JP6503994B2 - Wireless positioning device and wireless positioning system - Google Patents

Description

  The present invention relates to a wireless positioning device and a wireless positioning system that perform positioning by wireless communication.

  When a wireless communication apparatus (hereinafter referred to as a mobile communication apparatus) mounted on a mobile moving on a road near the reference station as in Patent Document 1 receives a wireless beacon periodically transmitted from the reference station There is known a technique for measuring the current position of a mobile communication device by detecting the received signal strength.

JP, 2013-257306, A

  However, if the transmission power of the wireless beacon changes as the reference station performs transmission power control, whether the change in the received power of the wireless beacon received by the mobile communication device is due to the change in transmission power or the movement of the mobile Can not be distinguished on the mobile communication device side. Therefore, there is a possibility that the current position can not be measured based on the received signal strength of the wireless beacon.

  The present invention has been made in view of these problems, and it is an object of the present invention to provide a technology that enables positioning even if the transmission power changes.

  A first invention made to achieve the above object is a wireless positioning device mounted on a mobile body, comprising: a wireless reception unit, a characteristic calculation unit, a tilt information acquisition unit, a reference information storage unit, and a position And a determination unit.

The wireless reception unit receives radio waves transmitted from a wireless communication device that wirelessly transmits data.
The characteristic calculation unit calculates propagation path characteristics when radio waves are received by the wireless reception unit. The propagation path characteristic of the first invention indicates the propagation path characteristic when radio waves are received by the wireless receiving unit, and for example, it is possible to transmit to the transmission signal or the frequency characteristic or time characteristic of the transfer function of the propagation path. The frequency characteristic of the received signal multiplied by the transfer function of the path or the time characteristic subjected to the convolution integration can be mentioned.

The inclination information acquisition unit acquires characteristic inclination information which is information on the inclination in the propagation path characteristic calculated by the characteristic calculation unit.
The reference information storage unit stores positioning reference information in which the correspondence relationship between the characteristic slope information of the propagation path characteristics and the position related information which is information related to the position of the wireless positioning device is set in advance.

  The position determination unit determines whether or not there is a matching part that matches the characteristic tilt information acquired by the inclination information acquisition unit in the positioning reference information stored by the reference information storage unit, and it is determined that there is a match part In this case, the current position of the wireless positioning device is determined based on the position related information corresponding to the matching portion in the positioning reference information.

  The wireless positioning device according to the first aspect of the invention configured as described above can determine the current position of the wireless communication device by performing wireless communication with one wireless communication device corresponding to the positioning reference information.

  Then, the wireless positioning device of the first invention determines the current position of the wireless positioning device based on the position related information corresponding to the matching portion that matches the characteristic slope information of the propagation path characteristic in the positioning reference information.

  Even if the transmission power of the radio wave transmitted from the wireless communication device changes, the propagation path does not change, and the propagation path characteristic does not depend on the value and has a constant magnitude according to the change in transmission power. Increase or decrease. That is, even if the transmission power of the radio wave transmitted from the wireless communication device changes, the slope in the propagation path characteristics does not change.

Thereby, the wireless positioning device of the first invention can perform positioning using the positioning reference information even if the transmission power of the radio wave transmitted from the wireless communication device changes.
A second invention made to achieve the above object is a wireless positioning system including the above-described wireless communication device and the wireless positioning device of the first invention.

  The wireless positioning system according to the second aspect of the invention configured as described above includes the wireless positioning device according to the first aspect, and can obtain the same effects as the wireless positioning device according to the first aspect.

FIG. 1 is a diagram showing a configuration of a wireless positioning system 1. FIG. 2 is a block diagram showing the configuration of a server 2; FIG. 2 is a block diagram showing the configuration of a mobile terminal 3; FIG. 5 is a block diagram showing the configuration of a measurement terminal 4; It is a flowchart which shows the position estimation process of 1st Embodiment. It is a figure explaining preceding wave PW and delay wave DW. It is a figure which shows the transmission power of the electromagnetic wave transmitted from a transmitting station, the frequency characteristic in a receiving station, and the frequency characteristic of a derivative value. It is a flowchart which shows a measurement process. It is a flowchart which shows the locus | trajectory update process of 1st Embodiment. It is a figure which shows the specific example of the position estimation in 1st Embodiment. It is a figure which shows a dip and a reference | standard dip map. It is a flowchart which shows the position estimation process of 2nd Embodiment. It is a figure which shows the detection method of the dip in 2nd Embodiment. It is a flow chart which shows dip detection processing of a 2nd embodiment. It is a figure which shows the detection method of the dip in 3rd Embodiment. It is a flow chart which shows dip detection processing of a 3rd embodiment. It is a figure which shows the propagation path characteristic in a reference | standard locus | trajectory, the propagation path characteristic acquired by the mobile terminal 3, and the propagation path characteristic after conversion in a reference | standard locus | trajectory. It is a flowchart which shows the position estimation process of 4th Embodiment. It is a flowchart which shows the position estimation process of 5th Embodiment. It is a flowchart which shows the locus | trajectory update process of 5th Embodiment. It is a figure which shows the transmission power of the electromagnetic wave transmitted from a transmitting station, the impulse response in a receiving station, and the time characteristic of a derivative value.

First Embodiment
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.
As shown in FIG. 1, the wireless positioning system 1 according to the present embodiment is installed in an area outside the GPS (Global Positioning System) out-of-range area to perform road-to-vehicle communication, and is mounted on a vehicle. A plurality of mobile terminals 3 performing communication and a plurality of measurement terminals 4 mounted on a vehicle and performing road-vehicle communication are provided. FIG. 1 shows one server 2, one mobile terminal 3 and one measurement terminal 4.

