JP6587784B2 - Radar signal processing apparatus and radar signal processing method - Google Patents

Description

  The present invention relates to a radar signal processing apparatus and a radar signal processing method for adding a received signal of a first radar and a received signal of a second radar.

When the power of the radar reception signal is low, it is difficult to distinguish between the target signal and noise contained in the radar reception signal. In recent years, the amplitude of multiple radar reception signals is added and reception after amplitude addition is performed. A radar signal processing device that detects a target from a signal has been proposed.
However, the radar signal processing apparatus, for example, when adding the amplitudes of the received signals of two radars, the observation areas of the two radars are not necessarily the same, so the resolution cell of one radar and the resolution of the other radar I don't know the correspondence with cells.
Therefore, the radar signal processing apparatus needs to associate the resolution cell of one radar with the resolution cell of the other radar when performing amplitude addition of signals related to the same target.

Patent Document 1 below discloses a radar signal processing device that associates a resolution cell of one radar with a resolution cell of the other radar when performing amplitude addition of signals related to the same target.
First, the radar signal processing apparatus sets an arbitrary resolution cell among the plurality of resolution cells in one radar as a test cell (processing 1).
Next, the radar signal processing apparatus sets a speed hypothesis regarding the target motion, and uses the set hypothesis and the installation positions of the two radars to perform verification in a plurality of resolution cells in the other radar. A resolution cell corresponding to the cell is specified (process 2).
Next, the radar signal processing apparatus sets a plurality of resolution cells within a certain area centered on the identified resolution cell as integration cell candidates (processing 3).

Next, the radar signal processing apparatus calculates an evaluation value for each of a plurality of set integration cell candidates, and determines an integration cell candidate having the highest evaluation value among the plurality of integration cell candidates as an integration cell ( Process 4).
Next, the radar signal processing apparatus adds the amplitude of the signal included in the verification cell and the signal included in the integration cell (processing 5).
This radar signal processing apparatus sets each of a plurality of resolution cells in one radar as a test cell, and adds the amplitude of the signal included in each test cell and the signal included in the integration cell. The above (Process 1) to (Process 5) are repeated.

JP 2012-194044 A

  The conventional radar signal processing apparatus needs to repeat (Process 1) to (Process 5) as many times as the number of resolution cells in one radar. For this reason, there has been a problem that processing for associating a plurality of resolution cells in one radar with a plurality of resolution cells in the other radar becomes enormous.

  The present invention has been made in order to solve the above-described problems, and some of the resolution cells in the plurality of resolution cells in the first radar and one of the plurality of resolution cells in the second radar. An object of the present invention is to obtain a radar signal processing apparatus and a radar signal processing method capable of adding signals related to a target only by associating with a resolution cell of each unit.

  The radar signal processing apparatus according to the present invention generates a first and second range Doppler maps from the received signals of the first and second radars, and a hypothesis relating to the target three-dimensional motion. A hypothesis generation unit, a motion prediction unit that predicts the target position and velocity at the first and second reception times, which are reception times of signals by the first and second radars, using the hypothesis; Among the plurality of resolution cells in the second and second range Doppler maps, the first and second resolution cells corresponding to the position and velocity at the first and second reception times predicted by the motion prediction unit are respectively set. Between the center cell calculation unit that calculates as the center cell, each resolution cell in the first area including the first center cell, and each resolution cell in the second area including the second center cell The likelihood of A likelihood calculating unit for calculating, and a signal adding unit for each resolution cell in the first region and each resolution in the second region based on the likelihood calculated by the likelihood calculating unit, respectively. At least one combination is selected from the combinations with the cells, and the signals included in the resolution cells related to the selected combination are added together.

  According to the present invention, among the plurality of resolution cells in the first and second range Doppler maps, the resolution cell corresponding to the position and velocity at the first and second reception times predicted by the motion prediction unit. A center cell calculation unit that calculates each as the first and second center cells, each resolution cell in the first area including the first center cell, and in the second area including the second center cell A likelihood calculating unit that calculates a likelihood between each of the resolution cells, and the signal adding unit is configured to calculate each likelihood in the first region based on the likelihood calculated by the likelihood calculating unit. At least one combination is selected from the combinations of the resolution cell and each resolution cell in the second region, and signals included in the resolution cell according to the selected combination are added together. Since configured The signals related to the target can be added by simply associating some of the resolution cells of the plurality of resolution cells in the radar of the second and some of the resolution cells of the plurality of resolution cells of the second radar. There is an effect that can be done.

BRIEF DESCRIPTION OF THE DRAWINGS It is a block diagram which shows the radar signal processing apparatus by Embodiment 1 of this invention. It is a hardware block diagram which shows the radar signal processing apparatus by Embodiment 1 of this invention. It is a hardware block diagram of a computer in case a radar signal processing apparatus is implement | achieved by software or firmware. It is a flowchart which shows the radar signal processing method which is a process sequence in case a radar signal processing apparatus is implement | achieved by software or firmware. It is explanatory drawing which shows an example of the 1st and 2nd range Doppler map produced | generated by the 1st signal processing part 1a and the 2nd signal processing part 1b. It is explanatory drawing which shows the 1st area | region and 2nd area | region set by the likelihood calculation part 6. FIG. It is explanatory drawing which shows the example by which the 2nd range Doppler map is produced | generated by the reception signal of three receiving beams being acquired by the 2nd signal processing part 1b. It is a block diagram which shows the radar signal processing apparatus by Embodiment 2 of this invention. It is a block diagram which shows the radar signal processing apparatus by Embodiment 3 of this invention. It is a hardware block diagram which shows the radar signal processing apparatus by Embodiment 3 of this invention. It is a flowchart which shows the radar signal processing method which is a process sequence in case a radar signal processing apparatus is implement | achieved by software or firmware. It is explanatory drawing which shows the noise area | region of a 1st range Doppler map.

  Hereinafter, in order to explain the present invention in more detail, modes for carrying out the present invention will be described with reference to the accompanying drawings.

Embodiment 1 FIG.
FIG. 1 is a block diagram showing a radar signal processing apparatus according to Embodiment 1 of the present invention.
FIG. 2 is a hardware configuration diagram showing the radar signal processing apparatus according to Embodiment 1 of the present invention.
1 and 2, the signal processing unit 1 includes a first signal processing unit 1a and a second signal processing unit 1b, and is realized by, for example, the signal processing circuit 21 illustrated in FIG.
The first signal processing unit 1a includes an analog-digital converter that converts the received signal of the first radar from an analog signal to a digital signal. When the received signal of the first radar input to the first signal processing unit 1a is a digital signal, the first signal processing unit 1a does not need to include an analog-digital converter.
The first signal processing unit 1 a performs a process of generating a first range Doppler map from the digital received signal of the first radar and outputting the first range Doppler map to the likelihood calculating unit 6.

The second signal processing unit 1b includes an analog-digital converter that converts the received signal of the second radar from an analog signal to a digital signal. When the received signal of the second radar input to the second signal processing unit 1b is a digital signal, the second signal processing unit 1b does not need to include an analog-digital converter.
The second signal processing unit 1 b performs a process of generating a second range Doppler map from the digital received signal of the second radar and outputting the second range Doppler map to the likelihood calculating unit 6.

The hypothesis generation unit 2 is realized by, for example, a hypothesis generation circuit 22 illustrated in FIG.
The hypothesis generation unit 2 performs a process of generating a hypothesis regarding the target three-dimensional motion.
The target three-dimensional movement is a movement of the target in Cartesian coordinates, and is defined by, for example, a distance to the target, a target azimuth, a target altitude, a target speed, and a target traveling direction.

The motion prediction unit 3 is realized by, for example, the motion prediction circuit 23 illustrated in FIG.
The motion prediction unit 3 uses the hypothesis generated by the hypothesis generation unit 2 to predict and predict the target position and velocity at the first reception time, which is the time when the signal is received by the first radar, respectively. A process of outputting the target position and speed to the central cell calculator 5 is performed.
Further, the motion prediction unit 3 predicts the target position and speed at the second reception time, which is the time when the signal is received by the second radar, using the hypothesis generated by the hypothesis generation unit 2. Then, a process of outputting the predicted target position and velocity to the central cell calculation unit 5 is performed.

