JP7286038B2 - Radar cross section measuring device - Google Patents

Description

The present disclosure relates to a radar cross section measuring device that measures a radar cross section (RCS) of an object using reflected waves from the object.

The radar cross-sectional area is a quantity representing the target radio wave reflection capability of a radar, and is used, for example, when designing a radar circuit.
Among radars, there is a radar in which a transmitting antenna and a receiving antenna are provided at separate positions. In this radar, the incident angle of the transmitted wave and the reflection angle of the reflected wave with respect to the target are different. This angular difference is called the bistatic angle and depends on the actual position of the target relative to the radar. Therefore, when designing a radar circuit, the radar cross-sectional area is measured for each bistatic angle (hereinafter, the radar cross-sectional area for each bistatic angle may be collectively referred to as "bistatic RCS"). .

When measuring the bistatic RCS, it is difficult to reproducibly measure the actual distance to the assumed target and the actual size of the assumed target.
On the other hand, Patent Literature 1 describes a radar reflection cross-section measuring device that measures in a compact range. Specifically, the radar reflection cross-section measuring device includes a transmitting compact range reflector and a receiving compact range reflector, and the transmitting antenna makes an incident wave enter the target via the transmitting compact range reflector, and the target A receiving antenna receives a reflected wave from an object via a receiving compact range reflector, and the received reflected wave is used to calculate a bistatic RCS.

Japanese Patent Application Laid-Open No. 09-159749

Conventionally, when measuring the bistatic RCS, there was a problem that it was necessary to provide a driving mechanism for moving the transmitting antenna and the receiving antenna in order to change the bistatic angle. In general, a radar cross-sectional area measuring device provided with the driving mechanism is large-scale.
The radar reflection cross section measurement device described in Patent Document 1 can reduce the distance to the target and the size of the target, but the driving mechanism for moving the transmitting antenna and the receiving antenna for changing the bistatic angle (the rail for running, the base plate, the driving device, etc. in Patent Document 1), and there are the same problems as in the conventional art.

An object of the present disclosure is to provide a radar cross-sectional area measuring device that does not require a driving mechanism for moving the transmitting antenna and the receiving antenna for changing the bistatic angle. .

A radar cross-sectional area measuring device of the present disclosure is a radar cross-sectional area measuring device that measures a bistatic radar cross-sectional area of a measurement object, and includes a signal generating unit that outputs a signal with a different frequency with the passage of time, a signal generating unit A signal transmission unit that radiates the signal output by the signal through the transmission antenna, and a signal reception unit that receives the reflected wave reflected by the object to be measured after the signal is radiated by the signal transmission unit through the reception antenna. Then, the reflected wave received by the signal receiving unit is separated into a direct reflected wave and a secondary reflected wave reflected by a reflector installed in advance, and the bistatic radar cross section is calculated using the secondary reflected wave. and a signal processing unit that performs a signal processing, and a driving unit that changes the position where the reflector is installed is provided with respect to the reflector, acquires angle information received before the start of processing, and uses the angle information and a drive control unit that calculates position information indicating a position to move the reflector, and controls the drive unit to move the reflector using the calculation result.

According to the present disclosure, since it is configured as described above, it is possible to provide a radar cross-sectional area measuring device that does not require a driving mechanism for moving the transmitting antenna and the receiving antenna for changing the bistatic angle. , It has the effect of

1 is a diagram showing the configuration of a radar cross-sectional area measuring system and a radar cross-sectional area measuring device according to Embodiment 1; FIG. 2 is a flow chart showing processing of the radar cross-sectional area measuring device of FIG. 1; FIG. 7 is a diagram showing the configuration of a radar cross-section measuring system and a radar cross-section measuring device according to Embodiment 2; FIG. 4 is a flow chart showing processing of the radar cross section measuring device of FIG. 3 ; FIG. FIG. 10 is a diagram showing the configuration of a radar cross-section measuring system and a radar cross-section measuring device according to Embodiment 3; FIG. 6 is a flow chart showing processing of the radar cross section measuring device of FIG. 5 ; FIG. 4 is a diagram showing the relationship between the position and angle of a reflector and the direction of a receiving antenna in the radar cross section measurement system of FIG. 3; FIG. FIG. 10 is a diagram showing configurations of a radar cross-section measuring system and a radar cross-section measuring device according to Embodiment 4; FIG. 10 is a diagram showing the configuration of a radar cross-section measuring system and a radar cross-section measuring device according to Embodiment 5; FIG. 9 is a diagram showing the relationship between the angle of reflection by the object to be measured and the direction of the receiving antenna in the radar cross section measurement system of FIG. 8;

Hereinafter, a radar cross-sectional area measuring system and a radar cross-sectional area measuring device according to the present disclosure will be described with reference to the drawings.
Embodiment 1.
FIG. 1 is a diagram showing the configuration of a radar cross-sectional area measuring system and a radar cross-sectional area measuring apparatus according to Embodiment 1. As shown in FIG.
The radar cross-sectional area measuring system shown in FIG. Although the radar cross-sectional area measuring device 100, the reflector 200, and the target holder 300 are shown as separate configurations, the radar cross-sectional area measuring device 100 includes at least one of the reflector 200 and the target holder 300. may be included.
A target holding table 300 fixes and holds a measuring object 301 assumed as a target.
Radar cross section measuring apparatus 100 measures the bistatic RCS of the measurement object without moving the positions of transmitting antenna 130 and receiving antenna 140 .