As illustrated in FIG. 2, the server 2 includes a road-vehicle communication device 11, a data storage device 12, and a control unit 13.
The road-to-vehicle communication device 11 performs wireless communication with the mobile terminal 3 and the measurement terminal 4 using an orthogonal frequency division multiplexing (OFDM) transmission scheme. The data storage device 12 stores reference trajectory information indicating a reference trajectory described later.

  The control unit 13 includes a CPU 21, a ROM 22 and a RAM 23. The control unit 13 controls the road-vehicle communication device 11 and the data storage device 12 by the CPU 21 executing processing based on the program stored in the ROM 22.

The server 2 periodically transmits a wireless beacon including the identification information of the server 2 itself to surrounding vehicles by road-to-vehicle communication.
As shown in FIG. 3, the mobile terminal 3 includes a position detector 31, a road-to-vehicle communication device 32, and a control unit 33.

  The position detector 31 includes a GPS receiver that receives satellite signals from GPS satellites, a distance sensor that detects the traveling distance of the vehicle from the rotation of wheels, and an azimuth sensor that detects the azimuth of the vehicle, etc. Based on the obtained signal, the position and heading of the vehicle are detected. The detection result of the position detector 31 is input to the control unit 33.

The road-to-vehicle communication device 32 is a device that performs wireless communication with the server 2 using the OFDM transmission method, and includes an OFDM transmission device 41 and an OFDM reception device 42.
The OFDM transmitter 41 generates an OFDM signal by modulating the data input from the control unit 33 according to the OFDM modulation scheme, and wirelessly transmits the generated OFDM signal.

  The OFDM receiver 42 includes an antenna 51, an RF (Radio Frequency) unit 52, an orthogonal demodulation unit 53, an analog-to-digital conversion unit 54, an FFT (Fast Fourier Transform) unit 55, a propagation path estimation unit 56, a propagation path compensation unit 57, and a phase. An error correction unit 58 and a subcarrier demodulation unit 59 are provided.

The antenna 51 receives the OFDM signal that has been wirelessly transmitted by the server 2 and has propagated along the propagation path.
The RF unit 52 downconverts the OFDM signal received by the antenna 51 into a received signal of a frequency band suitable for signal processing.

The orthogonal demodulation unit 53 generates two baseband signals representing the I component and the Q component from the reception signal down-converted by the RF unit 52.
The analog-to-digital converter 54 samples each of the two baseband signals generated by the quadrature demodulator 53 to generate two data strings representing the I component and the Q component.

  The FFT unit 55 performs fast Fourier transform processing on the two data strings generated by the analog-to-digital converter 54, and converts the data sequence into a signal in the frequency domain including subcarriers of the OFDM signal (hereinafter referred to as a frequency domain signal).

  The propagation path estimation unit 56 extracts a known signal (for example, a pilot symbol) known on both the transmitting and receiving sides from the frequency domain signal converted by the FFT unit 55, and uses the extracted known signal to propagate the propagation path. Estimate the characteristics.

The propagation path compensation unit 57 compensates for the distortion of the frequency domain signal caused by the propagation path using the propagation path characteristic estimated by the propagation path estimation unit 56.
The phase error correction unit 58 corrects the phase of the signal compensated by the propagation path compensation unit 57.

The subcarrier demodulation unit 59 demodulates the signal output from the phase error correction unit 58 for each subcarrier to generate a data string.
The control unit 33 includes a CPU 61, a ROM 62, and a RAM 63. The control unit 33 controls the road-vehicle communication device 32 by the CPU 61 executing processing based on the program stored in the ROM 62.

As shown in FIG. 4, the measurement terminal 4 includes a position detector 71, a road-to-vehicle communication device 72, and a control unit 73.
The position detector 71 detects the position and the heading of the vehicle in the same manner as the position detector 31. The detection result of the position detector 71 is input to the control unit 73.

The road-to-vehicle communication device 72 is a device that performs wireless communication with the server 2 using the OFDM transmission scheme, and includes an OFDM transmission device 81 and an OFDM reception device 82.
The OFDM transmitter 81 generates an OFDM signal by modulating the data input from the control unit 73 according to the OFDM modulation scheme, and wirelessly transmits the generated OFDM signal.

  Similar to the OFDM receiver 42, the OFDM receiver 82 includes an antenna 91, an RF unit 92, an orthogonal demodulator 93, an analog-to-digital converter 94, an FFT unit 95, a channel estimator 96, a channel compensator 97, and a phase error. A correction unit 98 and a subcarrier demodulation unit 99 are provided, and operate in the same manner as the OFDM reception apparatus 42.

  The control unit 73 includes a CPU 101, a ROM 102, and a RAM 103. The control unit 73 controls the road-vehicle communication device 72 by the CPU 101 executing processing based on the program stored in the ROM 102.

  In the wireless positioning system 1 configured as described above, the mobile terminal 3 executes a position estimation process described later. The measurement terminal 4 executes a measurement process described later. The server 2 executes trajectory update processing described later.

First, the procedure of the position estimation process executed by the CPU 61 of the mobile terminal 3 will be described. The position estimation process is a process repeatedly executed while the CPU 61 is in operation.
When this position estimation process is executed, the CPU 61 first determines in S10 whether or not a wireless beacon is detected, as shown in FIG. Here, when the wireless beacon is not detected, it transfers to S90. On the other hand, when the wireless beacon is detected, it is determined in S20 whether or not the server 2 specified by the identification information included in the detected wireless beacon is the server for which the mobile terminal 3 has acquired the reference trajectory. to decide. Here, if the server has already acquired the reference trajectory, the process proceeds to S40.

  On the other hand, if the server has not acquired the reference trajectory, in S30, a reference trajectory request command requesting transmission of reference trajectory information is transmitted to the server 2 corresponding to the detected wireless beacon, and the process proceeds to S40. Do.

