WO2021181590A1

WO2021181590A1 - Calibration value calculation device, radar calibration device, and calibration value calculation method

Info

Publication number: WO2021181590A1
Application number: PCT/JP2020/010695
Authority: WO
Inventors: 善樹高橋; 正資大島; 龍平高橋
Original assignee: 三菱電機株式会社
Priority date: 2020-03-12
Filing date: 2020-03-12
Publication date: 2021-09-16

Abstract

A calibration value calculation device (300) comprises: a calibration data acquisition unit (11) that acquires calibration data corresponding to a calibration signal received by individual antenna elements (3) included in individual sub-arrays (2) included in a first array antenna (1); a calibration value calculation unit (12) that uses the calibration data to calculate calibration values (H, G), including a first calibration value (H) that corresponds to a intra-sub-array measurement error in the individual sub-arrays (2) and a second calibration value (G) that corresponds to an inter-sub-array measurement error in the first array antenna (1); and a calibration value output unit (13) that outputs the calibration values (H, G). The calibration data corresponds to a calibration signal received by the individual antenna elements (3) in a state where a calibration signal source (4) is positioned in a prescribed area (A). The area (A) is included in a distant boundary of the individual sub-arrays (2), and is included in a nearby boundary of the first array antenna (1).

Description

Calibration value calculation device, radar calibration device and calibration value calculation method

This disclosure relates to a calibration value calculation device, a radar calibration device, and a calibration value calculation method.

Conventionally, radar using an array antenna has been developed. Specifically, for example, a distributed radar using a distributed array antenna has been developed. Further, for example, a MIMO radar using a MIMO (Multi Input Multi Output) array antenna has been developed. Also, for example, distributed MIMO radar has been developed.

In a radar using an array antenna, an error occurs due to mutual coupling between elements in the array antenna. That is, when a signal is received by a plurality of antenna elements included in the array antenna, the amplitude and phase of the received signal vary. From the viewpoint of improving the angular resolution of the radar, it is preferable to calibrate the radar so that such an error is corrected. Non-Patent Document 1 discloses such a calibration method.

The error due to mutual coupling between elements has an angle dependence. Therefore, when calculating the calibration value for correcting such an error, it is required to use the data corresponding to a plurality of incident angles different from each other. Such data is collected, for example, as follows. That is, one signal source for calibration is sequentially arranged at a plurality of known positions. Alternatively, a plurality of signal sources for calibration are arranged at the plurality of positions. By sequentially transmitting calibration signals from the one signal source or the plurality of signal sources, data corresponding to the plurality of positions (that is, data corresponding to a plurality of incident angles different from each other) are collected. Will be done.

Here, the number of data required to calculate such a calibration value differs depending on the number of antenna elements included in the array antenna. Therefore, the number of times the signal is transmitted (that is, the number of times the data is acquired) required for collecting such data also differs depending on the number of such antenna elements. When the number of antenna elements included in the array antenna is large, there is a problem that the number of times the signal is transmitted (that is, the number of times the data is acquired) required for collecting such data is large.

The present disclosure has been made to solve the above-mentioned problems, and an object of the present disclosure is to calculate a calibration value using data collected with a smaller number of data acquisitions.

The calibration value calculation device according to the present disclosure includes a calibration data acquisition unit that acquires calibration data corresponding to calibration signals received by individual antenna elements included in the individual sub-arrays included in the first array antenna. Using the calibration data, a calibration value calculation unit that calculates a calibration value including a first calibration value corresponding to an error in the sub-array in each sub-array and a second calibration value corresponding to an error between sub-arrays in the first array antenna, and a calibration value calculation unit. It is equipped with a calibration value output unit that outputs calibration values, and the calibration data corresponds to the calibration signal received by each antenna element with the calibration signal source arranged in a predetermined area. Yes, the region is included in the far field for each sub-array and is included in the near field for the first array antenna.

According to the present disclosure, since it is configured as described above, the calibration value can be calculated using the data collected with a smaller number of data acquisitions.

It is a block diagram which shows the main part of the calibration data collection system which concerns on Embodiment 1. FIG. It is explanatory drawing which shows the example of a plurality of incident angles. It is a block diagram which shows the main part of the radar calibration apparatus which concerns on Embodiment 1. FIG. It is a block diagram which shows the main part of the calibration value calculation part in the calibration value calculation apparatus which concerns on Embodiment 1. FIG. It is a block diagram which shows the hardware composition of the main part of the radar calibration apparatus which concerns on Embodiment 1. FIG. It is a block diagram which shows the other hardware configuration of the main part of the radar calibration apparatus which concerns on Embodiment 1. FIG. It is a block diagram which shows the other hardware configuration of the main part of the radar calibration apparatus which concerns on Embodiment 1. FIG. It is a flowchart which shows the operation of the calibration value calculation apparatus which concerns on Embodiment 1. FIG. It is a flowchart which shows the operation of the radar calibration apparatus which concerns on Embodiment 1. FIG. It is a block diagram which shows the main part of the calibration data collection system which concerns on Embodiment 2. It is a block diagram which shows the main part of the calibration data collection system which concerns on Embodiment 3. It is a block diagram which shows the main part of the radar calibration apparatus which concerns on Embodiment 3. It is a block diagram which shows the main part of the calibration value calculation part in the calibration value calculation apparatus which concerns on Embodiment 3. FIG. It is a flowchart which shows the operation of the calibration value calculation apparatus which concerns on Embodiment 3. It is a flowchart which shows the operation of the radar calibration apparatus which concerns on Embodiment 3.

Hereinafter, in order to explain this disclosure in more detail, a mode for carrying out this disclosure will be described with reference to the attached drawings.

Embodiment 1.
FIG. 1 is a block diagram showing a main part of the calibration data collection system according to the first embodiment. The calibration data collection system according to the first embodiment will be described with reference to FIG.

The calibration data collection system 100 includes an array antenna 1. The array antenna 1 includes M sub-arrays 2. Each sub-array 2 includes L antenna elements 3. Here, M is an integer of 2 or more. Further, L is an integer of 2 or more. Hereinafter, the array antenna 1 may be referred to as a "first array antenna".

M sub-arrays 2 are distributed. That is, the array antenna 1 is composed of a distributed array antenna. The array antenna 1 is used for distributed radar.

Hereinafter, the arrangement shape of the L antenna elements 3 in each sub array 2 is referred to as an “element arrangement shape”. The M sub-arrays 2 have element arrangement shapes common to each other. That is, the M sub-arrays 2 have the same element arrangement shape.

The calibration data collection system 100 includes a calibration signal source 4. The calibration signal source 4 is arranged in a predetermined area A. More specifically, the calibration signal source 4 is sequentially arranged at a plurality of positions P included in the area A by moving in the area A. The individual positions P are known.

Here, the region A is included in the far field for each sub-array 2 and is included in the near field for the entire array antenna 1. That is, each of the plurality of positions P is included in the far field with respect to the individual sub-array 2 and is included in the near field with respect to the entire array antenna 1.

