JP2991080B2 - Radar equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radar system, and more particularly, to a radar system for an anti-aircraft target including a helicopter, and more particularly, to easily detect a hovering helicopter. The present invention relates to a radar device capable of performing the following.

[0002]

2. Description of the Related Art FIG. 9 is a block diagram showing an example of the configuration of a conventional radar device. In FIG. 9, reference numeral 1001 denotes an antenna that radiates a transmission wave to a space in a specific direction and receives a reflected wave reflected from an object other than the target (clutter), such as an aircraft or a helicopter, or an anti-aircraft target, and 1002, a transmission wave. , And 1003 is an antenna 100
1 is a circulator that supplies a transmission signal from the transmitter 1002 to the antenna 1 and separates a reception signal received by the antenna 1001. Reference numeral 1004 denotes a receiver for converting a reception signal of the antenna 1001 sent from the circulator 1003 into a digital video signal, and 1005 denotes a receiver 100
(Moving Target In) that introduces the digital video signal from
1006 is an MTI device 1
This is a frequency analyzer that introduces the output signal of 005 and performs narrow band filtering. 1007 is a frequency analyzer 1
No. 006 is introduced to detect a reflected signal from the target, and a CFAR (Constant False)
Alarm Rate) device, 1008 is CFA
A frequency axis synthesizer for introducing the output signal of the R apparatus 1007 and compressing the detection information spread in the frequency direction into one, and 1009 for introducing the output signal of the frequency axis synthesizer 1008 and performing correlation between antenna beam scans. This is a scan correlator that removes a signal with clutter as clutter.

FIG. 10 shows a CFAR device 1 shown in FIG.
007 is a block diagram illustrating an example of a configuration of 007. FIG. In FIG. 10, reference numeral 1007a denotes N for introducing and delaying an input signal.
+3 stage shift register (N is an arbitrary even number)
Reference numeral 007b denotes two adders for adding the first half N / 2 stage and the second half N / 2 stage of the shift register 1007a, respectively.
007c is an output signal of the adder 1007b (here, A is an output signal of the adder 1007b for adding the first N / 2 stages of the shift register 1007a, and
The output signal of the adder 1007b for adding the latter N / 2 stages of 7a is B. ) To perform the operation represented by x = f (A, B). The type of calculation by the calculator 1007c includes (A + B), max (A, B), min (A, B), and the like. (A + B) is an adder 100 that adds the first N / 2 stages of the shift register 1007a.
7b and the second half N / 2 of the shift register 1007a
The case where the output B of the adder 1007b for adding the stages is added, and max (A, B) is the case where one of the outputs A and B is obtained, and min (A, B)
Is a case where one of the outputs A and B is determined to be smaller. 1007d outputs the CFA to the output of the arithmetic unit 1007c.
A multiplier 1007e multiplies by an R constant K. An input signal 1007e receives an output signal C output from a central portion (hereinafter, referred to as a target cell) of a shift register 1007a and an output signal D output from a multiplier 1007d. Is larger than the output signal D of the multiplier 1007d (when C> D), the output signal H1 = 1 of the comparator 1007d is output,
The output signal c of the cell of interest is the output signal D of the multiplier 1007d.
Is equal to or smaller than the output D of the multiplier 1007d (when C ≦ D), the output signal H of the comparator 1007d
1 = 0 is a comparator that outputs 1 = 0, and 1007f is a comparator 1
A switch that introduces the output signal H1 of the comparator 007d, outputs the signal C of the cell of interest when the output signal H1 of the comparator 1007d = 1, and outputs zero amplitude when the output signal H1 of the comparator 1007d = 0. .

Next, the operation of the conventional radar device will be described. The transmission wave radiated from the antenna 1 is reflected from clutters other than a target such as an airplane or a helicopter such as an anti-aircraft target or the ground surface, and the antenna 1001 and the circulator 10
03, converted into a digital video signal by the receiver 1004 via the receiver 1004,
Sent to The MTI apparatus 1005 suppresses clutter using a difference in Doppler frequency of a reflected signal from a target and a clutter other than the target. The frequency analyzer 1006
The signal-to-noise ratio (S / N ratio) is obtained by coherently integrating the clutter-suppressed signal in the MTI device 1005.
To improve. Further, the frequency analyzer 1006 suppresses clutter by removing the vicinity of the Doppler frequency where clutter exists. Note that the frequency analyzer 100
As means of coherent integration in F.6, FFT
(Fast Fourier Transform; Fast Fourier Transform) is often used.

[0005] The CFAR device 1007 calculates a reference level from a signal level around a range bin of interest with respect to a distance sampling (hereinafter, referred to as a range bin) for each frequency of an output signal of the frequency analysis device 1006,
The presence / absence of a target signal is extracted by comparing the calculated reference level with the range bin signal of interest.

[0006] The target signal detected by the CFAR device 1007 is compressed into one signal by the frequency axis synthesizing device 1008 in order to suppress and display the spread in the frequency direction. As the compression method, for example, there is a method of calculating the logical sum of the frequency direction detection information, a method of outputting the maximum value of the frequency direction detection signal, and the like. The clutter signal is suppressed by the MTI device 1005 and the frequency analysis device 1006 in order to increase the detection accuracy on the radar, but the clutter signal still remains due to the spread of the Doppler frequency due to the fluctuation of the clutter. May be. Scan correlation is performed by the scan correlator 1009 in order to remove the remaining clutter signal. The scan correlator 1009 detects signals existing in the same direction and the same distance between scans from the signal output from the frequency axis synthesizer 1008, and removes this detected signal as clutter.

[0007]

When the target is a helicopter, the antenna 100 combines the reflected signal from the airframe and the reflected signal from the rotor blade.
1 is input. At this time, if the helicopter is hovering, the Doppler frequency of the reflected signal from the fuselage becomes zero, so that the MTI device 1005 and the frequency analyzer 1006 suppress the signal as in the case of the clutter, and the CFAR device 1007
Is difficult to detect. In addition, the signal from the rotor blade may be detected by the CFAR device 1007 due to the presence of a Doppler frequency component due to the rotation of the rotor, but on average, a small RCS (Radar Cros) is used.
s Section), the CFAR device 100
7 is difficult to detect. When the aspect angle of the rotor blade with respect to the radar is just 90 degrees, an extremely large RCS is exhibited. However, it is rare that the transmission pulse of the radar strikes the rotor blade at an aspect angle of 90 degrees with good timing. Therefore, the pulse repetition period of the radar (PR
I: Pulse Repetition Interv
al) is changed little by little so that observation at an aspect angle of 90 ° can be performed without fail. However, in this method, it takes a very long time to adjust the pulse repetition period so that observation can be performed at an aspect angle of 90 degrees, and the measurement time increases. Even if the reflected signal of the rotor blade can be detected by the CFAR device 1007, since the hovering helicopter is located at the same position as the rotor blade, the hovering helicopter is removed by imitating clutter in the inter-scan correlation processing. . As mentioned above,
In the above-mentioned conventional radar device, it is difficult to detect a hovering helicopter. Even if the hovering helicopter is detected, the hovering helicopter is regarded as a clutter in the scan correlation process and is removed. Therefore, an object of the present invention is to provide a radar apparatus that can easily detect a hovering helicopter and can prevent removal of the hovering helicopter by scan correlation processing.