The database unit 4 is realized by, for example, the recording circuit 24 shown in FIG.
The database unit 4 stores the coordinates of the position where the first radar is present and the coordinates of the position where the second radar is present.

The center cell calculation unit 5 is realized by, for example, the center cell calculation circuit 25 shown in FIG.
The center cell calculation unit 5 uses the coordinates of the position where the first radar is present, and moves among the plurality of resolution cells in the first range Doppler map output from the first signal processing unit 1a. A process of calculating a resolution cell corresponding to the target position and velocity at the first reception time predicted by the prediction unit 3 as the first central cell is performed.
Further, the center cell calculation unit 5 uses the coordinates of the position where the second radar is present, among the plurality of resolution cells in the second range Doppler map output from the second signal processing unit 1b. Then, a process of calculating a resolution cell corresponding to the target position and velocity at the second reception time predicted by the motion prediction unit 3 as the second central cell is performed.
The center cell calculation unit 5 performs a process of outputting the calculated first and second center cells to the likelihood calculation unit 6.

The likelihood calculating unit 6 is realized by, for example, the likelihood calculating circuit 26 illustrated in FIG.
The likelihood calculation unit 6 determines each resolution cell in the first region including the first center cell output from the center cell calculation unit 5 and the second center cell output from the center cell calculation unit 5. A process of calculating the likelihood between each resolution cell in the second region to be included is performed.

The signal addition unit 7 includes a combination selection unit 8 and an amplitude addition unit 9, and is realized by, for example, the signal addition circuit 27 illustrated in FIG.
Based on the likelihood calculated by the likelihood calculating unit 6, the combination selecting unit 8 selects a combination of each resolution cell in the first region and each resolution cell in the second region, A process of selecting at least one combination is performed.
The amplitude adding unit 9 performs a process of adding the signals included in the resolution cells related to at least one combination selected by the combination selecting unit 8.

In FIG. 1, each of the signal processing unit 1, the hypothesis generation unit 2, the motion prediction unit 3, the database unit 4, the center cell calculation unit 5, the likelihood calculation unit 6, and the signal addition unit 7 that are components of the radar signal processing device. However, it is assumed to be realized by dedicated hardware as shown in FIG. That is, it is assumed that the signal processing circuit 21, the hypothesis generation circuit 22, the motion prediction circuit 23, the recording circuit 24, the center cell calculation circuit 25, the likelihood calculation circuit 26, and the signal addition circuit 27 are realized.
Here, the recording circuit 24 may be, for example, a RAM (Random Access Memory), a ROM (Read Only Memory), a flash memory, an EPROM (Erasable Programmable Read Only Memory), or an EEPROM (Electrically Erasable Memory). A volatile semiconductor memory, a magnetic disk, a flexible disk, an optical disk, a compact disk, a mini disk, or a DVD (Digital Versatile Disc) is applicable.
The signal processing circuit 21, the hypothesis generation circuit 22, the motion prediction circuit 23, the center cell calculation circuit 25, the likelihood calculation circuit 26, and the signal addition circuit 27 are, for example, a single circuit, a composite circuit, a programmed processor, and a parallel processor. A programmed processor, an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or a combination thereof is applicable.

The components of the radar signal processing device are not limited to those realized by dedicated hardware, and the radar signal processing device may be realized by software, firmware, or a combination of software and firmware. Good.
Software or firmware is stored as a program in the memory of a computer. The computer means hardware that executes a program, for example, a CPU (Central Processing Unit), a central processing unit, a processing unit, a processing unit, a microprocessor, a microcomputer, a processor, or a DSP (Digital Signal Processor) To do.

FIG. 3 is a hardware configuration diagram of a computer when the radar signal processing apparatus is realized by software or firmware.
When the radar signal processing device is realized by software or firmware, the database unit 4 is configured on the memory 41 of the computer, and the signal processing unit 1, the hypothesis generation unit 2, the motion prediction unit 3, the center cell calculation unit 5, A program for causing the computer to execute the processing procedure of the likelihood calculating unit 6 and the signal adding unit 7 may be stored in the memory 41, and the processor 42 of the computer may execute the program stored in the memory 41.
FIG. 4 is a flowchart showing a radar signal processing method as a processing procedure when the radar signal processing apparatus is realized by software or firmware.

  2 shows an example in which each component of the radar signal processing device is realized by dedicated hardware, and FIG. 3 shows an example in which the radar signal processing device is realized by software, firmware, or the like. However, some components in the radar signal processing device may be realized by dedicated hardware, and the remaining components may be realized by software, firmware, or the like.

Next, the operation will be described.
The first signal processing unit 1a converts the received signal of the first radar from an analog signal to a digital signal.
The first signal processing unit 1a performs a beam forming process, an unnecessary wave suppression process, a signal integration process, and the like as well-known signal processes for the digital received signal of the first radar, thereby the first range Doppler map. Is generated (step ST1 in FIG. 4).
The first signal processing unit 1 a outputs the generated first range Doppler map to the likelihood calculating unit 6.

The second signal processing unit 1b converts the received signal of the second radar from an analog signal to a digital signal.
The second signal processing unit 1b performs a beam forming process, an unnecessary wave suppression process, a signal integration process, and the like as well-known signal processes for the digital received signal of the second radar, so that the second range Doppler map Is generated (step ST1 in FIG. 4).
The second signal processing unit 1 b outputs the generated second range Doppler map to the likelihood calculating unit 6.
FIG. 5 is an explanatory diagram illustrating an example of first and second range Doppler maps generated by the first signal processing unit 1a and the second signal processing unit 1b.
As shown in FIG. 5, the first and second range Doppler maps are two-dimensional maps showing the relationship between the target Doppler speed and the distance to the target.
FIG. 5 shows an example in which each of the first and second range Doppler maps includes 110 (= 10 × 11) resolution cells, and each resolution cell is defined by Doppler resolution and distance resolution. It has a size.

式（１）において、ｒ_ｉは、或る基準位置を原点とする北基準直交座標系における目標までの距離、Ａ_ｉは、目標の方位角、ｈ_ｉは、目標の高度である。
また、Ｖ_ｉは、目標の速度、φ_ｉは、目標の北を基準とする場合の水平面における進行方向、ε_ｉは、目標の進行方向における鉛直成分である。The hypothesis generation unit 2 generates a hypothesis h _i (t) related to the target three-dimensional motion (step ST2 in FIG. 4).
The target three-dimensional movement is a movement of the target in Cartesian coordinates, and is defined by, for example, a distance to the target, a target azimuth, a target altitude, a target speed, and a target traveling direction.
The following equation (1) shows an example of a hypothesis h _i (t) at time t generated by the hypothesis generation unit 2. i is a hypothesis number for identifying a hypothesis. However, in the first embodiment, it is assumed that the number of hypotheses h _i (t) generated by the hypothesis generation unit 2 is one for simplification of explanation. For this reason, in this Embodiment 1, i = 1.

In equation (1), r _i is the distance to the target in the north reference orthogonal coordinate system with a certain reference position as the origin, A _i is the target azimuth, and h _i is the target altitude.
Further, V _i is a target speed, φ _i is a traveling direction in a horizontal plane with reference to the north of the target, and ε _i is a vertical component in the traveling direction of the target.

The motion prediction unit 3 uses the hypothesis h _i (t) generated by the hypothesis generation unit 2 and the position of the target at the _first reception time T ₁ , which is the time when the signal is received by the first radar. Each speed is predicted, and the predicted target position and speed are output to the central cell calculator 5 (step ST3 in FIG. 4).
In addition, the motion prediction unit 3 uses the hypothesis h _i (t) generated by the hypothesis generation unit 2 to set the target at the _second reception time T ₂ that is the time when the signal is received by the second radar. The position and speed are predicted, respectively, and the predicted target position and speed are output to the central cell calculator 5 (step ST3 in FIG. 4).

