JP2000098022A - Radar system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a false target from being detected in advance by using output from a frequency analyzer for detecting the power level of a side lobe clutter and adjusting an STC(sensitivity time control) threshold for the detected noise level adaptively. SOLUTION: A frequency analyzer 6 performs a frequency analysis for a reception signal from a clutter canceler 5 for outputting by eliminating a main beam clutter from the reception signal. A target detector 7 detects a target signal for a reception signal that was subjected to frequency analysis, decides the distance of the target signal, and sends the signal to an STC generator 9. A noise level detector 31 uses output from the frequency analyzer 6 for detecting the power level of the side lobe clutter, and an STC level adjuster 32 monitors output from the noise level detector 31 and at the same time adjusts the offset level of the STC threshold of the STC generator 9 according to the noise level of the noise level detector 31.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radar apparatus for preventing deterioration of target detection sensitivity and detection of a false target.

[0002]

2. Description of the Related Art FIG. 12 shows the configuration of a conventional radar apparatus. In FIG. 12, 1 is a transmitter, 2 is an antenna, 3 is a receiver, 4 is a transmission / reception switch, 5 is a clutter canceller, and 6 is a clutter canceller. Denotes a frequency analyzer, 7 denotes a target detector, 8 denotes a first correlator, 9 denotes an STC (Sensitivity T).
im Control) generator, 10 a second correlator, 11 a third correlator, 12 a blanking circuit, 13 a first correlator 8, an STC generator 9, a second correlator
STC processor 14 comprising a correlator 10, a third correlator 11 and a blanking circuit 12; a clutter canceller 5, a frequency analyzer 6, a target detector 7,
A signal processor composed of the TC processor 13 and 15 is a controller.

Next, the operation will be described. The transmitter 1
The local oscillation signal “a” is received from the receiver 3, the frequency of the signal is converted into an X-band frequency band, and then amplified and output. A transmission signal b output from the transmitter 1 is transmitted and received by a transmission / reception switch 4 having a function of switching a signal transmission path between transmission and reception.
Radiated from the antenna 2 to the outside. The transmission signal b radiated from the antenna 2 is irradiated to the target and reflected, and is received by the antenna 2 as a reception signal c. The received signal c received by the antenna 2 is input to the receiver 3 via the transmission / reception switch 4. The receiver 3 amplifies the received signal c and frequency-converts the signal to a baseband frequency band, and then A / D (Analog to Digital).
l) Perform conversion and output to the signal processor 14. In the signal processor 14, the target signal d is selected from the received signals c.
Is detected.

Next, the operation of the signal processor 14 will be described with reference to FIG.
3 will be described. FIG. 13A is a schematic diagram showing the flight status of the own aircraft and the target aircraft, and FIG.
Medium PRF (Pulse R) received under the condition of (a)
This is a representation of a received signal of a general pulse Doppler radar using an epitaxy frequency) in a time axis direction and a frequency axis direction. In the figure, 16
Is the own machine on which the radar device is mounted, 17 is the main beam of the antenna 2, 18 is the side lobe of the antenna 2, 19
Is a target aircraft, 20 is a building on the ground surface, 21 is a main beam clutter generated when the main beam 17 of the antenna 2 irradiates the ground surface, and 22 is a side lobe 18 of the antenna 2 irradiates the ground or the like. 23 indicates a target signal, and 24 indicates a side lobe discrete in which a building 20 or the like on the ground surface is received through the side lobe 18 of the antenna 2.
The side lobe clutter 22 changes in a complicated manner depending on the shape of the side lobe 18 of the antenna 2;
Here, for convenience of explanation, the side lobe clutter received from some protruding side lobes and the side lobe clutter received from the entire side lobe 18 of the antenna 2 are represented on average. The received signal c received by the antenna 2 includes all of the main beam clutter 21, the side lobe clutter 22, the target signal 23, and the side lobe discrete 24 shown in FIG. From this, the target signal 23 must be extracted. The clutter canceller 5 receives the received signal c
, The main beam clutter 21 is removed, and the received signal c is output to the frequency analyzer 6. Frequency analyzer 6
Performs a frequency analysis on the received signal c by a technique such as Fourier transform, and outputs the received signal c to the target detector 7. The target detector 7 applies a CFAR (Constant) to the frequency-analyzed received signal c.
False Alarm Ratio) processing to extract a signal from a state competing with the side lobe clutter 22, determine distance information of the signal by multi-PRF ranging or the like, and output it to the STC processor 13. S
The TC processor 13 removes a signal having a possibility of side lobe discrete or side lobe clutter from the signal input from the target detector 7 and extracts a true target signal 23.