Then, in S40, the propagation path characteristic is acquired from the propagation path compensation unit 57 of the road-to-vehicle communication device 32.
Here, channel characteristics will be described. As shown in FIG. 6, when transmitting a radio wave from the transmitting station TS, the receiving station RS transmits to the receiving station RS the preceding wave PW that directly reaches the receiving station RS from the transmitting station TS and after being reflected by the building BL etc. The delayed wave DW that arrives is received.

  As shown by the graph G2 in FIG. 7A, the channel characteristic acquired in S40 is that the radio wave transmitted from the transmitting station TS (that is, the server 2) is received by the receiving station RS (that is, the mobile terminal 3) It is the frequency characteristic of the transfer function of the propagation path in the case.

  Then, when the process of S40 ends, as shown in FIG. 5, in S50, the channel characteristic obtained in S40 is differentiated in the frequency direction to create a frequency characteristic of the differential value. The graph G3 of FIG. 7A shows the frequency characteristic of the differential value.

  Then, when the reference trajectory information corresponding to the detected wireless beacon has already been acquired in S60, it is created in S50 on the reference trajectory (see the reference trajectory TR in FIG. 10) indicated by the reference trajectory information. The frequency characteristics are superimposed (see the differential value frequency characteristic DF in FIG. 10) to determine whether there is a coincident portion. The reference trajectory indicates the correspondence between the distance traveled on the road near the server 2 from the closest point from the server 2 (hereinafter referred to as the reference travel distance) and the frequency characteristic of the differential value. (See reference trajectory TR in FIG. 10). In S60, when the reference trajectory information corresponding to the detected wireless beacon is not acquired, it is determined that there is no matching portion.

  Here, if there is a coincident portion, in S70, on the road which is traveling based on the reference movement distance (refer to the current movement distance DN1 in FIG. 10) corresponding to the coincident portion. The current position of the host vehicle at is calculated, and the process proceeds to S90. On the other hand, when there is no matching part, at S80, the current position of the vehicle is calculated based on the detection result of the position detector 31, and the process proceeds to S90.

  And if it transfers to S90, it will be judged whether reference track information was received from server 2 corresponding to the detected wireless beacon. Here, when the reference trajectory information is not received, the position estimation process is temporarily ended. On the other hand, when the reference trajectory information is received, the received reference trajectory information is stored in the RAM 63 in S100, and the position estimation process is temporarily ended.

Next, the procedure of the measurement process performed by the CPU 101 of the measurement terminal 4 will be described. This measurement process is a process repeatedly executed while the CPU 101 is in operation.
When this measurement process is executed, the CPU 101 first determines in step S210 whether or not a wireless beacon has been detected, as shown in FIG. Here, when the wireless beacon is not detected, the measurement process is temporarily ended. On the other hand, when the wireless beacon is detected, the propagation path characteristic is acquired from the propagation path compensation unit 97 of the OFDM receiving apparatus 82 in S220, similarly to S40.

  Further, at S230, the channel characteristic obtained at S220 is differentiated in the frequency direction in the same manner as at S50, and the frequency characteristic of the differential value is created. Also, at S240, the current position of the vehicle is calculated based on the detection result of the position detector 71.

  Then, in S250, locus creation information is created in which position information indicating the current position calculated in S240 is added to the information indicating the frequency characteristic of the differential value generated in S230. Thereafter, in S260, the information for creating a trajectory created in S250 is transmitted to the server 2 by road-to-vehicle communication, and the measurement process is temporarily ended.

Next, a procedure of trajectory update processing executed by the CPU 21 of the server 2 will be described. The trajectory update process is a process repeatedly executed while the CPU 21 is in operation.
When the trajectory update process is executed, the CPU 21 first determines at S310 whether or not a reference trajectory request command has been received from the mobile terminal 3 as shown in FIG. Here, when the reference trajectory request command has not been received, the process proceeds to S330. On the other hand, when the reference trajectory request command is received, in S320, the reference trajectory information stored in the data storage device 12 is transmitted to the mobile terminal 3 by road-to-vehicle communication, and the process proceeds to S330.

  And if it transfers to S330, it will be judged whether the information for trace preparation was received from the measurement terminal 4. As shown in FIG. Here, if the trajectory creation information has not been received, the trajectory update process is temporarily ended. On the other hand, if the trajectory creation information is received, the reference trajectory information stored in the data storage device 12 is updated based on the received trajectory creation information in S340, and the trajectory update process is temporarily ended. . Specifically, in S340, first, based on the position indicated by the position information added to the received information for generating a locus, a reference movement distance corresponding to this position is specified. Information indicating the correspondence relationship between the position and the reference movement distance is stored in advance in the data storage device 12. Then, in S340, the reference trajectory information is updated by replacing the frequency characteristics of the differential value corresponding to the specified reference movement distance with the frequency characteristics of the differential value indicated by the received trajectory creation information.

The mobile terminal 3 configured in this way is a wireless positioning device mounted on a car, and includes an OFDM receiving device 42.
The OFDM receiver 42 receives radio waves transmitted from the server 2 that transmits data wirelessly.

  The channel estimation unit 56 of the OFDM receiver 42 calculates channel characteristics. This propagation path characteristic is the frequency characteristic of the transfer function of the propagation path when radio waves are received by the OFDM receiver 42.

The control unit 33 of the mobile terminal 3 differentiates the channel characteristic in the frequency direction, and acquires the frequency characteristic of the differential value (S50).
The control unit 33 of the mobile terminal 3 stores reference trajectory information in which the correspondence between the frequency characteristic of the differential value in the channel characteristic and the reference movement distance is preset (S100).