The reflector 200 is installed in advance between the radar cross section measuring device 100 and the target holding table. Specifically, the reflector 200 is arranged at a position outside the straight line connecting the transmission antenna 130 that radiates the transmission wave a and the measurement object 301 held on the target holder 300 . Moreover, the reflector 200 is arranged outside the straight line connecting the measurement object 301 held by the target holder 300 and the receiving antenna 140 for receiving the reflected waves b, b1, and b2.
Reflector plate 200 further reflects reflected wave b 1 , which is reflected by measurement object 301 from transmitted wave a.
The reflector 200 is made of metal such as aluminum, iron, or copper, and has a square shape of about 1 meter by 1 meter.
The reflector 200 has, for example, an area sufficiently large with respect to the area of the object to be measured that reflects the transmitted wave.
However, the reflecting plate 200 is not limited to this, as long as it can further reflect the reflected wave b1 of the transmitted wave a reflected by the measurement object 301 .

The radar cross section measuring apparatus 100 includes a signal generating section 110 , a signal transmitting section 120 , a transmitting antenna 130 , a receiving antenna 140 , a signal receiving section 150 and a signal processing section 160 .
The radar cross-sectional area measurement device 100 also includes a control section (not shown) that controls the above components.

The signal generator 110 outputs a signal with a different frequency over time. The signal output by the signal generating section 110 contains a plurality of frequencies that differ with the lapse of time.
For example, the signal generator 110 outputs a signal whose frequency changes at a constant rate over time. This signal is a so-called frequency sweeping signal.
Further, for example, the signal generator 110 may output a pulse signal including different frequencies for each elapsed time.
As will be described later, even if the received signal includes reflected waves of signals radiated at different times, they can be separated according to the radiated times.
In the following description, unless otherwise specified, the signal generating section 110 outputs a signal whose frequency changes at a constant rate over time.

The signal transmission unit 120 radiates the signal output by the signal generation unit 110 via the transmission antenna 130, and transmits the signal output by the signal generation unit 110 to the signal reception unit 150 for processing. Output as a reference signal to be used.

Transmitting antenna 130 is connected to signal transmitting section 120 and radiates the signal received from signal transmitting section 120 .
After the signal is radiated by the signal transmitting section 120, the receiving antenna 140 receives the reflected waves b and b2 reflected by the measurement object 310, and transmits the received reflected waves b and b2 to the signal processing section 160. Output. Of the reflected waves b and b2 received by the receiving antenna 140 , the reflected wave b is a direct reflected wave directly received by the receiving antenna 140 from the measurement object 301 . A reflected wave b2 is a secondary reflected wave received by the receiving antenna 140 after being further reflected by the reflecting plate 200 from the object 301 to be measured.
In FIG. 1, the transmitting antenna 130 and the receiving antenna 140 are provided adjacent to each other. The transmitting antenna 130 and the receiving antenna 140 are provided at substantially the same position when viewed from the measurement object 301 .
However, the transmitting antenna 130 and the receiving antenna 140 may be installed at positions separated from each other, and the present disclosure is not obstructed even if it is other than the above.

The signal receiving section 150 receives the reflected waves b and b2 reflected by the measurement object 310 after the signal is radiated by the signal transmitting section 120 via the receiving antenna 140 .
The signal receiver 150 conforms to a VNA (Vector Network Analyzer), and acquires the amplitude and phase frequency characteristics of the received signal by comparing with the reference signal obtained from the signal transmitter 120 .

The signal processing unit 160 separates the reflected waves b and b2 received by the signal receiving unit 150 into a direct reflected wave b and a secondary reflected wave b2, and calculates a bistatic RCS using the secondary reflected wave b2.
As described above, the directly reflected wave b is the reflected wave directly received by the receiving antenna 140 among the reflected waves b and b2 reflected by the object to be measured. Also, the secondary reflected wave b2 is a reflected wave reflected by the reflector 200 as described above.
Specifically, the signal processing section 160 includes a reflected wave separation section 160a, a frequency characteristic calculation section 160b, and a bistatic RCS calculation section 160c.
A reflected wave separation unit 160a in the signal processing unit 160 converts the frequency characteristics of the received signal into a time response signal using an algorithm such as IFFT (Inverse Fast Fourier Transform).
Reflected wave separator 160 a separates the time response signal into direct reflected wave b and secondary reflected wave b 2 based on the time corresponding to the distance from the antenna to the target and the distance to reflector 200 .
For example, the reflected wave separating unit 160a separates the direct reflected wave and the secondary reflected wave by multiplying the vicinity of the peak of the time response corresponding to the secondary reflected wave by an appropriate window function.
The frequency characteristic calculator 160b converts the time response signal of the secondary reflected wave b2 out of the direct reflected wave b and the secondary reflected wave b2 into a frequency characteristic using an algorithm such as FFT (Fourier transform). This frequency characteristic indicates amplitude and phase.
Thus, the signal processing unit 160 acquires the amplitude and phase of the secondary reflected wave b2 used for calculating the bistatic RCS.
Before calculating the bistatic RCS for the measurement object 310, the signal processing unit 160 performs the same measurement as described above on a target used for calibration (hereinafter referred to as a calibration target). A calibration target is, for example, a conductive sphere.
Note that the above measurement may be performed on the calibration target in advance and the measurement result may be stored in a storage unit (not shown), and the signal processing unit 160 may acquire the measurement result of the calibration target from the storage unit.

