave.

  The arrival time difference calculation unit 25 calculates the arrival time difference of the radio wave from the wave source 3 using the cross-correlation for a plurality of combinations of a plurality of baseband signals for the pair of the receiving devices 1. That is, the arrival time difference calculation unit 25 includes a plurality of first baseband signals of the first receiving device 1 and a second receiving device for a pair of the first receiving device 1 and the second receiving device 1. The arrival time difference using the cross-correlation is calculated by adding the cross-correlations corresponding to a plurality of combinations with a plurality of one second baseband signals. The arrival time difference is a difference between the propagation time of the radio wave from the wave source 3 to the first receiving device 1 and the propagation time of the radio wave from the wave source 3 to the second receiving device 1. Specifically, the arrival time difference calculation unit 25 may calculate the arrival time difference as in the following equation.

First, the arrival time difference calculating unit 25 calculates a cross-correlation C _ij (τ) related to a pair of the i-th receiving device 1 and the j-th receiving device 1. As shown in the following equation, the cross-correlation indicates that the baseband signal r _i ^(u) (n) of the i-th receiver 1 and the baseband signal r _j ^{( v)} It is calculated for the combination with (n−τ).

Here, N _i is the number of RF circuits 13 included in the i-th receiving device 1. Moreover, τ is an integer that satisfies −L ₂ ≦ τ ≦ L ₂ . L ₂ is a predetermined positive integer. ^{_{Also, E [r i (u)}} (n) r j (v) * (n-τ)] is as follows.

In the above equation, N _b is the number of samples for calculating the correlation. The N _b may be the same as or different from the aforementioned N _a . The arrival time difference calculation unit 25 calculates the arrival time difference | τ _ij ^(max) | using the above-described cross-correlation C _ij (τ) as shown in the following equation. That is, the time difference τ at which the cross-correlation peaks is taken as the arrival time difference. Strictly speaking, δ | τ _ij ^(max) | obtained by multiplying | τ _ij ^(max) | by the sampling period δ is an arrival time difference in units of time.

Here, the merit of calculating the arrival distance difference as described above will be described. When calculating the arrival time difference as described above, the baseband signal of the i-th receiving device 1 and the baseband signal of the j-th receiving device 1, for example, as shown by the formula of C _ij above. The correlation will be summed for multiple pairs of that baseband signal. By such a summation, the number of samples is substantially equal to N _i N _j times. Therefore, for example, even if the number of samples of the baseband signal for calculating the arrival distance difference is 1 / (N _i N _j ), the baseband received by the two receiving apparatuses 1 having only one RF circuit. The arrival distance difference can be calculated with the same degree of accuracy as when the arrival distance difference is calculated using the signal. Therefore, when the number of samples of the baseband signal is the same as in the case of one RF circuit, the arrival distance difference can be calculated with high accuracy. Also, when the number of samples of the baseband signal is larger than the value obtained by multiplying the number of samples of one RF circuit by 1 / (N _i N _j ), the accuracy is improved while reducing the number of samples. can do. In the above description, when the cross-correlation is calculated with the baseband signal of the i-th receiving device 1 and the baseband signal of the j-th receiving device 1, the cross-correlations for all combinations of the baseband signals are summed up. Although the case has been described, this need not be the case. When calculating the cross-correlation between the baseband signal of the i-th receiving apparatus 1 and the baseband signal of the j-th receiving apparatus 1, cross-correlations regarding at least a plurality of combinations may be added. This is because even in that case, the accuracy is improved as compared with the case of one RF circuit using the same number of samples.

  The arrival time difference calculation unit 25 may calculate the arrival time difference for all pairs of the three or more receiving apparatuses 1 used for calculating the position of the wave source 3, and at least two of the pairs are calculated. The arrival time difference may be calculated for the pairs, preferably for three or more pairs. Moreover, the arrival time difference calculation unit 25 may calculate the arrival time differences only for a plurality of pairs of the selected three or more receiving apparatuses 1.

  The wave source position calculating unit 26 calculates the position of the wave source 3 using the position of the receiving device 1 and the arrival time difference calculated by the arrival time difference calculating unit 25 for each of a plurality of pairs of the receiving device 1. Note that the position of the receiving device 1 is the position of the receiving device 1 included in the set of a plurality of pairs of the receiving device 1 for which the arrival time difference is calculated. The position of the receiving device 1 may be, for example, latitude / longitude, or a coordinate value with a certain position as a reference point. The positions of the plurality of receiving apparatuses 1 are stored in a recording medium (not shown) that can be accessed by the wave source position calculating unit 26. Specifically, the wave source position calculation unit 26 may calculate the position of the wave source 3 as follows.