ｘ_ｉ（ｔ）は、北基準直交座標系における目標のｘ軸方向の位置ベクトル、ｙ_ｉ（ｔ）は、北基準直交座標系における目標のｙ軸方向の位置ベクトル、ｚ_ｉ（ｔ）は、北基準直交座標系における目標のｚ軸方向の位置ベクトルである。
Ｖｘ_ｉ（ｔ）は、北基準直交座標系における目標のｘ軸方向の速度ベクトル、Ｖｙ_ｉ（ｔ）は、北基準直交座標系における目標のｙ軸方向の速度ベクトル、Ｖｚ_ｉ（ｔ）は、北基準直交座標系における目標のｚ軸方向の速度ベクトルである。Hereinafter, the target position and speed prediction processing by the motion prediction unit 3 will be described in detail.
First, the motion prediction unit 3 uses the hypothesis h _i (t) generated by the hypothesis generation unit 2 as shown in the following equations (2) to (7) at time t in the north reference orthogonal coordinate system. The target position vector and velocity vector are calculated.

x _i (t) is a position vector in the x-axis direction of the target in the north reference orthogonal coordinate system, y _i (t) is a position vector in the y-axis direction of the target in the north reference orthogonal coordinate system, and z _i (t) is , A position vector in the z-axis direction of the target in the north reference orthogonal coordinate system.
Vx _i (t) is the velocity vector in the x-axis direction of the target in the north reference orthogonal coordinate system, Vy _i (t) is the velocity vector in the y-axis direction of the target in the north reference orthogonal coordinate system, and Vz _i (t) is , A velocity vector in the z-axis direction of the target in the north reference orthogonal coordinate system.

ｘ_ｉ（ｔ＋ΔＴ_１）は、第１の受信時刻Ｔ_１での目標のｘ軸方向の位置ベクトル、ｙ_ｉ（ｔ＋ΔＴ_１）は、第１の受信時刻Ｔ_１での目標のｙ軸方向の位置ベクトル、ｚ_ｉ（ｔ＋ΔＴ_１）は、第１の受信時刻Ｔ_１での目標のｚ軸方向の位置ベクトルである。
Ｖｘ_ｉ（ｔ＋ΔＴ_１）は、第１の受信時刻Ｔ_１での目標のｘ軸方向の速度ベクトル、Ｖｙ_ｉ（ｔ＋ΔＴ_１）は、第１の受信時刻Ｔ_１での目標のｙ軸方向の速度ベクトル、Ｖｚ_ｉ（ｔ＋ΔＴ_１）は、第１の受信時刻Ｔ_１での目標のｚ軸方向の速度ベクトルである。Next, as shown in the following formulas (8) to (13), the motion prediction unit 3 calculates the time difference ΔT ₁ (=) between the time t in the hypothesis h _i (t) and the first reception time T _1. By correcting the specifications of the hypothesis h _i (t) by T ₁ -t), the target position and velocity at the first reception time T ₁ are respectively predicted.

x _i (t + ΔT ₁ ) is a target position vector in the x-axis direction at the _first reception time T ₁ , and y _i (t + ΔT ₁ ) is a target position in the y-axis direction at the _first reception time T _1. A vector, z _i (t + ΔT ₁ ) is a target position vector in the z-axis direction at the _first reception time T ₁ .
Vx _i (t + ΔT ₁ ) is the target velocity vector in the x-axis direction at the _first reception time T ₁ , and Vy _i (t + ΔT ₁ ) is the target velocity in the y-axis direction at the _first reception time T _1. The vector, Vz _i (t + ΔT ₁ ) is a target velocity vector in the z-axis direction at the _first reception time T ₁ .

ｘ_ｉ（ｔ＋ΔＴ_２）は、第２の受信時刻Ｔ_２での目標のｘ軸方向の位置ベクトル、ｙ_ｉ（ｔ＋ΔＴ_２）は、第２の受信時刻Ｔ_２での目標のｙ軸方向の位置ベクトル、ｚ_ｉ（ｔ＋ΔＴ_２）は、第２の受信時刻Ｔ_２での目標のｚ軸方向の位置ベクトルである。
Ｖｘ_ｉ（ｔ＋ΔＴ_２）は、第２の受信時刻Ｔ_２での目標のｘ軸方向の速度ベクトル、Ｖｙ_ｉ（ｔ＋ΔＴ_２）は、第２の受信時刻Ｔ_２での目標のｙ軸方向の速度ベクトル、Ｖｚ_ｉ（ｔ＋ΔＴ_２）は、第２の受信時刻Ｔ_２での目標のｚ軸方向の速度ベクトルである。Next, as shown in the following formulas (14) to (19), the motion predicting unit 3 calculates the time difference ΔT ₂ (=) between the time t in the hypothesis h _i (t) and the second reception time T _2. The target position and velocity at the second reception time T ₂ are predicted by correcting the specifications of the hypothesis h _i (t) by T ₂ -t).

x _i (t + ΔT ₂ ) is a target position vector in the x-axis direction at the _second reception time T ₂ , and y _i (t + ΔT ₂ ) is a target position in the y-axis direction at the _second reception time T _2. The vector, z _i (t + ΔT ₂ ) is a target position vector in the z-axis direction at the _second reception time T ₂ .
Vx _i (t + ΔT ₂ ) is the target velocity vector in the x-axis direction at the _second reception time T ₂ , and Vy _i (t + ΔT ₂ ) is the target velocity in the y-axis direction at the _second reception time T _2. The vector, Vz _i (t + ΔT ₂ ), is a target velocity vector in the z-axis direction at the _second reception time T ₂ .

式（２０）〜（２２）において、ｘ_１は、第１のレーダが存在しているｘ軸方向の位置の座標、ｙ_１は、第１のレーダが存在しているｙ軸方向の位置の座標、ｚ_１は、第１のレーダが存在しているｚ軸方向の位置の座標である。
ｘ_ｉ，１（ｔ＋ΔＴ_１）は、第１のレーダが存在している位置からの目標のｘ軸方向の相対座標、ｙ_ｉ，１（ｔ＋ΔＴ_１）は、第１のレーダが存在している位置からの目標のｙ軸方向の相対座標、ｚ_ｉ，１（ｔ＋ΔＴ_１）は、第１のレーダが存在している位置からの目標のｚ軸方向の相対座標である。The center cell calculation unit 5 acquires, from the database unit 4, the position coordinates of the north reference orthogonal coordinate system where the first radar exists and the position coordinates of the north reference orthogonal coordinate system where the second radar exists. .
Next, as shown in the following formulas (20) to (22), the center cell calculation unit 5 uses the coordinates of the position where the first radar is present to formulas (8) to (10). The coordinates of the target position at the _first reception time T1 shown are converted into relative coordinates from the position where the first radar is present.

In the formula (20) ~ (22), x 1 is the position of the coordinates of the x-axis direction in which the first radar is present, y ₁ is the position in the y-axis direction in which the first radar is present coordinates, z ₁ is a position of the coordinates of the z-axis direction in which the first radar is present.
x _{i, 1} (t + ΔT ₁ ) is the relative coordinate in the x-axis direction of the target from the position where the first radar exists, and y _{i, 1} (t + ΔT ₁ ) is the first radar. The relative coordinate in the y-axis direction of the target from the position, z _{i, 1} (t + ΔT ₁ ), is the relative coordinate in the z-axis direction of the target from the position where the first radar is present.