  The control unit 33 of the mobile terminal 3 determines whether or not there is a matching portion that matches the frequency characteristic of the differential value acquired in the stored reference trajectory information, and when it is determined that there is a matching portion, The current position of the mobile terminal 3 is determined based on the reference movement distance corresponding to the matching part in the trajectory information (S60, S70).

As described above, the mobile terminal 3 can determine the current position of the mobile terminal 3 by performing wireless communication with one server 2 corresponding to the reference trajectory information.
Then, the mobile terminal 3 determines the current position of the mobile terminal 3 based on the reference movement distance corresponding to the matching portion that matches the frequency characteristic of the differential value in the propagation path characteristic in the reference trajectory information.

  Even if the transmission power of the radio wave transmitted from the server 2 changes, the propagation path does not change, and the propagation path characteristic has its value (that is, the strength of the transfer function) independent of its value and the change of transmission power Increase or decrease by a fixed size according to. That is, even if the transmission power of the radio wave transmitted from the server 2 changes, the inclination in the frequency direction does not change for the propagation path characteristics.

  As shown by the graph G11 in FIG. 7B, when the transmission power of the radio wave transmitted from the transmitting station TS (that is, the server 2) decreases, as shown by the graph G12 in FIG. 7B. The propagation path characteristic in the case of reception at the receiving station RS (ie, the mobile terminal 3) is generally lowered in level without changing its shape (see the arrow AL1). For this reason, as shown by the graph G3 of FIG. 7A and the graph G13 of FIG. 7B, even if the transmission power changes, the frequency characteristic of the differential value does not change. The graph G13 of FIG. 7 (B) shows the frequency characteristic of the differential value when the transmission power decreases.

Thereby, the mobile terminal 3 can perform positioning using the reference trajectory information even if the transmission power of the radio wave transmitted from the server 2 changes.
Further, the server 2 is fixedly installed at a preset installation position. The reference movement distance in the reference trajectory information is information indicating the position on the road installed near the server 2. Thereby, the area | region which performs positioning can be limited on a road, and the information content of reference | standard locus | trajectory information required for the positioning of the mobile terminal 3 can be reduced. In addition, "the information which shows the position on a road" means the information which can specify the position of the mobile terminal 3 on a road.

  In the embodiment described above, the mobile terminal 3 is the wireless positioning device in the present invention, the server 2 is the wireless communication device in the present invention, the OFDM receiving device 42 is the wireless reception unit in the present invention, and the propagation path estimation unit 56 is the characteristic in the present invention It is a calculation unit.

Further, the processing of S50 is the inclination information acquisition unit in the present invention, the processing of S100 is the reference information storage unit in the present invention, and the processing of S60 and S70 is the position determination unit in the present invention.
Further, with respect to propagation path characteristics, the differential value in the frequency direction of the propagation path characteristics is the characteristic slope information in the present invention, the reference trajectory information is the positioning reference information in the present invention, and the reference movement distance is the position related information in the present invention.

Second Embodiment
Hereinafter, a second embodiment of the present invention will be described with reference to the drawings. In the second embodiment, parts different from the first embodiment will be described.

  The wireless positioning system 1 of the second embodiment is that the data storage device 12 of the server 2 stores reference map information indicating a reference dip map instead of storing reference trajectory information indicating a reference trajectory according to the first embodiment. It is different from

As shown in FIG. 11A, the dip is a portion where a deep and sharp level drop occurs in the propagation path characteristics (see dips DP1 and DP2).
In the reference dip map, as shown in FIG. 11B, the distance (reference movement distance) of traveling on the road near the server 2 from the point closest to the server 2 as a base point, and dip occur It shows the correspondence with the frequency.

In addition, the position estimation process, the measurement process, and the trajectory update process of the second embodiment are different from those of the first embodiment.
First, the procedure of the position estimation process performed by the CPU 61 of the mobile terminal 3 according to the second embodiment will be described.

  When this position estimation process is executed, the CPU 61 first determines at S410 whether a wireless beacon has been detected, as shown in FIG. Here, when the radio | wireless beacon is not detected, it transfers to S510. On the other hand, when the wireless beacon is detected, in S420, whether or not the server 2 specified by the identification information included in the detected wireless beacon is the server from which the mobile terminal 3 has acquired the reference dip map To judge. Here, if the server has already obtained the reference dip map, the process proceeds to S440.

  On the other hand, if the server has not acquired the reference dip map, in S430, the reference map request command for requesting transmission of reference map information is transmitted to the server 2 corresponding to the detected wireless beacon, and to S440. Transition.

  Then, in S440, propagation path characteristics are acquired as in S40 of the first embodiment. Furthermore, in S450, dip detection processing described later is executed, and a dip is detected from the propagation path characteristics acquired in S440.

  When reference map information corresponding to the detected wireless beacon has already been obtained in S460, the reference dip information (see reference dip map DM in FIG. 11B) indicated by the reference map information is obtained. Then, the dips detected in S450 are superimposed (see the detection dips DD1, DD2, and DD3 in FIG. 11B), and it is determined whether or not there is a matching portion.

  Here, if there is a matching portion, in S470, superimpose the dip detected before the current time (see the detection dips DD11 and DD12 in FIG. 11B) on the reference dip map. It is determined whether there is a matching site. The reference movement distance corresponding to the dip detected before the current time can be specified based on the detection result of the position detector 31.

  Here, if there is a matching portion, in S480, the vehicle travels based on the reference moving distance (see current moving distance DN2 in FIG. 11B) corresponding to the matching portion determined in S460. Calculate the current position of the vehicle on the road. Further, in S480, the “high” reliability is set for the calculated current position, and the process proceeds to S510. There are two types of reliability, “high” indicating high and “low” indicating low.