[0008]

A radar apparatus according to a first aspect of the present invention includes a transmitter for generating a transmission wave and an antenna for radiating the transmission wave generated by the transmitter in a space in a designated direction and receiving a reflected wave. A circulator that supplies a signal from the transmitter to the antenna, and supplies a received signal received by the antenna to a receiver; a receiver that converts a received signal from the circulator to a digital video signal; (Moving Target India) which introduces a digital video signal from the video camera and suppresses the clutter signal.
a frequency analyzer for introducing the output signal of the MTI device and performing narrow band filtering, and a first CFAR (Constant False) for introducing the output signal of the frequency analyzer and detecting a reflected signal from a target.
e Alarm Rate device, an integrator for incoherently integrating the output amplitude of the frequency analyzer in the frequency direction, a second CFAR device for introducing the output signal of the integrator and detecting a reflected signal from a target, 1
And the second CFAR device output is introduced, the first CFAR device output is set to H1, the second CFAR device output is set to H2, and (H1, H2) =
At (0,0), it is determined that there is no hit, and (H1, H2) =
When (1, 0), it is determined that the target is a hit other than the helicopter. When (H1, H2) = (0, 1), it is determined that the target is a helicopter hit, and (H1, H2) = (1,
In the case of 1), there is provided a detection / judgment device for judging a hit of the helicopter and a target other than the helicopter.

A radar apparatus according to a second aspect of the present invention includes a transmitter for generating a transmission wave, an antenna for emitting a transmission wave generated by the transmitter in a space in a designated direction and receiving a reflected wave, and transmitting the reflected wave to the antenna. A circulator for supplying a signal from a transmitter and receiving a signal received by the antenna to a receiver, a receiver for converting a signal received from the circulator to a digital video signal, and a digital video signal from the receiver And MTI (M
Ovating Target Indicator), a frequency analyzer that introduces the output signal of the MTI device and performs narrow band filtering, and a first C that introduces the output signal of the frequency analyzer and detects a reflected signal from a target.
FAR (Constant False Alarm)
Rate) device, an integrator that performs pseudo-coherent integration in the frequency direction after phase-compensating the output amplitude of the frequency analyzer to the signal of each frequency bin with the phase of the adjacent range bin, and introduces the output signal of the integrator. A second CFAR device for detecting a reflected signal from a target, the first CFAR device output and the second CFAR device output are introduced, the first CFAR device output is set to H1, and the second CFAR device output is set to H1.
The output of the CFAR device is H2, and (H1, H2) =
At (0,0), it is determined that there is no hit, and (H1, H2) =
When (1, 0), it is determined that the target is a hit other than the helicopter. When (H1, H2) = (0, 1), it is determined that the target is a helicopter hit, and (H1, H2) = (1,
In the case of 1), there is provided a detection / judgment device for judging a hit of the helicopter and a target other than the helicopter.

[0010] A radar apparatus according to a third aspect of the present invention includes a transmitter for generating a transmission wave, an antenna for emitting a transmission wave generated by the transmitter in a space in a designated direction and receiving a reflected wave, and A circulator that supplies a signal from a transmitter and supplies a received signal received by the antenna to a receiver, a receiver that converts a received signal from the circulator into a digital video signal, and a digital video signal from the receiver. MTI (Mo) to introduce and suppress clutter signals
Ving Target Indicator) device, a frequency analyzer that introduces an MTI device output signal and performs narrow band filtering, and a first CF that introduces the frequency analyzer output signal and detects a reflected signal from a target
AR (Constant False Alarm R)
a) a device, an integrator for incoherently integrating the output amplitude of the frequency analyzer in the frequency direction, a second CFAR device for introducing an output signal of the integrator and detecting a reflected signal from a target, and the first CFAR A first maximum amplitude detector for detecting a maximum amplitude of a signal detected by the device, a second maximum amplitude detector for detecting a maximum amplitude of a signal detected by the second CFAR device, and the first CF.
An AR device output, the second CFAR device output, and the first
And the second maximum amplitude detection device output is introduced, the first CFAR device output is set to H1, the second CFAR device output is set to H2, and the first CFAR device output is set to H2.
, The output of the second maximum amplitude detector is M2, and (H1, H2) = (0,
0), it is determined that there is no hit, and (H1, H2) = (1,
At (0), it is determined that the target is a hit other than the helicopter. When (H1, H2) = (0, 1), it is determined that the target is a helicopter hit. When (H1, H2) = (1, 1) Time, and M1> k (k: integral effect constant in the frequency direction)
When × M2, it is determined that the target is a hit other than a helicopter, and when (H1, H2) = (1, 1) and M
A detection / judgment device for judging a helicopter hit when 1 ≦ k × M2, and a scan for introducing an output signal of the detection / judgment device and removing hits having a correlation between scans only when the target is a hit other than a helicopter A correlation device.

According to a fourth aspect of the present invention, there is provided a radar apparatus for transmitting a transmission wave, an antenna for emitting a transmission wave generated by the transmitter in a space in a designated direction and receiving a reflected wave, and A circulator for supplying a signal from a transmitter and receiving a signal received by the antenna to a receiver, a receiver for converting a signal received from the circulator to a digital video signal, and a digital video signal from the receiver And MTI (M
Ovating Target Indicator) device, a frequency analyzer that introduces an MTI device output signal and performs narrow band filtering, and a first CF that introduces the frequency analyzer output signal and detects a reflected signal from a target
AR (Constant False Alarm R)
a) a device, an integrator for performing pseudo-coherent integration in the frequency direction after phase-compensating the output amplitude of the frequency analyzer to the signal of each frequency bin with the phase of an adjacent range bin, and introducing the integrator output signal to the target. A second CFAR device for detecting a reflected signal from the first CF
A first maximum amplitude detection device that detects the maximum amplitude of the signal detected by the AR device, a second maximum amplitude detection device that detects the maximum amplitude of the signal detected by the second CFAR device,
The first CFAR device output, the second CFAR device output, the first maximum amplitude detection device output, and the second maximum amplitude detection device output are introduced, and the first CFAR device output is set to H1. , The output of the second CFAR device to H2
The output of the first maximum amplitude detector is M1, the output of the second maximum amplitude detector is M2, and (H1, H
2) When = (0, 0), it is determined that there is no hit, and (H1, H
2) When = (1, 0), it is determined that the target is a hit other than the helicopter, when (H1, H2) = (0, 1), it is determined that the target is a helicopter hit, and (H1, H2) =
When (1, 1) and M1> k (integral effect constant in the frequency direction) × M2, it is determined that the target is a hit other than a helicopter, and (H1, H2) = (1, 1), And a detection / judgment device for judging a helicopter hit when M1 ≦ k × M2, and a scan that introduces the output of the detection / judgment device and removes a hit having a correlation between scans only when the target is a hit other than a helicopter A correlation device.

According to a fifth aspect of the present invention, there is provided a radar apparatus as defined in the first aspect.
Is characterized by having a signal detecting means for detecting a signal having a low threshold value level, and the integrator having an integral range control means for controlling an integral range in a frequency direction.