First, the wave source position calculation unit 26 uses the arrival time difference to determine the arrival distance difference Δd that is the difference between the distance from the wave source 3 to the i-th receiver 1 and the distance from the wave source 3 to the j-th receiver 1. Calculate _ij . The arrival distance difference Δd _ij is expressed by the following equation. In the following equation, χ is the speed of light.

Although it is already known that the position of the wave source 3 is identified using the arrival distance differences for a plurality of pairs of the receiving device 1, the wave source position calculating unit 26 calculates the position of the wave source as follows, for example. Also good.

ここで、Δｄ_m ^eは、上述のようにして算出された到来距離差である。また、Δｄ_m(Ｓ)は、次式で示されるように、位置座標から算出される到来距離差である。なお、Ｓ_iは、ｉ番目の受信装置１の位置座標である。

Here, ^Se is an estimated wave source position coordinate, which is a calculation target of the wave source position calculation unit 26. m is a combination of ij, that is, an index of the receiving device 1 constituting a pair of the receiving device 1, and M is a total number of pairs of the receiving device 1. S is a wave source position coordinate, and | e _m (S) | ² is as follows.

Here, Δd _m ^e is the arrival distance difference calculated as described above. Further, Δd _m (S) is an arrival distance difference calculated from position coordinates, as shown by the following equation. Note that S _i is the position coordinate of the i-th receiving device 1.

The wave source position calculation unit 26 may calculate the estimated wave source position coordinates ^Se by, for example, the nonlinear least square method, or may calculate by other methods. When the selection of the receiving device 1 is performed by the selection unit 24, the wave source position calculation unit 26 uses the arrival time differences calculated for each of a plurality of pairs of the selected three or more receiving devices 1. The position of the wave source 3 may be calculated. For example, as described above, when arrival time differences are calculated only for a plurality of pairs of three or more selected receiving apparatuses 1, the wave source position calculation unit 26 uses all the calculated arrival time differences. By calculating the position of the wave source 3, the wave source position is calculated using the arrival time differences calculated for each of a plurality of pairs of the three or more selected receiving apparatuses 1. On the other hand, when the arrival time differences are calculated for all the pairs of the receiving devices 1, the wave source position calculating unit 26 selects the plurality of pairs of the three or more selected receiving devices 1 among the calculated arrival time differences. The wave source position may be calculated using the arrival time difference calculated in (1).

ここで、α_mは、次式で示されるものであり、受信装置１のペアに対応する２個の受信電力に応じた重みである。なお、次式において、Ｎ_sは、波源３の位置の算出に用いられる受信装置１の個数であり、例えば、選択部２４によって選択された受信装置１の個数であってもよい。

すなわち、波源位置算出部２６は、受信装置１のペアの到来時間差（例えば、｜ｅ_m(Ｓ)｜^２に含まれるΔｄ_m ^e＝χδ｜τ_ij ^(max)｜）を、その受信装置１のペア（例えば、ｉｊ）に対応する２個の受信電力（例えば、Ｐ_iＰ_j）に応じた重み（例えば、α_m）と共に用いて波源３の位置を算出してもよい。なお、上述した以外の方法によって、波源位置算出部２６は、受信装置１のペアの到来時間差を、その受信装置１のペアに対応する２個の受信電力（に応じた重みと共に用いて波源３の位置を算出してもよいことは言うまでもない。 Moreover, the wave source position calculation section 26, when calculating the estimated wave source position coordinates S ^e, using the weight corresponding to the received power of the reception power acquisition unit 22 has acquired, it may be carried out the calculation. Specifically, the equation of the estimated wave source coordinates S ^e, it may be the following equation.

Here, α _m is expressed by the following equation, and is a weight according to the two received powers corresponding to the pair of the receiving device 1. In the following equation, N _s is the number of receiving apparatuses 1 used for calculating the position of the wave source 3, and may be the number of receiving apparatuses 1 selected by the selection unit 24, for example.

