JP6411831B2 - Direction of arrival estimation device, position estimation device, position estimation system - Google Patents

Description

  The present invention relates to a technique for estimating the position of a transmitter using a wireless communication signal.

  Conventionally, a radio wave transmitted from a portable device is received by an in-vehicle device equipped with an array antenna, and the in-vehicle device receives the radio wave based on reception intensity and phase information of a received signal obtained from each antenna element constituting the array antenna. A technique for obtaining the arrival direction and the relative position between the portable device and the vehicle-mounted device is known (see Patent Document 1).

  In an environment where an object that reflects radio waves, such as a metal wall, is present around a vehicle equipped with a portable device or in-vehicle device, the in-vehicle device reflects the reflected light from the object in addition to the direct wave from the portable device. A so-called multipath is generated in which waves are also received. In this case, in the prior art, the direction of arrival is obtained assuming that the incoming wave having the highest received intensity is a direct wave.

JP 2009-257769 A

  By the way, radio waves of radio communication, for example, several GHz band radio waves used in WiFi (registered trademark) and Bluetooth (registered trademark) are not only easily reflected by metal, but also greatly attenuated by the human body and water. There is a feature to do.

  For this reason, as shown in FIG. 16, when there is an object that attenuates radio waves, such as a person or water, between the portable device and the vehicle-mounted device, the direct wave is not necessarily received more than the reflected wave. The strength does not always increase. In such a case, the conventional apparatus has a problem that the reliability of the estimation result of the direct wave arrival direction and the reliability of the relative position with the vehicle-mounted device obtained based on the arrival direction are significantly reduced. was there.

  The present invention has been made in view of these problems, and an object of the present invention is to provide a technique that realizes highly reliable estimation and positioning of an arrival direction even in an environment where a reflected wave exists.

  The arrival direction estimation device of the present invention includes an orientation extraction unit and an orientation selection unit. The azimuth extraction unit extracts the arrival direction of the designated wave designated in advance based on the received signals from the antenna elements constituting the array antenna. When there are a plurality of arrival directions extracted by the direction extraction unit, the direction selection unit generates a reproduction signal that is a reception signal of an incoming wave from each direction of arrival by beamforming, and uses the phase difference between the reproduction signals. Select the direction of the incoming wave that arrived earliest. Then, the selected direction is output as the true arrival direction of the designated wave.

According to such a configuration, even in an environment where multipath occurs, the direct wave arrival direction, that is, the direction in which the transmission source of the designated wave exists can be obtained correctly.
The position estimation apparatus of the present invention includes a plurality of arrival direction estimation apparatuses and a position estimation unit. The arrival direction estimation apparatus operates based on received signals from different array antennas. The position estimation unit estimates the position of the designated wave generation source from the true arrival direction of the designated wave estimated by each arrival direction estimation device.

According to such a configuration, since the estimation result of the arrival direction with high reliability obtained from the arrival direction estimation device is used, the estimation accuracy of the position of the designated wave generation source can be improved.
The position estimation system of the present invention includes a transmission side device and a reception side device. The transmission side device transmits the designated wave. The receiving-side apparatus estimates the position of the transmitting-side apparatus that is the generation source of the designated wave based on one or more array antennas that receive the designated wave and the received signal from the array antenna.

According to such a configuration, the position of the transmission side device can be accurately estimated by the reception side device.
In addition, the code | symbol in the parenthesis described in the claim shows the correspondence with the specific means as described in embodiment mentioned later as one aspect, Comprising: The technical scope of this invention is limited is not.