A bistatic RCS calculation unit 160c in the signal processing unit 160 divides the frequency characteristic of the measurement object 310 by using the amplitude and phase of the secondary reflected wave b2 when measured with respect to the calibration target, and obtains a theoretical is multiplied by the calculated bistatic RCS of the calibration target to calculate the bistatic RCS at the bistatic angle θb with respect to the measurement target 310 .
As described above, the bistatic RCS at the bistatic angle θb with respect to the measurement object 310 can be obtained by calculating the bistatic RCS using the secondary reflected wave from the reflector 200 .
The bistatic angle θb is an angle formed by a straight line connecting the transmitting antenna 130 and the object to be measured 310 and a straight line connecting the object to be measured 310 and the reflector 200 .
When obtaining the bistatic RCS, for example, the reflector 200 is placed at a position offset by half the distance between the transmitting antenna 130 and the measuring object 310 (target) from the line connecting the transmitting antenna 130 and the measuring object 310 (target). , and when performing measurement by changing the bistatic angle θb from 0 degrees to 90 degrees, the measurement space in the direction perpendicular to the line connecting the transmission antenna of the measurement system and the target in the conventional measurement device can be halved. can be
Note that the bistatic angle θb can be changed by changing the installation position of the reflector 200, for example.

FIG. 2 is a flow chart showing processing of the radar cross-sectional area measurement device 100 of FIG.
The radar cross-sectional area measuring device 100 starts processing when a control unit (not shown) receives a command from the outside of the radar cross-sectional area measuring device, for example.
Signal generator 110 outputs a signal whose frequency changes at a constant rate over time (step ST101).
Signal transmitting section 120 radiates the signal output from signal generating section 110 via transmitting antenna 130 (step ST102).
The signal receiving unit 150 receives, via the receiving antenna 140, the reflected waves b and b2 reflected by the measurement object 310 after the signal is radiated by the signal transmitting unit 120 (step ST103).
The signal processing unit 160 separates the reflected waves b and b2 received by the signal receiving unit 150 into a direct reflected wave b and a secondary reflected wave b2, and calculates a bistatic RCS using the secondary reflected wave b2.
Specifically, the reflected wave separating unit 160a in the signal processing unit 160 converts the frequency characteristics of the received signal (the reflected wave including the reflected wave b and the reflected wave b2) into a time response using an algorithm such as IFFT (Inverse Fast Fourier Transform). A time response signal is converted into a direct reflected wave b and a secondary reflected wave b based on the time corresponding to the distance from the transmitting antenna 130 (and receiving antenna 140) to the measurement object 310 and the distance to the reflector 200. Wave b2 is separated (step ST104). For example, the signal processing unit 160 separates the direct reflected wave b and the secondary reflected wave b2 by multiplying an appropriate window function near the peak of the time response corresponding to the secondary reflected wave b2.
The frequency characteristic calculation unit 160b in the signal processing unit 160 converts the time response signal of the secondary reflected wave b2 out of the direct reflected wave b and the secondary reflected wave b2 into frequency characteristics using an algorithm such as FFT (Fourier transform). (step ST105).
The bistatic RCS calculator 160c in the signal processor 160 is theoretically calculated by dividing the frequency characteristic of the above-described measurement target using the amplitude and phase of the secondary reflected wave b2 when measured with respect to the calibration target. By multiplying by the bistatic RCS of the calibration target obtained, the bistatic RCS of the measurement target is obtained (step ST106).

In the radar cross section measuring apparatus 100, at least part of each function of the control unit (not shown) and the signal processing unit 160 is realized by a processing circuit.
The processing circuit may be dedicated hardware or may be a CPU (Central Processing Unit) that executes a program stored in the memory 1004 .
If the processing circuit is dedicated hardware, the processing circuit may be, for example, a single circuit, a decoding circuit, a programmed processor, a parallel programmed processor, an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array). , or a combination thereof.
When the processing circuit is a CPU, some of the functions of the radar cross section measuring device 100 are implemented by software, firmware, or a combination of software and firmware. That is, for example, the control unit (not shown) and the signal processing unit 160 are realized by a processing circuit such as a CPU that executes a program stored in a HDD (Hard Disc Drive), a memory, or the like, or a system LSI (Large-Scale Integration). be done. It can also be said that the programs stored in the HDD or memory cause the computer to execute the procedures and methods of processing by the control unit and the signal processing unit 160 (not shown), for example.
Here, the memory includes, for example, RAM (Random Access Memory), ROM (Read Only Memory), flash memory, EPROM (Erasable Programmable Read Only Memory), EEPROM (Electrically Erasable Programmable Read- non-volatile such as Memory Only) Alternatively, a volatile semiconductor memory, a magnetic disk, a flexible disk, an optical disk, a compact disk, a mini disk, a DVD (Digital Versatile Disc), or the like.
Also, the functions of the control unit (not shown) and the signal processing unit 160 may be partly implemented by dedicated hardware and partly implemented by software or firmware.