The calibration signal source 4 transmits a calibration signal (hereinafter referred to as "calibration signal") in a state of being arranged at each of a plurality of positions P. That is, the calibration signal source 4 transmits the calibration signal a plurality of times. The transmitted calibration signal is received by the individual antenna elements 3 included in the individual sub-arrays 2.

The calibration data collection system 100 includes M analog-to-digital converters (hereinafter referred to as "A / D converters") 5. The M A / D converters 5 have a one-to-one correspondence with the M sub-arrays 2. Each time the calibration signal source 4 transmits a calibration signal, each A / D converter 5 digitally data the calibration signal received by each of the L antenna elements 3 included in the corresponding sub-array 2. It is to be converted to. Each A / D converter 5 outputs the changed digital data. Hereinafter, the converted digital data is referred to as "calibration signal data".

In each A / D converter 5, the frequency of the received calibration signal is converted into a frequency in the baseband by executing the frequency conversion process for the received calibration signal. .. Further, in each A / D converter 5, the received calibration signals are sampled at timings synchronized with each other.

The calibration data collection system 100 includes a storage device 6. The storage device 6 stores calibration signal data output by each A / D converter 5. Further, the storage device 6 stores data indicating the position P corresponding to each calibration signal data (hereinafter, referred to as “signal source position data”). Hereinafter, the calibration signal data and the corresponding signal source position data may be collectively referred to as “calibration data”.

In this way, calibration data corresponding to the plurality of positions P are collected. Also, as mentioned above, the individual positions P are known. Therefore, with respect to the M incident angles θ corresponding to the M sub-arrays 2 on a one-to-one basis, a data table showing the correspondence between the individual positions P and the M incident angles θ (hereinafter referred to as “position-angle data table””. .) DT is generated. Figure 2 shows an example of a correspondence between the two incident angle theta _1, theta _M of the one position P and M of the incident angle theta _{1 ~} theta _M of a plurality of positions P There is.

Here, the calibration signal data stored in the storage device 6 includes a component corresponding to an error in each sub-array 2 (hereinafter referred to as “error in sub-array”) (hereinafter referred to as “error component in sub-array”). It is an error. That is, when the calibration signal is received by the L antenna elements 3 included in the individual sub-arrays 2, the amplitude, phase, delay time, and the like of the received calibration signal may vary. In other words, the amplitude, phase, delay time, and the like may differ between each of the two antenna elements 3 of the L antenna elements 3. As a result, the calibration signal data includes the error component in the sub-array. The error in the sub-array is due to mutual coupling between elements in each sub-array 2.

Further, the calibration signal data stored in the storage device 6 has a component corresponding to an error between each of the two sub-arrays 2 of the M sub-arrays 2 (hereinafter referred to as “sub-array error”) (hereinafter, “sub-array error”). It is called "error component between sub-arrays"). That is, when the calibration signal is received by the M sub-arrays, the amplitude, phase, delay time, etc. of the received calibration signal may vary. In other words, the amplitude, phase, delay time, etc. may differ between each of the two sub-arrays 2 of the M sub-arrays 2. As a result, the calibration signal data includes an error component between sub-arrays.

Hereinafter, the calibration value H corresponding to the error in the sub-array may be referred to as "calibration value in sub-array" or "first calibration value". Further, the calibration value G corresponding to the error between sub-arrays may be referred to as "calibration value between sub-arrays" or "second calibration value".

As described above, the error in the sub-array is due to the mutual coupling between the elements in each sub-array 2. Therefore, in order to calculate the calibration value H in the sub-array, it is required to collect calibration data corresponding to a plurality of incident angles θ different from each other. More specifically, it is required to collect calibration data corresponding to (L + 1) or more incident angles θ different from each other.

In the calibration data collection system 100, the calibration signal source 4 is arranged in the area A as described above. The region A is included in the far field for each sub-array 2 and is included in the near field for the entire array antenna 1. Therefore, each time the calibration signal source 4 transmits a calibration signal once (that is, each time the calibration signal source 4 transmits a calibration signal at one position P), a plurality of incidents different from each other are incident. Calibration data corresponding to the angle θ is acquired. More specifically, calibration data corresponding to M different incident angles θ are acquired.

As a result, the number of times the calibration signal is transmitted by the calibration signal source 4 (that is, the number of positions P) can be reduced when collecting calibration data corresponding to (L + 1) or more incident angles θ different from each other. .. In other words, the number of acquisitions of calibration data can be reduced.

When the number M of the sub-array 2 is sufficiently larger than the number L of the antenna elements 3 (for example, when M is set to a value of (L + 1) or more), the calibration signal source 4 is included in the region A. Instead of being sequentially arranged at a plurality of positions P, it may be arranged at one position P included in the area A. The calibration signal source 4 may transmit a calibration signal in a state of being arranged at the one position P. That is, the calibration signal source 4 may transmit the calibration signal once instead of transmitting the calibration signal a plurality of times. Hereinafter, an example in which the calibration signal source 4 is arranged at the one position P will be mainly described.

FIG. 3 is a block diagram showing a main part of the radar calibration device according to the first embodiment. FIG. 4 is a block diagram showing a main part of the calibration value calculation unit in the calibration value calculation device according to the first embodiment. The radar calibration device according to the first embodiment will be described with reference to FIGS. 3 and 4, and the calibration value calculation device according to the first embodiment will be described.

As shown in FIG. 3, the radar calibration device 200 includes a calibration data acquisition unit 11, a calibration value calculation unit 12, a calibration value output unit 13, and a calibration processing unit 14. The calibration value calculation unit 12 includes a first calibration value calculation unit 21 and a second calibration value calculation unit 22. The calibration data acquisition unit 11, the calibration value calculation unit 12, and the calibration value output unit 13 constitute a main part of the calibration value calculation device 300.

As shown in FIG. 4, the first calibration value calculation unit 21 includes the position-angle data table DT and the calibration value calculation unit 31 in the sub-array. The second calibration value calculation unit 22 includes a position-angle data table DT, a beam formation processing unit 41, and a calibration value calculation unit 42 between sub-arrays.

The position-angle data table DT is included in either the first calibration value calculation unit 21 or the second calibration value calculation unit 22, and the position-angle data table DT is used as the first calibration value. It may be shared by the calculation unit 21 and the second calibration value calculation unit 22.

The calibration data acquisition unit 11 acquires the calibration data stored in the storage device 6. The calibration data acquisition unit 11 outputs the acquired calibration data to the calibration value calculation unit 31 in the sub-array and the beam formation processing unit 41.

The calibration value calculation unit 31 in the sub-array acquires the calibration data output by the calibration data acquisition unit 11. The calibration value calculation unit 31 in the sub-array uses the position-angle data table DT to calculate the incident angle θ corresponding to the position P indicated by the individual signal source position data included in the acquired calibration data. be.