It is a block diagram which shows the structure of the position estimation system of 1st Embodiment. It is a flowchart of the starting process in 1st Embodiment. It is a flowchart of the azimuth | direction estimation process in 1st Embodiment. It is explanatory drawing which shows an example of the extraction method of a direction candidate. It is explanatory drawing which shows the method of producing | generating a reproduction signal from a received signal. It is a graph which illustrates the receiving characteristic adjusted by beam forming. It is explanatory drawing which illustrates the relationship between the reproduction | regeneration signal input into a synchronous circuit, and the synchronous adjustment value produced | generated by a synchronous circuit. It is a block diagram which shows the modification of a receiving side apparatus. It is a block diagram which shows the modification of a receiving side apparatus. It is a block diagram which shows the structure of the receiving side apparatus in the position estimation system of 2nd Embodiment. It is a flowchart of the starting process in 2nd Embodiment. It is a flowchart of the direction estimation process in 2nd Embodiment. It is explanatory drawing which illustrates the procedure in which an arrival direction is selected. It is a block diagram which shows the modification of a receiving side apparatus. It is a block diagram which shows the modification of a receiving side apparatus. It is explanatory drawing which shows the problem of a conventional apparatus.

Embodiments to which the present invention is applied will be described below with reference to the drawings.
[1. First Embodiment]
A position estimation system that estimates the position of the transmission source of a wireless communication signal using the wireless communication signal will be described.

[1.1. Constitution]
As illustrated in FIG. 1, the position estimation system 1 includes a device under measurement (transmission side device) 2 and a measurement device (reception side device) 3. The device under measurement 2 includes, for example, a mobile phone or a smart key, and the measurement device 3 is configured as an on-vehicle device mounted on a vehicle, for example.

  The device under measurement 2 includes an antenna 21, a transmitter 22, a receiver 23, and a communication controller 24. The transmitter 22 and the receiver 23 use the high UHF band (several GHz) via the antenna 21 to transmit wireless communication signals according to a predetermined communication standard (for example, WiFi (registered trademark) or Bluetooth (registered trademark)). Send and receive. The communication controller 24 controls communication using a wireless communication signal. Hereinafter, the radio wave transmitted by the device under test 2 is also referred to as “designated wave”.

  The measuring device 3 includes a first array antenna 31, a second array antenna 32, a first receiver 33, a second receiver 34, an activation control unit 35, a storage unit 36, an azimuth estimation unit 37, A position estimation unit 38 is provided.

  Each of the first and second array antennas 31 and 32 includes a plurality of antenna elements arranged in the horizontal direction. Further, the two array antennas 31 and 32 are arranged at different positions at least in the horizontal direction. The first receiver 33 samples received signals from the antenna elements constituting the first array antenna 31 and supplies them to the activation control unit 35 and the storage unit 36. The second receiver 34 samples received signals from the respective antenna elements constituting the second array antenna 32 and supplies them to the storage unit 36.

  The activation control unit 35 controls the operations of the storage unit 36 and the direction estimation unit 37 according to the reception signal supplied from the first receiver 33. The storage unit 36 includes a first time series device 361 and a second time series device 362, and operates for a predetermined period of time in accordance with a command from the activation control unit 35. The fixed period is set to be longer than the time required for synchronizing circuits 373 and 374 described later to synchronize signals. The first time series device 361 stores the time series of the received signals (sampling values) supplied from the first receiver 33 in a state that can be identified for each antenna element. The second time series device 362 stores the time series of the received signals (sampling values) supplied from the second receiver 34 in a state that can be identified for each antenna element.

  The direction estimation unit 37 includes first and second estimation units 371 and 372 and first and second synchronization circuits 373 and 374. The first estimation unit 371 estimates the arrival direction of the designated wave (direct wave) viewed from the position of the first array antenna 31 using the first synchronization circuit 373 based on the stored value of the first time series device 361. To do. The second estimation unit 372 estimates the arrival direction of the designated wave (direct wave) viewed from the position of the second array antenna 32 using the second synchronization circuit 374 based on the stored value of the second time series device 362. To do. The first and second synchronization circuits 373 and 374 have the same configuration, and are well-known circuits used in so-called rake reception. Specifically, the first and second synchronization circuits 373 and 374 receive a synchronization adjustment value, which is a control amount necessary for superimposing two input signals input at different timings at the same timing, At least a process generated by obtaining a correlation or the like is executed.

  The position estimation unit 38 includes a first arrival direction DR1 estimated by the first estimation unit 371, a second arrival direction DR2 estimated by the second estimation unit 372, and an installation interval between the first array antenna 31 and the second array antenna 32. The position of the device under measurement 2 that is the transmission source of the designated wave is estimated using a known triangulation technique.