A radar device according to a sixth aspect of the present invention introduces an output signal of the frequency analysis device, extracts a dispersion coefficient of a sampling signal amplitude in a frequency direction, and outputs a comparison result between the extracted dispersion coefficient and a threshold level. Frequency direction variance extraction device, introducing the detection determination device output and the frequency direction variance extraction device output, if the variance coefficient of the frequency direction sampling signal amplitude is smaller than the threshold level, and is a helicopter hit, noise jammer and And a noise jammer judging device for judging.

According to a seventh aspect of the present invention, there is provided a radar apparatus having a spectrum change pattern extraction device for introducing the output signal of the frequency analysis device and the output signal of the detection determination device and extracting a time change pattern of amplitude spread in the frequency direction. It is a feature.

[0015]

According to the first aspect of the present invention, by utilizing the fact that the reflected signal from the helicopter spreads in the frequency direction, the signal after the frequency analysis is incoherently integrated in the frequency direction, so that the signal from the helicopter spread in the frequency direction is obtained. Since the S / N ratio of the reflected signal can be improved, the helicopter can be easily and accurately detected.

In the second invention, the helicopter expanded in the frequency direction by subjecting the signal after the frequency analysis to the signal of each frequency bin and performing phase compensation with the phase of the adjacent range bin and then performing pseudo coherent integration in the frequency direction. Since it is possible to further improve the S / N ratio of the reflected signal from the incoherent integration, the helicopter can be easily constructed.
And it can detect with high precision.

In the third invention, the signal after frequency analysis is incoherently integrated in the frequency direction, so that the S / N ratio of the reflected signal from the helicopter spread in the frequency direction can be improved. Detection can be performed easily and accurately. In addition, by comparing the presence or absence of signal detection before and after integration and the amplitude of the detection signal before and after integration, it is possible to reliably detect a helicopter from targets other than the helicopter, and to prevent helicopter removal by scan correlation. Can be.

In the fourth invention, the helicopter expanded in the frequency direction by subjecting the signal after the frequency analysis to the signal of each frequency bin by performing phase compensation with the phase of the adjacent range bin and then performing pseudo coherent integration in the frequency direction. It is possible to further improve the S / N ratio of the reflected signal from the case where the incoherent integration is performed, so that the helicopter can be easily and accurately detected. Also, by comparing the presence or absence of signal detection before and after integration and the amplitude of the detection signal before and after integration, the helicopter can be reliably distinguished and detected from targets other than the helicopter, thereby preventing helicopter removal due to scan correlation. Can be.

According to the fifth aspect of the invention, by controlling the integration range in the frequency direction by the signal level before integration, it is possible to extract the spread of the clutter in the frequency direction and not to integrate the clutter. The effect of improving the N ratio can be improved.

In the sixth invention, the variance coefficient of the sampling signal amplitude in the frequency direction is extracted by the variance extraction device in the frequency direction based on the output signal of the frequency analysis device, and the output of the detection determination device and the output of the variance extraction device in the frequency direction are extracted. If the amplitude that spreads in the frequency direction based on the noise jammer is constant, it is possible to know that the noise jammer has been input to the radar device by determining the noise jammer by the noise jammer determination device.

In the seventh invention, the time-dependent pattern of the spread of the amplitude in the frequency direction extracted based on the output signal of the frequency analysis device and the output signal of the detection / judgment device is extracted, whereby the spread of the amplitude in the frequency direction determined in advance is obtained. By comparing reference data on the relationship between the time change pattern of the helicopter and the number of times of the rotor of the helicopter with the extracted time change pattern, the detected rotor speed of the helicopter can be estimated.
Therefore, if the number of rotors is known, the type of helicopter detected based on the estimated rotor speed can be estimated.

[0022]

【Example】

Embodiment 1 FIG. FIG. 1 is a block diagram illustrating a configuration of a radar apparatus according to a first embodiment of the present invention. In FIG. 1, reference numeral 1 denotes an antenna that radiates a transmission wave to a space in a specific direction and receives a reflected wave reflected from an object other than a target (clutter) such as an aircraft or a helicopter, or an air target or the ground, and 2 denotes a transmission wave. Is a circulator that supplies a transmission signal from the transmitter 2 to the antenna 1 and separates a reception signal received by the antenna 1. 4 is a circulator 3
Is a receiver for converting a reception signal of the antenna 1 transmitted from the receiver into digital video, and an MT 5 for introducing a digital video signal from the receiver 4 and suppressing a clutter signal.
Reference numeral 6 denotes a frequency analyzer that introduces an output signal of the MTI device 5 and performs narrow-band filtering. 7
a is an integrator for incoherently integrating the output amplitude of the frequency analyzer 6 in the frequency direction; 8a is a first CFAR device for introducing an output signal of the frequency analyzer 6 and detecting a reflected signal from a target; 8b is an integrator 7
a CFA device for introducing the output signal and detecting the reflected signal from the target, wherein 10a is the first CFA device
The output of the R device 8a and the output of the second CFAR device 8b are introduced, the output of the first CFAR device 8a is set to H1, the output of the second CFAR device 8b is set to H2, and (H1, H2) =
At (0,0), it is determined that there is no hit, and (H1, H2) =
When (1, 0), it is determined that the target is a hit other than the helicopter. When (H1, H2) = (0, 1), it is determined that the target is a helicopter hit, and (H1, H2) = (1,
This is a detection / determination device that determines a hit of a helicopter and a target other than the helicopter at the time of 1). In addition,
The antenna 1 to the frequency analyzer 6 are the same as the conventional radar device shown in FIG. Next, the operation of the radar device of the present embodiment will be described. The transmission wave radiated from the antenna 1 is reflected from clutters other than the target such as an airplane or a helicopter or the like, or a target such as the ground surface.
The signal is converted into a digital video signal by the receiver 4 via the circulator 2 and sent to the MTI device 5. MT
The I device 5 suppresses clutter using a difference in Doppler frequency of a reflected signal from a target and a clutter other than the target. The frequency analysis device 6 performs a coherent integration of the clutter-suppressed signal to obtain a signal-to-noise ratio (S / N).
Ratio). Furthermore, the frequency analyzer 6 removes the vicinity of the Doppler frequency where clutter exists,
Suppress clutter. As a means of coherent integration in the frequency analysis device 6, FFT is often used.

The first CFAR device 8a introduces an output signal of the frequency analysis device 6 and detects a reflected signal from a target. The integrator 7a incoherently integrates the output amplitude of the frequency analyzer 6 in the frequency direction, and outputs the second CF
The AR device 8b detects the reflection signal from the target by introducing the output signal of the integration device 7a. Note that the CFAR devices 8a and 8b calculate a reference bell from the signal level around the range bin of interest with respect to the distance sampling (range bin) for each frequency of the output signal of the frequency analysis device 6, and The presence or absence of the target signal is extracted by comparing with the range bin signal. Then, the detection determination device 10a
, The output of the first CFAR device 8a is set to H1, the output of the second CFAR device 8b is set to H2, and (H1, H2)
= (0, 0), it is determined that there is no hit, and (H1, H2)
= (1, 0), it is determined that the target is a hit other than the helicopter, (H1, H2) = (0, 1), it is determined that the target is a helicopter hit, and (H1, H2) =
At the time of (1, 1), it is determined that the hit is a helicopter and a target other than the helicopter.