式（２３）〜（２５）において、ｘ_２は、第２のレーダが存在しているｘ軸方向の位置の座標、ｙ_２は、第２のレーダが存在しているｙ軸方向の位置の座標、ｚ_２は、第２のレーダが存在しているｚ軸方向の位置の座標である。
ｘ_ｉ，２（ｔ＋ΔＴ_２）は、第２のレーダが存在している位置からの目標のｘ軸方向の相対座標、ｙ_ｉ，２（ｔ＋ΔＴ_２）は、第２のレーダが存在している位置からの目標のｙ軸方向の相対座標、ｚ_ｉ，２（ｔ＋ΔＴ_２）は、第２のレーダが存在している位置からの目標のｚ軸方向の相対座標である。Next, as shown in the following formulas (23) to (25), the center cell calculation unit 5 uses the coordinates of the position where the second radar is present to formulas (14) to (16). The coordinates of the target position at the _second reception time T2 shown are converted into relative coordinates from the position where the second radar is present.

In Expressions (23) to (25), x ₂ is the coordinate of the position in the x-axis direction where the second radar is present, and y ₂ is the position in the y-axis direction where the second radar is present. coordinates, z ₂ is a position of the coordinates of the z-axis direction in which the second radar is present.
x _{i, 2} (t + ΔT ₂ ) is the relative coordinate in the x-axis direction of the target from the position where the second radar exists, and y _{i, 2} (t + ΔT ₂ ) is the second radar. The relative coordinate in the y-axis direction of the target from the position, z _{i, 2} (t + ΔT ₂ ), is the relative coordinate in the z-axis direction of the target from the position where the second radar is present.

また、中心セル算出部５は、以下の式（２７）に示すように、式（１１）〜（１３）に示す第１の受信時刻Ｔ_１での目標の速度ベクトル及び式（２０）〜（２２）に示す相対座標を用いて、第１の中心セルｃ_１におけるドップラ速度ＶＲ_ｉ，１（ｔ＋ΔＴ_１）を算出する。

式（２７）において、ＰＦＲは、第１のレーダにおけるパルス繰り返し周波数である。
ｍｏｄ（ａ，ｂ）は、ａをｂで除算したときの余りを算出する関数である。
中心セル算出部５は、算出した第１の中心セルｃ_１（Ｒ，ＶＲ）を尤度算出部６に出力する。Next, the center cell calculation unit 5 uses the first reception time T predicted by the motion prediction unit 3 among the plurality of resolution cells in the first range Doppler map output from the first signal processing unit 1a. _The resolution cell corresponding to the target position and velocity at ₁ is calculated as the first central cell c ₁ (R, VR) (step ST4 in FIG. 4).
Specifically, as shown in the following formula (26), the center cell calculation unit 5 uses the relative coordinates shown in the formulas (20) to (22), and the distance R _i in the first center cell c ₁ . _{, 1} (t + ΔT ₁ ).

Further, as shown in the following equation (27), the center cell calculation unit 5 sets the target velocity vector and the equations (20) to (20) at the _first reception time T1 shown in the equations (11) to (13). The Doppler velocity VR _{i, 1} (t + ΔT ₁ ) in the first center cell c ₁ is calculated using the relative coordinates shown in 22).

In Expression (27), PFR is a pulse repetition frequency in the first radar.
mod (a, b) is a function for calculating the remainder when a is divided by b.
The center cell calculation unit 5 outputs the calculated first center cell c ₁ (R, VR) to the likelihood calculation unit 6.

また、中心セル算出部５は、以下の式（２９）に示すように、式（１７）〜（１９）に示す第２の受信時刻Ｔ_２での目標の速度ベクトル及び式（２３）〜（２５）に示す相対座標を用いて、第２の中心セルｃ_２におけるドップラ速度ＶＲ_ｉ，２（ｔ＋ΔＴ_２）を算出する。

中心セル算出部５は、算出した第２の中心セルｃ_２（Ｒ，ＶＲ）を尤度算出部６に出力する。Next, the center cell calculation unit 5 uses the second reception time T predicted by the motion prediction unit 3 among the plurality of resolution cells in the second range Doppler map output from the second signal processing unit 1b. ₂ is calculated as the second central cell c ₂ (R, VR) (step ST4 in FIG. 4).
Specifically, as shown in the following formula (28), the center cell calculation unit 5 uses the relative coordinates shown in the formulas (23) to (25), and the distance R _{i in the second} center cell c ₂ . _{, 2} (t + ΔT ₂ ).

Further, as shown in the following equation (29), the center cell calculation unit 5 sets the target velocity vector and the equations (23) to (23) at the _second reception time T2 shown in the equations (17) to (19). 25) The Doppler velocity VR _{i, 2} (t + ΔT ₂ ) in the second center cell c ₂ is calculated using the relative coordinates shown in 25).

The center cell calculation unit 5 outputs the calculated second center cell c ₂ (R, VR) to the likelihood calculation unit 6.

The likelihood calculation unit 6 sets a first region including the first center cell c ₁ (R, VR) output from the center cell calculation unit 5, and sets the second region output from the center cell calculation unit 5. A second region including the center cell c ₂ (R, VR) is set.
FIG. 6 is an explanatory diagram showing the first region and the second region set by the likelihood calculating unit 6.
In the example of FIG. 6, the first region is a region including 15 (= 5 × 3) resolution cells in which the first center cell c ₁ (R, VR) is arranged at the center.
The second region is a region including nine (= 3 × 3) resolution cells in which the second center cell c ₂ (R, VR) is arranged at the center.
The size of the first region only needs to be smaller than the size of the first range Doppler map, and may be any size. Further, the size of the second area only needs to be smaller than the size of the second range Doppler map, and may be any size.
Hereinafter, each resolution cell included in the first region is represented by c _{1, (a, b)} , and each resolution cell included in the second region is represented by c _{2, (d, e)} .
a is a variable indicating the resolution cell in the VR direction of the first region, and b is a variable indicating the resolution cell in the R direction of the first region.
d is a variable indicating the resolution cell in the VR direction of the second region, and e is a variable indicating the resolution cell in the R direction of the second region.

Next, the likelihood calculation unit 6 includes the first center cell c ₁ (R, VR) output from the center cell calculation unit 5 in the first region as shown in the following equation (30). Each resolution cell c _{1, (a, b)} and each resolution cell c ₂ in the second region including the second center cell c ₂ (R, VR) output from the center cell calculator 5 _{(d, e)} the likelihood _{I (a, b)} between the _{- (d, e)} the calculated respectively (step ST5 in FIG. 4).
In the example of FIG. 6, the first region includes 15 resolution cells c _{1, (a, b)} , and the second region includes 9 resolution cells c _{2, (d, e)} . The likelihood calculation unit 6 calculates 135 (= 15 × 9) likelihoods I _{(a, b) − (d, e)} in total.

In equations (30) to (34), ln is a natural logarithm, and p (u, v) is a transition probability from u to v.
z ₁ is the amplitude value of the resolution cell c _{1, (a, b)} , z ₂ is the amplitude value of the resolution cell c _{2, (d, e)} , and z bar is a plurality of values in the first region. This is an expected value of an average amplitude value in the resolution cell c _{1, (a, b)} and the plurality of resolution cells c _{2, (d, e)} in the second region. In the specification, the symbol “-” cannot be added above the character for the convenience of electronic application, and is therefore represented as a z-bar.
[sigma] is a parameter representing a variation in signals included in the resolution cell c1 _{, (a, b)} and the resolution cell c2 _{, (d, e)} , and is set in advance. I ₀ is an initial value set in advance.

c _{1, (a, b)} are four-dimensional coordinates represented by the distance R, Doppler velocity VR, azimuth angle A, and elevation angle E in the first radar, and the coordinates of the distance R are given by Equation (26). It is obtained by dividing the indicated distance R _{i, 1} (t + ΔT ₁ ) by the distance resolution. The coordinates of the Doppler velocity VR can be obtained by dividing the Doppler velocity VR _{i, 1} (t + ΔT ₁ ) shown in Expression (27) by the resolution of the Doppler velocity.
The coordinate of the azimuth angle A is obtained by dividing the azimuth angle A _{i, 1} (t + ΔT ₁ ) shown in the following formula (35) by the resolution of the azimuth angle, and the coordinate of the elevation angle E is given by the following formula (36) Is obtained by dividing the elevation angle E _{i, 1} (t + ΔT ₁ ) shown in FIG.

c _{2, (d, e)} are four-dimensional coordinates represented by the distance R, Doppler velocity VR, azimuth angle A, and elevation angle E in the second radar. It is obtained by dividing the indicated distance R _{i, 2} (t + ΔT ₂ ) by the distance resolution. The coordinates of the Doppler velocity VR can be obtained by dividing the Doppler velocity VR _{i, 2} (t + ΔT ₂ ) shown in Expression (29) by the resolution of the Doppler velocity.
The coordinates of the azimuth angle A are obtained by dividing the azimuth angle A _{i, 2} (t + ΔT ₂ ) shown in the following formula (37) by the resolution of the azimuth angle, and the coordinates of the elevation angle E are given by the following formula (38) Is obtained by dividing the elevation angle E _{i, 2} (t + ΔT ₂ ) shown in FIG.