That is, the wave source position calculation section 26, the arrival time difference between the receiving apparatus 1 pair _{(e.g., | e m (S) |} 2 to Δd _m ^e = χδ included | τ _ij ^{(max) |),} and the reception apparatus 1 The position of the wave source 3 may be calculated using a weight (for example, α _m ) corresponding to two received powers (for example, P _i P _j ) corresponding to a pair (for example, ij). Note that the wave source position calculation unit 26 uses a method other than the above to use the difference in arrival time of the pair of the receiving device 1 together with the two received powers corresponding to the pair of the receiving device 1 (the wave source 3 It goes without saying that the position of may be calculated.

  The output unit 27 outputs the position of the wave source 3 calculated by the wave source position calculating unit 26. Here, the output may be, for example, display on a display device (for example, a CRT or a liquid crystal display), transmission via a communication line to a predetermined device, printing by a printer, or output to a recording medium. It may be accumulated or transferred to another component (for example, a component that calculates white space). The output unit 27 may or may not include an output device (for example, a display device or a printer). Further, the output unit 27 may be realized by hardware, or may be realized by software such as a driver that drives these devices.

  Next, the operation of the receiving apparatus 1 will be described using the flowchart of FIG. In this flowchart, operations of the reception power calculation unit 14, the multipath information calculation unit 15, and the transmission unit 16 will be described. The reception of radio waves by the antenna 11, distribution of received signals by the distributor 12, conversion of received signals distributed by the RF circuit 13 into baseband signals, etc. are performed separately from the flowchart shown in FIG. And

  (Step S <b> 101) The transmission unit 16 determines whether to acquire a plurality of baseband signals that are outputs of the plurality of RF circuits 13. If a plurality of baseband signals are acquired, the process proceeds to step S102. If not, the process of step S101 is repeated until it is determined to acquire. For example, the transmission unit 16 may determine to acquire a plurality of baseband signals when a predetermined timing synchronized between the plurality of reception devices 1 is reached.

  (Step S <b> 102) The transmission unit 16 acquires a baseband signal having a predetermined length from each of the plurality of RF circuits 13. The acquired plurality of baseband signals may be stored in a recording medium (not shown).

  (Step S103) The received power calculation unit 14 calculates received power using a plurality of baseband signals acquired by the transmission unit 16.

  (Step S <b> 104) The multipath information calculation unit 15 calculates multipath information using a plurality of baseband signals acquired by the transmission unit 16.

(Step S105) The transmission unit 16 transmits the plurality of baseband signals acquired in Step S102, the received power calculated in Step S103, and the multipath information calculated in Step S104 to the server 2. Then, a series of processes for transmitting a baseband signal or the like to the server 2 is completed.
Note that the order of processing in the flowchart of FIG. 4 is an example, and the order of the steps may be changed as long as similar results can be obtained.

  Next, the operation of the server 2 will be described using the flowchart of FIG. In this flowchart, it is assumed that the server 2 receives a plurality of baseband signals and the like from four or more receiving apparatuses 1.

  (Step S201) Each of the reception unit 21, the reception power acquisition unit 22, and the multipath information acquisition unit 23 determines whether or not a plurality of baseband signals, reception power, and multipath information transmitted from the reception device 1 have been received. If received, the process proceeds to step S202, and if not, the process proceeds to step S203.

  (Step S202) The receiving unit 21 and the like accumulate a plurality of received baseband signals and the like in a recording medium (not shown). Note that when the plurality of baseband signals and the like are stored, they may be stored in association with a receiving device identifier for identifying the receiving device 1 that is the transmission source. The receiving device identifier may be, for example, the address of the receiving device 1.

  (Step S203) The arrival time difference calculation unit 25 determines whether to calculate the position of the wave source 3. And when performing the calculation, it progresses to step S204, and when that is not right, it returns to step S201. Note that the arrival time difference calculation unit 25 may determine to calculate the position of the wave source 3 when, for example, baseband signals and the like are received from all the reception devices 1, or in each reception device 1, It may be determined that the position of the wave source 3 is calculated when a predetermined period has elapsed since the timing for acquiring a plurality of baseband signals.

  (Step S204) The selection unit 24 selects three or more receiving apparatuses 1 from the four or more receiving apparatuses 1 that have transmitted a plurality of baseband signals. Details of this processing will be described later with reference to a flowchart of FIG. 6A and the like.

  (Step S205) The arrival time difference calculation unit 25 calculates the arrival time differences for a plurality of pairs of the plurality of receiving apparatuses 1 selected by the selection unit 24, respectively.