Next, CFAR processing in the target detector 7 will be described with reference to FIG. In the figure, 25 is a narrow band Doppler filter, 26 is a range gate corresponding to a transmission pulse width, 27 is a matrix composed of several rows of narrow band Doppler filters 25 and several rows of range gates 26. In a general medium PRF pulse Doppler radar, the received signal c is analyzed into components in the frequency axis direction and the time axis direction, and the power at the center of the matrix 27 shown in FIG. The average power is compared, and if an S / N ratio equal to or higher than a certain value is obtained, the signal at the center of the matrix 27 is detected as the target signal 23. Matrix 2 if the clutter environment is not harsh
7 is only the receiver noise having a uniform spectrum, and the reflected wave from the true target has been greatly improved in power by the Fourier transform and the like in the frequency analyzer 6. Since a large S / N ratio can be obtained in a receiver noise having such a spectrum, it is detected as a target by the CFAR processing using the matrix 27.

Next, the operation of the STC processor 13 will be described with reference to FIG.
5 will be described. FIG. 15A shows an STC threshold generated by the STC generator 9. Normal,
In a pulse Doppler radar using a medium PRF in one channel, false targets such as side lobe clutter 22 and side lobe discrete 24 are input as means for preventing detection as true targets. For signals below the possible distance, an STC threshold that is inversely proportional to the fourth power of the distance as shown in FIG. 15A and whose threshold is higher for shorter distances is provided, and only signals that exceed this threshold are extracted. Processing is performed. Since the side lobe clutter 22 and the side lobe discrete 24 are signals received from the side lobes 18, the power levels of the received signals are extremely small. Therefore, by applying such an STC threshold, a weak signal such as a false target can be removed. The true target signal is detected beyond the STC threshold because the signal power is large at a short distance.

The signal detected by the target detector 7 is
In the three types of correlators, the presence or absence of signal detection is recorded for each range gate. FIG. 15B shows the STC processor 1
The first correlator 8 and the second correlator 1 forming the third correlator 3
FIG. 15B is a schematic diagram showing a signal recording state of the third correlator 11. In FIG. 15B, reference numeral 28 denotes a range memory of the first correlator 8, and 29 denotes a second correlator 10.
Reference numeral 30 denotes a range memory of the third correlator 11. When a signal is detected by the target detector 7, the range memory 28 of the first correlator and the range memory 30 of the third correlator, as shown in FIG. The presence or absence of a signal is recorded for each range gate. The STC generator 9 generates an STC threshold that is inversely proportional to the fourth power of the distance as shown in FIG. 15A with respect to the signal detected by the target detector 7, and the threshold increases as the distance decreases.
Only signals exceeding the STC threshold are detected as targets. In the range memory 29 of the second correlator, only the signal exceeding the STC threshold in the STC generator 9 is recorded for each range gate as shown in FIG. Next, in the blanking circuit 12, the recording state of the signals in the range memory 28 of the first correlator and the range memory 29 of the second correlator are compared for each range gate. As a result of the comparison for each range gate, the range memory 30 of the third correlator is recorded for the range gate in which the signal exists in both the range memory 28 of the first correlator and the range memory 29 of the second correlator. Although the information of the signal is not changed, the signal exists in the range memory 28 of the first correlator but does not exist in the range memory 29 of the second correlator. The storage of the signal in the range memory 30 of the third correlator is deleted.
In this way, the signal finally stored in the range memory 30 of the third correlator is output from the STC processor 13,
That is, it is output as a true target signal d.

