JP2002139563A - Radar device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect targets at an improved target detection rate while suppressing a false alarm rate. SOLUTION: This radar device is provided with a transmitter outputting transmission signals, an antenna receiving the reflected waves for the transmission signals, and a receiver receiving and processing the reflected waves received by the antenna, a threshold detecting means accepting the reception signals received and processed by the receiver and detecting a reception signal exceeding a set threshold value, and a threshold control means controlling the threshold value of the threshold detecting means according to the elapsed time after the transmission of the transmission signal so that the threshold value at the transmission of the transmission signal is made higher than a reference value and the threshold value is reduced from the reference value when the prescribed time elapses after the transmission of the transmission signal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radar device for detecting a target such as an aircraft or a ship.

[0002]

2. Description of the Related Art Conventionally, as a radar apparatus for detecting a target, for example, there is a radar apparatus described in Japanese Patent Application Laid-Open No. Hei 10-260247. In such a radar device, it is important to keep the false alarm detection probability (hereinafter, false alarm probability) constant. FIG. 3 shows a radar that switches the CFAR coefficient of the Rayleigh CFAR circuit based on the distance information. An apparatus is disclosed. As described above, the false alarm probability is one index in target detection, and by controlling the threshold value of the so-called threshold detection means so that the false alarm probability is constant, the target value can be obtained without deteriorating the false alarm probability. Target detection can be performed.

[0003]

However, since the conventional radar device is configured as described above, when a target such as an aircraft is located at a position distant from the radar device, the target is reflected from the target. When the signal level of the reflected signal becomes smaller than the threshold value set in the threshold detecting means, the target signal itself cannot be detected and the threshold value is set so that the false alarm probability becomes constant. Is controlled, there is a problem that the target detection rate at a long distance deteriorates.

When a wide range of targets is detected by scanning a beam in the azimuth or elevation direction, a desired target detection rate can be obtained near the nose of each beam. In, the target detection rate decreases,
If the threshold value in the threshold detecting means is lowered to increase the target detection rate, the target detection rate near the valley between the beams is improved, but the probability of false alarm near each beam nose deteriorates.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems.
It is an object of the present invention to obtain a radar device having a novel configuration capable of improving a target detection rate.

[0006]

According to a first aspect of the present invention, there is provided a radar apparatus for transmitting a transmission signal, an antenna for receiving a reflected wave corresponding to the transmission signal, and the reflected wave received by the antenna. A threshold value detecting means for receiving a received signal processed by the receiver and detecting a received signal exceeding a set threshold value; and transmitting the threshold value of the threshold value detecting means to the threshold value. The threshold value at the time of transmission of the transmission signal is higher than a reference value, and the threshold value after a lapse of a predetermined time from the transmission of the transmission signal is the reference value. And a threshold control means for lowering the threshold value.

According to a second aspect of the present invention, there is provided a radar apparatus for transmitting a transmission signal, an antenna for receiving a reflected wave corresponding to the transmission signal, and receiving processing of the reflected wave received by the antenna. A receiver, an integrator for integrating the reception signal received by the receiver between two adjacent beams, and a threshold value higher than a reference value set by a false alarm probability, and the threshold value exceeding the threshold value is set. And a threshold detecting means for detecting a reception signal from the integrator as a target signal.

According to a third aspect of the present invention, there is provided a radar apparatus for transmitting a transmission signal, an antenna for receiving a reflected wave corresponding to the transmission signal, and receiving and processing the reflected wave received by the antenna. A receiver and a reception signal of one of the adjacent beams of the reception signal received and processed by the receiver are input, and a reception signal exceeding a first threshold value higher than a reference value determined by a false alarm probability is detected. A first threshold detection unit, a second threshold detection unit that receives a reception signal of the other beam adjacent to the reception-processed reception signal and detects a reception signal exceeding the first threshold value, 1
And a received signal detected by the second threshold detecting means is inputted, a 1 in 2 test process is performed on these received signals, and a 1 in 2 tester for detecting a detection result of 1 in 2 as a target signal is provided. Things.

According to a fourth aspect of the present invention, there is provided a radar apparatus for transmitting a transmission signal, an antenna for receiving a reflected wave corresponding to the transmission signal, and receiving processing of the reflected wave received by the antenna. A receiver and a reception signal of one of the adjacent beams of the reception signal received and processed by the receiver are input, and a reception signal exceeding a first threshold value higher than a reference value determined by a false alarm probability is detected. A first threshold detection unit, a second threshold detection unit that receives a reception signal of the other beam adjacent to the reception-processed reception signal and detects a reception signal exceeding the first threshold value, 1
And a received signal detected by the second threshold detecting means is inputted, and an N-in-two N-tester for performing an N-in-two-test process, and a detection signal of one in two of the two-in-N-tester are inputted,
The second threshold value set higher than the first threshold value
Threshold detection means for detecting a detection signal of 1 out of 2 exceeding the threshold value of the second threshold value, and a detection signal of the third threshold detection means or 2 out of 2 of the 1 in 2 tester.
And a combiner to which the detection signal is input and outputs one of the detection signals as a target signal.