A radar cross-sectional area measuring device according to the present disclosure is a radar cross-sectional area measuring device that measures a bistatic radar cross-sectional area of a measurement object, and includes a signal generating unit that outputs a signal with a different frequency over time; A signal transmission unit that radiates the signal output by the unit through a transmission antenna, and a signal reception that receives the reflected wave reflected by the measurement object through the reception antenna after the signal is radiated by the signal transmission unit. and the signal receiving unit, the reflected wave received by the signal receiving unit is separated into a direct reflected wave and a secondary reflected wave reflected by a reflector installed in advance, and the bistatic radar cross-sectional area is calculated using the secondary reflected wave. and a signal processing unit for calculating.
As a result, it is possible to provide a radar cross-sectional area measuring device that does not require a driving mechanism for moving the transmitting antenna and the receiving antenna in order to change the bistatic angle.

Embodiment 2.
A radar cross-sectional area measuring system and a radar cross-sectional area measuring apparatus according to Embodiment 2 will be described with reference to FIGS. 3 and 4. FIG.
FIG. 3 is a diagram showing the configuration of a radar cross-sectional area measuring system and a radar cross-sectional area measuring device according to Embodiment 2. As shown in FIG.

The radar cross-sectional area measuring system shown in FIG. 3 is provided with a driving unit for moving the position of the reflector 202, and the radar cross-sectional area measuring device 102 controls the driving unit, unlike the radar cross-sectional area measuring system shown in FIG. It differs in that it includes a drive control unit 172 that performs
Therefore, the configuration different from that of the radar cross section measuring system shown in FIG. 1 will be described, and the description of the same configuration will be omitted.

A driver is provided for the reflector 202 . That is, the reflector 202 is a reflector with a drive unit.
The driving part in the reflector 202 has a mechanism for changing the position where the reflector 202 is installed.
The driving unit is positioned on a straight line that does not intersect the straight line connecting the antenna (transmitting antenna 130) and the object to be measured 310 and parallel to the straight line connecting the antenna (transmitting antenna 130 or receiving antenna 140) and the object to be measured 310. The reflector 202 is moved on a straight line.
The drive section changes the position where the reflector 202 is installed based on a command from the drive control section 172 .

A storage unit (not shown) in the radar cross-sectional area measurement device 102 stores a plurality of pieces of angle information indicating the desired bistatic angle θb received and set before the start of processing.
A storage unit (not shown) in the radar cross section measuring device 102 stores angle information and a window function in association with each other.
In the radar cross section measuring apparatus 102, the signal processing section 162 includes a reflected wave separation section 162a, a frequency characteristic calculation section 162b, a bistatic RCS calculation section 162c, and a driving condition determination section 162d.
Reflected wave separation section 162a, frequency characteristic calculation section 162b, and bistatic RCS calculation section 162c are similar to reflected wave separation section 160a, frequency characteristic calculation section 160b, and bistatic RCS calculation section 160c shown in FIG. Therefore, detailed description thereof is omitted.
Drive condition determination unit 162d receives angle information indicating bistatic angle θb desired by the user before the start of processing. The angle information may be stored in advance, for example, in a storage unit (not shown) before the processing is started.
The drive condition determining unit 162d determines a drive condition indicating the position to move the reflector by referring to pre-stored information in which the angle information and the reflector position indicating the position of the reflector are associated. Information in which the angle information and the reflector position indicating the position of the reflector are associated is stored in advance in, for example, a storage unit (not shown).
The radar cross-sectional area measurement device 102 further includes a drive control section 172 .
The drive control section 172 may include a drive condition determination section 162d. In the following explanation of the processing, the processing when the drive control unit 172 includes the function of the drive condition determination unit 162d will be explained.
The drive control unit 172 sequentially acquires angle information indicating the bistatic angle θb received and set before the start of processing, and uses the acquired angle information to calculate position information indicating the position at which the reflector 202 is to be moved. , the calculation result is used to control the driving unit to move the reflecting plate 202 in the arrow direction (1) shown in FIG.

The reflected wave separating unit 162a in the signal processing unit 162 of the radar cross section measuring device 102 separates the secondary reflected wave by changing the time of the window function during signal processing according to the changed position of the reflecting plate 202. do.

FIG. 4 is a flow chart showing the processing of the radar cross section measuring device 102 of FIG.
Processing different from the processing shown in the flowchart of FIG. 2 will be described below.
The radar cross-sectional area measuring device 102 starts processing in response to a command acquired from the outside of the radar cross-sectional area measuring device, for example.
First, the drive control unit 172 acquires angle information indicating the desired bistatic angle θb received and set before the start of processing. The drive control unit 172 uses the obtained angle information to calculate position information indicating the position to move the reflector 202 . The drive control unit 172 uses the calculation result to control the drive unit to move the reflector 202 (step ST201).
Steps ST202 to ST207 are the same as steps ST101 to ST106 shown in FIG. 2, respectively, so description thereof will be omitted.
In step ST207, after calculating the bistatic RCS of the measurement object 310, the signal processing section 162 determines whether or not the process of calculating the bistatic RCS for the angle information indicating all the set bistatic angles has been completed. decision (step ST208).
The signal processing unit 162 ends the series of processing when the processing for all the angle information indicating the bistatic angles is completed (“YES” in step ST208). If the processing of all the angle information indicating the bistatic angle has not been completed (“NO” in step ST208), that is, if there is unprocessed angle information, signal processing section 162 returns to the processing of step ST201. repeat.