The calibration value calculation unit 31 in the sub-array calculates the calibration value H in the sub-array using the calibration signal data included in the acquired calibration data and the calculated incident angle θ. The method of calculating the calibration value H in the sub-array will be described later. The calibration value calculation unit 31 in the sub-array outputs the calculated calibration value H in the sub-array to the calibration value output unit 13 and the beam forming processing unit 41.

The beam forming processing unit 41 acquires the calibration data output by the calibration data acquisition unit 11, and also acquires the calibration value H in the sub-array output by the calibration value calculation unit 31 in the sub-array. The beam forming processing unit 41 uses the position-angle data table DT to calculate the incident angle θ corresponding to the position P indicated by the individual signal source position data included in the acquired calibration data. Further, the beam forming processing unit 41 uses the acquired calibration value H in the sub-array to correct the calibration signal data included in the acquired calibration data.

The beamforming processing unit 41 executes digital beamforming processing (hereinafter referred to as “first DBF processing”) corresponding to each sub-array 2 by using the corrected calibration signal data and the calculated incident angle θ. To do. As a result, data corresponding to the beam output by each sub-array 2 is generated. The beam forming processing unit 41 outputs the generated data to the calibration value calculation unit 42 between sub-arrays.

The calibration value calculation unit 42 between sub-arrays acquires the data output by the beam formation processing unit 41. The inter-sub array calibration value calculation unit 42 calculates the inter-sub array calibration value G using the acquired data. The method of calculating the calibration value G between sub-arrays will be described later. The inter-sub array calibration value calculation unit 42 outputs the calculated inter-sub array calibration value G to the calibration value output unit 13.

The calibration value output unit 13 acquires the calibration value H in the sub-array output by the calibration value calculation unit 31 in the sub-array, and also acquires the calibration value G in the sub-array output by the calibration value calculation unit 42 between sub-arrays. .. The calibration value output unit 13 outputs the acquired calibration values H and G to the outside of the calibration value calculation device 300. That is, the calibration value output unit 13 outputs the acquired calibration values H and G to the calibration processing unit 14.

The calibration processing unit 14 acquires the calibration values H and G output by the calibration value output unit 13. The calibration processing unit 14 executes the calibration processing of the radar (not shown) using the array antenna 1 by using the acquired calibration values H and G. That is, the calibration processing unit 14 executes the calibration processing of the distributed radar. Various known techniques can be used for such calibration processing. Detailed description of these techniques will be omitted.

In this way, the main part of the radar calibration device 200 is configured.

Hereinafter, the code of "F1" may be used for the function of the calibration data acquisition unit 11. In addition, the code "F2_1" may be used for the function of the first calibration value calculation unit 21. In addition, the code "F2_2" may be used for the function of the second calibration value calculation unit 22. Further, the reference numeral "F3" may be used for the function of the calibration value output unit 13. Further, the reference numeral "F4" may be used for the function of the calibration processing unit 14.

Hereinafter, the processes executed by the calibration data acquisition unit 11 may be collectively referred to as "calibration data acquisition process". Further, the processes executed by the first calibration value calculation unit 21 may be collectively referred to as "first calibration value calculation process". Further, the processes executed by the second calibration value calculation unit 22 may be collectively referred to as "second calibration value calculation process". Further, the processes executed by the calibration value output unit 13 may be collectively referred to as "calibration value output process". Further, the processes executed by the calibration value calculation device 300 may be collectively referred to as "calibration value calculation process". Further, the processing executed by the calibration processing unit 14 may be collectively referred to as "radar calibration processing".

Next, the hardware configuration of the main part of the radar calibration device 200 will be described with reference to FIGS. 5 to 7.

As shown in FIG. 5, the radar calibration device 200 has a processor 51 and a memory 52. The memory 52 stores programs corresponding to a plurality of functions F1, F2_1, F2_2, F3, and F4. The processor 51 reads and executes the program stored in the memory 52. As a result, a plurality of functions F1, F2_1, F2_2, F3, and F4 are realized.

Alternatively, as shown in FIG. 6, the radar calibration device 200 has a processing circuit 53. The processing circuit 53 executes processing corresponding to a plurality of functions F1, F2_1, F2_2, F3, and F4. As a result, a plurality of functions F1, F2_1, F2_2, F3, and F4 are realized.

Alternatively, as shown in FIG. 7, the radar calibration device 200 includes a processor 51, a memory 52, and a processing circuit 53. The memory 52 stores programs corresponding to some of the plurality of functions F1, F2_1, F2_2, F3, and F4. The processor 51 reads and executes the program stored in the memory 52. As a result, some of these functions are realized. Further, the processing circuit 53 executes processing corresponding to the remaining functions of the plurality of functions F1, F2_1, F2_2, F3, and F4. As a result, such a residual function is realized.

The processor 51 is composed of one or more processors. As each processor, for example, a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), a microprocessor, a microcontroller, or a DSP (Digital Signal Processor) is used.

The memory 52 is composed of one or more non-volatile memories. Alternatively, the memory 52 is composed of one or more non-volatile memories and one or more volatile memories. That is, the memory 52 is composed of one or more memories. The individual memory uses, for example, a semiconductor memory, a magnetic disk, an optical disk, a magneto-optical disk, a magnetic tape, or a magnetic drum. More specifically, each volatile memory uses, for example, a RAM (Random Access Memory). In addition, individual non-volatile memories include, for example, ROM (Read Only Memory), flash memory, EPROM (Erasable Programmable Read Only Memory), EEPROM (Electrically Erasable Programmory), EEPROM (Electrically Erasable Programmory), flexible disk drive A compact disc, a DVD (Digital Versaille Disc), a Blu-ray disc, or a mini disc is used.

The processing circuit 53 is composed of one or more digital circuits. Alternatively, the processing circuit 53 is composed of one or more digital circuits and one or more analog circuits. That is, the processing circuit 53 is composed of one or more processing circuits. The individual processing circuits are, for example, ASIC (Application Special Integrated Circuit), PLD (Programmable Logic Device), FPGA (Field Programmable Gate Array), FPGA (Field Program Is.

Here, when the processor 51 is composed of a plurality of processors, the correspondence between the plurality of functions F1, F2_1, F2_2, F3, F4 and the plurality of processors is arbitrary. That is, each of the plurality of processors may read and execute a program corresponding to one or more corresponding functions among the plurality of functions F1, F2_1, F2_2, F3, and F4. The processor 51 may include a dedicated processor corresponding to each function F1, F2_1, F2_2, F3, F4.

Further, when the memory 52 is composed of a plurality of memories, the correspondence between the plurality of functions F1, F2_1, F2_2, F3, F4 and the plurality of memories is arbitrary. That is, each of the plurality of memories may store a program corresponding to one or more of the plurality of functions F1, F2_1, F2_2, F3, and F4. The memory 52 may include a dedicated memory corresponding to each function F1, F2_1, F2_2, F3, F4.

Further, when the processing circuit 53 is composed of a plurality of processing circuits, the correspondence between the plurality of functions F1, F2_1, F2_2, F3, F4 and the plurality of processing circuits is arbitrary. That is, each of the plurality of processing circuits may execute processing corresponding to one or more corresponding functions among the plurality of functions F1, F2_1, F2_2, F3, and F4. The processing circuit 53 may include a dedicated processing circuit corresponding to each function F1, F2_1, F2_2, F3, F4.