  The activation control unit 35, the first estimation unit 371, the second estimation unit 372, and the position estimation unit 38 are realized by processing executed by a microcomputer. However, the realization of each of these units by software is merely an example, and the whole or a part thereof may be realized by hardware such as a logic circuit.

[1.2. processing]
Next, the startup process executed by the startup control unit 35 and the azimuth estimation process executed by the first and second estimation units 371 and 372 will be described.

<Startup process>
First, the activation process will be described with reference to the flowchart shown in FIG. This process is repeatedly executed while the measuring apparatus 3 is powered on.

  When this process is activated, the microcomputer functioning as the activation control unit 35 first determines the reception intensity of the positioning frequency channel (here, the high UHF band) based on the reception signal from the first receiver 33 in S110. get. Specifically, frequency analysis (for example, FFT) processing is performed on the reception signal obtained from any one of the antenna elements, and the frequency component corresponding to the positioning frequency channel is received from the frequency spectrum obtained as a result of the processing. Get strength.

  In subsequent S120, it is determined whether or not the reception intensity acquired in S110 is equal to or greater than a preset threshold value. If the reception intensity has not reached the threshold value (S120: NO), it is determined that the radio wave from the device under measurement 2 has not been received, and the process returns to S110, and the processes of S110 and S120 are repeated. On the other hand, when the received intensity is equal to or higher than the threshold (S120: NO), the flow proceeds to S130 assuming that the radio wave from the device under measurement 2 is received.

  In S130, an activation command for the storage unit 36 is output. Thus, the first and second time series devices 361 and 362 store the received signals (sampling values) from the respective antenna elements for a certain period.

  In continuing S140, the starting instruction | command with respect to the direction estimation part 37 is output, and this process is complete | finished. Thereby, the 1st and 2nd estimation parts 371 and 372 start the azimuth | direction estimation process based on the memory | storage value of the 1st and 2nd time series apparatuses 361 and 362, respectively.

<Direction estimation processing>
Next, the direction estimation processing will be described along the flowchart shown in FIG. This process is started by an activation command from the activation control unit 35 to the direction estimation unit 37.

  When this process is started, the microcomputer functioning as the first and second estimation units 371 and 372 first extracts orientation candidates based on the stored value of the storage unit 36 in S210. Specifically, using a well-known method for estimating the direction of the incoming wave, such as a beam forming method or a MUSIC method, all the azimuths that provide a reception intensity equal to or higher than a predetermined determination threshold are extracted as azimuth candidates. FIG. 4 illustrates the received intensity distribution obtained by sweeping within the search range (−90 ° to + 90 °) by the beam forming method. In the case of FIG. 4, two azimuth candidates are extracted.

  In subsequent S220, for all the extracted azimuth candidates, a so-called beam forming is performed by weighting and adding the stored values in the storage unit 36 using weights corresponding to the azimuth candidates (see FIG. 5). A reproduction signal (a time series of sampling values) corresponding to the reception signal for the incoming wave is generated. As shown in FIG. 5, assuming that the distance between the antenna elements is d and the direction of arrival is θ, the received signal of each antenna element has a phase difference corresponding to the path difference of dsin θ. Such a weight wi (θ) may be set. Thereby, for example, when the detected arrival direction is −30 °, a reproduction signal corresponding to a reception signal from an antenna having reception characteristics as shown in FIG. 6 is generated by beam forming.

In subsequent S230, one of the orientation candidates is set as a provisional orientation.
In subsequent S240, it is determined whether or not there is an unprocessed azimuth candidate that has not been set as a comparative azimuth in the process described later, except for a azimuth candidate set as a provisional azimuth. When there is an unprocessed azimuth candidate (S240: YES), the process proceeds to S250.