The radar cross-sectional area measurement device according to the present disclosure further acquires angle information indicating the bistatic angle received before the start of processing, and uses the acquired angle information to calculate position information indicating the position to move the reflector. Then, a driving control section is provided for controlling the movement of the reflecting plate with respect to the driving section using the calculation result.
As a result, it is possible to provide a radar cross-sectional area measuring device that does not require a driving mechanism for moving the transmitting antenna and the receiving antenna in order to change the bistatic angle.

Embodiment 3.
A radar cross-sectional area measuring system and a radar cross-sectional area measuring apparatus according to Embodiment 3 will be described with reference to FIGS. 5 to 7. FIG.

FIG. 5 is a diagram showing the configuration of a radar cross-sectional area measuring system and radar cross-sectional area measuring device 103 according to the third embodiment.
The radar cross-sectional area measuring system shown in FIG. 5 is the radar cross-sectional area measuring system shown in Embodiment 2, in which the driving section further changes the angle of reflector 203 with respect to receiving antenna 143 .
In addition, the receiving antenna 143 is an antenna having directivity, and is provided with a direction changing unit for changing the direction of the receiving antenna 143 so that the direction of the receiving antenna 143 changes. be.
In this radar cross-sectional area measurement system, the width of the reflector 203 is, for example, less than the half width of the beam of the directional antenna within the assumed movable range. However, the width of the reflector 203 is not limited to this.

A storage unit (not shown) in the radar cross-sectional area measurement device 103 stores a plurality of pieces of angle information indicating the desired bistatic angle θb received and set before the start of processing.
A storage unit (not shown) in the radar cross section measuring device 103 stores angle information and a window function in association with each other.
In the radar cross section measuring device 103, the signal processing section 163 includes a reflected wave separation section 163a, a frequency characteristic calculation section 163b, a bistatic RCS calculation section 163c, and a drive condition determination section 163d.
The functions of the reflected wave separator 163a, the frequency characteristic calculator 163b, and the bistatic RCS calculator 163c are the same as those of the reflected wave separator 162a, the frequency characteristic calculator 162b, and the bistatic RCS calculator 162c shown in FIG. Since they are the same, the common description is omitted.
The drive condition determination unit 163d refers to pre-stored information in which the angle information, the position of the reflector, the angle of the reflector, and the direction of the receiving antenna are associated with each other, and determines the angle information, the position of the reflector, and the direction of the reception antenna. A drive condition is determined that indicates the angle of the plate and the orientation of the receive antenna. Information in which the angle information, the position of the reflector, the angle of the reflector, and the direction of the receiving antenna are associated is pre-stored in, for example, a storage unit (not shown).

The radar cross-sectional area measuring device 103 shown in FIG. 5 includes a drive control section 173 instead of the drive control section 172 shown in FIG. The drive control section 173 may be provided with a drive condition determination section 163d. The drive control section 173 including the function of the drive condition determination section 163d will be described below.
The drive control unit 173 sequentially acquires angle information indicating the desired bistatic angle θb received and set before the start of processing, and uses the acquired angle information to obtain position information indicating the position to move the reflector 203 . Along with the calculation, the driving information indicating the angle of the reflector 203 and the direction information indicating the orientation of the receiving antenna 143 are calculated.
The drive control unit 173 uses the position information to control the drive unit to move the reflector 203 in the arrow direction (1) shown in FIG.
Further, the drive control unit 173 uses the drive information to control the drive unit to change the angle of the reflector 203 in the direction of the arrow (2) shown in FIG.
In addition, the driving control unit 173 uses the directivity information to change the orientation of the receiving antenna 143 in the direction of the arrow (3) shown in FIG. change.

The radar cross-sectional area measuring system according to the third embodiment may be applied to the radar cross-sectional area measuring system shown in the first embodiment.

FIG. 6 is a flow chart showing the processing of the radar cross section measuring device 103 of FIG.
Processing different from the processing shown in the flowchart of FIG. 2 will be described below.
The radar cross-sectional area measuring device 103 starts processing in response to a command acquired from the outside of the radar cross-sectional area measuring device, for example.
The drive control unit 173 acquires angle information indicating the desired bistatic angle received and set before the start of processing, and uses the acquired angle information to calculate position information indicating the position to move the reflector 202. At the same time, drive information indicating the angle of reflector 203 and direction information indicating the orientation of receiving antenna 143 are calculated.
The drive control unit 173 uses the drive information to control the drive unit to change the angle of the reflector 203, and uses the position information to control the drive unit to move the position of the reflector 203. (Step ST301).
Using the acquired angle information, drive control section 173 changes the orientation of receiving antenna 143 so that the directivity direction of receiving antenna 143 changes (step ST302).