Next, the operation of the calibration value calculation device 300 will be described with reference to the flowchart shown in FIG.

First, the calibration data acquisition unit 11 executes the calibration data acquisition process (step ST1). As a result, the calibration data stored in the storage device 6 is acquired.

Next, the first calibration value calculation unit 21 executes the first calibration value calculation process (step ST2_1). As a result, the calibration value H in the sub array is calculated. The method of calculating the calibration value H in the sub-array will be described later.

Next, the second calibration value calculation unit 22 executes the second calibration value calculation process (step ST2_2). As a result, the calibration value G between sub-arrays is calculated. The method of calculating the calibration value G between sub-arrays will be described later.

Next, the calibration value output unit 13 executes the calibration value output process (step ST3). As a result, the calibration value H in the sub-array calculated in step ST2_1 and the calibration value G between sub-arrays calculated in step ST2_1 are output to the outside of the calibration value calculation device 300.

Next, the operation of the radar calibration device 200 will be described with reference to the flowchart shown in FIG.

First, the calibration value calculation device 300 executes the calibration value calculation process (step ST11). As a result, the processes of steps ST1, ST2_1, ST2_2, and ST3 shown in FIG. 8 are executed. That is, the calibration value H in the sub-array and the calibration value G between sub-arrays are calculated, and the calculated calibration values H and G are output.

Next, the calibration processing unit 14 executes the radar calibration processing (step ST4). The calibration values H and G output in step ST11 are used for the radar calibration process.

Next, the calculation method of the calibration value H in the sub-array will be described.

Hereinafter, when any element in an arbitrary formula is described in a sentence, the element is described in a non-bold type regardless of whether the typeface of the element in the formula is bold or not. In addition, the element is described in non-italic type regardless of whether the typeface of the element in the mathematical formula is italic. This is mainly due to the request for electronic filing, and the typeface in the mathematical formula is correct for the typeface of each element.

It is assumed that there is an error in the array antenna 1 now. Further, it is assumed that the corresponding time sample number is Ns and the corresponding incident wave number is K for the calibration signal data stored in the storage device 6. At this time, with respect to the calibration data acquired by the calibration data acquisition unit 11, the input data vector z of L × Ns is represented by the following equations (1) to (3).

Here, _ARx is a matrix of L × K in which K reception array steering vectors a _{Rx are arranged in the column direction.} The individual received array steering vector a _Rx contains information indicating the direction of the incoming wave (that is, the incident angle θ). S is a signal matrix of K × Ns, and includes information that varies depending on the number of incoming waves (that is, the number k of incident waves) and time. C is an error matrix and indicates an error in the array antenna 1.

As described above, when an error exists in the array antenna 1, the received data (that is, the calibration data acquired by the calibration data acquisition unit 11) has a form in which the steering vector is multiplied by the error matrix. Become.

Here, first, as described above, the M sub-arrays 2 have the same element arrangement shape. Secondly, for the sake of simplicity, it is assumed that the number K of the incident waves is 1. Third, as described above, the M sub-arrays 2 are distributed. That is, the distance between each of the two sub-arrays 2 of the M sub-arrays 2 is set to a sufficiently large value. Then, the above equation (2) is rewritten as the following equations (4) to (6).

Here, G is a matrix of LM × LM, and indicates a calibration value between sub-arrays. H is an L × L matrix and indicates a calibration value in the sub-array. a _{sub, m} (θ) indicates a steering vector corresponding to the mth sub-array 2 of the M sub-arrays 2.

The calibration value H in the sub-array is calculated by using, for example, the method described in Reference 1 below. By using such a method, the calibration value H in the sub-array can be calculated based on the calibration signal data and the signal source position data indicating the corresponding known position P.

[Reference 1]
Takahiro Arai, Rokuzo Hara, Hiroki Yamada, Yoshio Yamaguchi, "On the Super Resolution Array Proofreading Method Using Known Wave Sources", IEICE Transactions B, Vol. J86-B, No. 3, pp. 527-535, March 2003.

That is, according to the description in Reference Document 1, a calibration filter can be obtained by solving the equations shown in the following equations (7) to (10).

Here, E N _^(q) is the calculated noise eigenvectors using q-th data in the calibration signal data matrix to the column element. θ _q indicates the incident direction (that is, the incident angle θ) corresponding to the qth data in the calibration signal data. E _N ^{(q) H} and a (θ _q) operator between is a Kronecker product operator. ^H indicates a complex conjugate transpose. ^T indicates transposition.

Such an equation can be solved using the method of least squares by fixing the value in the first row and first column of the matrix representing the calibration value to 1. That is, it can be solved as shown in the following equations (11) to (12).

In this way, the calibration value H in the sub array is calculated. That is, the calibration value H in the sub-array can be calculated using the calibration data collected at the reduced number of data acquisitions as described above.

When the calibration signal data includes data corresponding to a plurality of waves (that is, K wave), the first calibration value calculation unit 21 separates the data corresponding to the plurality of waves into the data corresponding to each one wave. It may be a thing. The first calibration value calculation unit 21 may calculate the calibration value H in the sub-array by the above method using the separated data. As a result, the calibration value H in the sub-array can be calculated by the above method not only when K = 1 but also when K ≧ 2. For the separation of such data, Doppler frequency or independent component analysis (Independent Component Analysis, ICA) or the like is used.

Further, the method of calculating the calibration value H in the sub-array is not limited to the above specific example. Various known techniques can be used to calculate the calibration value H in the sub-array. Detailed description of these techniques will be omitted.

Next, the method of calculating the calibration value G between sub-arrays will be described.

When the calibration value H in the sub-array is calculated by the calibration value calculation unit 31 in the sub-array, the calibration value calculation unit 42 between sub-arrays generates the received data (that is, generated by the first DBF process) reflecting the calculated calibration value H in the sub-array. The calibration value G between sub-arrays is calculated using the obtained data).

Here, as described above, the distance between each of the two sub-arrays 2 of the M sub-arrays 2 is set to a sufficiently large value. Therefore, in the calculation of the calibration value G between sub-arrays, mutual coupling between elements can be ignored. Therefore, in calculating the individual calibration values g _m in sub-array between calibration value G, it is not necessary to use the data corresponding to the calibration data corresponding to a plurality of incident angle theta. Individual calibration value g _m, using the data corresponding to the calibration signal data corresponding to the selected angle of incidence the theta of a plurality of incident angle theta, is calculated by the following equation (13).

Here, z _m (θ) indicates the data corresponding to the calibration signal data corresponding to the mth sub-array 2 corresponding to the selected incident angle θ. In addition, z _m (θ) may be acquired by using a measuring instrument such as a network analyzer. Further, z _m (θ) may be obtained by executing an integration process such as FFT (Fast Fourier Transform) or pulse compression on the corresponding calibration signal data.