At this time, the output of the frequency analyzer 6 is the first
Of the signal reflected from the helicopter spread in the frequency direction in the frequency direction incoherent integrator 7a, the S / N ratio is improved.
Reflected signals from targets other than the helicopter that do not spread in the frequency direction do not spread in the frequency direction,
Conversely, the S / N ratio deteriorates due to integration in the frequency direction.

As described above, in the present embodiment, the signal after frequency analysis by the frequency analyzer 6 is incoherently integrated in the frequency direction by the integrator 7a, so that the S signal of the reflected signal from the helicopter spread in the frequency direction is obtained. Since the / N ratio can be improved, the second CFAR device 8b can easily and accurately detect and display the helicopter. Further, targets other than the helicopter can be detected and displayed by the first CFAR device 8a based on the output of the frequency analysis device 6. Therefore, by detecting the presence or absence of signal detection before and after the frequency direction incoherent integration device 7a by the detection determination device 10a, it is possible to distinguish between detection of a helicopter and detection of a target other than a helicopter, such as an airplane. In the first embodiment, the case where the helicopter to be detected is irrespective of the presence or absence of hovering is shown. However, the first embodiment is particularly effective for a helicopter which is hard to detect and is hovering.

Embodiment 2 FIG. FIG. 2 is a block diagram illustrating a configuration of a radar device according to a second embodiment of the present invention. In FIG. 2, the same reference numerals as those in FIG.
Reference numeral b denotes a pseudo-coherent integrator that performs pseudo-coherent integration in the frequency direction after performing phase compensation on the signal of each frequency bin with the phase of the adjacent range bin. Here, the configuration other than the integration device 7b is the same as that of the first embodiment in FIG.
The operation other than the pseudo coherent integration device 7b is exactly the same as that of the first embodiment shown in FIG. Next, the operation of the radar device of the present embodiment will be described. The transmitted wave radiated from the antenna 1 is reflected from clutters other than the target, such as an aircraft or a helicopter, such as an anti-aircraft target or the ground, and is converted into a digital video signal by the receiver 4 via the antenna 1, the circulator 2, and the receiver 4. It is converted and sent to the MTI device 5. M
The TI device 5 suppresses clutter using a difference in Doppler frequency of a reflected signal from a target and a clutter other than the target. The frequency analysis device 6 performs a coherent integration of the clutter-suppressed signal to obtain a signal-to-noise ratio (S / N).
Ratio). Furthermore, the frequency analyzer 6 removes the vicinity of the Doppler frequency where clutter exists,
Suppress clutter. As a means of coherent integration in the frequency analysis device 6, FFT is often used.

The first CFAR device 8a detects the reflected signal from the target by introducing the output signal of the frequency analysis device 6. The integrator 7b performs pseudo-coherent integration in the frequency direction after performing phase compensation on the signal of each frequency bin with the phase of the adjacent range bin, and then performs the second CFAR device 8b
Detects the reflected signal from the target by introducing the output signal of the integrator 7b. The CFAR devices 8a and 8b
Calculates the reference bell from the signal level around the range bin of interest for the distance direction sampling (range bin) of each frequency of the output signal of the frequency analyzer 6 and compares the calculated reference level with the range bin signal of interest. Thus, the presence or absence of the target signal is extracted. If the phase information of the signals spread in the frequency direction is completely known, the signals can be integrated in phase. This is the same as the case of coherent integration.
When detecting a helicopter, phase information of a signal spread in the frequency direction is not known, but pseudo coherent integration can be performed by using phase information of an adjacent range bin. Noise also has a correlation with an adjacent range bin, but is not perfect, so that the S / N ratio improvement effect by integration is greater than in the case of incoherent integration.

Then, the detection / judgment device 10a sets the first C
The output of the FAR device 8a and the output of the second CFAR device 8b are introduced, the output of the first CFAR device 8a is set to H1, the output of the second CFAR device 8b is set to H2, and (H1, H2) =
At (0,0), it is determined that there is no hit, and (H1, H2) =
When (1, 0), it is determined that the target is a hit other than the helicopter. When (H1, H2) = (0, 1), it is determined that the target is a helicopter hit, and (H1, H2) = (1,
At the time of 1), it is determined that the hit is a hit of the helicopter and a target other than the helicopter.

At this time, the output of the frequency analyzer 6 is the first
Of the signal reflected from the helicopter spread in the frequency direction in the pseudo-coherent integrator 7b in the frequency direction, the S / N ratio is improved.
Reflected signals from other than the helicopter that has not spread in the frequency direction do not spread in the frequency direction, and consequently the S / N ratio deteriorates due to integration in the frequency direction.

As described above, in the present embodiment, the signal after the frequency analysis by the frequency analyzer 6 is phase-compensated with the signal of each frequency bin by the integrator 7b with the phase of the adjacent range bin, and then the signal is shifted in the frequency direction. By performing the pseudo-coherent integration, it is possible to improve the S / N ratio of the reflected signal from the helicopter spread in the frequency direction. Moreover, the S / N ratio of the reflected signal from the helicopter spread in the frequency direction can be further improved as compared with the case of performing the incoherent integration of the first embodiment. Therefore, the second CFAR device 8b can easily and accurately detect and display the helicopter. The targets other than the helicopter are output to the first CFAR device 8 based on the output of the frequency analyzer 6.
a and can be detected and displayed. Therefore, by detecting the presence or absence of signal detection before and after the integration device 7b by the detection determination device 10a, it is possible to distinguish between detection of a helicopter and detection of a target such as an airplane other than the helicopter.
In the second embodiment, the case where the helicopter to be detected is irrespective of the presence or absence of hovering has been described.
Is especially useful for hovering helicopters that are difficult to detect.

Embodiment 3 FIG. Third Embodiment FIG. 3 is a block diagram illustrating a configuration of a radar device according to a third embodiment of the present invention. In FIG. 3, the same reference numerals as those in FIG.
7a and 8a, 8b are completely the same as those of the first embodiment shown in FIG. In FIG. 3, reference numeral 9a denotes a first CFAR device 8a.
Is a first maximum amplitude detection device for detecting the maximum amplitude of the signal detected by the above, and 9b is a second maximum amplitude detection device for detecting the maximum amplitude of the signal detected by the second CFAR device 9b. 10b is the output of the first CFAR device 8a and the second C
The output of the FAR device 8b, the output of the first maximum amplitude detector 9a, and the output of the second maximum amplitude detector 9b are introduced, and the first C
The output of the FAR device 8a is H1, the output of the second CFAR device 8b is H2, the output of the first maximum amplitude detection device 9a is M1, the output of the second maximum amplitude detection device 9b is M2, When (H1, H2) = (0, 0), it is determined that there is no hit, and when (H1, H2) = (1, 0), it is determined that the target is a hit other than a helicopter.
2) It is determined that the helicopter is hit when (0, 1), and when (H1, H2) = (1, 1) and M1> k
When (k: integral effect constant in the frequency direction) × M2, it is determined that the target is a hit other than the helicopter, and (H1,
When H2) = (1,1) and M1 ≦ k × M2, it is determined that the helicopter is hit. Reference numeral 11 denotes a scan correlation device that introduces an output of the detection determination device 10b and removes a hit having a correlation between scans only when the hit is a target other than a helicopter.