In S250, one of the unprocessed azimuth candidates is set as the comparison azimuth.
In subsequent S260, a synchronization adjustment value representing a phase difference between the reproduction signal for the provisional azimuth and the reproduction signal for the comparison azimuth is acquired. Specifically, the synchronization adjustment value is acquired by operating the synchronization circuit 373 or 374 with both playback signals as input signals. The synchronization adjustment value is a positive value when the phase of the playback signal is delayed in the provisional direction compared to the comparison direction, that is, when the arrival wave from the provisional direction is later in arrival time, and vice versa. That is, it is assumed that the arrival wave from the provisional direction has a negative value when the arrival time is earlier. That is, in the case of FIG. 7, the synchronization adjustment value is a negative value.

In subsequent S270, it is determined whether or not the synchronization adjustment value is a positive value. If the synchronization adjustment value is a positive value, that is, the arrival time from the comparison direction is earlier (S270: YES), the comparison direction is set to a new provisional direction in S280, and the process returns to S240. On the other hand, when the synchronization adjustment value is not a positive value, that is, when the arrival time from the provisional direction is earlier (S270: NO), the process returns to S240 as it is In the previous S240, there is an unprocessed direction candidate If it is determined not to do so (S240: NO), it is determined in S290 that the incoming wave from the provisional azimuth is a direct wave with the earliest arrival time, and this provisional azimuth is determined as the arrival direction DRi (in the first estimation unit 371) i = 1, and the second estimation unit 372 selects i = 2), supplies this to the position estimation unit 38, and ends this processing.

[1.3. effect]
As described above, when it is detected that the designated wave transmitted from the device under measurement 2 has arrived from a plurality of directions in the measuring device 3, the arrival time arrives earliest, that is, arrives in the shortest time. The direction of the direct wave is selected as the arrival direction of the specified wave. Therefore, even in an environment where multipath occurs, the direction in which the device under measurement 2 exists can be detected correctly, and the position of the device under measurement 2 can be obtained with high accuracy.

[1.4. Modified example]
In this embodiment, the storage unit 36 and the direction estimation unit 37 receive two systems of received signals obtained from the first and second receivers 33 and 34, and the device groups 361, 371, 272/362 prepared for each system. , 372, and 374, the processing is executed in parallel. However, the two received signals may be processed in a time division manner by a single device group. In this case, for example, as in the measurement device 3a shown in FIG. 8, the storage unit 36a is configured by one time series device 363, and the azimuth estimation unit 37a is configured by one estimation unit 375 and a synchronization circuit 376. Furthermore, a changeover switch 39 is provided that alternately switches the two systems of received signals supplied from the first and second receivers 33 and 34 and supplies them to the time series device 363. Then, the reception signals of both systems are stored in the time series device 363, and the estimation unit 375 and the synchronization circuit 376 are caused to execute the direction estimation processing of each system in a time division manner.

  Further, as in the measurement apparatus 3b shown in FIG. 9, by transmitting and receiving the two array antennas 31 and 32 to the single receiver 33a, the received signals of each antenna element are output in a time division manner in the subsequent stage. Further, a configuration in which the changeover switch 39 is further omitted from the measurement apparatus 3a shown in FIG.

[2. Second Embodiment]
Since the basic configuration of the second embodiment is the same as that of the first embodiment, the description of the common configuration will be omitted, and the description will focus on the differences.

  In the first embodiment described above, the reception signals supplied from the receivers 33 and 34 are once stored in the storage unit 36, and then the azimuth estimation unit 37 executes processing using the stored values. In contrast, the second embodiment is different from the first embodiment in that the received signal is processed in real time without being stored in the storage unit 36.

[2.1. Constitution]
In this embodiment, the configuration of the measuring device 3c is different from that of the first embodiment. As shown in FIG. 10, the measuring device 3c has a configuration in which the storage unit 36 is omitted from the measuring device 3 shown in FIG.

[2.2. processing]
Hereinafter, in the activation control unit 35, an activation process executed in place of the activation process (FIG. 2) of the first embodiment, and in the first and second estimation units 371 and 372, the direction estimation process (FIG. An orientation estimation process executed instead of 3) will be described.

<Startup process>
As shown in FIG. 11, the activation process is the same as that in the first embodiment except that S130 is omitted.