Next, the operation of the controller 15 will be described.
The controller 15 controls the operation timing of each of the transmitter 1, the antenna 2, the receiver 3, and the signal processor 14 and the transmission and reception of signals necessary for control of each component, by using an antenna control signal e and a transmitter control signal. This is performed by the signal f, the receiver control signal g, and the signal processor control signal h.

The target can be detected as described above.

[0010]

The conventional radar is configured as described above. When the level of the side lobe clutter changes according to the state of the ground surface or the sea surface, the STC threshold is fixed. When the power level of the side lobe clutter is low, the detection sensitivity of the small true target is degraded, and when the power level of the side lobe level or the side lobe clutter is high, the side lobe discrete, side lobe clutter, etc. There is a problem that the target is easily detected.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problem. The power level of a side lobe clutter is detected using an output from a frequency analyzer, and the STC is adjusted in accordance with the detected noise level. An object of the present invention is to obtain a radar apparatus characterized in that detection of a false target is prevented beforehand by adjusting the threshold adaptively.

[0012]

According to a first aspect of the present invention, there is provided a radar apparatus for detecting a power level of a side lobe clutter using an output from a frequency analyzer, and an output from the noise level detector. And an STC level adjuster for adjusting the STC threshold level of the STC generator according to the noise level of the noise level detector.

Further, the radar apparatus according to the second invention is provided with an STC level input section for adjusting the offset level of the STC threshold of the STC generator from the outside.

Further, the radar apparatus according to the third aspect of the present invention stores a plurality of offset levels of the STC threshold corresponding to the altitude of its own device in advance, and, in response to the altitude of the own device inputted from the outside, sends a signal to the STC generator. And an altitude STC adjuster for outputting a previously stored STC threshold offset level.

The radar apparatus according to a fourth aspect of the present invention is provided with an STC distance setting unit for controlling a start distance of an STC threshold of an STC generator based on external distance information.

Further, the radar apparatus according to the fifth aspect of the present invention detects a side lobe level from an antenna pattern input from the outside, stores an offset level of an STC threshold corresponding to the side lobe level in advance, and A side lobe STC adjuster for outputting an STC threshold offset level stored in advance to the STC generator according to the level magnitude is provided.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. 1 is a block diagram showing a first embodiment of the present invention. In FIG. 1, reference numeral 31 denotes a noise level detector for detecting a power level of a side lobe clutter using an output from the frequency analyzer 6;
Reference numeral 2 denotes an STC level adjuster for monitoring the output from the noise level detector 31 and adjusting the offset level of the STC threshold of the STC generator 9 according to the noise level of the noise level detector 31.

FIG. 2 is a schematic view showing a state in which the protruding side lobe irradiates the ground surface. In FIG. 2, 33 is
A side lobe whose level is more prominent than peripheral side lobes is shown. The clutter input from the side lobe discrete 24 in FIG. 11 and the side lobe whose level is more prominent than the surrounding side lobe 33 as shown in FIG.
Power P _c of the side lobe clutter received from projecting side lobes 33, peak transmission power P _t of the radar device, the antenna gain G, the transmission wavelength lambda, the distance to the ground surface R, the ground or The reflection coefficient of the sea surface is γ, the horizontal beam width of the protruding side lobe 33 is θ _H , the vertical beam width of the protruding side lobe is θ _v , and the angle between the ground surface and the protruding side lobe 33 is ψ. Then, it can be expressed as Equation 1.