The combination selection unit 8 of the signal addition unit 7 compares the likelihoods I _{(a, b)-(d, e)} calculated by the likelihood calculation unit 6 with each other.
Based on the comparison result of the likelihoods I _{(a, b)-(d, e)} , the combination selection unit 8 uses each resolution cell c _{1, (a, b)} in the first region and the second region. At least one combination is selected from the combinations with each of the resolution cells c _{2 and (d, e)} (step ST6 in FIG. 4).
For example, the combination selection unit 8 includes a combination of each resolution cell c _{1, (a, b)} in the first region and each resolution cell c _{2, (d, e)} in the second region. From the above, the combination having the maximum likelihood I _{(a, b)-(d, e)} is selected.
Alternatively, the combination selection unit 8 may select a combination of each resolution cell c _{1, (a, b)} in the first region and each resolution cell c _{2, (d, e)} in the second region. The top N combinations with the highest likelihood I _{(a, b)-(d, e)} are selected. N is a value set in advance.
Alternatively, the combination selection unit 8 may select a combination of each resolution cell c _{1, (a, b)} in the first region and each resolution cell c _{2, (d, e)} in the second region. Then, a combination having _a likelihood I _{(a, b)-(d, e)} equal to or higher than a preset threshold is selected.

The amplitude adding unit 9 of the signal adding unit 7 adds the signals included in the resolution cells related to at least one combination selected by the combination selecting unit 8 (step ST7 in FIG. 4).
The amplitude adding unit 9 outputs the added signal to a subsequent processing unit that performs target detection processing and the like.
If the combination selected by the combination selection unit 8 is, for example, a combination of resolution cell c _{1, (3, 2)} and resolution cell c _{2, (3, 2)} , resolution cell c _{1, (3, 2 ) And the} signal contained in the resolution cell c2 _{, (3, 2)} are added. At this time, the signals may be added by adding only the amplitude value of the signal to be added.
The combination selected by the combination selection unit 8 is, for example, a combination of the resolution cell c _{1, (3, 2)} and the resolution cell c _{2, (3, 2)} , or the resolution cell c _{1, (4, 3). )} And the resolution cell c _{2, (3 , 3)} are included in the resolution cell c _{1, (3, 2)} and the resolution cell c _{2, (3, 2).} The signal contained in the resolution cell c1 _{, (4, 3)} and the signal contained in the resolution cell c2 _{, (3, 3)} are added.

As apparent from the above, according to the first embodiment, the first and second reception times predicted by the motion prediction unit 3 among the plurality of resolution cells in the first and second range Doppler maps. A center cell calculation unit 5 for calculating each of the resolution cells corresponding to the position and velocity at the first and second center cells, and each resolution cell in the first region including the first center cell; A likelihood calculating unit 6 is provided for calculating the likelihood between each resolution cell in the second region including the second center cell, and the signal adding unit 7 is calculated by the likelihood calculating unit 6 respectively. Based on the obtained likelihood, at least one combination is selected from the combinations of the resolution cells in the first area and the resolution cells in the second area, and the selected combinations are selected. Included in such resolution cell Since the signals are added to each other, the correspondence between some of the resolution cells in the plurality of resolution cells in the first radar and some of the resolution cells in the plurality of resolution cells in the second radar It is possible to add the signals related to the target only by adding them.
Thereby, compared with the radar signal processing apparatus disclosed in Patent Document 1, it is possible to greatly reduce the processing load required to add signals related to targets.

In the first embodiment, the first signal processing unit 1a obtains the reception signal of one reception beam as the reception signal of the first radar, but as the reception signal of the first radar, The reception signals of a plurality of reception beams may be acquired.
Further, the second signal processing unit 1b shows an example in which the reception signal of one reception beam is acquired as the reception signal of the second radar, but a plurality of reception beams are used as the reception signals of the second radar. The received signal may be acquired.

FIG. 7 is an explanatory diagram illustrating an example in which three second range Doppler maps are generated by receiving reception signals of three reception beams by the second signal processing unit 1b.
In the example of FIG. 7, the second signal processing unit 1b causes the second range Doppler map for the reception beam b-1, the second range Doppler map for the reception beam b, and the second range Doppler map for the reception beam b + 1. A range Doppler map has been generated.
In this case, the likelihood calculation unit 6 sets a first region including the first center cell c ₁ (R, VR) output from the center cell calculation unit 5.
In addition, as shown in FIG. 7, the likelihood calculating unit 6 uses the second center cell c ₂ (R, VR) output from the center cell calculating unit 5 in the second range Doppler map of the reception beam b-1. ) Is set.
In addition, as shown in FIG. 7, the likelihood calculating unit 6 sets a second region including the second center cell c ₂ (R, VR) in the second range Doppler map of the received beam b, In the second range Doppler map of the reception beam b + 1, a second region including the second center cell c ₂ (R, VR) is set.

The likelihood calculating unit 6 includes each resolution cell c _{1, (a, b)} in the first region and each resolution cell c _{2, (d, e )} in the second region in the reception beam b-1. ₎ likelihood _{I (a, b between) - (d, e)} is calculated, respectively.
In addition, the likelihood calculating unit 6 includes each resolution cell c _{1, (a, b)} in the first region and each resolution cell c _{2, (d, e )} in the second region in the reception beam b. ₎ likelihood _{I (a, b between) - (d, e)} is calculated, respectively.
In addition, the likelihood calculating unit 6 includes each resolution cell c _{1, (a, b)} in the first region and each resolution cell c _{2, (d, e )} in the second region in the reception beam b + 1. ₎ likelihood _{I (a, b between) - (d, e)} is calculated, respectively.
In the example of FIG. 7, the first region includes 15 resolution cells c _{1, (a, b)} , and the three second regions include 15 resolution cells c _{2, (d, e)} . Therefore, the likelihood calculating unit 6 calculates 675 (= 15 × (15 × 3)) likelihoods I _{(a, b) − (d, e)} in total.

Based on the comparison result of the likelihoods I _{(a, b)-(d, e)} , the combination selection unit 8 and each of the resolution cells c _{1, (a, b)} in the first region and the three first At least one combination is selected from the combinations with the respective resolution cells c _{2, (d, e)} in the two regions.
For example, the combination selection unit 8 includes each resolution cell c _{1, (a, b)} in the first region and each resolution cell c _{2, (d, e) in} the three second regions. From the combinations, the combination having the maximum likelihood I _{(a, b)-(d, e)} is selected.
Alternatively, the combination selection unit 8 includes each resolution cell c _{1, (a, b)} in the first region and each resolution cell c _{2, (d, e) in} the three second regions. From the combinations, the top N combinations having the highest likelihood I _{(a, b)-(d, e)} are selected. N is a value set in advance.
Alternatively, the combination selection unit 8 includes each resolution cell c _{1, (a, b)} in the first region and each resolution cell c _{2, (d, e) in} the three second regions. A combination having a likelihood I _{(a, b) − (d, e)} equal to or higher than a preset threshold is selected from the combinations.
The amplitude adding unit 9 adds signals included in the resolution cells related to at least one combination selected by the combination selecting unit 8.