Next, the operation of the radar apparatus according to this embodiment will be described. The transmitted wave radiated from the antenna 1 is reflected from clutters other than the target, such as an aircraft or a helicopter, such as an anti-aircraft target or the ground, and is converted into a digital video signal by the receiver 4 via the antenna 1, the circulator 2, and the receiver 4. It is converted and sent to the MTI device 5. MTI device 5
Suppresses clutter using the difference in Doppler frequency of the reflected signal from the target and clutter other than the target. The frequency analyzer 6 improves the signal-to-noise ratio (S / N ratio) by coherently integrating the clutter-suppressed signal. Further, the frequency analysis device 6 suppresses clutter by removing the vicinity of the Doppler frequency where clutter exists. As a means of coherent integration in the frequency analysis device 6, FFT is often used.

The first CFAR device 8a introduces the output signal of the frequency analysis device 6 to detect a reflected signal from the target, and the integration device 7a performs incoherent integration of the output amplitude of the frequency analysis device 6 in the frequency direction. , The second CFAR
The device 8b introduces the output signal of the integrator 7a and detects the reflected signal from the target. The CFAR device 8
a and 8b calculate a reference level from the signal level around the range bin of interest with respect to the distance direction sampling (range bin) of each frequency of the output signal of the frequency analyzer 6 and calculate the reference level and the range bin signal of interest. The presence or absence of the target signal is extracted by comparison. The first maximum amplitude detection device 9a detects the maximum amplitude of the signal detected by the first CFAR device 8a,
Only the maximum value in the frequency direction for each range bin and the maximum value in the range direction are output. Second maximum amplitude detector 9b
Detects the maximum amplitude of the signal detected by the second CFAR device 8b and outputs only the maximum value in the range direction. And
The detection determination device 10b introduces the output of the first CFAR device 8a, the output of the second CFAR device 8b, the output of the first maximum amplitude detection device 9a, and the output of the second maximum amplitude detection device 9b,
The output of the first CFA device 8a is set to H1, and the second CFA
The output of the R device 8b is set to H2, and the first maximum amplitude detecting device 9
The output a is set to M1, the output of the second maximum amplitude detector 9b is set to M2, and when (H1, H2) = (0, 0), it is determined that there is no hit, and when (H1, H2) = (1, 0) Is determined to be a hit of a target other than the time helicopter, and (H1, H
2) It is determined that the helicopter hit when (0,1), and when (H1, H2) = (1,1) and M1> k
When × M2, it is determined that the target is a hit other than the helicopter, and when (H1, H2) = (1, 1) and M1
It is determined that the helicopter is hit when ≦ k × M2.
As described above, when (H1, H2) = (0, 0), it is determined that there is no hit, and when (H1, H2) = (1, 0), it is determined that there is a hit of a target other than the helicopter. ,
The determination that a helicopter hit when H2) = (0, 1) can be explained as follows. In the case of a target other than a helicopter, (H1, H2) = (1, 0) because there is no integration effect in the frequency direction by the integrator 7a. In the case of a helicopter, since there is an integration effect in the frequency direction by the integration device 7a, (H1, H2) = (0,
1). Similarly, also in the case of (H1, H2) = (1, 1), the presence or absence of the integration effect is determined by comparing the amplitude changes before and after the integration to detect a hit by the helicopter.

The output of the frequency analyzer 6 is the first CFA
The S / N ratio of the reflected signal from the helicopter, which is sent to the R device 8a and spread in the frequency direction in the frequency direction incoherent integrator 7a, is improved. Reflected signals from other than the helicopter that does not spread in the frequency direction
Since there is no spread in the frequency direction, the S / N ratio is degraded by integration in the frequency direction.

As described above, in this embodiment, when the reflected wave of the helicopter is received by the antenna 1, the signal after the frequency analysis by the frequency analyzer 6 is incoherently integrated in the frequency direction by the integrator 7a. Since the S / N ratio of the reflected signal from the helicopter spread in the frequency direction can be improved by the integration effect in the frequency direction by the integrating device 7a, the second CFAR device 8b can easily and accurately detect the helicopter. be able to. When a reflected wave of a target such as an airplane other than a helicopter is received by the antenna 1, the target other than the helicopter has no integration effect in the frequency direction by the integrator 7a. It can be detected by the CFAR device 8a. In this embodiment, a reflected wave of a target such as a helicopter and an airplane other than the helicopter is transmitted to the antenna 1.
, The signal of the helicopter is processed by the integrator 7a, and the scan correlator 11 determines whether there is an integration effect to such an extent that the signal is not removed even if scan correlation is applied.
If the signal of the helicopter has the integration effect as described above, it is possible to prevent the signal of the helicopter from being removed even if it is subjected to scan correlation by the scan correlation device 11. For this reason, it is possible to detect a hit by the helicopter and display a good image without being removed by the scan correlation. Although the third embodiment shows a case where the helicopter to be detected is not related to the presence or absence of hovering, the second embodiment is particularly effective for a helicopter hovering which is hard to detect.

Embodiment 4 FIG. FIG. 4 is a block diagram illustrating a configuration of a radar device according to a third embodiment of the present invention. In FIG. 4, the same reference numerals as those in FIG.
7b and 8a, 8b are exactly the same as those of the second embodiment shown in FIG. In FIG. 3, reference numeral 9a denotes a first CFAR device 8a.
Is a first maximum amplitude detection device for detecting the maximum amplitude of the signal detected by the above, and 9b is a second maximum amplitude detection device for detecting the maximum amplitude of the signal detected by the second CFAR device 9b. 10b is the output of the first CFAR device 8a and the second C
The output of the FAR device 8b, the output of the first maximum amplitude detector 9a, and the output of the second maximum amplitude detector 9b are introduced, and the first C
The output of the FAR device 8a is H1, the output of the second CFAR device 8b is H2, the output of the first maximum amplitude detection device 9a is M1, the output of the second maximum amplitude detection device 9b is M2, When (H1, H2) = (0, 0), it is determined that there is no hit. When (H1, H2) = (1, 0), it is determined that the target is a hit other than the helicopter.
2) It is determined that the helicopter is hit when (0, 1), and when (H1, H2) = (1, 1) and M1> k
When (k: integral effect constant in the frequency direction) × M2, it is determined that the target is a hit other than the helicopter, and (H1,
When H2) = (1,1) and M1 ≦ k × M2, it is determined that the helicopter is hit. Reference numeral 11 denotes a scan correlation device that introduces an output of the detection determination device 10b and removes a hit having a correlation between scans only when the hit is a target other than a helicopter.

Next, the operation of the radar apparatus according to this embodiment will be described. The transmitted wave radiated from the antenna 1 is reflected from clutters other than the target, such as an aircraft or a helicopter, such as an anti-aircraft target or the ground, and is converted into a digital video signal by the receiver 4 via the antenna 1, the circulator 2, and the receiver 4. It is converted and sent to the MTI device 5. MTI device 5
Suppresses clutter using the difference in Doppler frequency of the reflected signal from the target and clutter other than the target. The frequency analyzer 6 improves the signal-to-noise ratio (S / N ratio) by coherently integrating the clutter-suppressed signal. Further, the frequency analysis device 6 suppresses clutter by removing the vicinity of the Doppler frequency where clutter exists. As a means of coherent integration in the frequency analysis device 6, FFT is often used.