[0019]

(Equation 1)

As shown in Equation 1, the power P _{c of the} side lobe clutter received from the protruding side lobe 33 is shown.
Varies depending on the reflection coefficient γ of the ground or the sea surface. For this reason, when operated at a fixed STC threshold, when the power level of the side lobe clutter is low, the detection sensitivity of a small true target is deteriorated, and when the power level of the side lobe clutter is high, the side lobe clutter is reduced. Are more likely to be detected as false targets.

The signal output from the frequency analyzer 6 is
This is a signal from which the main beam clutter 21 of FIG. 13 has been removed, and includes a side lobe clutter 22, a side lobe discrete 24, and a target signal 23. The noise level detector 31 detects the level of the side lobe clutter 22 in the output signal of the frequency analyzer 6.

FIG. 3 is a schematic diagram showing the storage status of the offset level of the STC threshold of the STC level adjuster 32 and the offset level. The STC level adjuster 32 includes a noise level detector 31 as shown in FIG.
The offset level of the STC threshold is recorded corresponding to the noise level including the level of the side lobe clutter 22 detected by. STC level adjuster 3
The offset level of the STC threshold stored in No. 2 is the portion of α shown in FIG. The STC level adjuster 32 outputs the previously stored offset level of the STC threshold to the STC generator 9 as the STC threshold adjustment signal j according to the noise level signal i input from the noise level detector 31. As shown in FIG. 3, the offset level of the STC threshold is stored such that it is high when the noise level is high and low when the noise level is low. The STC generator 9 operates by offsetting the level of the STC threshold by the input.

Thus, according to the clutter environment,
By adaptively adjusting the STC threshold, deterioration of target detection sensitivity and detection of a false target are prevented beforehand.

Embodiment 2 FIG. FIG. 4 is a block diagram showing a second embodiment of the present invention. In FIG. 4, reference numeral 34 denotes an STC level input unit for outputting an STC threshold offset level inputted from the outside to the STC generator 9.

The operator of the radar apparatus determines whether or not the sea surface is wavy by visual inspection or the like, whether or not the flight condition of the own aircraft is at a low altitude, the condition of the ground or the sea surface, the flight status of the own aircraft, and the like. When it is determined that the level of the clutter received by the radar apparatus may increase based on the above, the offset level data k of the STC threshold is input to the STC level input unit 34. ST
The C level input unit 34 supplies the STC generator 9 with an STC based on the offset level data k input from the outside.
The threshold offset level is output as an STC threshold adjustment signal j. The STC generator 9 outputs S
It operates by offsetting the STC threshold by the level input from the TC level input section.

As described above, the operator himself / herself adaptively adjusts the offset level of the STC threshold depending on whether or not the level of the clutter received by the radar apparatus may be increased. The detection of false targets is prevented beforehand.

Embodiment 3 FIG. 5 is a block diagram showing a third embodiment of the present invention. In FIG. 5, reference numeral 35 denotes a plurality of STC threshold offset levels which are stored in correspondence with the altitude of the own vehicle, and a radar device operator or a radar device is mounted. An altitude STC adjuster that outputs a previously stored offset level of an STC threshold to an STC generator 9 in accordance with an altitude of the aircraft that is externally input, such as an altimeter of the aircraft that is equipped with the aircraft. is there.

The side lobe clutter is a function of the distance R as shown in Equation 1, and the closer the R is, the more the power P
_c becomes stronger, and this distance R is expressed by the own altitude H, and the angle の between the protruding side lobe 33 and the ground surface. It looks like 2.

[0029]

(Equation 2)

As shown in Equation 2, the higher the altitude H of the vehicle is, the lower the clutter power is. Focusing on this feature, the altitude STC adjuster 35 has S
The TC threshold offset level is stored, and the S threshold corresponding to the own altitude data 1 input from outside is stored in S
Search for TC threshold offset level, ST
It outputs to the C generator 9 as an STC threshold adjustment signal j. FIG. 6 shows the storage state of the offset level of the STC threshold of the advanced STC adjuster 35 and the outline of the offset level. The advanced STC adjuster 35 includes
As shown in FIG. 6 (a), the STC
The threshold offset level is recorded.
The offset level of the STC threshold stored in the altitude STC adjuster 35 is a portion of α shown in FIG. The STC generator 9 operates by offsetting the STC threshold by the level input from the altitude STC adjuster 35.