  (Step S206) The wave source position calculation unit 26 calculates the position of the wave source 3 using the plurality of arrival time differences calculated in step S205.

  (Step S207) The output unit 27 outputs the position of the wave source 3 calculated in Step S206. And a series of processes which calculate the position of the wave source 3 are complete | finished.

FIG. 6A is a flowchart showing details of the selection process (step S204) in the flowchart of FIG. 5, and is a flowchart showing the selection process using received power.
(Step S301) The selection unit 24 sorts the reception power for each reception device acquired by the reception power acquisition unit 22 in descending order of reception power.

(Step S302) The selection unit 24 determines whether the third received power after sorting, that is, the third received power from the larger one is smaller than a predetermined threshold P _{TH of} received power. If the third received power is smaller than the threshold value P _TH , the process proceeds to step S303, and if not, the process proceeds to step S304.

  (Step S303) The selection unit 24 selects the receiving device 1 corresponding to the first to third received power. Then, the process returns to the upper flowchart.

  (Step S304) The selection unit 24 sets the counter i to 4.

(Step S305) The selection unit 24 determines whether or not the i-th received power is smaller than the threshold value P _TH . If the i-th received power is smaller than the threshold value P _TH , the process proceeds to step S306. Otherwise, the process proceeds to step S307.

  (Step S306) The selection unit 24 selects the receiving device 1 corresponding to the first to (i−1) th received power. Then, the process returns to the upper flowchart.

  (Step S307) The selection unit 24 increments the counter i by one.

  (Step S308) The selection unit 24 determines whether or not the i-th received power exists. If the i-th received power is present, the process returns to step S305. If not, the process proceeds to step S306.

In the flowchart of FIG. 6A, the receiving device 1 corresponding to the received power larger than the threshold value P _TH is selected, and when there are not three such receiving devices 1, the three receiving devices with the highest received power are used. However, it is needless to say that the selection of the receiving device 1 may be performed by another method. In the flowchart of FIG. 6A, an upper limit may be provided for the number of receiving apparatuses 1 to be selected.

FIG. 6B is a flowchart showing details of the selection process (step S204) in the flowchart of FIG. 5, and is a flowchart showing the selection process using multipath information. In this flowchart, the case where the multipath information is delay wave total power will be described.
(Step S401) The selection unit 24 sorts the delayed wave total power, which is the multipath information for each receiving device 1 acquired by the multipath information acquisition unit 23, in ascending order of the delayed wave total power.

(Step S402) selector 24, the third delayed wave total power after sorting, i.e., the third delayed wave total power from the smaller, if the threshold value PD or _TH is greater than the predetermined delayed wave total power to decide. When the third delayed wave total power is greater than the threshold value PD _TH, the process proceeds to step S403, otherwise, the process proceeds to step S404.

  (Step S403) The selection unit 24 selects the receiving device 1 corresponding to the total delay wave power from the first to the third. Then, the process returns to the upper flowchart.

  (Step S404) The selection unit 24 sets the counter j to 4.

(Step S405) selector 24, j-th delayed wave total power, to determine if the threshold value PD or _TH larger. If the j-th received power is greater than the threshold value PD _TH , the process proceeds to step S406. Otherwise, the process proceeds to step S407.

  (Step S406) The selection unit 24 selects the receiving apparatus 1 corresponding to the total delay wave power from the first to the (j-1) th. Then, the process returns to the upper flowchart.

  (Step S407) The selection unit 24 increments the counter j by 1.

  (Step S408) The selection unit 24 determines whether or not the j-th delay wave total power exists. If the j-th delayed wave total power is present, the process returns to step S405. If not, the process proceeds to step S406.

In the flowchart of FIG. 6B, the receiving device 1 corresponding to the delayed wave total power smaller than the threshold value PD _TH is selected, and when there are no three such receiving devices 1, the delayed wave total power is small. Although the case where three receiving devices 1 are selected from the above has been described, it goes without saying that the receiving device 1 may be selected by another method. In the flowchart of FIG. 6B, an upper limit may be provided for the number of receiving apparatuses 1 to be selected.

In addition, when performing selection using both received power and multipath information, the selection unit 24 may use, for example, a merged result of the selection of both. Further, for example, as shown in FIG. 6C, a final selection result may be obtained by further narrowing down the selection results of both.
(Step S501) The selection unit 24 selects the receiving device 1 using the received power. The process may be performed as shown in the flowchart of FIG. 6A, for example.