  On the other hand, if there is no matching site, the vehicle travels based on the reference travel distance (see current travel distance DN2 of FIG. 11B) corresponding to the matching site determined in S460 in S490. Calculate the current position of the vehicle on the road. Further, in S490, the “low” reliability is set for the calculated current position, and the process proceeds to S510.

  If there is not a matching portion at S460, the current position of the vehicle is calculated based on the detection result of the position detector 31 at S500. Furthermore, in S500, the "low" reliability is set for the calculated current position, and the process proceeds to S510.

  And if it transfers to S510, it will be judged whether reference | standard map information was received from the server 2 corresponding to the detected wireless beacon. Here, when the reference map information is not received, the position estimation process is temporarily ended. On the other hand, when the reference map information is received, the received reference map information is stored in the RAM 63 in S520, and the position estimation process is temporarily ended.

Next, the procedure of the dip detection process executed in S450 will be described.
In this dip detection processing, as shown in FIG. 13, in the propagation path characteristics, the decrease side frequency f1 where the value of the transfer function (hereinafter referred to as transfer function value) falls below the determination value Ith, and the transfer function value becomes the determination value Ith. The frequency at which the dip occurs is detected by detecting the increase frequency f2 that is higher.

  When this dip detection process is executed, the CPU 61 first sets the detection frequency Fd to a preset detection start frequency fs in S610 as shown in FIG. Then, in S620, it is determined whether or not the transfer function value at the detection frequency Fd is smaller than a predetermined determination value Ith for the propagation path characteristic. Here, when the transfer function value at the detection frequency Fd is equal to or greater than the determination value Ith, at S630, an addition value obtained by adding the frequency increase amount Δf set in advance to the detection frequency Fd is set as a new detection frequency Fd. Set and go to S620. On the other hand, if the transfer function value at the detection frequency Fd is less than the determination value Ith, the decrease side frequency f1 is set to the detection frequency Fd at S640.

  Then, in S650, an addition value obtained by adding the frequency increase amount Δf to the detection frequency Fd is set as a new detection frequency Fd. Thereafter, in S660, it is determined whether or not the transfer function value at the detection frequency Fd exceeds the determination value Ith for the propagation path characteristic. Here, when the transfer function value at the detection frequency Fd is equal to or less than the determination value Ith, the process proceeds to S650.

  On the other hand, if the transfer function value at the detection frequency Fd exceeds the determination value Ith, at S670, the increase side frequency f2 is set to the detection frequency Fd. Then, in S680, the average value of the decrease side frequency f1 and the increase side frequency f2 is calculated, and in S690, the average value calculated in S680 is stored as the dip frequency.

  Next, in S700, it is determined whether the detection frequency Fd is equal to or higher than a predetermined detection end frequency fe. Here, if the detection frequency Fd is less than the detection end frequency fe, in S710, an addition value obtained by adding the frequency increase amount Δf to the detection frequency Fd is set as a new detection frequency Fd, and the process proceeds to S620. On the other hand, when the detection frequency Fd is equal to or higher than the detection end frequency fe, the dip detection process is ended.

The measurement process and the trajectory update process of the second embodiment are different from those of the first embodiment in that a dip is used instead of the frequency characteristic of the differential value.
The control unit 33 of the mobile terminal 3 configured as described above detects the frequency at which the dip occurs in the propagation path characteristic, and acquires the frequency characteristic of the dip (S450).

The control unit 33 of the mobile terminal 3 stores reference map information in which the correspondence between the frequency characteristic of the dip in the propagation path characteristic and the reference movement distance is preset (S520).
The control unit 33 of the mobile terminal 3 determines whether or not there is a matching portion that matches the frequency characteristic of the dip acquired in the stored reference trajectory information, and when it is determined that there is a matching portion, the reference map The current position of the mobile terminal 3 is determined based on the reference movement distance corresponding to the matching part in the information (S460 to S490).

  As described above, the mobile terminal 3 performs positioning by using the frequency at which the channel characteristic becomes the minimum value. This makes it possible to determine whether there is a matching part by a simple method of determining whether the detected dip frequency matches the dip frequency set in the reference map information. The processing load of the control unit 33 can be reduced.

  In the embodiment described above, the processing of S450 is the inclination information acquisition unit in the present invention, the processing of S520 is the reference information storage unit in the present invention, and the processing of S460 to S490 is the position determination unit in the present invention.

  Further, dip is frequency tilt information and characteristic tilt information in the present invention, reference map information is positioning reference information in the present invention, and dip frequency is a frequency which becomes a local minimum value in the present invention.

Third Embodiment
Hereinafter, a third embodiment of the present invention will be described with reference to the drawings. In the third embodiment, parts different from the second embodiment will be described.

The wireless positioning system 1 of the third embodiment is different from that of the second embodiment in that the dip detection process is changed.
Next, the procedure of the dip detection process according to the third embodiment will be described.

  In this dip detection process, as shown in FIG. 15, first, the channel characteristic (see graph G21) is differentiated in the frequency direction to create the frequency characteristic of the differential value (see graph G22).

  Then, in the dip detection processing, a local minimum frequency f11 which is a local minimum and a local maximum frequency f12 which is a local maximum are detected in the frequency characteristics of the differential value. Furthermore, in the dip detection process, when the difference ΔD between the minimum value and the maximum value exceeds the preset dip judgment value Dth, the intermediate frequency between the minimum frequency f11 and the maximum frequency f12 is taken as the frequency at which the dip occurs. To detect.

  When this dip detection process is executed, the CPU 61 first differentiates in the frequency direction the propagation path characteristic acquired in S440 in S810 in the same manner as in S50 as shown in FIG. Create frequency characteristics.