In this way, the calibration value G between sub-arrays is calculated.

Incidentally, each of the calibration values g _m in sub-array between calibration value G may be one that is calculated by the equation (14) below instead of the equation (13). That is, the sub-array calibration value calculation unit 42 calculates a plurality of g _m corresponding to different incident angles θ, and smoothes the calculated plurality of g _m to obtain individual calibration values g _m. May be calculated.

Further, when the error between sub-arrays is non-independent (that is, when the error between sub-arrays is due to mutual coupling between elements or the like), the second calibration value calculation unit 22 performs the calibration value G between sub-arrays as follows. May be calculated. That is, the second calibration value calculation unit 22 executes a process of converting the near field and the far field with respect to the calibration signal data. The second calibration value calculation unit 22 uses the data corresponding to a plurality of different incident angles θ among the converted data by the same method as that described in Reference Document 1 (that is, in the sub-array). The calibration value G between sub-arrays is calculated (by the same calculation method as the calculation method of the calibration value H).

Further, when the calibration signal source 4 moves in the area A (that is, when the calibration signal source 4 is sequentially arranged at a plurality of positions P), the second calibration value calculation unit 22 , An error related to the positional relationship between each position P and each sub-array 2 (hereinafter referred to as “position error”) may be estimated. In other words, the second calibration value calculation unit 22 may estimate the position error between each of the two sub-arrays 2 (that is, the position error corresponding to each sub-array 2). The second calibration value calculation unit 22 may calculate the calibration value G between sub-arrays corrected according to the estimated position error. For the estimation of such a position error, for example, the technique described in Reference Document 2 below is used.

[Reference 2]
International Publication No. 2016/067321

In addition, various known techniques can be used to calculate the calibration value G between sub-arrays. Detailed description of these techniques will be omitted.

Next, a modified example of the calibration data collection system 100 will be described.

The array antenna 1 may include one or more other sub-arrays in addition to the M sub-arrays 2. Each of the one or more other sub-arrays may have an element arrangement shape different from the element arrangement shape in each sub-array 2. That is, in the array antenna 1, all the sub-arrays may have the same element arrangement shape, or only some of the sub-arrays may have the same element arrangement shape.

As described above, the calibration value calculation device 300 according to the first embodiment is for calibration corresponding to the calibration signal received by the individual antenna elements 3 included in the individual sub-arrays 2 included in the first array antenna 1. Between the calibration data acquisition unit 11 for acquiring data and the first calibration value (calibration value H in the sub-array) corresponding to the error in the sub-array in each sub-array 2 and the sub-array in the first array antenna 1 using the calibration data. It is provided with a calibration value calculation unit 12 for calculating calibration values H and G including a second calibration value (calibration value G between sub-arrays) corresponding to an error, and a calibration value output unit 13 for outputting calibration values H and G. The calibration data corresponds to the calibration signal received by the individual antenna elements 3 with the calibration signal source 4 arranged in the predetermined area A, and the area A is for each sub-array 2. It is included in the far field and is included in the near field with respect to the first array antenna 1. Thereby, the calibration values H and G can be calculated using the calibration data collected by the number of data acquisitions reduced according to the number M of the sub-array 2.

Further, the individual sub-arrays 2 have an element arrangement shape common to each other, and the individual sub-arrays 2 are arranged in a distributed manner. Thereby, the calibration value H in the sub-array can be calculated by using the methods described with reference to the equations (4) to (12).

Further, the calibration data corresponds to the calibration signal transmitted by the calibration signal source 4 and then received by the individual antenna elements 3. Thereby, the calibration values H and G can be calculated using the calibration data collected by the calibration data collection system 100 including the calibration signal source 4 having a function of transmitting the calibration signal.

Further, when the calibration value calculation unit 12 includes data corresponding to a plurality of waves (K waves), the calibration value calculation unit 12 separates the data corresponding to the plurality of waves (K waves) into the data corresponding to each one wave. As a result, the calibration value H in the sub-array can be calculated by using the method described with reference to the equations (4) to (12) not only when K = 1 but also when K ≧ 2. can.

Further, the calibration signal source 4 is sequentially arranged at a plurality of positions P included in the area A, and the calibration data is such that the calibration signal source 4 is arranged at each of the plurality of positions P. It corresponds to the calibration signal received by each antenna element 3 in the state. Thereby, the calibration values H and G can be calculated using the calibration data collected by the calibration data collection system 100 including the calibration signal source 4 moving in the area A.

Further, the radar calibration device 200 according to the first embodiment includes a calibration value calculation device 300, a calibration processing unit 14 that executes a radar calibration process using the first array antenna 1 using the calibration values H and G, and a calibration processing unit 14. To be equipped. This makes it possible to calibrate the distributed radar. Such calibration can improve the angular resolution of such distributed radar. As a result, highly accurate angle measurement can be realized.

Further, in the calibration value calculation method according to the first embodiment, the calibration data acquisition unit 11 uses the calibration signal received by the individual antenna elements 3 included in the individual sub-arrays 2 included in the first array antenna 1 as the calibration signal. Step ST1 to acquire the corresponding calibration data and the calibration value calculation unit 12 use the calibration data to obtain the first calibration value (calibration value H in the sub-array) and the first calibration value corresponding to the error in the sub-array in each sub-array 2. Steps ST2_1 and ST2_2 for calculating calibration values H and G including a second calibration value (calibration value G between sub-arrays) corresponding to an error between sub-arrays in the 1-array antenna 1, and calibration value output units 13 perform calibration values H and G. The calibration data includes the step ST3 for outputting the above, and the calibration data corresponds to the calibration signal received by the individual antenna elements 3 with the calibration signal source 4 arranged in the predetermined area A. The region A is included in the far field with respect to each sub-array 2 and is included in the near field with respect to the first array antenna 1. Thereby, the calibration values H and G can be calculated using the calibration data collected by the reduced number of data acquisitions as described above.

Embodiment 2.
FIG. 10 is a block diagram showing a main part of the calibration data collection system according to the second embodiment. The calibration data collection system according to the second embodiment will be described with reference to FIG. In FIG. 10, the same blocks as those shown in FIG. 1 are designated by the same reference numerals, and the description thereof will be omitted.

As shown in FIG. 10, the calibration data collection system 100a includes a calibration signal source 4a instead of the calibration signal source 4. The calibration signal source 4a is composed of a reflective object such as a conductor sphere or a reflector. The calibration signal source 4a does not have a function of transmitting a calibration signal. Further, the calibration data collection system 100a includes an antenna 7 for transmission.

The antenna 7 transmits the calibration signal in a state where the calibration signal source 4a is arranged at one position P or each of the plurality of positions P. The transmitted calibration signal is reflected by the calibration signal source 4a. The reflected calibration signal is received by the individual antenna elements 3 included in the individual sub-arrays 2.

By providing the transmission antenna 7 in this way, the calibration data collection system 100a can be realized by using the calibration signal source 4a that does not have the function of transmitting the calibration signal.