Steps ST303 to ST308 are the same as steps ST101 to ST106 shown in FIG. 2, respectively, so description thereof will be omitted.
After calculating the bistatic RCS of the measurement object 310 in step ST308, the signal processing section 163 determines whether or not the process of calculating the bistatic RCS for the angle information indicating all the set bistatic angles θb has been completed. is determined (step ST309).

If the signal processing section 163 has finished processing all the angle information indicating the bistatic angle θb and there is no next instruction (“YES” in step ST309), the series of processing ends (end). If the signal processing unit 163 has not finished processing all the angle information indicating the bistatic angle θb and there is a next instruction (“NO” in step ST309), the signal processing unit 163 returns to the processing in step ST301 and repeats the processing.

Here, the control contents of the drive control unit 173 will be described.
FIG. 7 is a diagram showing the relationship between the position and angle of reflector 203 and the direction of receiving antenna 143 in the radar cross section measurement system of FIG.
FIG. 7 shows the set bistatic angle θb, the position x1 of the reflector 203, the direction θ2 of the reflector 203, and the direction θ1 of the receiving antenna 143. FIG.
The drive control unit 173 performs control processing so that the set bistatic angle θb, the position x1 of the reflector 203, the direction θ2 of the reflector 203, and the direction θ1 of the reception antenna 143 satisfy the following equations.
Specifically, the drive control unit 173 acquires the set bistatic angle θb, and changes the position x1 of the reflector 203 according to the acquired bistatic angle θb to x1=b/tan θb (1). ), and the direction θ2 of the reflector 203 is controlled so as to satisfy θ2=1/2(θb−θ1) (2).
In addition, the drive control unit 173 interlocks the direction θ1 of the receiving antenna 143 so as to satisfy the relationship θ1=atan(b/(a−x1)) (3) to determine the position and direction of the reflector 203. and the orientation of the receiving antenna 143 .
This indicates that the directions of the receiving antenna 143 and the reflecting plate 203 are controlled to an angle that satisfies the law of reflection so that the secondary reflected wave can be received.
Thereby, the radar cross-sectional area measuring system and the radar cross-sectional area measuring device can accurately measure the bistatic RCS corresponding to the bistatic angle.

In the radar cross-sectional area measuring device according to the present disclosure, the receiving antenna is further an antenna having directivity, and direction change is performed by changing the direction of the receiving antenna so that the direction of the receiving antenna changes with respect to the receiving antenna. The driving control unit is further configured to acquire direction information indicating the direction in which the receiving antenna is directed using the acquired angle information, and control the direction changing unit using the direction information.
As a result, it is possible to provide a radar cross-sectional area measuring device that does not require a driving mechanism for moving the transmitting antenna and the receiving antenna in order to change the bistatic angle.

In the radar cross-sectional area measuring device according to the present disclosure, the drive unit further changes the angle of the reflector with respect to the receiving antenna, and the drive control unit further uses the acquired angle information to change the angle of the reflector is calculated, and the calculation result is used to control the drive unit to change the angle of the reflector.
As a result, it is possible to provide a radar cross-sectional area measuring device that does not require a driving mechanism for moving the transmitting antenna and the receiving antenna in order to change the bistatic angle.

Embodiment 4.
A radar cross-sectional area measuring system and a radar cross-sectional area measuring apparatus according to Embodiment 4 will be described with reference to FIG.

FIG. 8 is a diagram showing the configuration of a radar cross-sectional area measuring system and radar cross-sectional area measuring device 104 according to the fourth embodiment.
The radar cross-sectional area measuring system and radar cross-sectional area measuring apparatus 104 shown in FIG. 8 differ from the radar cross-sectional area measuring system and radar cross-sectional area measuring apparatus 100 of Embodiment 1 in the following points.
In other words, reflector 204 has a surface that extends in a direction parallel to a straight line connecting both antennas and object of measurement 310, assuming that transmitting antenna 130 and receiving antenna 140 are at approximately the same position. ing.

A storage unit (not shown) in the radar cross-sectional area measurement device 104 stores a plurality of pieces of angle information indicating the desired bistatic angle θb received and set before the start of processing.
A storage unit (not shown) in the radar cross section measuring device 104 stores angle information and a window function in association with each other.
In the radar cross section measuring device 104, the signal processing section 164 includes a reflected wave separation section 164a, a frequency characteristic calculation section 164b, a bistatic RCS calculation section 164c, and a driving condition determination section 164d.
The functions of the reflected wave separator 164a, the frequency characteristic calculator 164b, and the bistatic RCS calculator 164c are the same as those of the reflected wave separator 160a, the frequency characteristic calculator 160b, and the bistatic RCS calculator 160c shown in FIG. Since they are the same, the common description is omitted.
The reflected wave separator 164a sequentially sets time windows corresponding to the set desired bistatic angles, and uses these time windows to separate the secondary reflected wave b2 at the desired bistatic angle from the received signal.

In the signal receiving section 150, the reflected waves b1 of the measurement target 310 reflected at various bistatic angles θb with respect to the measurement target are incident on the reflector 204 via the receiving antenna 140, and are superimposed on each other. Receive the next reflected wave.
A reflected wave separation unit 164a in the signal processing unit 164 refers to a storage unit (not shown) based on the time response of the received signal, and sets a time window corresponding to the desired bistatic angle θb received and set before the start of processing. Then, using this time window, the secondary reflected wave b2 with the desired bistatic angle θb is separated from the received signal.
By changing the time of this window function, the signal processing unit 164 changes the corresponding bistatic angle and acquires the bistatic RCS for each bistatic angle.