A radar apparatus according to a fifth aspect of the present invention is provided with a transmission frequency control means for changing a frequency of a transmission signal output from the transmitter so as to provide a frequency difference between the adjacent beams. It was done.

According to a sixth aspect of the present invention, there is provided a radar apparatus for transmitting a transmission signal, an antenna for receiving a reflected wave corresponding to the transmission signal, and receiving and processing the reflected wave received by the antenna. A receiver, a received signal processed by the receiver, a threshold detecting means for detecting a received signal exceeding a threshold value higher than a reference value determined by a false alarm probability for each scan, and a threshold detecting means; A detection signal is input for each detected scan, an N-in-M tester that performs N-in-M test processing of the received signal in each scan, and detects the N-in-M detection signal as a target signal. is there.

A radar apparatus according to a seventh aspect of the present invention provides a transmitter that outputs transmission signals having different pulse widths, an antenna that receives a reflected wave corresponding to the transmission signal, and the reflected wave that is received by the antenna. And a threshold detection unit that receives a reception signal processed by this receiver for each pulse and detects a reception signal exceeding a threshold value higher than a reference value determined by a false alarm probability. Received signals for each pulse width detected by the threshold detecting means are input, and an N-in-M test process is performed on the received signals for each pulse width.
And an N-in-M tester for detecting the detection signal as a target signal.

[0013] A radar apparatus according to an eighth aspect of the present invention provides a transmitter for outputting a transmission signal, an antenna for receiving a reflected wave corresponding to the transmission signal, and a receiving process for the reflected wave received by the antenna. A receiver, a reception signal to which a reception signal processed by the receiver is input, and a threshold detection means for detecting a reception signal exceeding a set threshold value; and a distance to a target is calculated based on a detection signal of the threshold detection means. And a pulse width control means for setting a pulse width of a transmission signal output from the transmitter according to the distance to the target calculated by the distance calculation means.

According to a ninth aspect of the present invention, there is provided the radar apparatus, wherein the threshold detecting means, the one-in-two verifier,
A detection signal of either the synthesizer or the N-in-M tester is input for each scan, an N-in-M test process is performed on the detection signal in each scan, and the N-in-M detection signal is output as a target signal. An inter-scan verifyer is provided.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 Hereinafter, Embodiment 1 of the present invention. Will be described with reference to FIG. 1 and FIG. FIG. 1 shows a first embodiment of the present invention. 1 is a block diagram showing a radar apparatus according to the present invention. In FIG. 1, 1 is a transmitter that outputs a transmission signal, 2 is a directional antenna that transmits a transmission signal output from the transmitter 1 in a predetermined direction, and receives a reflected signal thereof, and 3 is a transmission / reception switch that switches transmission / reception operations. Container, 4
Is an A / D converter that receives (amplifies and detects) the reflected signal received by the antenna 2 and converts it into a video signal, and 5 is an A / D converter that converts the received signal received by the receiver 4 into a digital signal. , 6 are digital signals converted by the A / D converter 5 and inputted, and a digital signal exceeding a set threshold value, that is, a threshold detecting means for detecting a received signal, and 7 is a process after transmitting a transmission signal. Threshold control means for changing the threshold value set in the threshold detection means 6 according to time. The A / D converter 5 and the threshold detection means 6 constitute a target detection processing unit 8,
The received signal detected by the threshold detecting means 6 is output as a target signal.

Next, the operation will be described. First, a transmission signal output from the transmitter 1 passes through the transmission / reception switch 3 and is transmitted in a predetermined direction from the antenna 2 as a beam-like transmission radio wave (hereinafter, simply referred to as a beam). The reflected radio wave of this beam is received by the antenna 2 and is input to the receiver 4 through the transmission / reception switch 3. The reflected signal input to the receiver 4 is subjected to amplification / detection processing and input to the target detection processing unit 8.
In the target detection processing unit 8, a so-called received signal from the receiver 4 is first converted into a digital signal in the A / D converter 5, and this digital signal is input to the threshold detection unit 6. The threshold detection means 6 keeps the false alarm probability (Pfa) constant in the distance direction, while controlling the threshold value by the threshold control means 7 so that the detection rate of a target such as an aircraft at a long distance does not decrease. The target signal is detected not only from a reflected signal from a target at a long distance but also from a reflected signal from a target at a long distance.