<Direction estimation processing>
As shown in FIG. 12, when this process is started, the microcomputer functioning as the first and second estimation units 371 and 372 first, in S310, a predetermined azimuth search range (for example, −90 ° with respect to the front direction). ˜ + 90 °), a sweep (scanning) for changing the direction by a predetermined angle and measuring the reception intensity by beam forming is started.

  In subsequent S320, it is determined whether or not a peak of received intensity has been detected. When the peak is not detected (S320: NO), the process proceeds to S330, and it is determined whether or not the sweep is finished. If the sweep is not completed (S330: NO), the process returns to S320 and the sweep is continued. On the other hand, when the sweep has been completed (S330: YES), the process proceeds to S340, an error notification indicating that no peak has been detected is performed by a not-illustrated notification device, and this process is terminated.

If a peak is detected in the previous S320 (S320: YES), the process proceeds to S350, the azimuth of the detected peak is set as a provisional azimuth, and the process proceeds to S360.
In S360, the sweep is resumed, and in subsequent S370, it is determined whether or not the peak of the received intensity is detected again. When a peak is detected (S370: YES), the process proceeds to S380, the direction of the detected peak is set as a comparison direction, and the process proceeds to S390.

  In S390, similar to the processing in S260 described in the first embodiment, the time difference between the arrival waves from the provisional direction and the arrival wave from the comparison direction, that is, the synchronization representing the phase difference between the time signals of both arrival waves. Get the adjustment value. However, in S260, the reproduction signal generated from the stored value of the storage unit 36 is used as the input signal of the synchronization circuit 373 or 374. However, in this embodiment, the received signal supplied from the receiver 33 or 34 is used in real time. The generated reproduction signal is used.

In subsequent S400, it is determined whether or not the synchronization adjustment value acquired in S390 is a positive value. When the synchronization adjustment value is a positive value, that is, when the arrival time from the comparison direction is earlier (S400: YES), the comparison direction is set to the provisional direction in S410, and the process returns to S360. On the other hand, if the synchronization adjustment value is not a positive value, that is, the arrival time from the provisional azimuth is earlier in arrival time (S400: NO), the process returns to S360 as it is. No peak of the received intensity is detected in the previous S370. In the case (S370: NO), the process proceeds to S420, and it is determined whether or not the sweep is finished. When the sweep is not completed (S420: NO), the process returns to S370 and continues the sweep. On the other hand, when the sweep is finished (S420: YES), the process proceeds to S430, and the provisional direction is changed to the arrival direction DRi (where i = 1 in the first estimation unit 371 and i = 2 in the second estimation unit 372). This is selected and supplied to the position estimation unit 38, and the present process is terminated.

[2.3. Operation]
In this way, in the direction estimation processing, as shown in FIG. 13, there are three incoming waves A, B, and C, the middle incoming wave B is a direct wave, and the other incoming waves A and C are reflected waves. It operates as follows.

That is, when the reception intensity sweep is started and the first peak based on the incoming wave A is detected, the direction (peak direction A) is set as the provisional direction.
When the sweep is resumed and the next peak based on the incoming wave B is detected, the direction (peak direction B) is set as the comparative direction, and the temporary direction (peak direction A) and the comparative direction (peak direction B) are set. Compare the arrival time of each incoming wave. Here, since the incoming wave with the peak direction B is earlier, the peak direction B is set as a new provisional direction.

  When the sweep is resumed and the next peak based on the incoming wave C is detected, the direction (peak direction C) is set as the comparison direction, and the temporary direction (peak direction B) and the comparison direction (peak direction C) are set. Compare the arrival time of each incoming wave. Here, since the incoming wave with the peak direction B is earlier, the provisional direction is not updated and the peak direction B is maintained.

  When the sweep is resumed without a new peak being detected, the peak direction set as the provisional direction at that time is selected as the arrival direction DRi and supplied to the position estimation unit.

[2.4. effect]
According to the second embodiment described in detail above, the following effects are obtained in addition to the effects of the first embodiment described above.

  That is, in this embodiment, since the processing is executed in real time without temporarily storing the received signal, the storage unit 36 can be omitted as compared with the measuring device 3 of the first embodiment. As a result, the apparatus configuration can be simplified.