  (Step S502) The selection unit 24 selects the receiving device 1 using multipath information. The processing may be performed as shown in the flowchart of FIG. 6B, for example.

  (Step S503) The selection unit 24 includes three or more overlaps in three or more receiving apparatuses 1 selected using received power and three or more receiving apparatuses 1 selected using multipath information. Determine whether exists. If three or more overlaps exist, the process proceeds to step S504, and if not, the process proceeds to step S505.

  (Step S504) The selection unit 24 selects three or more receiving apparatuses 1 selected using received power and three or more receiving apparatuses 1 selected using multipath information. The receiving device 1 is set as a final selection result. Then, the process returns to the upper flowchart.

  (Step S505) The selection unit 24 receives three or more receiving devices 1 selected using the received power and three or more receiving devices 1 selected using the multipath information. And the receiving apparatus with large received power is selected so that the number of receiving apparatuses 1 as a selection result is three. That is, when the number of receiving apparatuses 1 that overlaps three or more receiving apparatuses 1 selected using received power and three or more receiving apparatuses 1 selected using multipath information is Q. (Q is an integer of 0 to 2), from the selection result of step S501, select 3-Q reception devices 1 in descending order of reception power, and the reception device 1 of the selection result, and A receiving device 1 that overlaps with three or more receiving devices 1 selected using received power and three or more receiving devices 1 selected using multipath information is set as a final selection result. Then, the process returns to the upper flowchart.

  In the flowchart of FIG. 6C, when there are no three or more overlaps between the selection result using the received power and the selection result using the multipath information, the reception device 1 is the final selection result. Although the case where additional selection is performed based on the selection result of the reception power has been described so that the number of is three, this need not be the case. You may make it perform additional selection from the selection result of multipath information.

  As described above, according to the communication system 10 according to the present embodiment, each receiving apparatus 1 acquires a plurality of baseband signals by using a plurality of RF circuits 13, and a plurality of combinations of the plurality of baseband signals. By calculating the arrival time difference by calculating the corresponding cross-correlation, the number of samples used in calculating the arrival time difference can be increased. Therefore, the noise included in the baseband signal is decorrelated, and the calculation accuracy of the arrival time difference is improved. As a result, the calculation accuracy of the position of the wave source 3 is also improved. Compared to the case of using one baseband signal converted by one RF circuit, the arrival time difference can be calculated with the same or higher accuracy even if the baseband signal has a shorter reception time. Therefore, the position of the wave source 3 that does not always transmit radio waves can be calculated more accurately. Further, by calculating reception power and multipath information using a plurality of baseband signals, it is possible to calculate reception power and the like with higher accuracy. In addition, by using such highly accurate received power and selecting the receiving device 1 used for calculating the position of the wave source 3, it is possible to calculate the arrival time difference by eliminating the receiving device 1 having a poor reception state. It becomes like this. In addition, when the cross-correlation is calculated for calculating the arrival time difference by selecting the receiving apparatus 1 used for calculating the position of the wave source 3 using such highly accurate multipath information, It is possible to eliminate the multi-path receiving apparatus 1 that peaks at different times. As a result, the position of the wave source 3 can be calculated more accurately.

  In the present embodiment, a case has been described in which the reception apparatus 1 performs both reception power calculation and multipath information calculation. However, this need not be the case. Either one may be performed or both may not be performed. When the reception power is not calculated, the reception device 1 may not include the reception power calculation unit 14. In addition, when the multipath information is not calculated, the reception device 1 may not include the multipath information calculation unit 15.

In the present embodiment, a case has been described in which the server 2 performs both reception power acquisition and multipath information acquisition. However, this need not be the case. Either one may be performed or both may not be performed. When the reception power is not acquired, the server 2 may not include the reception power acquisition unit 22. In addition, when the multipath information is not acquired, the server 2 may not include the multipath information acquisition unit 23. When neither acquisition is performed, the server 2 may not include the selection unit 24. Even when the received power is acquired, when the received power is used only for the weight (for example, α _m described above) when calculating the position of the wave source 3, the server 2 selects the selection unit 24. May not be provided.

  In the above embodiment, each process or each function may be realized by centralized processing by a single device or a single system, or may be distributedly processed by a plurality of devices or a plurality of systems. It may be realized by doing.