Embodiment 2. FIG.
In the first embodiment, an example in which the radar signal processing apparatus includes a signal processing unit 1 that generates first and second range Doppler maps from the received signals of the first and second radars is shown. Yes.
In the second embodiment, a radar signal processing apparatus including a signal processing unit 1 that generates N range Doppler maps from each of N (N is an integer of 3 or more) received radar signals will be described.

FIG. 8 is a block diagram showing a radar signal processing apparatus according to Embodiment 2 of the present invention. In FIG. 8, the same reference numerals as those in FIG.
The Nth signal processing unit 1N includes an analog / digital converter that converts the received signal of the Nth radar from an analog signal to a digital signal. When the received signal of the Nth radar input to the Nth signal processing unit 1N is a digital signal, the Nth signal processing unit 1N does not need to include an analog-digital converter.
The Nth signal processing unit 1N performs processing for generating an Nth range Doppler map from the digital received signal of the Nth radar and outputting the Nth range Doppler map to the likelihood calculating unit 6.
In FIG. 8, the signal processing unit between the second signal processing unit 1b and the Nth signal processing unit 1N is omitted, but the third signal processing unit, ..., (N-1) th. An example in which a signal processing unit or the like is mounted can be considered.
The processing contents of the third signal processing unit,..., The (N−1) th signal processing unit are the same as the processing content of the Nth signal processing unit 1N, and thus the description thereof is omitted.

Next, the operation will be described.
The Nth signal processing unit 1N converts the received signal of the Nth radar from an analog signal to a digital signal.
The Nth signal processing unit 1N performs the same processing as the first signal processing unit 1a and the second signal processing unit 1b, so that the Nth range Doppler map is obtained from the digital received signal of the Nth radar. Is generated.
The Nth signal processing unit 1N outputs the generated Nth range Doppler map to the likelihood calculating unit 6.

Motion prediction unit 3, in the same manner as in the first embodiment, the target position and velocity predicted respectively at a first reception time T ₁ is the time when the signal is received by the first radar, the 2 of the radar by the position and velocity of the target in the second reception time T _2, the time at which the signal was received to predict respectively.
Further, the motion prediction unit 3, in a similar way to predict respective target position and the speed of the receiving time T _N of the N is the time when the signal is received by the radar of the N.

The center cell calculation unit 5 acquires the coordinates of the position where the first, second, and Nth radars are present from the database unit 4, respectively.
The center cell calculation unit 5 uses the coordinates of the position where the first radar is present in the same manner as in the first embodiment, and moves among the plurality of resolution cells in the first range Doppler map. A resolution cell corresponding to the target position and velocity at the _first reception time T ₁ predicted by the prediction unit 3 is calculated as the first center cell c ₁ (R, VR).
The center cell calculation unit 5 uses the coordinates of the position where the second radar is present in the same manner as in the first embodiment, and moves among the plurality of resolution cells in the second range Doppler map. A resolution cell corresponding to the target position and velocity at the _second reception time T ₂ predicted by the prediction unit 3 is calculated as the second center cell c ₂ (R, VR).
The center cell calculation unit 5 is predicted by the motion prediction unit 3 among the plurality of resolution cells in the Nth range Doppler map using the coordinates of the position where the Nth radar is present in the same manner. and it calculates the resolution cells corresponding to the position and velocity of the target in the reception time T _N of the N center cell c _{N (R,} VR) of the N as.
The center cell calculation unit 5 outputs the first center cell c ₁ (R, VR) to the Nth center cell c _N (R, VR) to the likelihood calculation unit 6.

Likelihood calculation unit 6 sets a first region including _first center cell c ₁ (R, VR) output from center cell calculation unit 5 as in the first embodiment, and calculates center cell. A second region including the second center cell c ₂ (R, VR) output from the unit 5 is set.
In addition, the likelihood calculating unit 6 sets the Nth region including the Nth center cell c _N (R, VR) output from the center cell calculating unit 5.
In the second embodiment, each resolution cell included in the Nth region is represented _{by cN, (f, g)} .

Next, the likelihood calculation unit 6 uses a method similar to that of the first embodiment, and includes the first center cell c ₁ (R, VR) output from the center cell calculation unit 5 in the first region. Each resolution cell c _{1, (a, b)} and each resolution cell c ₂ in the second region including the second center cell c ₂ (R, VR) output from the center cell calculator 5 _{(d, e)} the likelihood _{I (a, b)} between the _{- (d, e)} is calculated, respectively.
In addition, the likelihood calculation unit 6 uses the same method to each of the resolution cells c _{1, (a, b)} in the first region including the first center cell c ₁ (R, VR ₎ and the center cell. Likelihood I _{(a, b )} between each resolution cell c _{N, (f, g)} in the Nth region including the Nth center cell c _N (R, VR) output from the calculation unit 5 _{) − (F, g)} , respectively.

The combination selection unit 8 of the signal addition unit 7 uses the likelihoods I _{(a, b)-(d, e)} and I _{(a, b)-(f, g)} calculated by the likelihood calculation unit 6 to each other. Compare.
Based on the comparison result of the likelihoods I _{(a, b)-(d, e)} , I _{(a, b)-(f, g)} , the combination selection unit 8 selects each resolution cell in the first region. combination of c _{1, (a, b)} and each resolution cell c _{2, (d, e) in the second} region and each resolution cell c _{1, (a, b) in} the first region At least one combination is selected from combinations with each resolution cell c _{N, (f, g)} in the Nth region.
For example, the combination selection unit 8 includes a combination of each resolution cell c _{1, (a, b)} in the first region and each resolution cell c _{2, (d, e)} in the second region, and Among the combinations of the resolution cells c _{1, (a, b) in one} area and the resolution cells c _{N, (f, g)} in the Nth area, the combination having the maximum likelihood is selected. select.
Alternatively, the combination selection unit 8 includes a combination of each resolution cell c _{1, (a, b)} in the first region and each resolution cell c _{2, (d, e)} in the second region, and Among the combinations of the respective resolution cells c _{1, (a, b) in one} region and the respective resolution cells c _{N, (f, g)} in the Nth region, the top N pieces having the highest likelihood Select a combination.
Alternatively, the combination selection unit 8 includes a combination of each resolution cell c _{1, (a, b)} in the first region and each resolution cell c _{2, (d, e)} in the second region, and Likelihood is set in advance from a combination of each resolution cell c _{1, (a, b) in one} region and each resolution cell c _{N, (f, g)} in the Nth region. Select a combination that is greater than or equal to the threshold value.
The amplitude adding unit 9 of the signal adding unit 7 adds the signals included in the resolution cells related to at least one combination selected by the combination selecting unit 8.

Embodiment 3 FIG.
In the first embodiment, an example is shown in which the hypothesis generation unit 2 generates one hypothesis.
In the third embodiment, an example in which the hypothesis generation unit 2 makes a plurality of hypotheses will be described.

FIG. 9 is a block diagram showing a radar signal processing apparatus according to Embodiment 3 of the present invention.
FIG. 10 is a hardware configuration diagram showing a radar signal processing apparatus according to Embodiment 3 of the present invention.
9 and 10, the same reference numerals as those in FIGS. 1 and 2 indicate the same or corresponding parts, and thus description thereof is omitted.
The hypothesis generation unit 11 is realized by, for example, a hypothesis generation circuit 31 illustrated in FIG.
The hypothesis generation unit 11 performs a process of generating a plurality of hypotheses relating to the target three-dimensional motion.
For example, the hypothesis generation unit 11 changes the distance, azimuth, altitude, speed, and travel direction while changing each of the distance to the target, the target azimuth, the target altitude, the target speed, and the target travel direction with random numbers. Based on this, a hypothesis about the target three-dimensional motion is generated.