The first CFAR device 8a detects the reflected signal from the target by introducing the output signal of the frequency analysis device 6. The integrator 7b performs phase compensation on the signal of each frequency bin with the phase of the adjacent range bin, and then performs pseudo-coherent integration in the frequency direction, and performs second CFAR 8b
Detects the reflected signal from the target by introducing the output signal of the integrator 7b. The CFAR devices 8a and 8b
Calculates the reference level from the signal level around the range bin of interest for the distance direction sampling (range bin) of each frequency of the output signal of the frequency analyzer 6;
The presence or absence of the target signal is extracted by comparing the calculated reference level with the range bin signal of interest. If the phase information of the signals spread in the frequency direction is completely known, the signals can be integrated in phase. This is the same as the case of coherent integration. When detecting a helicopter, phase information of a signal spread in the frequency direction is not known, but pseudo coherent integration can be performed by using phase information of an adjacent range bin. Noise also has a correlation with an adjacent range bin, but is not perfect, so that the S / N ratio improvement effect by integration is greater than in the case of incoherent integration. First
The maximum amplitude detection device 9a detects the maximum amplitude of the signal detected by the first CFAR device 8a, and outputs only the maximum value in the frequency direction and the maximum value in the range direction for each range bin. The second maximum amplitude detecting device 9b includes a second CFAR
The maximum amplitude of the signal detected by the device 8b is detected, and only the maximum value in the range direction is output. Then, the detection determination device 10b
Introduces the output of the first CFAR device 8a, the output of the second CFAR device 8b, the output of the first maximum amplitude detector 9a, and the output of the second maximum amplitude detector 9b, and outputs the output of the first CFAR device 8a to H1. And the output of the second CFAR device 8b is H
2, the output of the first maximum amplitude detector 9a is M1,
The output of the second maximum amplitude detector 9b is M2, and (H1,
When (H2) = (0,0), it is determined that there is no hit, and (H1,
When (H2) = (1,0), it is determined that the target is a hit other than the helicopter, and when (H1, H2) = (0, 1), it is determined that the target is a helicopter hit, and (H1, H2)
= (1, 1) and when M1> k × M2, it is determined that the target is a hit other than the helicopter, and (H1,
When H2) = (1,1) and M1 ≦ k × M2, it is determined that the helicopter is hit. Thus, (H
When (1, H2) = (0, 0), it is determined that there is no hit and (H
When (1, H2) = (1, 0), it is determined that the target is a hit other than the target of the helicopter, and (H1, H2) = (0,
In the case of 1), it is determined that the helicopter is hit,
It can be explained as follows. In the case of a target other than a helicopter, (H1, H2) = (1, 0) because there is no integration effect in the frequency direction by the integrator 7a. In the case of a helicopter, (H1, H2) = (0, 1) because of the integration effect in the frequency direction by the integrator 7a. Similarly, also in the case of (H1, H2) = (1, 1), the presence or absence of the integration effect is determined by comparing the change in amplitude before and after integration to detect a helicopter hit.

The output of the frequency analyzer 6 is the first CFA
While being sent to the R device 8a, the reflection signal from the helicopter spread in the frequency direction in the frequency direction pseudo coherent integrator 7a has an improved S / N ratio. Reflected signals from other than the helicopter that does not spread in the frequency direction
Since there is no spread in the frequency direction, the S / N ratio is degraded by integration in the frequency direction.

As described above, in this embodiment, when the reflected wave of the helicopter is received by the antenna 1, the signal after the frequency analysis by the frequency analyzer 6 is converted into the signal of each frequency bin by the integrator 7b. After performing phase compensation with the phase of, the pseudo coherent integration in the frequency direction is performed, so that the reflection signal S from the helicopter expanded in the frequency direction due to the integration effect in the frequency direction by the integrator 7b.
/ N ratio can be improved. Moreover, the S / N ratio of the reflected signal from the helicopter spread in the frequency direction can be further improved as compared with the case where the incoherent integration of the first and third embodiments is performed. For this reason, the second CFAR device 8b
Thus, the helicopter can be easily and accurately detected and displayed. When a reflected wave of a target such as an airplane other than a helicopter is received by the antenna 1, the target other than the helicopter has no integration effect in the frequency direction by the integrator 7b.
Can be detected and displayed by the CFAR device 8a.
In the present embodiment, when a reflected wave of a target such as a helicopter and an airplane other than the helicopter is received by the antenna 1, the signal of the helicopter is processed by the integrator 7 b, and the signal is not removed even when the scan correlation is performed by the scan correlator 11. It is determined by the detection / determination device 10b whether or not the helicopter signal has an integration effect. If the signal of the helicopter has the integration effect as described above, the signal of the helicopter may be prevented from being removed even when the scan correlation device 11 applies scan correlation. it can. Therefore, a good image can be detected and detected as a hit by the helicopter without being removed by the scan correlation. In the fourth embodiment, the case where the helicopter to be detected is not related to the presence or absence of hovering has been described.
Is especially useful for hovering helicopters that are difficult to detect.

Embodiment 5 FIG. FIG. 5 is a block diagram illustrating a configuration of a radar apparatus according to Embodiment 5 of the present invention. 5, the same reference numerals as those in FIGS. 3 and 4 denote the same or corresponding parts, and the configuration other than the integrator 7c and the first CFAR device 8c is exactly the same as the third and fourth embodiments shown in FIGS. is there. In FIG. 5, reference numeral 7c denotes a frequency direction integrator that can control the integration range in the frequency direction, and 8c denotes a CFAR device to which a detection output with a threshold level lower than usual is added. The low threshold added to the first CFAR device 8c selects only the signal having the frequency direction integration effect. Here, the integrating device 7c and the first CFAR device 8
The description will focus on c. The integrator 7c may be constituted by any of a frequency-direction incoherent integrator and a frequency-direction pseudo-coherent integrator.

FIG. 6 is a block diagram showing an example of the configuration of the first CFAR device 8c shown in FIG. 6, 21 to 26 are CFAR devices 1007 shown in FIG.
The configuration is the same as 24a is a multiplier for calculating a lower threshold level (threshold level) than usual, and 45a is a comparator for detecting the presence / absence of a signal of a cell of interest at a lower threshold level. When the signal output C of the cell of interest is greater than the output D of the multiplier 24a, the signal C of the cell of interest is output and integrated as the output H0 of the comparator 25a, and the signal output C of the cell of interest is equal to or less than the output D of the multiplier 24a. At this time, the output H0 of the comparator 25a is set to 0 so as not to integrate.

As described above, in this embodiment, by controlling the integration range in the frequency direction according to the signal level before integration, it is possible to extract the spread of the clutter in the frequency direction and prevent the clutter from being integrated. Therefore, the effect of improving the S / N ratio by the integration of the integrating device 7c can be improved.

Embodiment 6 FIG. FIG. 7 is a block diagram illustrating a configuration of a radar apparatus according to Embodiment 6 of the present invention. In FIG. 7, the same reference numerals as those in FIG.
11 are the same as those of the fifth embodiment shown in FIG. FIG.
, 31 is a frequency-direction variance that introduces the output signal of the frequency analyzer 6 to extract the variance coefficient of the frequency-direction sampling signal amplitude, and outputs a comparison result between the extracted variance coefficient of the frequency-direction sampling signal amplitude and the threshold level. 32 is an extraction device, and 32 is a detection determination device 10b.
And the output of the frequency direction dispersion extraction device 31 are introduced,
This is a noise jammer determination device that determines a noise jammer when a variance coefficient of a frequency direction sampling signal amplitude is smaller than a threshold level and a helicopter hit occurs. Here, the frequency direction dispersion extraction device 31
And the noise jammer determination device 32 will be mainly described.