  In the above embodiment, the information exchange between the components is performed by one component when, for example, the two components that exchange the information are physically different from each other. It may be performed by outputting information and receiving information by the other component, or when two components that exchange information are physically the same, one component May be performed by moving from the phase of the process corresponding to to the phase of the process corresponding to the other component.

  In the above embodiment, information related to processing executed by each component, for example, information received, acquired, selected, generated, transmitted, or received by each component In addition, information such as threshold values, mathematical formulas, addresses, and the like used by each constituent element in processing may be temporarily or for a long time held in a recording medium (not shown), even if not specified in the above description. Further, the storage of information on the recording medium (not shown) may be performed by each component or a storage unit (not shown). Further, reading of information from the recording medium (not shown) may be performed by each component or a reading unit (not shown).

  In the above embodiment, when information used by each component, for example, information such as a threshold value, an address, and various setting values used by each component may be changed by the user, Even if it is not specified in the description, the user may be able to change the information as appropriate, or may not be so. If the information can be changed by the user, the change is realized by, for example, a not-shown receiving unit that receives a change instruction from the user and a changing unit (not shown) that changes the information in accordance with the change instruction. May be. The change instruction received by the receiving unit (not shown) may be received from an input device, information received via a communication line, or information read from a predetermined recording medium, for example. .

  In the above embodiment, when two or more components included in the receiving device 1 or the server 2 include a communication device or an input device, the two or more components have a physically single device. Or may have separate devices.

  In the above-described embodiment, each component may be configured by dedicated hardware, or a component that can be realized by software may be realized by executing a program. For example, each component can be realized by a program execution unit such as a CPU reading and executing a software program recorded on a recording medium such as a hard disk or a semiconductor memory. At the time of execution, the program execution unit may execute the program while accessing the storage unit or the recording medium. In addition, the software which implement | achieves the receiver 1 in the said embodiment is the following programs. In other words, this program communicates a computer with three or more receiving devices that receive radio waves from a wave source, and a server that calculates the position of the wave source using the arrival time difference of radio waves from the wave source to the receiving device. Each of a plurality of RF circuits that function as a receiving device in the system and convert a plurality of reception signals divided by a distributor that divides a reception signal received by an antenna that receives radio waves from a wave source into baseband signals, respectively. A program for causing a plurality of converted baseband signals to function as a transmission unit that transmits to a server.

  Moreover, the software which implement | achieves the server 2 in the said embodiment is the following programs. In other words, this program uses a computer to divide a received signal that has received radio waves from a wave source into a plurality of signals by a distributor, and convert a plurality of received signals into a plurality of baseband signals by a plurality of RF circuits, respectively. A cross-correlation for a plurality of combinations of a plurality of baseband signals is used for a pair of a receiving unit and a receiving device that function as a server in a communication system including a device and a server and receive a plurality of baseband signals from the receiving device The arrival time difference calculation unit for calculating the arrival time difference of the radio wave from the wave source, the position of the reception device, and the arrival time difference calculated by the arrival time difference calculation unit for each of a plurality of pairs of the reception devices are used to determine the position of the wave source. It is a program for making it function as a wave source position calculation part to calculate.

  In the program, the functions realized by the program do not include functions that can be realized only by hardware. For example, the above program is a function that can be realized only by hardware such as a modem or an interface card in a receiving unit that receives information, a transmitting unit that transmits information, an acquiring unit that acquires information, and an output unit that outputs information. It is at least not included in the functions to be realized.

  Further, this program may be executed by being downloaded from a server or the like, and a program recorded on a predetermined recording medium (for example, an optical disk such as a CD-ROM, a magnetic disk, a semiconductor memory, or the like) is read out. May be executed by Further, this program may be used as a program constituting a program product.

  Further, the computer that executes this program may be singular or plural. That is, centralized processing may be performed, or distributed processing may be performed.

  FIG. 8 is a schematic diagram illustrating an example of an external appearance of a computer that executes the program and realizes the receiving device 1 and the server 2 according to the embodiment. The above-described embodiment can be realized by computer hardware and a computer program executed on the computer hardware.

  In FIG. 8, the computer system 900 includes a computer 901 including a CD-ROM drive 905, a keyboard 902, a mouse 903, and a monitor 904.