The signal addition unit 12 includes a combination selection unit 8 and an amplitude addition unit 13, and is realized by, for example, a signal addition circuit 32 illustrated in FIG.
The amplitude addition unit 13 performs a process of adding the signals included in the resolution cells related to at least one combination selected by the combination selection unit 8 to the hypothesis unit generated by the hypothesis generation unit 11. .
In addition, the amplitude adding unit 13 compares the signals added in units of hypotheses with each other, and performs a process of selecting any one of the hypothetical units based on the comparison result of the added signals.

In FIG. 9, each of the signal processing unit 1, the hypothesis generation unit 11, the motion prediction unit 3, the database unit 4, the center cell calculation unit 5, the likelihood calculation unit 6, and the signal addition unit 12 which are components of the radar signal processing device. However, this is assumed to be realized by dedicated hardware as shown in FIG. That is, it is assumed that the signal processing circuit 21, the hypothesis generation circuit 31, the motion prediction circuit 23, the recording circuit 24, the center cell calculation circuit 25, the likelihood calculation circuit 26, and the signal addition circuit 32 are realized.
Here, the signal processing circuit 21, the hypothesis generation circuit 31, the motion prediction circuit 23, the center cell calculation circuit 25, the likelihood calculation circuit 26, and the signal addition circuit 32 are, for example, a single circuit, a composite circuit, a programmed processor, A parallel-programmed processor, ASIC, FPGA, or a combination thereof is applicable.

The components of the radar signal processing device are not limited to those realized by dedicated hardware, and the radar signal processing device may be realized by software, firmware, or a combination of software and firmware. Good.
When the radar signal processing device is realized by software or firmware, the database unit 4 is configured on the memory 41 of the computer shown in FIG. 3, and the signal processing unit 1, the hypothesis generation unit 11, the motion prediction unit 3, and the central cell. A program for causing the computer to execute the processing procedure of the calculation unit 5, the likelihood calculation unit 6, and the signal addition unit 12 is stored in the memory 41, and the processor 42 of the computer executes the program stored in the memory 41. do it.
FIG. 11 is a flowchart showing a radar signal processing method which is a processing procedure when the radar signal processing apparatus is realized by software or firmware.

  FIG. 10 shows an example in which each component of the radar signal processing device is realized by dedicated hardware, and FIG. 3 shows an example in which the radar signal processing device is realized by software, firmware, or the like. However, some components in the radar signal processing device may be realized by dedicated hardware, and the remaining components may be realized by software, firmware, or the like.

Next, the operation will be described.
The first signal processing unit 1a converts the received signal of the first radar from an analog signal to a digital signal, as in the first embodiment.
The first signal processing unit 1a generates a first range Doppler map by performing known signal processing on the digital received signal of the first radar, as in the first embodiment (FIG. 11). Step ST11).
The first signal processing unit 1 a outputs the generated first range Doppler map to the likelihood calculating unit 6.

The second signal processing unit 1b converts the received signal of the second radar from an analog signal to a digital signal as in the first embodiment.
The second signal processing unit 1b generates a second range Doppler map by performing known signal processing on the digital received signal of the second radar, as in the first embodiment (FIG. 11). Step ST11).
The second signal processing unit 1 b outputs the generated second range Doppler map to the likelihood calculating unit 6.

The hypothesis generation unit 11 generates a hypothesis h _i (t) related to the target three-dimensional motion (step ST12 in FIG. 11).
When the hypothesis generation unit 11 generates the hypothesis h _i (t), for example, the distance r to the target, the target azimuth A, the target altitude h, the target speed V, the target traveling direction φ, and the traveling direction The average value and the upper and lower limit range of each vertical component ε are acquired.
The hypothesis generation unit 11 uses a random number to determine each value of the distance r, the azimuth angle A, the altitude h, the velocity V, the traveling direction φ, and the vertical component ε within the upper and lower limit ranges centering on the respective average values. By determining, a hypothesis h _i (t) is generated.
As the random number, for example, a normal random number or a uniform random number can be used.

Similar to the first embodiment, the motion prediction unit 3 uses the hypothesis h _i (t) generated by the hypothesis generation unit 11 to receive the first reception that is the time when the signal is received by the first radar. target position and velocity predicted respectively at time T _1, and outputs the position and speed of the target which is predicted center cell calculator 5 (step ST13 in FIG. 11).
Similarly to the first embodiment, the motion prediction unit 3 uses the hypothesis h _i (t) generated by the hypothesis generation unit 11 and uses the second time when the signal is received by the second radar. predicted position and velocity of the target in receiving time T ₂ of the respective outputs the position and velocity of targets predicted in the center cell calculator 5 (step ST13 in FIG. 11).

Similarly to the first embodiment, the center cell calculation unit 5 selects the target at the _first reception time T ₁ predicted by the motion prediction unit 3 among the plurality of resolution cells in the first range Doppler map. A resolution cell corresponding to the position and velocity is calculated as the first central cell c ₁ (R, VR) (step ST14 in FIG. 11).
In the first embodiment, the center cell calculation unit 5 adds the target position at the _second reception time T ₂ predicted by the motion prediction unit 3 among the plurality of resolution cells in the second range Doppler map, and The resolution cell corresponding to the speed is calculated as the second center cell c ₂ (R, VR) (step ST14 in FIG. 11).

Like the first embodiment, the likelihood calculation unit 6 includes each resolution cell c in the first region including the first center cell c ₁ (R, VR) output from the center cell calculation unit 5. _{1, (a, b)} and each resolution cell c _{2, (d, e) in} the second region including the second center cell c ₂ (R, VR) output from the center cell calculator 5 The likelihoods I _{(a, b)-(d, e)} are calculated respectively (step ST15 in FIG. 11).

The combination selection unit 8 of the signal addition unit 7 compares the likelihoods I _{(a, b)-(d, e)} calculated by the likelihood calculation unit 6 with each other as in the first embodiment.
Similarly to the first embodiment, the combination selection unit 8 determines each resolution cell c _{1, (1 )} in the first region based on the comparison result of the likelihoods I _{(a, b)-(d, e). At} least one combination is selected from the combinations of _{a, b)} and each resolution cell c _{2, (d, e)} in the second region (step ST16 in FIG. 11).
Similar to the first embodiment, the amplitude addition unit 9 of the signal addition unit 7 adds the signals included in the resolution cells related to at least one combination selected by the combination selection unit 8 (see FIG. 11 step ST17).

If the number of hypotheses h _i (t) that have already been generated has not reached the predetermined number J set in advance (in the case of step ST18: NO in FIG. 11), the hypothesis generation unit 11 again sets the target three-dimensional A hypothesis h _i (t) relating to motion is generated (step ST12 in FIG. 11).
The hypothesis h _i (t) is generated by reassigning the previously determined distance r, azimuth angle A, altitude h, velocity V, traveling direction φ, and vertical component ε with random numbers.
Thereafter, the processes of steps ST13 to ST18 are performed. The processes of steps ST12 to ST18 are repeatedly performed until the number of hypotheses h _i (t) that have already been generated reaches the specified number J.

If the number of hypotheses h _i (t) already generated by the hypothesis generation unit 11 has reached the specified number J (step ST18 in FIG. 11: YES), the amplitude addition unit 13 adds them in units of hypotheses. The J addition signals as signals are compared with each other.
Based on the comparison result of the J addition signals, the amplitude addition unit 13 selects the maximum addition signal from the J addition signals (step ST19 in FIG. 11).
Alternatively, the amplitude adding unit 13 selects the large top N added signals from the J added signals.
Or the amplitude addition part 13 selects the addition signal more than the preset threshold value from J addition signals.
The amplitude adding unit 13 outputs at least one selected addition signal to a subsequent processing unit that performs target detection processing and the like.