  Further, at S820, the detection frequency Fd is set to a preset detection start frequency fs. Then, in S830, it is determined whether or not the differential value at the detection frequency Fd is a minimum value with respect to the frequency characteristic of the differential value. Here, when the differential value at the detection frequency Fd is not the minimum value, at S840, an addition value obtained by adding the frequency increase amount Δf preset to the detection frequency Fd is set as a new detection frequency Fd, and S840. Migrate to

  On the other hand, when the differential value at the detection frequency Fd is the minimum value, at S850, the minimum frequency f11 is set to the detection frequency Fd. Further, in S860, the local minimum value d1 is set to the differential value at the detection frequency Fd.

  Then, in S870, an addition value obtained by adding the frequency increase amount Δf to the detection frequency Fd is set as a new detection frequency Fd. Thereafter, in S880, it is determined whether the differential value at the detection frequency Fd is a maximum value. Here, when the differential value at the detection frequency Fd is not the maximum value, the process proceeds to S870.

  On the other hand, when the differential value at the detection frequency Fd is the maximum value, at S890, the maximum frequency f12 is set to the detection frequency Fd. Further, in S900, the local maximum value d2 is set to the differential value at the detection frequency Fd.

  Then, in S910, the subtraction value obtained by subtracting the local minimum value d1 from the local maximum value d2 is set as the difference ΔD. Next, in S920, it is determined whether the difference ΔD exceeds a preset dip determination value Dth. Here, when the difference ΔD is equal to or less than the dip determination value Dth, in S930, an addition value obtained by adding the frequency increase amount Δf to the detection frequency Fd is set as a new detection frequency Fd, and the process proceeds to S830.

  On the other hand, when the difference ΔD exceeds the dip determination value Dth, the average value of the local minimum frequency f11 and the local maximum frequency f12 is calculated in S940, and the average calculated in S940 is the dip frequency in S950. Remember as.

  Next, in S960, it is determined whether the detection frequency Fd is equal to or higher than a predetermined detection end frequency fe. Here, when the detection frequency Fd is less than the detection end frequency fe, the process proceeds to S930. On the other hand, when the detection frequency Fd is equal to or higher than the detection end frequency fe, the dip detection process is ended.

  The control unit 33 of the mobile terminal 3 configured in this way determines the minimum frequency f11 and the maximum frequency f12 when the difference ΔD obtained by subtracting the minimum value d1 from the maximum value d2 exceeds the preset dip determination value Dth. And the average value of and the dip frequency. As a result, it is possible to detect as a dip a portion that changes from a decrease to an increase with a steep slope.

In the embodiment described above, the judgment condition of S920 is the steep inclination judgment condition in the present invention.
Fourth Embodiment
The fourth embodiment of the present invention will be described below with reference to the drawings. In the fourth embodiment, parts different from the first embodiment will be described.

  In the wireless positioning system 1 of the fourth embodiment, as shown in FIGS. 17A and 17B, the frequency characteristic of the differential value in the reference trajectory and the frequency characteristic of the differential value acquired by the mobile terminal 3 Between the frequency band, the number of frequency resolution samples, and the resolution bandwidth (RBW).

As shown in FIG. 17A, the frequency characteristic of the differential value in the reference trajectory is 10 MHz, the number of frequency-resolved samples is 8192 ponnt, and the RBW is 1220.7 Hz.
The frequency characteristic of the differential value acquired by the mobile terminal 3 is, as shown in FIG. 17B, a band of 5 MHz, the number of frequency-resolved samples is 1024, and the RBW is 4882.8 Hz.

  In the trajectory conversion process, as shown in FIG. 17C, the RBW of the frequency characteristic of the differential value in the reference trajectory is converted to match the RBW of the frequency characteristic of the differential value acquired by the mobile terminal 3.

The wireless positioning system 1 of the fourth embodiment is different from the first embodiment in that the position estimation process is changed.
The position estimation process of the fourth embodiment differs from the first embodiment in that the processes of S92, S94, and S96 are added and the process of S100 is omitted.

  That is, as shown in FIG. 18, when the reference trajectory information is received in S90, the conversion parameter is calculated in S92. Specifically, first, a value obtained by dividing the band of the frequency characteristic of the differential value acquired by the mobile terminal 3 by the number of frequency-resolved samples is calculated as a post-conversion RBW. The band of frequency characteristics of the differential value and the number of frequency-resolved samples are set in advance in the mobile terminal 3. For example, when the band of the frequency characteristic of the differential value acquired by the mobile terminal 3 is 5 MHz and the number of frequency-resolved samples is 1024, the post-conversion RBW is 4882.8 Hz. Then, the converted RBW is divided by the RBW of the frequency characteristic of the differential value on the reference trajectory, and this divided value is calculated as a conversion parameter. The RBW information indicating the RBW of the frequency characteristic of the differential value in the reference trajectory is added to the reference trajectory information, and can be acquired from the received reference trajectory information. For example, if the RBW indicated by the RBW information is 1220.7 Hz, the conversion parameter is 4 points.

  Then, at S94, in the reference trajectory indicated by the reference trajectory information, conversion is performed in which the points indicated by the conversion parameter are grouped into one point (see FIG. 17C). Further, in S96, information indicating the converted reference trajectory is stored in the RAM 63 as converted reference trajectory information, and the position estimation process is temporarily ended.

The OFDM receiver 42 of the mobile terminal 3 configured in this way receives the reference trajectory information transmitted from the server 2.
The control unit 33 of the mobile terminal 3 converts the resolution bandwidth of the reference trajectory information received by the OFDM receiving apparatus 42 so as to match the resolution bandwidth of the stored reference trajectory information (S92, S94).