Here, the operation of detecting the target signal by the threshold detecting means 6 will be described in detail with reference to FIG. FIG. 2 is a distance characteristic diagram showing a false alarm probability and a target detection rate of the entire beam in the distance direction of the radar apparatus shown in FIG. 1, wherein the upper part of FIG. 2 is a distance characteristic diagram of the false alarm probability (Pfa), and the lower part of FIG. It is a distance characteristic figure of target detection rate (Pd). In FIG. 2, the apparent Pfa indicates the false alarm probability in the entire beam distance direction, and indicates the false alarm probability of the entire radar apparatus. The threshold control means 7 controls the threshold detection means 6 so that the actual Pfa and the actual Pd have characteristics as shown in FIG.
Controls the threshold value set in. Specifically, before the predetermined time elapses after the beam transmission, the actual P
The threshold value of the threshold detecting means 6 is set to the apparent Pfa so that fa becomes smaller than the apparent Pfa.
The threshold value is set higher than a threshold value (hereinafter, referred to as a reference value) determined from the above, and after a predetermined time has elapsed after beam transmission, the threshold value of the threshold detecting means 6 is set lower than the reference value. Thereby, Pfa as a whole in the distance direction of the beam, that is, apparent Pfa can be made constant.

Further, since the threshold value of the threshold detecting means 6 is set lower than the reference value after a lapse of a predetermined time after the beam transmission, it is possible to detect the target signal from the reflected signal from the target at a long distance. Can,
The target detection rate (Pd) at a long distance can be improved while Pfa is kept constant. The lower part of FIG. 2 shows this state. Although the actual Pd before the elapse of a predetermined time after the beam transmission is lower than that after the elapse of the predetermined time after the beam transmission, the overall Pd in the distance direction of the beam is lower. Pd, that is, apparent Pd, can be constant.

In fact, the signal level of the reflected signal from the target at a short distance is considerably higher than the signal level of noise or the like detected as an erroneous target, and the threshold value of the threshold detecting means 6 is set to be slightly higher than the reference value. However, even if the actual Pfa becomes smaller than the apparent Pfa, the signal level of the signal reflected from the target does not become lower than this threshold value, and the target signal cannot be detected. As described above, the threshold control means 7 receives the distance to the target such that the signal level of the reflected signal from the target becomes lower than the set threshold value, that is, receives the reflected signal from the target located at such a distance. The threshold value of the threshold detecting means 6 is changed in accordance with the elapsed time after the beam transmission up to.

As described above, in the radar device according to the present embodiment, the threshold control means 7 changes the threshold value set in the threshold detection means 6 in accordance with the elapsed time after the beam transmission, so that the beam distance While the false alarm probability (Pfa) in the entire direction is constantly suppressed, a reflected signal from a target at a long distance can be detected and output as a target signal, and the target detection rate in a long distance region can be improved. it can.

Embodiment 2 FIG. Next, Embodiment 2 of the present invention. Will be described with reference to FIGS. 3 and 4. FIG. The radar apparatus according to the present embodiment improves a target detection rate of a valley between adjacent beams when, for example, a beam is scanned over a wide range. FIG. FIG. 3 is a block diagram showing a radar apparatus according to the present invention. In FIG. 3, reference numerals 9 and 10 denote threshold detecting means to which a digital signal converted by the A / D converter 5 is input, and 9-1 denotes two adjacent beams. Is a first threshold detecting means to which one of the received signals is inputted, and 9-2 is a second threshold detecting means to which the other received signal of two adjacent beams is inputted. Note that threshold values higher than a threshold value (hereinafter, referred to as a reference value) determined from the false alarm probability Pfa are set in these threshold detection means 9-1 and 9-2, respectively.

Reference numeral 10 denotes a threshold detecting means 9-
An integrator to which detection signals detected by the threshold detection means 9-1 and 9-2 are input, respectively, and to perform integration processing on the detection signals detected by the threshold detection means 9-1 and 9-2;
Reference numeral 11 denotes a third threshold detecting means which receives a detection signal integrated by the integrator 10 and detects a target signal from the integrated detection signal. The third threshold detecting means 11 includes a first threshold detecting means 11. And a threshold value higher than the threshold value set in the second threshold detecting means 9-1 and 9-2. The threshold value of the third threshold detecting means 11 is changed to the first and second threshold detecting means 9-1,
By setting the threshold value higher than the threshold value set in 9-2, the target detection rate of the valley between adjacent beams can be improved, while the false alarm probability of the entire beam can be suppressed. Note that reference numeral 8b denotes a target detection processing unit of the radar apparatus according to the present embodiment, and the same reference numerals in the drawings denote the same or corresponding parts.

Next, the operation will be described in more detail with reference to FIG. FIG. 4 is a gain characteristic diagram showing the beam gain of two adjacent beams. In FIG. 4, 12 is the beam gain in the case of a single beam, and 13 is the beam gain of the two adjacent beams integrated by the integrator 10. is there. Receiver 4
Is converted into a digital signal by the A / D converter 5, one of the two adjacent beams is sent to the first threshold detecting means 9-1 and the other of the two adjacent beams is sent to the second threshold detector 9-1. Each is input to the threshold detection means 9-2. A threshold value higher than the reference value is set in the first and second threshold detecting means 9-1 and 9-2 as described above, and a received signal exceeding the threshold value is detected, and the integrator 1 is detected.
Input to 0.