The processing of the radar cross section measuring apparatus according to Embodiment 4 does not include the processing of step ST201 in the processing shown in the flowchart of FIG. 4, so detailed description thereof will be omitted.

In the radar cross section measuring device according to the present disclosure, the signal processing unit separates the reflected wave received by the signal receiving unit into a direct reflected wave and a plurality of secondary reflected waves, and uses the plurality of secondary reflected waves to It is configured to calculate the bistatic radar cross section for each of a plurality of bistatic angles.
As a result, it is possible to provide a radar cross-sectional area measuring device that does not require a driving mechanism for moving the transmitting antenna and the receiving antenna in order to change the bistatic angle.

Embodiment 5.
A radar cross-sectional area measuring system and a radar cross-sectional area measuring device 105 according to Embodiment 5 will be described with reference to FIGS. 9 and 10. FIG.
FIG. 9 is a diagram showing the configuration of a radar cross-sectional area measuring system and radar cross-sectional area measuring device 105 according to the fifth embodiment.
FIG. 10 is a diagram showing the relationship between the angle of reflection by the object to be measured and the direction of the receiving antenna 145 in the radar cross section measuring system of FIG.

A storage unit (not shown) in the radar cross-sectional area measurement device 105 stores a plurality of pieces of angle information indicating the desired bistatic angle θb received and set before the start of processing.
A storage unit (not shown) in the radar cross section measuring device 105 stores the angle information and the window function in association with each other.
In the radar cross section measuring device 105, the signal processing section 165 includes a reflected wave separation section 165a, a frequency characteristic calculation section 165b, a bistatic RCS calculation section 165c, and a driving condition determination section 165d.
The functions of the reflected wave separator 165a, the frequency characteristic calculator 165b, and the bistatic RCS calculator 165c are the same as those of the reflected wave separator 164a, the frequency characteristic calculator 164b, and the bistatic RCS calculator 164c shown in FIG. Since they are the same, the common description is omitted.
The reflected wave separator 165a sequentially sets time windows corresponding to the set desired bistatic angles, and uses the time windows to separate secondary reflected waves b2 at the desired bistatic angles from the received signal.

The radar cross-sectional area measuring system and radar cross-sectional area measuring apparatus 105 according to Embodiment 5 differ from the radar cross-sectional area measuring system and radar cross-sectional area measuring apparatus 104 shown in FIG. 8 in the following points.

In contrast to the reflector 204 shown in FIG. 8, the reflector 205 shown in FIG. It has a mirror shape formed so that the wave b2 reaches the receiving antenna 145 .
This is because, as shown in FIG. 10, when the reflected wave b1 from the measurement object 310 is incident on the reflector 205, the law of reflection is always applied at an arbitrary position along the direction between the antenna targets on the reflector 205. The mirror surface of the reflector 205 is curved so that the fixed receiving antenna 145 is located ahead of the reflecting direction that satisfies the requirements.
The conditions in the radar cross-sectional area measurement system according to Embodiment 5 are, for example, that the direction along the straight line connecting the measurement object 310 and the antennas (the transmitting antenna 130 and the receiving antenna 145) on the reflector 205 is an ellipsoid, It can be obtained by placing the transmitting antenna 130 and the receiving antenna 145 at one of the two focal points of the ellipsoid and placing the measurement object 310 at the other focal point.

In contrast to the signal processing unit 164 shown in FIG. 8, the signal processing unit 165 shown in FIG. 9 acquires angle information indicating the set bistatic angle θb, and uses the acquired angle information to convert the direct reflected wave b and the secondary reflected wave b2, and using the secondary reflected wave b2 to calculate the bistatic RCS,
In contrast to the receiving antenna 140 shown in FIG. 8, the receiving antenna 145 shown in FIG. 9 is a directional antenna. A direction changer is provided for the receiving antenna 145 .
The direction changing unit changes the orientation of the receiving antenna 145 so that the directivity direction of the receiving antenna 145 changes.
In contrast to the radar cross-sectional area measuring apparatus shown in FIG. 8, the radar cross-sectional area measuring apparatus 105 shown in FIG.
The drive control unit 175 acquires angle information indicating the bistatic angle θb received and set before the start of processing, acquires direction information indicating the direction in which the receiving antenna 145 is directed using the acquired angle information, and obtains direction information indicating the direction in which the receiving antenna 145 is directed. The direction information is used to control the direction changer.
The receiving antenna 145 may be a directional antenna, in which case the drive control unit 175 changes the direction of the antenna according to the desired bistatic angle θb so as to satisfy the above equation (2). control the department. The signal processing unit 165 changes the time window according to the bistatic angle and acquires the angle pattern of the bistatic RCS with high accuracy.

In the radar cross section measuring device according to the present disclosure, the reflector is arranged so that the secondary reflected wave reaches the receiving antenna at each position on the reflecting plate corresponding to each position between the object to be measured and the receiving antenna. The signal processing unit acquires the received angle information before the start of processing, separates the direct reflected wave and the secondary reflected wave using the acquired angle information, and separates the secondary reflected wave into the It is configured to calculate the bistatic radar cross section using the reflected wave.
As a result, it is possible to provide a radar cross-sectional area measuring device that does not require a driving mechanism for moving the transmitting antenna and the receiving antenna in order to change the bistatic angle.