Note that the antenna 7 may be included in the array antenna 1. That is, the selected antenna element 3 among the (L × M) antenna elements 3 included in the array antenna 1 may perform the function of the antenna 7. In other words, the antenna 7 may perform the function of the selected antenna element 3.

The radar calibration device 200 according to the second embodiment is the same as the radar calibration device 200 according to the first embodiment. That is, the calibration value calculation device 300 according to the second embodiment is the same as the calibration value calculation device 300 according to the first embodiment. However, in the calibration value calculation device 300 according to the second embodiment, the calibration values H and G are calculated using the calibration data collected by the calibration data collection system 100a. The method of calculating the calibration values H and G is the same as that described in the first embodiment.

As described above, in the calibration value calculation device 300 according to the second embodiment, the calibration data is transmitted by the transmitting antenna 7, then reflected by the calibration signal source 4a, and then the individual antennas. It corresponds to the calibration signal received by the element 3. Thereby, the calibration values H and G can be calculated using the calibration data collected by the calibration data collection system 100a including the calibration signal source 4a which does not have the function of transmitting the calibration signal.

Embodiment 3.
FIG. 11 is a block diagram showing a main part of the calibration data collection system according to the third embodiment. The calibration data collection system according to the third embodiment will be described with reference to FIG. In FIG. 11, the same blocks as those shown in FIG. 10 are designated by the same reference numerals, and the description thereof will be omitted.

As shown in FIG. 11, the calibration data collection system 100b includes a transmission array antenna (hereinafter referred to as “second array antenna”) 8 instead of the transmission antenna 7. The second array antenna 8 includes a plurality of antennas 9.

With the calibration signal source 4a arranged at one position P or each of the plurality of positions P, the individual antennas 9 included in the second array antenna 8 transmit the calibration signal. The transmitted calibration signal is reflected by the calibration signal source 4a. The reflected calibration signal is received by the individual antenna elements 3 included in the individual sub-arrays 2.

That is, the MIMO array antenna is composed of the second array antenna 8 and the individual sub-arrays 2. Further, as described in the first embodiment, the M sub-arrays 2 are distributed and arranged. Therefore, the second array antenna 8 and the first array antenna 1 are used for the distributed MIMO radar.

By providing the second array antenna 8 for transmission in this way, the calibration data collection system 100b can be realized by using the calibration signal source 4a which does not have the function of transmitting the calibration signal.

The second array antenna 8 may be included in the first array antenna 1. That is, the selected sub-array 2 out of the M sub-arrays 2 may function as the second array antenna 8. In other words, the second array antenna 8 may perform the function of the selected sub-array 2. In this case, the second array antenna 8 includes L antennas 9 and has the same element arrangement shape as the element arrangement shape in each sub array 2.

Here, as described in the first embodiment, the calibration signal data stored in the storage device 6 includes an error component in the sub-array and an error component between sub-arrays. In addition to this, in the calibration data collection system 100b, the calibration signal data stored in the storage device 6 includes an error corresponding to the calibration signals transmitted by the antennas 9 different from each other (hereinafter, "" It contains a component corresponding to "error in transmission array" or "error in array"). _{Hereinafter, the calibration value CTx} corresponding to the error in the transmission array may be referred to as a “calibration value in the transmission array” or a “third calibration value”.

FIG. 12 is a block diagram showing a main part of the radar calibration device according to the third embodiment. FIG. 13 is a block diagram showing a main part of the calibration value calculation unit in the calibration value calculation device according to the third embodiment. The radar calibration device according to the third embodiment will be described with reference to FIGS. 12 and 13, and the calibration value calculation device according to the third embodiment will be described.

Note that, in FIG. 12, the same blocks as those shown in FIG. 3 are designated by the same reference numerals, and the description thereof will be omitted. Further, in FIG. 13, the same blocks as those shown in FIG. 4 are designated by the same reference numerals, and the description thereof will be omitted.

As shown in FIG. 12, the radar calibration device 200a includes a calibration data acquisition unit 11, a calibration value calculation unit 12a, a calibration value output unit 13, a calibration processing unit 14, and a calibration data separation unit 15. The calibration value calculation unit 12a includes a first calibration value calculation unit 21, a second calibration value calculation unit 22, and a third calibration value calculation unit 23. The main part of the calibration value calculation device 300a is composed of the calibration data acquisition unit 11, the calibration value calculation unit 12a, the calibration value output unit 13, and the calibration data separation unit 15.

As shown in FIG. 13, the third calibration value calculation unit 23 includes a position-angle data table DT, a beam formation processing unit 61, and a calibration value calculation unit 62 in the transmission array. The position-angle data table DT is included in any one of the first calibration value calculation unit 21, the second calibration value calculation unit 22, and the third calibration value calculation unit 23, and the position-is such. The angle data table DT may be shared by the first calibration value calculation unit 21, the second calibration value calculation unit 22, and the third calibration value calculation unit 23.

The calibration data acquisition unit 11 acquires the calibration data stored in the storage device 6. The calibration data acquisition unit 11 outputs the acquired calibration data to the calibration data separation unit 15.

The calibration data separation unit 15 acquires the calibration data output by the calibration data acquisition unit 11. The calibration signal data included in the acquired calibration data includes data corresponding to the calibration signals transmitted by the plurality of antennas 9. Therefore, the calibration data separation unit 15 executes MIMO demodulation processing on the calibration signal data. As a result, the calibration signal data is separated into data corresponding to the calibration signals transmitted by the individual antennas 9.

Hereinafter, the separated data may be referred to as "calibration signal data after separation". Further, the calibration signal data after separation and the corresponding signal source position data may be collectively referred to as "calibration data after separation". The calibration data separation unit 15 outputs the calibration data after separation to the calibration value calculation unit 31, the beam formation processing unit 41, and the beam formation processing unit 61 in the sub-array.

In the first calibration value calculation unit 21, the same processing as that described in the first embodiment is executed using the calibration data after separation. As a result, the calibration value H in the sub array is calculated. The sub-array calibration value calculation unit 31 outputs the calculated sub-array calibration value H to the calibration value output unit 13, the beam formation processing unit 41, and the beam formation processing unit 61.

In the second calibration value calculation unit 22, the same processing as that described in the first embodiment is executed using the calibration data after separation. As a result, the calibration value G between sub-arrays is calculated. The inter-sub-array calibration value calculation unit 42 outputs the calculated inter-sub-array calibration value G to the calibration value output unit 13 and the beam forming processing unit 61.

The beam forming processing unit 61 is subjected to the calibration data after separation output by the calibration data separation unit 15, the calibration value H in the sub-array output by the calibration value calculation unit 31 in the sub-array, and the calibration value calculation unit 42 between sub-arrays. The output calibration value G between sub-arrays is acquired. The beam forming processing unit 61 uses the position-angle data table DT to calculate the incident angle θ corresponding to the position P indicated by the individual signal source position data included in the acquired calibration data. Further, the beam forming processing unit 61 uses the acquired calibration value H in the sub-array and the acquired calibration value G between sub-arrays for post-separation calibration included in the acquired post-separation calibration data. It corrects the signal data.