In this way, the STC according to the own altitude
By adaptively adjusting the threshold,
Degradation of target detection sensitivity and detection of a false target are prevented beforehand.

Embodiment 4 FIG. FIG. 7 is a block diagram showing a fourth embodiment of the present invention. Reference numeral 36 designates a start distance of an STC threshold inside the STC generator 9 based on externally input data, and the STC generator 9 This is an STC distance setting unit that outputs the STC distance.

As shown in FIG. 8, the STC threshold is a curve inversely proportional to the fourth power of the distance.
, The start level of the STC is shifted in the long or short distance direction, so that the offset level of the STC threshold can be adjusted equivalently. FIG. 8 is a schematic diagram showing how the STC threshold level can be adjusted by the start distance of the STC threshold. As shown in FIG. 8, when the STC threshold is slid in the long distance direction, the STC threshold level at the same distance increases.

The STC distance setting section 36 sets the STC start distance shown in FIG. 8 as an STC start distance setting signal o to the STC generator 9 based on STC start distance data n indicating the STC start distance input from the outside. Output to S
The TC generator 9 operates by sliding the start distance of the STC threshold by the distance input from the STC distance setting unit 36.

As described above, by inputting the STC start distance from the outside, it is possible to adaptively adjust the STC threshold equivalently, thereby preventing the deterioration of the target detection sensitivity and the detection of the false target. are doing.

Embodiment 5 FIG. 9 is a block diagram showing a fifth embodiment of the present invention. In the figure, reference numeral 37 denotes a side lobe level detected from an externally input antenna pattern, and an STC threshold corresponding to the magnitude of the side lobe level in advance. A plurality of offset levels are stored, and an offset level of an STC threshold corresponding to the detected side lobe size is output to the STC generator 9.
It is a regulator.

The side lobe clutter is a function of the antenna gain G, as shown in Equation 1, and the higher the side lobe level, the higher the received power level. FIG.
Shows a schematic diagram of a general antenna pattern. FIG.
If the side lobe level for the main lobe of the antenna pattern is high as shown in FIG. In FIG. 10, β indicates a side lobe level with respect to the main lobe. Focusing on this feature, the side lobe STC adjuster 37 stores different offset levels of the STC threshold for each side lobe level with respect to the main beam. As shown in FIG. , The side lobe level for the main beam is calculated using the antenna pattern data p composed of the antenna gain for the main beam, the STC threshold corresponding to the side lobe level is searched, and the offset level of the previously stored STC threshold is set to the STC threshold adjustment signal j. To the STC generator 9. FIG. 11 shows the storage state of the offset level of the STC threshold of the side lobe STC adjuster 37. As shown in FIG. 11A, the side lobe STC adjuster 37 stores the offset level of the STC threshold corresponding to the side lobe level for the main beam. The offset level of the STC threshold stored in the side lobe STC adjuster 37 is shown in FIG.
This is the portion of α shown in FIG. The STC generator 9 operates by offsetting the STC threshold by the level input from the side lobe STC adjuster 37.

As described above, the STC threshold is adaptively adjusted in accordance with the side lobe level of the main lobe of the antenna pattern, thereby preventing the deterioration of the target detection sensitivity and the detection of the false target.

[0039]

According to the first invention, a noise level detector for detecting a power level of a side lobe clutter using an output from a frequency analyzer, an output from the noise level detector is monitored, and a noise is detected. By providing an STC level adjuster that adjusts the offset level of the STC threshold of the STC generator according to the noise level of the level detector, the STC threshold can be adaptively adjusted according to the clutter environment. Thus, there is an effect that deterioration of target detection sensitivity and detection of a false target can be prevented beforehand.