Further, in the radar cross-sectional area measuring device according to the present disclosure, the receiving antenna is an antenna having directivity, and the direction changing method for changing the direction of the receiving antenna so as to change the direction of the receiving antenna with respect to the receiving antenna is provided, and the drive control unit acquires the angle information received before the start of processing, acquires direction information indicating the direction in which the receiving antenna is directed using the acquired angle information, and uses the direction information to determine the direction Configured to control the change part.
As a result, it is possible to provide a radar cross-sectional area measuring device that does not require a driving mechanism for moving the transmitting antenna and the receiving antenna in order to change the bistatic angle.

It should be noted that, within the scope of the disclosure, the present disclosure can be a free combination of each embodiment, a modification of any component in each embodiment, or an omission of any component in each embodiment. It is possible.

The radar cross section measuring apparatus according to the present disclosure can measure the bistatic RCS without providing a large-scale driving mechanism for moving the transmitting antenna and the receiving antenna. It is suitable for use in a radar cross section measurement system for measuring RCS.

100, 102, 103, 104, 105 radar cross section measuring device, 110 signal generating section, 120 signal transmitting section, 130 transmitting antenna, 140, 143, 145 receiving antenna, 150 signal receiving section, 160, 162, 163, 164, 165 signal processor, 172, 173, 175 drive controller, 200, 202, 203, 204, 205 reflector, 300 target holder, 310 object to be measured.

Claims (7)

A radar cross-sectional area measuring device for measuring a bistatic radar cross-sectional area of a measurement object,
a signal generator that outputs a signal with a different frequency over time;
a signal transmission unit that radiates the signal output by the signal generation unit through a transmission antenna;
a signal receiving unit that receives, via a receiving antenna, a reflected wave reflected by the measurement object after the signal is radiated by the signal transmitting unit;
The reflected wave received by the signal receiving unit is separated into a direct reflected wave and a secondary reflected wave reflected by a reflector installed in advance, and the bistatic radar cross section is calculated using the secondary reflected wave. a signal processing unit;
with
A driving unit is provided for changing the position where the reflector is installed with respect to the reflector,
Obtaining angle information received before the start of processing, calculating position information indicating a position to move the reflector using the angle information, and moving the reflector with respect to the driving unit using the calculation result. Equipped with a drive control unit that controls to
A radar cross section measuring device characterized by: The driving unit further changes the angle of the reflector with respect to the receiving antenna,
The driving control unit further calculates angle information indicating the angle of the reflector using the obtained angle information, and controls the driving unit to change the angle of the reflector using the calculation result. ,
The radar cross section measuring device according to claim 1. The receiving antenna is a directional antenna,
A direction changing unit for changing the direction of the receiving antenna so as to change the directivity direction of the receiving antenna is provided with respect to the receiving antenna,
The drive control unit further uses the acquired angle information to acquire direction information indicating the direction in which the receiving antenna is directed, and controls the direction changing unit using the direction information.
The radar cross section measuring device according to claim 1 or 2. A radar cross-sectional area measuring device for measuring a bistatic radar cross-sectional area of a measurement object,
a signal generator that outputs a signal with a different frequency over time;
a signal transmission unit that radiates the signal output by the signal generation unit through a transmission antenna;
a signal receiving unit that receives, via a receiving antenna, a reflected wave reflected by the measurement object after the signal is radiated by the signal transmitting unit;
The reflected wave received by the signal receiving unit is separated into a direct reflected wave and a secondary reflected wave reflected by a reflector installed in advance, and the bistatic radar cross section is calculated using the secondary reflected wave. a signal processing unit;
with
The signal processing unit is
The reflected wave received by the signal receiving unit is separated into a direct reflected wave and a plurality of secondary reflected waves by obtaining the angle information received before the start of processing, using the obtained angle information, and dividing the reflected wave into a plurality of secondary reflected waves. Calculate the bistatic radar cross section for each of a plurality of bistatic angles using reflected waves,
The reflecting plate is formed so that secondary reflected waves from the reflecting plate reach the receiving antenna at positions on the reflecting plate corresponding to positions between the object to be measured and the receiving antenna. has a mirror-like shape,
The receiving antenna is a directional antenna,
A direction changing unit for changing the direction of the receiving antenna so as to change the directivity direction of the receiving antenna is provided with respect to the receiving antenna,
A drive control unit that acquires angle information received before the start of processing, acquires direction information indicating a direction in which the receiving antenna is directed using the acquired angle information, and controls the direction changing unit using the direction information. , a radar cross section measuring device. moreover,
the transmitting antenna;
the receiving antenna;
the reflector;
the drive unit;
The radar cross section measuring device according to claim 1 or 2, comprising: moreover,
the transmitting antenna;
the receiving antenna;
the direction changing unit;
the reflector;
the drive unit;
The radar cross section measuring device according to claim 3, comprising: moreover,
the transmitting antenna;
the receiving antenna;
the direction changing unit;
the reflector;
The radar cross section measuring device according to claim 4 , comprising:

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