The integrator 10 integrates each detection signal detected by the first and second threshold detection means 9-1 and 9-2, and outputs the integration result to the third threshold detection means 11. Here, the beam gain of two adjacent beams integrated by the integrator 10 will be described. As shown in FIG. 4, the beam gain 13 of the two adjacent beams integrated by the integrator 10 is equal to the value obtained by setting the threshold values of the first and second threshold detecting means 9-1 and 9-2 higher. However, the gain of the beam nose portion is lower than the beam gain 12 in the case of a single beam, but the beam gain of the valley portion between adjacent beams is improved by the integration process of the integrator 10, whereby The target detection rate can be improved in the valley portion between the beams.

The integration result of the integrator 10 is further input to the third threshold detecting means 11, and a signal exceeding the threshold value set in the third threshold detecting means 11 is output as a target signal. As mentioned above,
Since the signal detected by the third threshold detecting means 11 is output as a target signal, the target detection rate of a valley between adjacent beams can be improved, while the false alarm probability of the entire beam can be reduced. Can be suppressed.

In the radar apparatus according to the present embodiment, the first and second threshold detecting means 9-1 and 9-2 detect received signals for two adjacent beams, and the first and second thresholds are detected. Means 9-1, 9
-2, the detection signal is integrated, and the integration result is further input to the third threshold detection means 11 to output the detection signal as a target signal, so that the beam can be scanned over a wide range. In such a case, the beam gain in the valley between adjacent beams can be improved and the target detection rate can be improved, but the false alarm probability of the entire beam can be suppressed.

Embodiment 3 Next, Embodiment 3 of the present invention. Will be described with reference to FIG.
Embodiment 2 above. The first and second radar systems
The detection signals detected by the threshold detection means 9 and 10 are integrated, and a target signal is output based on the integration result. However, a 1 in 2 tester is provided, and the 1 in 2 tester is detected. A signal may be output as a target signal. FIG. FIG. 5 is a block diagram showing a radar apparatus according to the present invention. In FIG. 5, reference numeral 14 denotes first and second threshold detecting means 9-1 and 9-2.
The detection signal for two adjacent beams detected by the above is input, and when the detection signal of either one of the beams is input, a verification process that there is detection, that is, a 1 in 2 tester that outputs a target signal, 8c is a target detection processing unit of the radar device according to the present embodiment. In the drawings, the same reference numerals indicate the same or corresponding parts.

In the radar apparatus according to the present embodiment, the first and second threshold detecting means 9-1 and 9-2 detect received signals for two adjacent beams, and the first and second thresholds are detected. Means 9-1, 9
-2, a one-in-two tester 14 that outputs a target signal as a detection when a detection signal is input to either one of the two.
Is provided, the beam gain in the beam nose portion decreases, but the target detection rate in two adjacent beams,
That is, since the sum of the probability of detecting a target by both beams and the probability of detecting a target by one of the beams can be increased, a valley between adjacent beams can be obtained when a beam is scanned over a wide area. The beam gain of the portion can be improved and the target detection rate can be improved, while the false alarm probability of the entire beam can be suppressed.

Embodiment 4 Next, Embodiment 4 of the present invention. Will be described with reference to FIG.
Embodiment 3 above. In the radar apparatus according to the present invention, a 1 in 2 tester 14 is provided, and the first and second threshold detecting means 9 are provided.
When either one of the detection signals of −1 and 9-2 is input, the target signal is output as the presence of the detection.
An N-in-two tester may be provided, and a target signal may be output based on the detection signal of the N-in-two tester. FIG. FIG. 6 is a block diagram showing a radar apparatus according to the present invention. In FIG. 6, reference numeral 15 denotes detection signals for two adjacent beams detected by the first and second threshold detection means 9-1 and 9-2, respectively. If the detection signal of either one of the beams is input, 2
The middle N detector 2 outputs the detection signal of the middle 1 and outputs the detection signal of the second 2 when the detection signals of both beams are input. The detection signal is input, and the first and second threshold detecting means 9-
Third threshold detecting means for outputting a detection signal exceeding a threshold value set higher than the threshold values of 1, 9-2, 17 is a detection signal of 2 out of 2 or 1 out of 2 of the N out of 2 tester 15 Is input and output as a target signal, and 8d is a target detection processing unit of the radar apparatus according to the present embodiment. In the drawings, the same reference numerals indicate the same or corresponding parts.

In the radar device according to the present embodiment, first, the first and second threshold detecting means 9-1 and 9-2 detect received signals for two adjacent beams, and the first and second thresholds are detected. Detecting means 9-
When the detection signal of either one of the beams 1 and 9-2 is input, the detection signal of one of the two is output to the combiner 17 via the third threshold detection means 16 and both beams are output. , An N-in-two N tester 16 that outputs a two-in-two detection signal to the synthesizer 17 when the detection signal of
Since the output signal of the combiner 17 is output as a target signal, the beam gain in the beam nose portion is reduced.
That is, the sum of the probability of detecting a target by both beams and the probability of detecting a target by one of the beams can be increased, and in a case where a beam is scanned over a wide area, a valley portion between adjacent beams is used. Can be improved and the target detection rate can be improved, while the false alarm probability of the entire beam can be suppressed.