When a noise jammer is input to the radar device, the signal becomes a signal spread in the frequency direction. Unlike a helicopter, a noise jammer has a uniform spread in the frequency direction, and thus can be determined to be a noise jammer when the dispersion coefficient of the frequency direction sampling signal is smaller than a reference value.

As described above, in the present embodiment, the variance coefficient of the amplitude in the frequency direction sampling signal is extracted by the frequency direction variance extraction device 31 based on the output signal of the frequency analysis device 6.
Output of detection determination device 10b and frequency direction variance extraction device 3
In the case where the amplitude spread in the frequency direction based on the output of No. 1 is constant, the noise jammer judging device 32 judges that the noise jammer is present, and displays that fact, thereby knowing that the noise jammer has been input to the radar device. Can be.

Embodiment 7 FIG. FIG. 8 is a block diagram illustrating a configuration of a radar apparatus according to Embodiment 7 of the present invention. In FIG. 8, the same reference numerals as those in FIG.
Reference numeral 11 is exactly the same as the fifth embodiment shown in FIG. In FIG. 8, reference numeral 41 denotes a spectrum change pattern extraction device for introducing an output signal of the frequency analysis device 6 and an output signal of the detection determination device 10 to extract a time change pattern of the spread of the amplitude in the frequency direction.

The reflected signal from the rotor blade of the helicopter has a different time-varying pattern of the spread of the amplitude in the frequency direction due to the difference in the number of rotations of the rotor blade. Therefore, reference data in which the relationship between the rotational speed of the rotor and the time change pattern of the spread of the amplitude in the frequency direction is created in advance, and this reference data and the time change pattern of the spread in the frequency direction extracted by the spectrum change pattern extraction device 41 are prepared. To estimate the rotor speed of the helicopter.

As described above, in this embodiment, the time change pattern of the spread of the amplitude in the frequency direction extracted by the spectrum change pattern extraction device 41 based on the output signal of the frequency analysis device 6 and the detection signal of the detection / judgment device 10b is created in advance. By collating with the above-mentioned reference data, the rotor speed of the helicopter can be estimated. Therefore, if the number of rotors is known, the model of the helicopter can be estimated based on the estimated rotor speed.

[0050]

According to the first aspect of the present invention, the signal after frequency analysis is incoherently integrated in the frequency direction by utilizing the fact that the reflected signal from the helicopter spreads in the frequency direction, thereby expanding in the frequency direction. Since the S / N ratio of the reflected signal from the helicopter can be improved, the helicopter can be easily and accurately detected.

According to the second aspect, the signal after the frequency analysis is spread in the frequency direction by subjecting the signal for each frequency bin to phase compensation with the phase of the adjacent range bin and then performing pseudo-coherent integration in the frequency direction. Since the S / N ratio of the reflected signal from the helicopter can be further improved as compared with the case of performing incoherent integration, there is an effect that the helicopter can be easily and accurately detected.

According to the third aspect, the signal after the frequency analysis is incoherently integrated in the frequency direction,
S / of reflected signal from helicopter spread in frequency direction
Since the N ratio can be improved, there is an effect that the helicopter can be easily and accurately detected. In addition, by comparing the presence or absence of signal detection before and after integration and the amplitude of the detection signal before and after integration, it is possible to reliably detect a helicopter from targets other than the helicopter, and to prevent helicopter removal by scan correlation. There is an effect that can be.

According to the fourth aspect, the signal after frequency analysis is spread in the frequency direction by performing pseudo-coherent integration in the frequency direction after performing phase compensation on the signal of each frequency bin with the phase of the adjacent range bin. Since the S / N ratio of the reflected signal from the helicopter can be further improved as compared with the case of simply performing incoherent integration, the helicopter can be easily and accurately detected. In addition, by comparing the presence or absence of signal detection before and after integration and the amplitude of the detection signal before and after integration, it is possible to reliably detect a helicopter from targets other than the helicopter, and to prevent helicopter removal by scan correlation. There is an effect that can be.

According to the fifth aspect, by controlling the integration range in the frequency direction according to the signal level before integration, it is possible to extract the spread of the clutter in the frequency direction and not to integrate the clutter. There is an effect that the effect of improving the S / N ratio can be further improved.

According to the sixth aspect, the dispersion coefficient of the amplitude in the frequency direction sampling signal is extracted by the frequency direction variance extraction device based on the output signal of the frequency analysis device, and the output of the detection / determination device and the frequency direction variance extraction device When the amplitude spread in the frequency direction based on the output is constant, there is an effect that it is possible to know that a noise jammer has been input to the radar apparatus, rather than determining that the noise jammer has occurred.

According to the seventh aspect of the present invention, the rotor rotation speed of the helicopter is estimated by extracting the time-varying pattern of the spread of the amplitude in the frequency direction extracted based on the output signal of the frequency analysis device and the output signal of the detection / judgment device. Therefore, if the number of rotors is known, the type of helicopter can be estimated based on the estimated rotor speed.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a radar apparatus according to a first embodiment of the present invention.

FIG. 2 is a block diagram illustrating a configuration of a radar device according to a second embodiment of the present invention.

FIG. 3 is a block diagram illustrating a configuration of a radar device according to a third embodiment of the present invention.

FIG. 4 is a block diagram illustrating a configuration of a radar apparatus according to a fourth embodiment of the present invention.

FIG. 5 is a block diagram illustrating a configuration of a radar apparatus according to a fifth embodiment of the present invention.

FIG. 6 is a block diagram showing an example of a configuration of a first CFAR device shown in FIG.

FIG. 7 is a block diagram illustrating a configuration of a radar device according to a sixth embodiment of the present invention.

FIG. 8 is a block diagram illustrating a configuration of a radar apparatus according to a seventh embodiment of the present invention.

FIG. 9 is a block diagram illustrating an example of a configuration of a conventional radar device.

FIG. 10 is a block diagram showing an example of the configuration of the CFAR device shown in FIG.