The control unit 33 of the mobile terminal 3 stores the reference trajectory information after the resolution bandwidth is converted (S96).
As a result, even if the resolution bandwidth of the reference trajectory information transmitted from the server 2 is different from the resolution bandwidth when the channel estimation unit 56 calculates the channel characteristics, the mobile terminal 3 has both With the resolution bandwidths matched, it can be determined whether there is a matching site.

In the embodiment described above, the processing of S92 and S94 is the positioning side conversion unit in the present invention, and the processing of S96 is the reference information storage unit in the present invention.
Fifth Embodiment
Hereinafter, a fifth embodiment of the present invention will be described with reference to the drawings. In the fifth embodiment, parts different from the first embodiment will be described.

The wireless positioning system 1 of the fifth embodiment is different from the first embodiment in that the position estimation process performed by the mobile terminal 3 and the trajectory update process performed by the server 2 are changed.
First, the procedure of the position estimation process of the fifth embodiment will be described.

The position estimation process of the fifth embodiment is different from that of the first embodiment in that the process of S35 is executed instead of S30 as shown in FIG.
That is, if the server does not acquire the reference trajectory in S20, in S35, the reference trajectory request command and the information for trajectory conversion are transmitted to the server 2 corresponding to the detected wireless beacon, and to S40. Transition. The locus conversion information includes band information indicating the band of the frequency characteristic of the differential value acquired by the mobile terminal 3 and sample number information indicating the number of frequency-resolved samples.

Next, the procedure of the trajectory update process of the fifth embodiment will be described.
The locus update process of the fifth embodiment differs from the first embodiment in that the processes of S312, S314, and S316 are executed instead of S320 as shown in FIG.

  That is, when the reference trajectory request command is received in S310, the conversion parameter is calculated in S312. Specifically, first, the converted RBW is calculated in the same manner as in S92 of the fourth embodiment using the band information and the sample number information included in the information for trajectory conversion received along with the reference trajectory request command. Then, the converted RBW is divided by the RBW of the frequency characteristic of the differential value on the reference trajectory, and this divided value is calculated as a conversion parameter. The RBW information indicating the RBW of the frequency characteristic of the differential value in the reference trajectory is preset in the server 2.

  Then, in S314, as in S94 of the fourth embodiment, in the reference trajectory indicated by the reference trajectory information stored in the data storage device 12, conversion is performed to combine points indicated by the conversion parameter into one point. Thereafter, in S316, reference trajectory information indicating the converted reference trajectory is transmitted to the mobile terminal 3 by road-vehicle communication, and the process proceeds to S330.

The OFDM receiver 42 of the mobile terminal 3 configured in this way receives the reference trajectory information transmitted from the server 2.
The controller 33 of the mobile terminal 3 stores the reference trajectory information received by the OFDM receiver 42 (S100).

The control unit 33 of the mobile terminal 3 transmits, to the server 2, trajectory conversion information that can specify the resolution bandwidth of the stored reference trajectory information (S35).
The server 2 uses the trajectory conversion information received from the mobile terminal 3 to set the resolution bandwidth of the reference trajectory information stored in the server 2 to match the resolution bandwidth specified by the trajectory conversion information. It converts (S312, S314). Then, the server 2 transmits the trajectory conversion information after the resolution bandwidth has been converted to the mobile terminal 3 (S316).

As a result, the mobile terminal 3 can omit the processing for the mobile terminal 3 to convert the resolution bandwidth of the trajectory conversion information, and can reduce the processing load of the mobile terminal 3.
In the embodiment described above, the processing of S35 is the conversion information transmission unit in the present invention, and the processing of S312 and S314 is the transmission side conversion unit in the present invention.

As mentioned above, although one Embodiment of this invention was described, this invention is not limited to the said embodiment, As long as it belongs to the technical scope of this invention, a various form can be taken.
(Modification 1)
For example, in the above embodiment, the frequency characteristic of the transfer function of the propagation path is acquired as the propagation path characteristic. However, as shown by the graph G4 in FIG. 21A, an impulse response indicating the relationship between the strength of the transfer function of the propagation path and the propagation delay time delayed by the propagation of the transmission signal through the propagation path is It may be acquired as a characteristic. As shown in FIGS. 21A and 21B, when the transmission power of the radio wave transmitted from the transmitting station TS (that is, the server 2) becomes smaller (see the graph G1 and the graph G11), The impulse response in the case of reception at the receiving station RS (ie, the mobile terminal 3) is generally low in level without any change in shape (see graph G4 and graph G14 and arrow AL2). Therefore, as shown by the graph G5 and the graph G15, even if the transmission power changes, the time characteristic of the differential value does not change. The derivative value in the time direction of the impulse response is the characteristic slope information in the present invention.

Further, since the amount of information in the impulse response decreases as the number of delayed waves decreases, the processing load in the above-described position estimation processing and measurement processing can be reduced when the number of delayed waves is small.
(Modification 2)
In the above embodiment, the wireless positioning system 1 performs the wireless communication using the OFDM transmission method. However, when the wireless positioning system 1 performs wireless communication by an Ultra Wide Band transmission method in which a signal with an extremely short pulse width is repeatedly transmitted, impulse response is used in the above-described position estimation processing and measurement processing. It is good to use. In the ultra wide band transmission system, the server 2 transmits a wireless beacon using a very short signal called an impulse.

(Modification 3)
In the above embodiment, the frequency characteristic of the transfer function of the propagation path is acquired as the propagation path characteristic, and the frequency characteristic of the differential value of the propagation path characteristic is created. However, the frequency characteristic of the power value of the received signal is acquired by performing the fast Fourier transform processing and the power value calculation by the IQ signal square sum on the received signal received by the road-to-vehicle communication device 32, and the received signal power value is calculated. The frequency characteristic may be differentiated in the frequency direction to create the frequency characteristic of the differential value. The frequency characteristic of the power value of the reception signal is the reception power frequency characteristic in the present invention.