The beamforming processing unit 61 uses the corrected calibration signal data after separation and the calculated incident angle θ to perform digital beamforming processing corresponding to the second array antenna 8 (hereinafter referred to as “second DBF processing”). .) Is executed. As a result, data corresponding to the beam output by the second array antenna 8 is generated. The beam forming processing unit 61 outputs the generated data to the calibration value calculation unit 62 in the transmission array.

The calibration value calculation unit 62 in the transmission array acquires the data output by the beam forming processing unit 61. The calibration value calculation unit 62 in the transmission array calculates the _{calibration value C Tx in the transmission array using the acquired data.} The method of calculating the calibration value C _{Tx in} the transmission array will be described later. The calibration value calculation unit 62 in the transmission array outputs the calculated calibration value C _Tx in the transmission array to the calibration value output unit 13.

The calibration value output unit 13 includes a calibration value H in the sub-array output by the calibration value calculation unit 31 in the sub-array, a calibration value G in the sub-array output by the calibration value calculation unit 42 between sub-arrays, and a calibration value calculation unit 62 in the transmission array. Acquires the _{calibration value C Tx} in the transmission array output by. The calibration value output unit 13 outputs the acquired calibration values H, G, C _Tx to the calibration processing unit 14.

The calibration processing unit 14 acquires the calibration values H, G, C _{Tx output by the calibration value output unit 13.} The calibration processing unit 14 uses the acquired calibration values H, G, and _CTx to perform calibration processing of a radar (not shown) using the second array antenna 8 and the first array antenna 1. That is, the calibration processing unit 14 executes the calibration processing of the distributed MIMO radar. Various known techniques can be used for such calibration processing. Detailed description of these techniques will be omitted.

In this way, the main part of the radar calibration device 200a is configured.

Hereinafter, the code of "F2_3" may be used for the function of the third calibration value calculation unit 23. Further, the reference numeral "F5" may be used for the function of the calibration data separation unit 15. Further, the processes executed by the third calibration value calculation unit 23 may be collectively referred to as "third calibration value calculation process". Further, the processes executed by the calibration data separation unit 15 may be collectively referred to as "calibration data separation processing". Further, the processes executed by the calibration value calculation device 300a may be collectively referred to as "calibration value calculation process".

The hardware configuration of the main part of the radar calibration device 200a is the same as that described with reference to FIGS. 5 to 7 in the first embodiment. Therefore, detailed description thereof will be omitted.

That is, the radar calibration device 200a has a plurality of functions F1, F2_1, F2_2, F2_3, F3, F4, and F5. Each of the plurality of functions F1, F2_1, F2_2, F2_3, F3, F4, and F5 may be realized by the processor 51 and the memory 52, or may be realized by the processing circuit 53. good. The processor 51 may include a dedicated processor corresponding to each function F1, F2_1, F2_2, F2_3, F3, F4, F5. The memory 52 may include a dedicated memory corresponding to each function F1, F2_1, F2_2, F2_3, F3, F4, F5. The processing circuit 53 may include a dedicated processing circuit corresponding to each function F1, F2_1, F2_2, F2_3, F3, F4, F5.

Next, the operation of the calibration value calculation device 300a will be described with reference to the flowchart shown in FIG.

Next, the calibration data separation unit 15 executes the calibration data separation process (step ST5). As a result, the calibration signal data included in the calibration data acquired in step ST1 is separated into data corresponding to the calibration signals transmitted by the individual antennas 9.

Next, the first calibration value calculation unit 21 executes the first calibration value calculation process (step ST2_1). As a result, the calibration value H in the sub array is calculated. The calibration data after separation is used to calculate the calibration value H in the sub-array.

Next, the second calibration value calculation unit 22 executes the second calibration value calculation process (step ST2_2). As a result, the calibration value G between sub-arrays is calculated. The calibration data after separation is used to calculate the calibration value G between sub-arrays.

Next, the third calibration value calculation unit 23 executes the third calibration value calculation process (step ST2_3). Thus, the calibration values C _Tx is the transmission array is calculated. The method of calculating the calibration value C _{Tx in} the transmission array will be described later.

Next, the calibration value output unit 13 executes the calibration value output process (step ST3). As a result, the calibration value H in the sub-array calculated in step ST2_1, the calibration value G between sub-arrays calculated in step ST2_2, and the calibration value C _Tx in the transmission array calculated in step ST2_3 are the calibration value calculation device 300a. It is output to the outside.

Next, the operation of the radar calibration device 200a will be described with reference to the flowchart shown in FIG.

First, the calibration value calculation device 300a executes the calibration value calculation process (step ST11a). As a result, the processes of steps ST1, ST5, ST2_1, ST2_2, ST2_3, and ST3 shown in FIG. 14 are executed. That is, the calibration value H in the sub-array, the calibration value G between sub-arrays, and the calibration value C _Tx in the transmission array are calculated, and the calculated calibration values H, G, C _Tx are output.

Next, the calibration processing unit 14 executes the radar calibration processing (step ST4). The calibration values H, G, and C _Tx output in step ST11a are used for the radar calibration process.

Next, a method of calculating the transmission array in the calibration values C _Tx.

It is assumed that an error exists in the second array antenna 8 and an error exists in the first array antenna 1. When K = 1, the input data vector z of L × Ns is represented by the following equation (15).

Here, n (t) indicates reception noise. When the signal-to-noise ratio in the calibration signal data is large enough, n (t) can be ignored. Hereinafter, for the sake of simplicity, the description of n (t) will be omitted.

As described above, the calibration signal data stored in the storage device 6 includes data corresponding to the calibration signals transmitted by the antennas 9 which are different from each other. Therefore, the calibration data separation unit 15 separates the calibration signal data into data corresponding to the calibration signals transmitted by the individual antennas 9 by executing MIMO demodulation processing. The separated data z _MIMO (θ) is represented by the following equation (16).

Here, _CRx is calculated by the same method as that described in the first embodiment or the second embodiment. The calibration value calculation unit 62 in the transmission array calculates the _{calibration value C Tx in the transmission array as follows.}

First, the calibration value calculation unit 62 in the transmission array calculates z _Tx (θ) corresponding to the received data in the second array antenna 8. The nth element in z _Tx (θ) is calculated by the following equations (17) to (18).

Next, the calibration value calculation unit 62 in the transmission array uses the calculated z _Tx (θ) in the transmission array by the same calculation method as the calculation method of the calibration value G between sub-arrays by the calibration value calculation unit 42 between sub-arrays. Calculate the calibration value C _Tx. That is, the calibration value calculation unit 62 in the transmission array uses the data generated by the second DBF process to perform the same processing as the processing executed by the calibration value calculation unit 42 between sub-arrays, thereby performing calibration in the transmission array. Calculate the value C _Tx.

In this way, the calibration value C _Tx in the transmission array is calculated.