According to the second aspect, the offset level of the STC threshold of the STC generator is adjusted based on the adjustment value of the STC threshold input from the outside.
By providing the TC level input unit, it becomes possible to adaptively adjust the STC threshold depending on whether or not the level of clutter received by the radar apparatus may be increased. There is an effect that detection of a target can be prevented beforehand.

According to the third aspect of the present invention, a plurality of STC threshold offset levels corresponding to respective altitudes are stored, and input from an altimeter or the like of an operator or an altimeter mounted on an aircraft on which a radar device is mounted. ST stored in advance according to the altitude
By providing an advanced STC adjuster that outputs the offset level of the C threshold to the STC generator,
Since the STC threshold can be adaptively adjusted according to the clutter environment, there is an effect that deterioration of target detection sensitivity and detection of a false target can be prevented beforehand.

According to the fourth aspect, the STC for setting the starting distance of the STC threshold of the STC generator based on the starting distance of the STC threshold input from the outside.
By providing the distance setting unit, the STC threshold can be adaptively adjusted according to the clutter environment, so that there is an effect that deterioration of target detection sensitivity and detection of a false target can be prevented beforehand.

According to the fifth aspect, different STC thresholds are stored for each side lobe level for the main lobe of the antenna pattern, and the side lobe level for the main lobe is calculated and calculated from the antenna pattern input from the outside. A side lobe STC that outputs a previously stored offset level of the STC threshold to the STC generator in accordance with the size of the side lobe with respect to the set main lobe.
By providing an adjuster, ST can be adjusted according to the clutter environment.
Since the C threshold can be adaptively adjusted, there is an effect that deterioration of target detection sensitivity and detection of a false target can be prevented beforehand.

[Brief description of the drawings]

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

FIG. 2 is an explanatory diagram showing a situation in which a protruding side lobe irradiates the ground surface.

FIG. 3 is an explanatory diagram showing a recording state of an STC threshold offset level in an STC level adjuster.

FIG. 4 is a diagram showing a second embodiment of the radar apparatus according to the present invention;

FIG. 5 is a diagram showing a third embodiment of the radar device according to the present invention;

FIG. 6 is an explanatory diagram showing a recording state of an STC threshold offset level in the advanced STC adjuster.

FIG. 7 is a diagram showing a fourth embodiment of the radar apparatus according to the present invention;

FIG. 8 is an explanatory diagram showing a state of setting an STC threshold start distance in an STC distance setting unit.

FIG. 9 is a diagram showing a fifth embodiment of the radar apparatus according to the present invention;

FIG. 10 is a schematic diagram of a general antenna pattern.

FIG. 11 STC in side lobe STC adjuster
FIG. 9 is an explanatory diagram showing a recording state of a threshold offset level.

FIG. 12 is a diagram illustrating a conventional radar device.

FIG. 13 is a diagram in which the operation status of the radar device and the components of the received signal of the radar device at that time are decomposed into components in the frequency axis direction and the time axis direction.

FIG. 14 is an explanatory diagram of target detection by CFAR processing in a target detector.

FIG. 15 is a schematic diagram showing a signal recording state of a first correlator, a second correlator, and a third correlator in the STC processor.

[Explanation of symbols]

1 transmitter, 2 antennas, 3 receivers, 4 transmission / reception switch, 5 clutter canceller, 6 frequency analyzer, 7
Target detector, 8 first correlator, 9 STC generator, 10 second correlator, 11 third correlator, 12 blanking circuit, 13 STC processor, 1
4 signal processor, 15 controller, 16 own machine, 17 main beam, 18 side lobe, 19 target machine, 20
Building on the ground surface, 21 Main beam clutter, 22
Sidelobe clutter, 23 Target signal, 24 Sidelobe discrete, 25 Doppler filter, 26
Range gate, 27 matrix, 28 first correlator range memory, 29 second correlator range memory, 30 third correlator range memory, 3
1 noise level detector, 32 STC level adjuster,
33 protruding side lobes, 34 STC level input section, 35 advanced STC adjuster, 36 STC distance setting section, 37 side lobe STC adjuster.