Embodiment 5 Next, Embodiment 5 of the present invention. Will be described with reference to FIG.
Embodiment 2 above. The radar apparatus according to the fourth to fourth embodiments scans a beam set to a single frequency to improve the beam gain of each two adjacent beams, but the radar apparatus according to the present embodiment Is to further provide a frequency difference between adjacent beams to reduce noise correlation between adjacent beams. FIG. FIG. 7 is a block diagram showing a radar apparatus according to the present invention. In FIG. 7, reference numeral 18 denotes transmission frequency control means for controlling the frequency of a transmission signal output from the transmitter 1 so as to give a frequency difference between two adjacent beams. In the drawings, the same reference numerals indicate the same or corresponding parts.

In the radar apparatus according to the present embodiment, transmission frequency control means 18 for controlling the transmission frequency of the transmitter 1 is provided, and the transmitter 1 controls the transmission frequency control means 18 so as to give a frequency difference between two adjacent beams. Since the frequency of the transmission signal output from is changed, the second embodiment is used.
To Embodiment 4. In addition to the improvement in the target detection rate as described in the above, it is possible to obtain a radar apparatus in which the correlation of noise between adjacent beams is further reduced. In addition,
In the radar device according to the present embodiment, the first and second threshold detecting means 9-1 and 9 are used as target detection processing units.
Although the target detection processing unit 8b configured to integrate the detection signal of −2 is illustrated as an example, the present invention is not limited to this, and another target detection processing unit 8c or 8d illustrated in FIG. 5 or FIG. The same effect can be obtained by applying the present invention.

Embodiment 6 FIG. Next, Embodiment 6 of the present invention. Will be described with reference to FIG.
Embodiment 2 above. The radar apparatus according to the fifth embodiment performs so-called inter-beam correlation processing to improve the beam gain between adjacent beams.
In each case, a target signal is detected based on a single scan. The radar apparatus according to the present embodiment repeats beam scanning a plurality of times and performs a correlation process between the plurality of scans to improve a beam gain between the plurality of scans. FIG. 1 is a block diagram showing a radar apparatus according to the present invention.

In FIG. 8, 19-1 to 19-M (M
Is an integer of 3 or more) is received by the receiver 4 and A /
The received signal digitally converted by the D converter 5 is input for each scan, and a threshold detecting means for detecting a received signal exceeding a threshold value defined by a false alarm probability (pfa), and 20 is a threshold detecting means 19-1 to 19-1 Each of the M detection signals detected by 19-M is input, and an N-in-M tester that outputs a target signal when N (an integer of 1 or more and an integer of M or less) or more detection signals is input, 8e Denotes a target detection processing unit of the radar apparatus according to the present embodiment, and the same reference numerals in the drawings denote the same or corresponding parts.

In the radar apparatus according to the present embodiment, the threshold detection processing is performed by the threshold detection means 19 every time a beam is scanned, and the detection processing for each of these scans is performed by the N-in-M tester 20. In the case where the coverage is defined by the cumulative detection probability (a specification of the radar apparatus), the beam gain in the entire scan can be improved, and the target detection rate can be further improved.

Embodiment 7 Next, Embodiment 7 of the present invention. Will be described with reference to FIG.
The radar apparatus according to the sixth embodiment performs so-called inter-scan correlation processing to improve the beam gain between a plurality of scans. However, the radar apparatus according to the sixth embodiment includes a beam transmitted in a certain direction. Change the pulse repetition period (hereinafter referred to as PRT) in
This is to detect a target signal in the distance direction based on signals received by a plurality of PRTs.

FIG. 9 shows a sixth embodiment. 10 is a block diagram showing a radar apparatus according to the present invention. In FIG. 9, 21-1 to 21-M (M is an integer of 3 or more) are subjected to reception processing by a receiver 4 by a transmitter 1, and by an A / D converter 5 The digitally converted received signals of a plurality of PRTs are input for each PRT, and a threshold detecting means for detecting a received signal exceeding a threshold value determined by a false alarm probability (pfa), 22 is a threshold detecting means 21-1 to 21-
Each of M detection signals detected by M is input, and an N-in-M tester that outputs a target signal when N (an integer of 1 or more and M or less) detection signals is input, 8f
Denotes a target detection processing unit of the radar apparatus according to the present embodiment, and the same reference numerals in the drawings denote the same or corresponding parts.

In general, when detecting a target such as an aircraft in a long-distance region, a PRT of a transmission signal having a relatively long pulse width is used. However, when a transmission signal having a long PRT is transmitted, a beam transmission time is required. While the area becomes longer, the reception time area for receiving the reflected signal from the target becomes shorter, and it becomes difficult to accurately detect the target in a long distance area.
By performing target detection with multiple PRT beams,
Mutual non-reception time (transmission time portion) can be compensated. FIG. 10 is an explanatory diagram of the reception time of each reflected signal when the target detection is performed by the beams of a plurality of PRTs. FIG. 10A shows the reflected signal of the beam set to a relatively long PRT. Reception time, FIG.
(B) shows the reception time of the reflected signal by the beams of a plurality of PRTs (PRT1 to PRT3). The vertical axis represents the S / N ratio, and the longer the PRT, the higher the S / N ratio.
This shows that the N ratio is high and suitable for target detection in a long-distance region.