[2.5. Modified example]
A configuration in which the storage unit 36a is omitted from the measurement device 3a illustrated in FIG. 8 as in the measurement device 3d illustrated in FIG. 14 or a storage from the measurement device 3b illustrated in FIG. 9 as in the measurement device 3e illustrated in FIG. A configuration in which the part 36a is omitted may be adopted.

[3. Other Embodiments]
As mentioned above, although embodiment of this invention was described, this invention can take a various form, without being limited to the said embodiment.

  (1) Although the case where the measuring device 3 is an in-vehicle device has been described in the above embodiment, the present invention is not limited to this. For example, both the device under measurement 2 and the measurement device 3 may be mounted on a portable device such as a mobile phone.

  (2) The functions of one component in the above embodiment may be distributed to a plurality of components, or the functions of a plurality of components may be integrated into one component. Further, at least a part of the configuration of the above embodiment may be replaced with a known configuration having the same function. Moreover, you may abbreviate | omit a part of structure of the said embodiment. Further, at least a part of the configuration of the above embodiment may be added to or replaced with the configuration of the other embodiment. In addition, all the aspects included in the technical idea specified only by the wording described in the claim are embodiment of this invention.

  (3) In addition to the arrival direction estimation device described above, the present invention can be realized in various forms such as a program for causing a computer to function as the arrival direction estimation device, a medium on which the program is recorded, and an arrival direction estimation method.

  DESCRIPTION OF SYMBOLS 1 ... Position estimation system 2 ... Device under test 3, 3a-3e ... Measuring device 21 ... Antenna 22 ... Transmitter 23 ... Receiver 24 ... Communication controller 31, 32 ... Array antenna 33, 34, 33a ... Receiver 35 ... Start-up control unit 36, 36a ... storage unit 37, 37a ... direction estimation unit 38 ... position estimation unit 39 ... changeover switch 361-363 ... time series device 371, 372, 375 ... estimation unit 373, 374, 376 ... synchronization circuit

Claims (5)

An azimuth extraction unit (371, 372, 373: S210, S310 to S330, S360 to S420) for extracting the arrival direction of a designated wave designated in advance based on the received signal from each antenna element constituting the array antenna;
When there are a plurality of arrival directions extracted by the azimuth extraction unit, a reproduction signal that is a reception signal of an arrival wave from each arrival direction is generated by beam forming, and arrives earliest from the phase difference between the reproduction signals. An azimuth selector (371, 372, 373: S220 to S290, S350, S380 to S410, S430) for selecting the direction of the incoming wave;
An activation control unit (35) for activating the azimuth extraction unit and the azimuth selection unit when reception in a frequency band to which the designated wave belongs is detected;
The direction-of-arrival estimation apparatus characterized in that the direction selected by the direction selection unit is output as the true direction of arrival of the designated wave.   The azimuth selection unit obtains a synchronization adjustment value that is a control value for synchronizing the reproduction signal by using a synchronization circuit that synchronizes two signals, and the phase advance between the reproduction signals is determined from the synchronization adjustment value. The arrival direction estimation apparatus according to claim 1, wherein a delay is determined. The activation control unit stores the time series of the received signals in the storage means (361, 362, 363) before activating the azimuth extraction unit and the azimuth selection unit,
The direction-of-arrival estimation apparatus according to claim 1 or 2 , wherein the azimuth extraction unit and the azimuth selection unit execute processing according to a reception signal stored in the storage unit. A plurality of direction-of-arrival estimation devices ( 35, 37 , 37a) according to any one of claims 1 to 3 , which operate based on received signals from different array antennas (31, 32);
A position estimation unit (38) for estimating a position of a generation source of the designated wave from a true arrival direction of the designated wave estimated by the plurality of arrival direction estimation devices;
A position estimation apparatus comprising: A transmission side device (2) for transmitting the designated wave;
The position estimation device according to claim 4 , wherein the position estimation device estimates one or more array antennas that receive the designated wave and a position of the transmitting-side device that is a generation source of the designated wave based on a reception signal from the array antenna. A receiving side device (3, 3a-3e) comprising:
A position estimation system comprising:

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