[Explanation of symbols]

1 antenna, 2 transmitter, 3 circulator, 4
Receiver, 5 MTI device, 6 frequency analyzer, 7a,
7b, 7c Integrator, 8a, 8c First CFAR device, 8b Second CFAR device, 9a First maximum amplitude detector, 9b Second maximum amplitude detector, 10a, 10
b detection determination device, 11 scan correlation device, 21 shift register, 22 adder, 23 arithmetic unit, 24, 2
4a multiplier, 25, 25a comparator, 26 switch,
31 frequency direction dispersion extraction device, 32 noise jammer determination device, 41 spectrum change pattern extraction device.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-3-172788 (JP, A) JP-A-7-146317 (JP, A) JP-A-5-215843 (JP, A) JP-A-4- 215085 (JP, A) JP-A-56-35079 (JP, A) JP-A-63-90181 (JP, U) JP-A-63-33479 (JP, U) JP-A-63-23676 (JP, U) US Patent 4,275,396 (US, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G01S 7/00-7/42 G01S 13/00-13/95

Claims (7)

(57) [Claims] A transmitter for generating a transmission wave; an antenna for emitting a transmission wave generated by the transmitter in a space in a designated direction and receiving a reflected wave; supplying a signal from the transmitter to the antenna; A circulator for supplying a reception signal received by an antenna to a receiver, a receiver for converting a reception signal from the circulator to a digital video signal, and an MTI for introducing a digital video signal from the receiver and suppressing a clutter signal Moving Target
Indicator), a frequency analyzer for introducing the output signal of the MTI device and performing narrow band filtering, and a first CFAR (Constant) for introducing the output signal of the frequency analyzer and detecting a reflected signal from a target
A false alarm rate device, an integrator for incoherently integrating the output amplitude of the frequency analyzer in the frequency direction, a second CFAR device for introducing the output signal of the integrator and detecting a reflected signal from a target, One CFAR device output and the second CFAR device output, and wherein the first CFAR device output and the second
A detection / judgment device for judging a hit, a hit of a target other than a helicopter, a hit of a helicopter, and a hit of a helicopter and a target other than a helicopter, respectively, based on the output of the CFAR device. apparatus. 2. A transmitter for generating a transmission wave, an antenna for emitting a transmission wave generated by the transmitter in a space in a designated direction and receiving a reflected wave, and supplying a signal from the transmitter to the antenna. A circulator for supplying a received signal received by the antenna to a receiver, a receiver for converting a received signal from the circulator to a digital video signal, and introducing a digital video signal from the receiver to suppress a clutter signal. MTI (Moving Target)
Indicator), a frequency analyzer for introducing the output signal of the MTI device and performing narrow band filtering, and a first CFAR (Constant) for introducing the output signal of the frequency analyzer and detecting a reflected signal from a target
A false alarm rate device, an integrator that performs pseudo-coherent integration in the frequency direction after phase-compensating the output amplitude of the frequency analyzer with the phase of an adjacent range bin for a signal of each frequency bin, and outputs the output signal of the integrator. A second CFAR device for introducing and detecting a reflected signal from a target, introducing the first CFAR device output and the second CFAR device output, and outputting the first CFAR device output and the second CFAR device.
A detection / judgment device for judging a hit, a hit of a target other than a helicopter, a hit of a helicopter, and a hit of a helicopter and a target other than a helicopter, respectively, based on the output of the CFAR device. apparatus. 3. A transmitter that generates a transmission wave, an antenna that radiates a transmission wave generated by the transmitter in a space in a designated direction and receives a reflected wave, and supplies a signal from the transmitter to the antenna, A circulator for supplying a reception signal received by the antenna to a receiver, a receiver for converting the reception signal from the circulator to a digital video signal, and an MTI (digital time signal) for introducing the digital video signal from the receiver and suppressing the clutter signal Moving Target I
a frequency analyzer that introduces an MTI device output signal and performs narrow band filtering; a first CFAR (Constant) that introduces the frequency analyzer output signal and detects a reflected signal from a target
A false alarm rate device, an integrator for incoherently integrating the frequency analyzer output amplitude in the frequency direction, a second CFAR device for introducing an integrator output signal and detecting a reflected signal from a target, and the first CFAR device. A first maximum amplitude detection device for detecting a maximum amplitude of a signal detected by the CFAR device; a second maximum amplitude detection device for detecting a maximum amplitude of a signal detected by the second CFAR device; And the second CFAR device output, the first maximum amplitude detection device output, and the second maximum amplitude detection device output, and the first CFAR device output is set to H1, Output of the CFAR device of H2
The output of the first maximum amplitude detector is M1, the output of the second maximum amplitude detector is M2, and (H1, H
2) When = (0,0), it is determined that there is no hit, and (H1, H
2) When = (1, 0), it is determined that the target is a hit other than the helicopter, when (H1, H2) = (0, 1), it is determined that the target is a helicopter hit, and (H1, H2) =
When (1, 1) and M1> k (k: integration effect constant in the frequency direction) × M2, it is determined that the hit is a target other than the helicopter, and (H1, H2) = (1, 1) And a detection / judgment device for judging a helicopter hit when M1 ≦ k × M2, and an output signal of the detection / judgment device is introduced, and there is a correlation between scans only when the target is a hit other than a helicopter. A radar device comprising: a scan correlation device that removes hits. 4. A transmitter for generating a transmission wave, an antenna for emitting a transmission wave generated by the transmitter in a space in a designated direction and receiving a reflected wave, supplying a signal from the transmitter to the antenna, A circulator for supplying a received signal received by the antenna to a receiver, a receiver for converting a received signal from the circulator to a digital video signal, and an MTI for introducing a digital video signal from the receiver and suppressing a clutter signal (Moving Target
Indicator), a frequency analyzer that introduces an MTI device output signal and performs narrow band filtering, and a first CFAR (Constant) that introduces the frequency analyzer output signal and detects a reflected signal from a target
A false alarm rate device, an integrator that performs pseudo-coherent integration in the frequency direction after phase-compensating the output amplitude of the frequency analyzer with the phase of an adjacent range bin for each frequency bin signal, and introduces an integrator output signal. A second CFAR device for detecting a reflected signal from the target, a first maximum amplitude detecting device for detecting a maximum amplitude of the signal detected by the first CFAR device, and a second CFAR device detecting the maximum amplitude of the signal detected by the first CFAR device. A second maximum amplitude detection device for detecting a maximum amplitude of the signal; an output of the first CFAR device, an output of the second CFAR device, an output of the first maximum amplitude detection device, and the second maximum amplitude detection device And the first CFAR device output is set to H1, and the second CFAR device output is set to H2.
The output of the first maximum amplitude detector is M1, the output of the second maximum amplitude detector is M2, and (H1, H
2) When = (0, 0), it is determined that there is no hit, and (H1, H
2) When = (1, 0), it is determined that the target is a hit other than the helicopter, when (H1, H2) = (0, 1), it is determined that the target is a helicopter hit, and (H1, H2) =
When (1, 1) and M1> k (k: integration effect constant in the frequency direction) × M2, it is determined that the hit is a target other than the helicopter, and (H1, H2) = (1, 1)
And a detection / judgment device for judging a helicopter hit when M1 ≦ k × M2, and a hit having a correlation between scans only when a hit of a target other than the helicopter is introduced by introducing an output signal of the detection / judgment device. A radar apparatus comprising: a scan correlator for removing. 5. The first CFAR device has signal detection means for detecting a signal having a low threshold level, and the integration device has integration range control means for controlling an integration range in a frequency direction. Claims 1 to 4
The described radar device. 6. A frequency direction variance extraction device for introducing an output signal of the frequency analysis device, extracting a dispersion coefficient of a frequency direction sampling signal amplitude, and outputting a comparison result between the extracted dispersion coefficient and a threshold level, A noise jammer judging device that introduces the detection judging device output and the output of the frequency direction variance extracting device, and when the variance coefficient of the frequency direction sampling signal amplitude is smaller than the threshold level, and is a helicopter hit, a noise jammer is determined. The radar device according to claim 1, further comprising: 7. A spectrum change pattern extraction device for introducing the output signal of the frequency analysis device and the output signal of the detection determination device and extracting a time change pattern of amplitude spread in the frequency direction. The described radar device.