In the radar device according to the present embodiment, the threshold detecting means 21- is used for a plurality of PRT beams.
Since the detection processing for each PRT in 1 to 21-M is performed, and the detection signal for each PRT is subjected to the verification processing by the N-in-M tester 20, each of the detection signals is obtained as shown in the result 1 in FIG. The non-reception time in the PRT beam can be mutually complemented, the beam gain in the distance direction can be improved, and the target detection rate can be improved.

Embodiment 8 FIG. Next, Embodiment 8 of the present invention. Will be described with reference to FIG. The radar device according to the seventh embodiment has a so-called P
In this method, a correlation between RTs is performed to improve the beam gain between a plurality of PRTs. However, when target detection is performed using beams of a plurality of PRTs, a so-called target detection process requires a long processing time, and a target detection is performed. Is not so desirable when the result of (1) is further used for target tracking or the like.
The radar device according to the present embodiment calculates the distance to the target, changes the PRT of the transmission signal transmitted from the transmitter 1 in accordance with the distance to the target, and optimizes the PRT in accordance with the distance to the target. The target detection is performed by using the beam.

FIG. 11 shows an eighth embodiment. 11 is a block diagram showing a radar apparatus according to the present invention. In FIG.
The threshold detection means for receiving the reception signal digitally converted by the / D converter 5 and detecting a reception signal exceeding a threshold value determined by the probability of false alarm (Pfa), and a threshold detection means 24 for detecting the target signal detected by the threshold detection means 23 A distance calculating means for calculating a distance to the target based on the PRT control for changing a PRT of a transmission signal output from the transmitter 1 to an optimum PRT according to the distance to the target calculated by the distance calculating means 24; Means, 8
g is a target detection processing unit of the radar device according to the present embodiment. In the drawings, the same reference numerals indicate the same or corresponding parts.

In the radar device according to the present embodiment, the distance to the target is calculated, and the PRT of the transmission signal output from the transmitter 1 is calculated according to the calculated distance to the target by the optimum PRT.
Since it is set to RT, it is possible to perform target detection with an improved target detection rate using a single PRT beam, and to significantly reduce the processing time in the target detection processing unit 8g. By greatly shortening the processing time in the target detection processing unit, it is possible to provide a radar device more suitable for use in target tracking and the like.

Embodiment 9 Next, a ninth embodiment of the present invention will be described. Will be described with reference to FIGS. 12 and 13. FIG. The radar devices according to each of the above embodiments may be implemented independently, or may be implemented in combination. For example, Embodiment 6. The radar apparatus according to the present invention performs so-called inter-scan correlation processing on a single beam. To Embodiment 4.
Device according to the seventh embodiment. By applying the present invention to a radar apparatus according to the present invention, it is possible to obtain a more advanced radar apparatus having these effects.

FIG. 12 shows a ninth embodiment. FIG. 4 is a block diagram showing a radar device according to the present invention, which is configured to perform a so-called inter-scan correlation process in the radar device shown in FIG. 3. In FIG. 12, 8b-1 to 8b-M (M is an integer of 3 or more) are target detection processing units of the radar apparatus according to the present embodiment, and 26 is a target detection processing unit 8b.
A detection signal for each scan detected in -1 to 8b-M is input, and an N-in-M test for outputting a target signal when N (an integer of 1 or more and an integer of M or less) or more detection signals is input. In the drawings, the same reference numerals indicate the same or corresponding parts.

FIG. 13 shows a ninth embodiment. FIG. 10 is a block diagram showing a radar apparatus according to the present invention, which is configured to perform a so-called inter-scan correlation process in the radar apparatus shown in FIG. 9. In FIG. 13, 8f-
1 to 8f-M (M is an integer of 3 or more) are target detection processing units of the radar apparatus according to the present embodiment, and 27 is a detection signal for each scan detected by the target detection processing units 8f-1 to 8f-M. Is input and N (an integer of 1 or more and M or less)
This is an N-in-M tester that outputs a target signal when more than two detection signals are input. In the figure, the same reference numerals indicate the same or corresponding parts.

In the radar apparatus according to the present embodiment, for example, so-called correlation processing between beams of two adjacent beams and correlation processing between scans, or so-called correlation processing between a plurality of PRTs and correlation processing between scans are performed. Therefore, it is possible to obtain a radar apparatus having a high processing capability having these effects.

In the radar apparatus according to each of the above-described embodiments, the reception signal processed by the receiver 4 is digitally processed by the target detection processing units 8, 8b, 8c, 8d, 8e, 8f and 8g. A / D converter 5
However, the signal processing may be performed in an analog manner without providing the A / D converter 5. A / D
Although the converters 5 are all provided in the target detection processing unit, they may be provided independently of the target detection processing unit, and the same effects as described above can be obtained.