As apparent from the above, according to the third embodiment, the hypothesis generation unit 11 that generates a plurality of hypotheses is provided, and the signal addition unit 12 selects the combination selected as the hypothesis unit generated by the hypothesis generation unit 11. The signals included in the resolution cell are added together, the signals added in hypothesis units are compared with each other, and one of the addition signals in hypothesis units is selected based on the comparison result of the added signals Therefore, as in the first embodiment, a part of the resolution cells in the plurality of resolution cells in the first radar and a part of the resolution cells in the plurality of resolution cells in the second radar. There is an effect that the signals related to the targets can be added only by performing the association.
In addition, the probability of adding a signal other than the target can be reduced as compared with the first embodiment, and the target detection accuracy in the subsequent processing unit can be increased.

Embodiment 4 FIG.
In the first embodiment, the combination selection unit 8 includes the resolution cells c _{1, (a, b)} in the first region and the resolution cells c _{2, (d, e) in} the second region. from the combination of the likelihood _{I (a, b) - (} d, e) combination of the maximum or the likelihood _{I (a, b) - (} d, e) high top N combinations An example of selecting is shown.
However, when the amplitude adding unit 9 includes a signal having a small signal-to-noise power ratio among the signals included in the resolution cells related to one or more combinations selected by the combination selecting unit 8. There is also.

Therefore, in the fourth embodiment, the amplitude adding unit 9 adds the signals included in the resolution cells related to the combination selected by the combination selecting unit 8 and calculates the signal-to-noise power ratio of the added signal. The calculated signal is valid only when the signal-to-noise power ratio is greater than or equal to the threshold value.
The configuration diagram of the radar signal processing apparatus in the fourth embodiment is the same as the configuration diagram of FIG. 1 in the first embodiment.

式（３９）において、ｖ_ｓは、組み合わせ選択部８により選択された組み合わせに係る分解能セルに含まれている信号同士を加算した加算信号である。
ｖ_ｎは、雑音電力であり、例えば、第１のレンジドップラマップの雑音領域から計算される振幅の平均値である。
図１２は、第１のレンジドップラマップの雑音領域を示す説明図である。
図１２の例では、図中、左上の領域と右上の領域を雑音領域としている。Specifically, as shown in the following formula (39), the amplitude adding unit 9 adds the signals included in the resolution cells related to the combination selected by the combination selecting unit 8, and A signal-to-noise power ratio SNR is calculated.

In Expression (39), v _s is an addition signal obtained by adding together signals included in the resolution cells related to the combination selected by the combination selection unit 8.
v _n is the noise power, for example, an average value of the amplitude calculated from the noise region of the first range Doppler map.
FIG. 12 is an explanatory diagram showing a noise region of the first range Doppler map.
In the example of FIG. 12, the upper left area and the upper right area in the figure are the noise areas.

Amplitude adding unit 9 compares the threshold _{SNR th} set in advance and the signal-to-noise power ratio SNR of the additional signal shown in Equation (39), there the signal-to-noise power ratio SNR of the additional signal is less than the threshold _{SNR th} For example, the addition signal is invalidated and is not output to the subsequent processing unit.
If the signal-to-noise power ratio SNR of the addition signal is equal to or greater than the threshold SNR _th , the amplitude addition unit 9 validates the addition signal and outputs it to the subsequent processing unit.

  As is apparent from the above, according to the fourth embodiment, the signal adding unit 7 adds the signals included in the resolution cell according to the selected combination, and the signal-to-noise power ratio of the added signal. If the signal-to-noise power ratio is less than the threshold, the added signal is invalidated, and if the signal-to-noise power ratio is greater than or equal to the threshold, the added signal is validated. Compared to the first embodiment, it is possible to increase the target detection accuracy in the subsequent processing unit.

  In the present invention, within the scope of the invention, any combination of the embodiments, any modification of any component in each embodiment, or omission of any component in each embodiment is possible. .

  The present invention is suitable for a radar signal processing apparatus and a radar signal processing method for adding the received signal of the first radar and the received signal of the second radar.

  1 signal processing unit, 1a first signal processing unit, 1b second signal processing unit, 1N Nth signal processing unit, 2 hypothesis generation unit, 3 motion prediction unit, 4 database unit, 5 center cell calculation unit, 6 Likelihood calculation unit, 7 signal addition unit, 8 combination selection unit, 9 amplitude addition unit, 11 hypothesis generation unit, 12 signal addition unit, 13 amplitude addition unit, 21 signal processing circuit, 22 hypothesis generation circuit, 23 motion prediction circuit, 24 recording circuit, 25 center cell calculating circuit, 26 likelihood calculating circuit, 27 signal adding circuit, 31 hypothesis generating circuit, 32 signal adding circuit, 41 memory, 42 processor.

Claims (6)

A signal processor for generating first and second range Doppler maps from the received signals of the first and second radars, respectively;
A hypothesis generation unit that generates a hypothesis regarding the target three-dimensional movement;
Using the hypothesis, a motion prediction unit that predicts the position and velocity of the target at the first and second reception times, which are the reception times of the signals by the first and second radars, respectively;
Among the plurality of resolution cells in the first and second range Doppler maps, each of the resolution cells corresponding to the target position and velocity at the first and second reception times predicted by the motion prediction unit is obtained. A center cell calculation unit for calculating the first and second center cells;
Likelihood for calculating the likelihood between each resolution cell in the first area including the first center cell and each resolution cell in the second area including the second center cell. A calculation unit;
Based on the likelihood calculated by the likelihood calculation unit, at least one or more of combinations of the resolution cells in the first area and the resolution cells in the second area And a signal adding unit that adds the signals included in the resolution cell related to the selected combination.   The signal adding unit has a high likelihood calculated by the likelihood calculating unit from a combination of each resolution cell in the first region and each resolution cell in the second region. The radar signal processing apparatus according to claim 1, wherein N combinations are selected, and signals included in the resolution cells related to the selected top N combinations are added together. The hypothesis generation unit generates a plurality of hypotheses relating to the target three-dimensional motion,
The motion prediction unit predicts the position and speed of the target using each hypothesis generated by the hypothesis generation unit,
The center cell calculation unit calculates the first and second center cells in a hypothesis unit generated by the hypothesis generation unit,
The likelihood calculation unit includes, in a hypothesis unit generated by the hypothesis generation unit, each resolution cell in the first region including the first center cell and a second center cell including the second center cell. Calculate the likelihood between each resolution cell in the region,
The signal adding unit adds the signals included in the resolution cell according to the selected combination to the hypothesis unit generated by the hypothesis generation unit, compares the signals added in hypothesis unit with each other, and adds the signals 2. The radar signal processing apparatus according to claim 1, wherein one of the addition signals in a hypothesis unit is selected based on the signal comparison result.   The hypothesis generation unit changes the distance, the azimuth, the altitude, the speed, and the distance while changing each of the distance to the target, the target azimuth, the target altitude, the target speed, and the target traveling direction with a random number. 4. The radar signal processing apparatus according to claim 3, wherein a hypothesis relating to the target three-dimensional motion is generated based on the traveling direction.   The signal addition unit adds the signals included in the resolution cell according to the selected combination, calculates a signal-to-noise power ratio of the added signal, and if the signal-to-noise power ratio is less than a threshold value The radar signal processing apparatus according to claim 1, wherein the added signal is invalidated and the added signal is validated if the signal-to-noise power ratio is equal to or greater than a threshold value. The signal processing unit generates first and second range Doppler maps from the received signals of the first and second radars, respectively.
The hypothesis generator generates a hypothesis about the target 3D motion,
The motion prediction unit predicts the position and velocity of the target at the first and second reception times, which are the reception times of the signals by the first and second radars, using the hypothesis,
The center cell calculation unit corresponds to the target position and velocity at the first and second reception times predicted by the motion prediction unit among the plurality of resolution cells in the first and second range Doppler maps. Calculating each of the resolution cells to be the first and second center cells;
A likelihood calculation unit is a likelihood between each resolution cell in the first area including the first center cell and each resolution cell in the second area including the second center cell. Respectively,
Based on the likelihood calculated by the likelihood calculating unit, the signal adding unit may select from among combinations of each resolution cell in the first region and each resolution cell in the second region. A radar signal processing method of selecting at least one combination and adding signals included in a resolution cell according to the selected combination.

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