(Modification 4)
Also, instead of the above-mentioned impulse response, the time characteristic of the power value of the received signal indicating the relationship between the power value of the received signal and the propagation delay time is acquired, and the time characteristic of the power value of this received signal is differentiated in the time direction To create time characteristics of differential values.

(Modification 5)
Moreover, in the said embodiment, what performed wireless positioning using the frequency characteristic of the transfer function of a propagation path was shown. However, wireless positioning is performed using at least two of the frequency characteristics of the transfer function of the propagation path, the time characteristics of the transfer function of the propagation path, the frequency characteristics of the power value of the received signal, and the time characteristics of the power value of the received signal You may do so.

(Modification 6)
Moreover, in the said embodiment, although the mobile terminal 3 showed what is mounted in a motor vehicle among moving objects (namely, mobile object), it is not limited to a motor vehicle, For example, it mounts in a two-wheeled vehicle, a pedestrian, etc. It may be done.

(Modification 7)
In the above embodiment, the reference movement distance is used as the “information indicating the position on the road”, but latitude and longitude, or two-dimensional coordinates may be used.

  Also, the function of one component in the above embodiment may be distributed as a plurality of components, or the function of a plurality of components may be integrated into one component. In addition, part of the configuration of the above embodiment may be omitted. Further, at least a part of the configuration of the above-described embodiment may be added to or replaced with the configuration of the other above-described embodiment. In addition, all the aspects contained in the technical thought specified only by the words described in the claim are an embodiment of the present invention.

  In addition to the mobile terminal 3 described above, the system according to the present invention includes a system having the mobile terminal 3 as a component, a program for causing a computer to function as the mobile terminal 3, a medium storing the program, a wireless positioning method, etc. Can also be realized.

  DESCRIPTION OF SYMBOLS 1 ... Wireless positioning system, 2 ... Server, 3 ... Mobile terminal, 32 ... Road-to-vehicle communication apparatus, 33 ... Control part, 42 ... OFDM receiving apparatus, 56 ... Propagation path estimation part,

Claims (9)

A wireless positioning device (3) mounted on a mobile body,
A wireless receiver (42) for receiving radio waves transmitted from a wireless communication device (2) for wirelessly transmitting data;
A characteristic calculation unit (56) that calculates channel characteristics when the radio wave is received by the wireless reception unit;
Inclination information acquisition units (S50, S450) for acquiring characteristic inclination information that is information related to the inclination of the propagation path characteristic calculated by the characteristic calculation unit;
A reference information storage unit (S96, S100, and S100, which stores positioning reference information in which a correspondence relationship between the characteristic slope information of the propagation path characteristic and position related information that is information related to the position of the wireless positioning device is preset. S520),
In the positioning reference information stored by the reference information storage unit, it is determined whether there is a matching portion that matches the characteristic tilt information obtained by the tilt information obtaining unit, and it is determined that the matching portion is present And a position determination unit (S60, S70, S460 to S490) for determining the current position of the wireless positioning device based on the position related information corresponding to the matching portion in the positioning standard information. Positioning device. The wireless communication device is fixedly installed at a preset installation position,
The wireless positioning device according to claim 1, wherein the position related information in the positioning reference information is information indicating a position on a road installed near the wireless communication device. The characteristic slope information is a differential value calculated by performing differentiation in the frequency direction when the propagation path characteristic is a frequency characteristic, and when the propagation path characteristic is a time characteristic, a time direction The wireless positioning device according to claim 1 or 2, which is a differential value calculated by performing differentiation in. The characteristic slope information is a frequency at which the propagation path characteristic is a local minimum value when the propagation path characteristic is a frequency characteristic, and when the propagation path characteristic is a time characteristic, the propagation path characteristic is It is the time used as the minimum value. The radio | wireless positioning apparatus of Claim 1 or Claim 2 characterized by the above-mentioned. The frequency at which the propagation path characteristics become the minimum value and the time at which the propagation path characteristics become the minimum value are locations that change from a decrease to an increase at a steep slope that satisfies a preset steep slope determination condition. The wireless positioning device according to claim 4. The propagation path characteristic is a time characteristic,
The wireless positioning device according to any one of claims 1 to 5, wherein the wireless receiving unit receives a radio wave transmitted from the wireless communication device according to an ultra wide band transmission method. The wireless reception unit receives the positioning reference information transmitted from the wireless communication device,
A positioning side conversion unit (S 92, S 94) that converts the resolution bandwidth of the positioning reference information received by the wireless reception unit to match the resolution bandwidth of the positioning reference information stored in the reference information storage unit Equipped with
The reference information storage unit (S96) stores the positioning reference information after the resolution bandwidth has been converted by the positioning side conversion unit. The wireless positioning device according to. The wireless reception unit receives the positioning reference information transmitted from the wireless communication device,
The reference information storage unit stores the positioning reference information received by the wireless reception unit,
The conversion information transmission unit (S35) transmits, to the wireless communication device, conversion information capable of specifying the resolution bandwidth of the positioning reference information stored in the reference information storage unit.
The wireless communication device is stored in the wireless communication device so as to match the resolution bandwidth specified by the conversion information using the conversion information received from the conversion information transmission unit. A transmission side conversion unit (S312, S314) for converting the resolution bandwidth of the positioning reference information, the positioning standard information after the resolution bandwidth being converted by the transmission side conversion unit to the wireless positioning device It transmits, The radio | wireless positioning apparatus in any one of the Claims 1-6 characterized by the above-mentioned.   A wireless positioning system (1) comprising the wireless communication device according to claim 1 and the wireless positioning device according to claim 1.