[0048]

As described above, according to the first aspect of the present invention, a transmitter that outputs a transmission signal, an antenna that receives a reflected wave corresponding to the transmission signal, and the reflected wave that is received by the antenna. A threshold value detecting means for receiving a received signal processed by the receiver and detecting a received signal exceeding a set threshold value; and transmitting the threshold value of the threshold value detecting means to the threshold value. The threshold value at the time of transmission of the transmission signal is higher than a reference value, and the threshold value after a lapse of a predetermined time from the transmission of the transmission signal is the reference value. Since the threshold control means is set to be lower, the false alarm probability (Pfa) in the distance direction of each beam is suppressed. That one can be output as detected target signal reflected signal from the target in the far, it is possible to improve the target detection rate in the far region zone.

According to the second aspect of the present invention, a transmitter for outputting a transmission signal, an antenna for receiving a reflected wave corresponding to the transmission signal, and a reception for receiving and processing the reflected wave received by the antenna. , An integrator for integrating the received signal processed by the receiver between two adjacent beams, and a threshold value higher than a reference value determined by a false alarm probability is set, and the integration value exceeding the threshold value is set. Threshold detection means for detecting a signal received from the beam detector as a target signal, the beam gain in the valley between adjacent beams can be improved, and the target detection rate can be improved. The alarm probability can be suppressed.

According to the third aspect of the present invention, there is provided a transmitter for outputting a transmission signal, an antenna for receiving a reflected wave corresponding to the transmission signal, and a reception for receiving and processing the reflected wave received by the antenna. And a receiver for receiving a reception signal of one of adjacent beams of a reception signal processed by the receiver and detecting a reception signal exceeding a first threshold value higher than a reference value defined by a false alarm probability. Threshold detection means, and a reception signal of the other beam adjacent to the reception-processed reception signal is input,
Second threshold detection means for detecting a received signal exceeding the first threshold value, and the first and second threshold values;
The received signals detected by the threshold detecting means are input, and the received signals are subjected to one-in-two test processing.
Since the 2nd 1 tester for detecting the 1st detection result as the target signal is provided, the beam gain in the valley between adjacent beams can be improved and the target detection rate can be improved, while the overall beam can be improved. False alarm probability can be suppressed.

According to the fourth aspect of the present invention, a transmitter for outputting a transmission signal, an antenna for receiving a reflected wave corresponding to the transmission signal, and a reception for receiving and processing the reflected wave received by the antenna. And a receiver for receiving a reception signal of one of adjacent beams of a reception signal processed by the receiver and detecting a reception signal exceeding a first threshold value higher than a reference value defined by a false alarm probability. Threshold detection means, and a reception signal of the other beam adjacent to the reception-processed reception signal is input,
Second threshold detection means for detecting a received signal exceeding the first threshold value, and the first and second threshold values;
, A received signal detected by the threshold detecting means, and a N-in-two N-testing device for performing N-in-two N-testing processing;
A third threshold detecting means for receiving a detection signal of 1 in 2 of the medium N tester and detecting a detection signal of 1 in 2 that exceeds a second threshold value set higher than the first threshold value; Since the detection signal of the third threshold detecting means or the detection signal of 2 out of 2 of the 1 in 2 tester is inputted and a synthesizer for outputting any one of the detection signals as a target signal is provided, The beam gain in the valley portion between the beams can be improved and the target detection rate can be improved, while the false alarm probability of the entire beam can be suppressed.

According to the fifth aspect of the present invention, there is provided transmission frequency control means for varying the frequency of the transmission signal output from the transmitter, so as to provide a frequency difference between the adjacent beams. Therefore, the beam gain in the valley between adjacent beams can be improved and the target detection rate can be improved, while the false alarm probability of the entire beam can be suppressed. Further, it is possible to obtain a radar device in which the correlation of noise between adjacent beams is reduced.

According to the sixth aspect of the present invention, a transmitter for outputting a transmission signal, an antenna for receiving a reflected wave corresponding to the transmission signal, and a reception for receiving and processing the reflected wave received by the antenna. And a threshold detection means for receiving a reception signal processed by the receiver and detecting a reception signal exceeding a threshold value higher than a reference value determined by the probability of false alarm for each scan, and a threshold detection means for detecting the reception signal. The received signals for each of the scans are inputted, and the N-in-M tester for performing the N-in-M test process on the received signals in each scan and detecting the N-in-M detection signal as the target signal is provided. The overall beam gain can be improved, and the target detection rate can be further improved.

According to the seventh aspect of the present invention, there is provided a transmitter for outputting transmission signals having different pulse widths, an antenna for receiving a reflected wave with respect to the transmission signal, and transmitting the reflected wave received by the antenna. A receiver for performing reception processing, threshold detection means for receiving a reception signal processed by the receiver for each pulse, and detecting a reception signal exceeding a threshold value higher than a reference value determined by a false alarm probability; A reception signal for each pulse width detected by the detection means is input, an N-in-M test process is performed on the reception signals for each pulse width, and an N-in-M tester that detects the N-in-M detection signal as a target signal. , The non-reception time of the transmission pulse width can be mutually complemented by beams of a plurality of transmission pulse widths, and the beam gain of the entire beam is improved. Is, it is possible to improve the target detection rate.