_{In addition, the calibration value calculation unit 62 in the transmission array calculates the calibration value C Tx} in the transmission array by the same calculation method as the calculation method of the calibration value G between sub-arrays by the calibration value calculation unit 42 between sub-arrays, instead of calculating the calibration value C Tx in the transmission array. _{The calibration value C Tx} in the transmission array may be calculated by the same calculation method as the calculation method of the calibration value H in the sub array by the internal calibration value calculation unit 31. That is, the calibration value calculation unit 62 in the transmission array may calculate the _{calibration value C Tx} in the transmission array by executing the same processing as the processing executed by the calibration value calculation unit 31 in the sub-array. ..

As described above, in the calibration value calculation device 300a according to the third embodiment, the calibration data is transmitted by the second array antenna 8 for transmission, then reflected by the calibration signal source 4a, and then reflected by the calibration signal source 4a. It corresponds to the calibration signal received by each antenna element 3. _{As a result, the calibration values H, G, and C Tx} can be calculated using the calibration data collected by the calibration data collection system 100b including the calibration signal source 4a that does not have the function of transmitting the calibration signal. can.

Further, the calibration value calculation device 300a includes a calibration data separation unit 15 that separates calibration data into data corresponding to individual antennas 9 included in the second array antenna 8, and the calibration value calculation unit 12a is after separation. The first calibration value (calibration value H in the sub-array), the second calibration value (calibration value G between sub-arrays), and the third calibration value (transmission) corresponding to the error in the array in the second array antenna 8 are used. Calculate the calibration values H, G, and C _Tx including the calibration value C _{Tx in the array.} Thereby, the calibration values H, G, C _Tx for the distributed MIMO radar can be calculated.

Further, the radar calibration device 200a according to the third embodiment uses the calibration value calculation device 300a and the calibration values H, G, and _CTx to perform radar calibration processing using the first array antenna 1 and the second array antenna 8. A calibration processing unit 14 for executing the above is provided. This makes it possible to calibrate the distributed MIMO radar. Such calibration can improve the angular resolution of such distributed MIMO radar. As a result, highly accurate angle measurement can be realized.

It should be noted that, within the scope of the disclosure of the present application, it is possible to freely combine each embodiment, modify any component of each embodiment, or omit any component in each embodiment. ..

The calibration value calculation device, radar calibration device, and calibration value calculation method according to the present disclosure can be used, for example, for a distributed radar or a distributed MIMO radar.

1 array antenna (1st array antenna), 2 sub array, 3 antenna elements, 4, 4a calibration signal source, 5 A / D converter, 6 storage device, 7 antenna, 8 second array antenna, 9 antenna, 11 calibration Data acquisition unit, 12, 12a calibration value calculation unit, 13 calibration value output unit, 14 calibration processing unit, 15 calibration data separation unit, 21 1st calibration value calculation unit, 22 2nd calibration value calculation unit, 23 3rd Calibration value calculation unit, 31 Sub-array calibration value calculation unit, 41 Beam formation processing unit, 42 Inter-sub-array calibration value calculation unit, 51 Processor, 52 Memory, 53 Processing circuit, 61 Beam formation processing unit, 62 Transmission array calibration value calculation Unit, 100, 100a, 100b Calibration data collection system, 200, 200a radar calibration device, 300, 300a calibration value calculation device.

Claims

A calibration data acquisition unit that acquires calibration data corresponding to the calibration signal received by the individual antenna elements included in the individual sub-arrays included in the first array antenna, and a calibration data acquisition unit.
Calibration value calculation using the calibration data to calculate a calibration value including a first calibration value corresponding to an error in the sub-array in the individual sub-array and a second calibration value corresponding to an error between sub-arrays in the first array antenna. Department and
A calibration value output unit that outputs the calibration value is provided.
The calibration data corresponds to the calibration signal received by the individual antenna elements in a state where the calibration signal source is arranged in a predetermined region.
A calibration value calculation device, characterized in that the region is included in the far field with respect to the individual sub-array and is included in the near field with respect to the first array antenna.
The individual sub-arrays have an element arrangement shape common to each other and have an element arrangement shape.
The calibration value calculation device according to claim 1, wherein the individual sub-arrays are arranged in a distributed manner.
The calibration value calculation according to claim 2, wherein the calibration data corresponds to the calibration signal transmitted by the calibration signal source and then received by the individual antenna elements. Device.
That the calibration data corresponds to the calibration signal transmitted by the transmitting antenna, then reflected by the calibration signal source, and then received by the individual antenna elements. The calibration value calculation device according to claim 2, which is characterized.
The calibration data corresponds to the calibration signal transmitted by the second array antenna for transmission, then reflected by the calibration signal source, and then received by the individual antenna elements. The calibration value calculation device according to claim 2, wherein the calibration value is calculated.
A calibration data separation unit for separating the calibration data into data corresponding to each antenna included in the second array antenna is provided.
The calibration value calculation unit uses the calibration data after separation to include the first calibration value, the second calibration value, and the third calibration value corresponding to the error in the array in the second array antenna. The calibration value calculation device according to claim 5, wherein the value is calculated.
The second aspect of claim 2, wherein the calibration value calculation unit separates the data corresponding to the plurality of waves into the data corresponding to each one wave when the calibration data includes the data corresponding to the plurality of waves. Calibration value calculation device.
The calibration value calculation device according to claim 7, wherein the calibration value calculation unit separates data corresponding to the plurality of waves into data corresponding to each one wave by using Doppler frequency or independent component analysis. ..
The calibration signal source is sequentially arranged at a plurality of positions included in the region.
The calibration data is characterized in that it corresponds to the calibration signal received by the individual antenna elements in a state where the calibration signal source is arranged at each of the plurality of positions. The calibration value calculation device according to claim 2.
The calibration value according to claim 9, wherein the calibration value calculation unit estimates a position error corresponding to each of the sub-arrays and calculates the second calibration value corrected according to the position error. Calculation device.
The calibration value calculation device according to claim 2 and
A calibration processing unit that executes a radar calibration process using the first array antenna using the calibration value, and a calibration processing unit.
Radar calibration device equipped with.
The calibration value calculation device according to claim 6 and
A calibration processing unit that executes calibration processing of the radar using the first array antenna and the second array antenna using the calibration value, and a calibration processing unit.
Radar calibration device equipped with.
A step in which the calibration data acquisition unit acquires calibration data corresponding to the calibration signal received by the individual antenna elements included in the individual sub-arrays included in the first array antenna.
The calibration value calculation unit uses the calibration data to include a first calibration value corresponding to an error in the sub-array in each of the individual sub-arrays and a second calibration value corresponding to an error between sub-arrays in the first array antenna. And the steps to calculate
The calibration value output unit includes a step of outputting the calibration value.
The calibration data corresponds to the calibration signal received by the individual antenna elements in a state where the calibration signal source is arranged in a predetermined area.
A calibration value calculation method, characterized in that the region is included in the far field with respect to the individual sub-array and is included in the near field with respect to the first array antenna.