  FIG. 9 is a diagram showing an internal configuration of the computer system 900. In FIG. 9, in addition to the CD-ROM drive 905, a computer 901 is connected to an MPU (Micro Processing Unit) 911, a ROM 912 for storing a program such as a bootup program, and the MPU 911, and receives instructions of an application program. A RAM 913 that temporarily stores and provides a temporary storage space, a hard disk 914 that stores application programs, system programs, and data, and a bus 915 that interconnects the MPU 911, the ROM 912, and the like are provided. The computer 901 may include a network card (not shown) that provides connection to a LAN, WAN, or the like.

  A program that causes the computer system 900 to execute the functions of the receiving device 1 and the server 2 according to the above-described embodiment may be stored in the CD-ROM 921, inserted into the CD-ROM drive 905, and transferred to the hard disk 914. Instead, the program may be transmitted to the computer 901 via a network (not shown) and stored in the hard disk 914. The program is loaded into the RAM 913 when executed. The program may be loaded directly from the CD-ROM 921 or the network. Further, the program may be read into the computer system 900 via another recording medium (for example, a DVD) instead of the CD-ROM 921.

  The program does not necessarily include an operating system (OS) or a third-party program that causes the computer 901 to execute the functions of the receiving device 1 and the server 2 according to the above-described embodiment. The program may include only a part of an instruction that calls an appropriate function or module in a controlled manner and obtains a desired result. How the computer system 900 operates is well known and will not be described in detail.

  Further, the present invention is not limited to the above-described embodiment, and various modifications are possible, and it goes without saying that these are also included in the scope of the present invention.

  As described above, according to the communication system and the like according to the present invention, the effect that the position of the wave source can be calculated with higher accuracy is obtained. For example, the calculation of the position of the wave source for acquiring the white space or the wave source of the illegal radio wave is obtained. This is useful as a system for calculating the position.

DESCRIPTION OF SYMBOLS 1 Receiver 2 Server 3 Wave source 10 Communication system 11 Antenna 12 Divider 13, 13-1 to 13-N RF circuit 14 Received power calculator 15 Multipath information calculator 16 Transmitter 21 Receiver 22 Received power acquirer 23 Multi Path information acquisition unit 24 selection unit 25 arrival time difference calculation unit 26 wave source position calculation unit 27 output unit

Claims (12)