Claims (5)

[Claims] 1. A transmitter, an antenna for emitting a transmission signal from the transmitter to a space and receiving a reflected wave from a target, and an amplifier for amplifying a reception signal received by the antenna to a predetermined frequency band. A receiver that performs frequency conversion, a clutter canceller that removes and outputs a main beam clutter from a received signal input from the receiver, a frequency analyzer that performs frequency analysis on the received signal input from the clutter canceller, A target detector that detects a target signal with respect to the frequency-analyzed received signal output from the frequency analyzer and determines the distance of the detected target signal;
An STC (Sensitivit) that removes a false target such as a side lobe discrete from the signal detected by the target detector and extracts a true target.
y STC processor, and the STC processor is a first correlator that stores the presence or absence of a signal detected by the target detector for each range gate, the target detector Generator for extracting only a signal exceeding an STC threshold from signals detected by a detector, a second correlator for storing the presence or absence of a signal detected by the STC generator for each range gate, and a first correlator A blanking circuit that compares the presence or absence of a signal stored for each range gate of the second correlator and outputs a comparison result; a first correlator output from the blanking circuit;
According to the comparison result of the presence / absence of the signal for each range gate of the correlator, the storage of the signal is deleted from the range gate in which the signal does not exist in both the first correlator and the second correlator, and the signals of the other range gates are removed. In a radar apparatus including a third correlator for holding signal data,
Using an output from the frequency analyzer, a noise level detector that detects a power level of side lobe clutter,
The output from the noise level detector is monitored, and the offset level of the STC threshold level stored in advance for each noise level is output to the STC generator according to the noise level of the noise level detector. And a STC level adjuster. 2. A transmitter, an antenna for emitting a transmission signal from the transmitter to a space and receiving a reflected wave from a target, and an amplifier for amplifying a reception signal received by the antenna to a predetermined frequency band. A receiver for frequency conversion, a clutter canceller for removing and outputting a main beam clutter from a received signal input from the receiver, and a received signal input from the clutter canceler perform frequency analysis of the received signal. A frequency analyzer, a target detector that detects a target signal with respect to the frequency-analyzed received signal output from the frequency analyzer, and determines a distance between the detected target signals, and a signal detected by the target detector. And a signal processor having an STC processor for removing a false target such as a side lobe discrete from the inside and extracting a true target. A first correlator for storing the presence / absence of a signal detected by the target detector for each range gate; and only a signal exceeding an STC threshold among signals detected by the target detector. An STC generator to be extracted, a second correlator for storing the presence or absence of a signal detected by the STC generator for each range gate, and a second correlator for each range gate of the first and second correlators. A blanking circuit that compares the presence or absence of a signal and outputs the comparison result;
According to the comparison result of the presence / absence of the signal for each range gate of the first correlator and the second correlator output from the blanking circuit, the range correlator from the range gate having no signal in both the first correlator and the second correlator In a radar apparatus including a third correlator for removing signal storage and retaining signal data of other range gates, the STC threshold value of the STC generator input from the outside may be adjusted by the offset level of the STC threshold. A radar apparatus comprising an STC level input unit for outputting an STC threshold offset level to a generator. 3. A transmitter, an antenna for emitting a transmission signal from the transmitter to a space and receiving a reflected wave from a target, and amplifying a reception signal received by the antenna, to a predetermined frequency band. A receiver for frequency conversion, a clutter canceller for removing and outputting a main beam clutter from a received signal input from the receiver, and a received signal input from the clutter canceler perform frequency analysis of the received signal. A frequency analyzer, a target detector that detects a target signal with respect to the frequency-analyzed received signal output from the frequency analyzer, and determines a distance between the detected target signals, and a signal detected by the target detector. And a signal processor having an STC processor for removing a false target such as a side lobe discrete from the inside and extracting a true target. A first correlator for storing the presence / absence of a signal detected by the target detector for each range gate; and only a signal exceeding an STC threshold among signals detected by the target detector. Generator, a second correlator for storing the presence or absence of a signal detected by the STC generator for each range gate, the first correlator and the second correlator.
A blanking circuit that compares the presence or absence of a signal stored for each range gate of each correlator and outputs a comparison result; and a first correlator and a second correlator output from the blanking circuit for each range gate. According to the comparison result of the presence / absence of the signal, the third memory that deletes the storage of the signal from the range gate where no signal exists in both the first correlator and the second correlator and holds the signal data of the other range gates In a radar device equipped with a correlator, different ST
The C threshold is stored, and the previously stored ST corresponding to the own altitude inputted from the outside is stored.
A radar apparatus comprising an altitude STC adjuster for outputting an offset level of a C threshold to the STC generator. 4. A transmitter, an antenna for emitting a transmission signal from the transmitter to a space, and receiving a reflected wave from a target, and an amplifier for amplifying a reception signal received by the antenna to a predetermined frequency band. A receiver for frequency conversion, a clutter canceller for removing and outputting a main beam clutter from the received signal input from the receiver, and a frequency for performing frequency analysis of the received signal for the received signal input from the clutter canceller. An analyzer, a target detector that detects a target signal with respect to a frequency-analyzed received signal output from the frequency analyzer, and determines a distance of the detected target signal; and a signal detected by the target detector. And a signal processor having an STC processor for removing a false target such as a side lobe discrete from the target and extracting a true target. Furthermore, the STC processor further includes:
A first correlator for storing the presence or absence of a signal detected by the target detector for each range gate; an STC generator for extracting only a signal exceeding an STC threshold from signals detected by the target detector; A second correlator for storing the presence or absence of a signal detected by the generator for each range gate; comparing the presence or absence of a signal stored for each range gate of the first and second correlators; Both the first correlator and the second correlator are based on the result of the comparison of the presence / absence of a signal for each range gate of the first correlator and the second correlator output from the blanking circuit that outputs the result. The third memory that deletes the signal storage from the range gate where no signal is present and retains the signal data of the other range gates The radar apparatus provided with a regulator, STC setting the starting distance of the STC threshold of the STC generator by the distance information inputted from the outside
A radar apparatus comprising a distance setting unit. 5. A transmitter, an antenna for emitting a transmission signal from the transmitter to a space and receiving a reflected wave from a target, and an amplifier for amplifying a reception signal received by the antenna to a predetermined frequency band. A receiver for frequency conversion, a clutter canceller for removing and outputting a main beam clutter from the received signal input from the receiver, and a frequency for performing frequency analysis of the received signal for the received signal input from the clutter canceller. An analyzer, a target signal for detecting a target signal with respect to a frequency-analyzed received signal output from the frequency analyzer, and a target detector for determining a distance of the detected target signal, of a signal detected by the target detector. A signal processing unit that removes a false target such as a side lobe discrete from the inside and extracts a true target. And a STC.
A first correlator for storing, for each range gate, the presence or absence of a signal detected by the target detector; an STC generator for extracting only a signal exceeding an STC threshold from signals detected by the target detector; , ST above
A second correlator for storing the presence or absence of a signal detected by the C generator for each range gate; comparing the presence or absence of a signal stored for each range gate of the first correlator and the second correlator; A blanking circuit that outputs a comparison result, a first correlator and a second correlator output from the blanking circuit. In a radar apparatus provided with a third correlator for deleting signal storage from a range gate having no signal in both of them and holding signal data of other range gates, a side lobe is removed from an antenna pattern input from the outside. Detects the level and offsets the STC threshold corresponding to the magnitude of the sidelobe level in advance Advance stores a plurality of bell, radar apparatus, characterized in that the offset level of the STC threshold corresponding to the magnitude of the detected side lobes with a sidelobe STC regulator for output to the STC generator.