A communication system comprising three or more receiving devices that receive radio waves from a wave source and a server,
The receiving device is:
An antenna for receiving radio waves from the wave source;
A distributor for dividing a received signal received by the antenna into a plurality of parts;
A plurality of RF circuits that respectively convert a plurality of received signals divided by the distributor into baseband signals;
A transmission unit that transmits a plurality of baseband signals respectively converted by the plurality of RF circuits to the server;
The server
A receiver that receives a plurality of baseband signals from the receiver;
For two of the receiving device is a pair of the receiving device, by using a plurality of baseband signals of one receiving device, the cross-correlation for a plurality of combinations of a plurality of baseband signals of the other receiver, the 2 Calculating an arrival time difference of radio waves from the wave source related to each of the receiving devices, for an at least two pairs of the receiving devices ;
A wave source position calculating unit that calculates the position of the wave source using the position of the receiving device and the arrival time difference calculated by the arrival time difference calculating unit for each of a plurality of pairs of the receiving devices. system. A receiving device in a communication system, comprising: three or more receiving devices that receive radio waves from a wave source; and a server that calculates a position of the wave source using a time difference of arrival of radio waves from the wave source to the receiving device. And
An antenna for receiving radio waves from the wave source;
A distributor for dividing a received signal received by the antenna into a plurality of parts;
A plurality of RF circuits that respectively convert a plurality of received signals divided by the distributor into baseband signals;
And a transmitter that transmits a plurality of baseband signals respectively converted by the plurality of RF circuits to the server. A reception power calculation unit that calculates reception power using two or more baseband signals converted by different RF circuits;
The receiving device according to claim 2, wherein the transmitting unit also transmits the received power calculated by the received power calculating unit to the server. A multipath information calculating unit that calculates multipath information, which is information on the power of the delayed wave, using two or more baseband signals converted by the different RF circuits;
The receiving device according to claim 2 or 3, wherein the transmitting unit also transmits the multipath information calculated by the multipath information calculating unit to the server. The reception signal received from the wave source is divided into a plurality of signals by a distributor, and each of the plurality of reception signals is converted into a plurality of baseband signals by a plurality of RF circuits, and a server is provided. A server in a communication system,
A receiver that receives a plurality of baseband signals from the receiver;
For two of the receiving device is a pair of the receiving device, by using a plurality of baseband signals of one receiving device, the cross-correlation for a plurality of combinations of a plurality of baseband signals of the other receiver, the 2 Calculating an arrival time difference of radio waves from the wave source related to each of the receiving devices, for an at least two pairs of the receiving devices ;
A server comprising: a wave source position calculating unit that calculates a position of the wave source using the position of the receiving device and the arrival time difference calculated by the arrival time difference calculating unit for each of a plurality of pairs of the receiving devices. The communication system includes four or more receiving devices,
For each of the four or more receivers, a received power acquisition unit that acquires received power calculated using two or more baseband signals converted by different RF circuits;
A selection unit that selects three or more reception devices having a large reception power acquired by the reception power acquisition unit;
The server according to claim 5, wherein the wave source position calculation unit calculates the position of the wave source using arrival time differences calculated for a plurality of pairs of three or more receiving devices selected by the selection unit. The communication system includes four or more receiving devices,
Multipath information for acquiring multipath information, which is information on the power of delayed waves, calculated using two or more baseband signals converted by different RF circuits for each of the four or more receiving apparatuses. An acquisition unit;
A selection unit that selects three or more receiving devices that are less affected by the delayed wave indicated by the multipath information acquired by the multipath information acquisition unit;
The server according to claim 5, wherein the wave source position calculation unit calculates the position of the wave source using arrival time differences calculated for a plurality of pairs of three or more receiving devices selected by the selection unit. For each of the three or more receiving devices, further comprises a received power acquisition unit that acquires received power calculated using two or more baseband signals converted by different RF circuits,
The said wave source position calculation part calculates the position of a wave source using the said arrival time difference of the said pair of receiving devices with the weight according to the two received power corresponding to the said pair of receiving devices. server. Processing in a receiving apparatus in a communication system comprising three or more receiving apparatuses that receive radio waves from a wave source and a server that calculates a position of the wave source using a time difference of arrival of radio waves from the wave source to the receiving apparatus A signal processing method, comprising:
Converting a plurality of received signals divided by a distributor that divides a received signal received by an antenna for receiving radio waves from the wave source into baseband signals by a plurality of RF circuits, respectively;
Transmitting the plurality of baseband signals to the server. The reception signal received from the wave source is divided into a plurality of signals by a distributor, and each of the plurality of reception signals is converted into a plurality of baseband signals by a plurality of RF circuits, and a server is provided. A wave source position calculation method processed in a server in a communication system,
Receiving a plurality of baseband signals from the receiving device;
For two of the receiving device is a pair of the receiving device, by using a plurality of baseband signals of one receiving device, the cross-correlation for a plurality of combinations of a plurality of baseband signals of the other receiver, the 2 Calculating an arrival time difference of radio waves from the wave source with respect to a plurality of receiving devices for at least two pairs of the receiving devices ;
Calculating the position of the wave source using the position of the receiving apparatus and the arrival time difference calculated for each of a plurality of pairs of the receiving apparatus. Computer
Function as a receiving apparatus in a communication system including three or more receiving apparatuses that receive radio waves from a wave source and a server that calculates a position of the wave source using a time difference of arrival of radio waves from the wave source to the receiving apparatus Let
A plurality of basebands respectively converted by a plurality of RF circuits that respectively convert a plurality of reception signals divided by a distributor that divides a reception signal received by an antenna that receives radio waves from the wave source into baseband signals. A program for causing a signal to function as a transmission unit that transmits a signal to the server. Computer
The reception signal received from the wave source is divided into a plurality of signals by a distributor, and each of the plurality of reception signals is converted into a plurality of baseband signals by a plurality of RF circuits, and a server is provided. Function as a server in a communication system,
A receiver that receives a plurality of baseband signals from the receiver;
For two of the receiving device is a pair of the receiving device, by using a plurality of baseband signals of one receiving device, the cross-correlation for a plurality of combinations of a plurality of baseband signals of the other receiver, the 2 An arrival time difference calculating unit that calculates an arrival time difference of radio waves from the wave source related to each of the receiving devices for at least two pairs of the receiving devices ;
A program for functioning as a wave source position calculating unit that calculates the position of the wave source using the position of the receiving device and the arrival time difference calculated by the arrival time difference calculating unit for each of a plurality of pairs of the receiving devices.

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