Further, according to the invention of claim 8, a transmitter for outputting a transmission signal, an antenna for receiving a reflected wave corresponding to the transmission signal, and a reception for receiving and processing the reflected wave received by the antenna. And a threshold detection unit for receiving a reception signal processed by the receiver and detecting a reception signal exceeding a set threshold value, and a distance for calculating a distance to a target based on a detection signal of the threshold detection unit. Calculating means, and a pulse width control means for setting a pulse width of a transmission signal output from the transmitter according to the distance to the target calculated by the distance calculating means, a single transmission pulse width The target beam can be detected with an improved target detection rate, and the processing time required for target detection can be significantly reduced. .

According to the ninth aspect of the present invention, a detection signal of any one of the threshold detecting means, the one-in-two tester, the synthesizer, or the M-in-M tester is input for each scan. N of M of these detection signals for each scan
Since the inter-scan tester that performs the test process and outputs the detection signal of N out of M as a target signal is provided, a radar device having a high processing capability having the above-mentioned plurality of effects can be obtained.

[Brief description of the drawings]

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

FIG. 2 is a distance characteristic showing a false alarm probability and a target detection rate of the entire beam in the distance direction of the radar apparatus shown in FIG. 1;

[FIG. 3] Embodiment 2 of the present invention. 1 is a block diagram showing a radar apparatus according to the present invention.

FIG. 4 is a gain characteristic diagram showing beam gains of two adjacent beams of the radar apparatus shown in FIG.

FIG. 5 is a third embodiment of the present invention. 1 is a block diagram showing a radar apparatus according to the present invention.

FIG. 6 shows a fourth embodiment of the present invention. 1 is a block diagram showing a radar apparatus according to the present invention.

FIG. 7 shows a fifth embodiment of the present invention. 1 is a block diagram showing a radar apparatus according to the present invention.

FIG. 8 shows a sixth embodiment of the present invention. 1 is a block diagram showing a radar apparatus according to the present invention.

FIG. 9 shows a seventh embodiment of the present invention. 1 is a block diagram showing a radar apparatus according to the present invention.

FIG. 10 is an explanatory diagram of a reception time for explaining a reception time in a plurality of PRT beams.

FIG. 11 shows an eighth embodiment of the present invention. 1 is a block diagram showing a radar apparatus according to the present invention.

FIG. 12 is a ninth embodiment of the present invention. 1 is a block diagram showing a radar apparatus according to the present invention.

FIG. 13 shows a tenth embodiment of the present invention. 1 is a block diagram showing a radar apparatus according to the present invention.

[Explanation of symbols]

Reference Signs List 1 transmitter, 2 antenna, 3 transmission / reception switch, 4 receiver, 6,23 threshold detection means, 7 threshold control means, 8, 8b, 8c, 8d, 8e, 8f, 8g target detection processing section, 9-1 1 threshold detecting means, 9-2 second threshold detecting means, 10 integrator, 11, 16 third threshold detecting means, 14 2
Medium 1 tester, 152 Medium N tester, 17 synthesizer, 18 Transmission frequency control means, 19 Threshold detection means (for each scan), 20, 22, 26, 27 M Medium N tester, 21 Threshold detection means (PRT Each), 24 distance calculation means, 25 PRT control means.

Claims (9)

[Claims] 1. A transmitter for outputting a transmission signal, an antenna for receiving a reflected wave corresponding to the transmission signal, a receiver for receiving and processing the reflected wave received by the antenna, and a receiver for receiving and processing the reflected wave. The received signal is input, threshold detection means for detecting a reception signal exceeding a set threshold value, and the threshold value of the threshold detection means is controlled according to the elapsed time after transmitting the transmission signal, A threshold value at the time of transmission of the transmission signal is higher than a reference value, and a threshold control means for lowering the threshold value after a predetermined time has elapsed after transmitting the transmission signal is lower than the reference value. Radar equipment. 2. A transmitter that outputs a transmission signal, an antenna that receives a reflected wave corresponding to the transmission signal, a receiver that receives and processes the reflected wave received by the antenna, and a reception processing that is performed by the receiver. An integrator for integrating the received signal between two adjacent beams, and a threshold value higher than a reference value determined by a false alarm probability is set, and a received signal from the integrator exceeding the threshold value is detected as a target signal. And a threshold detecting means. 3. A transmitter that outputs a transmission signal, an antenna that receives a reflected wave corresponding to the transmission signal, a receiver that receives and processes the reflected wave received by the antenna, and a reception processing that is performed by the receiver. A first threshold detecting means for receiving a received signal of one adjacent beam to the received signal and detecting a received signal exceeding a first threshold value higher than a reference value determined by a false alarm probability; A received signal of the other beam adjacent to the received signal is input and detected by a second threshold detecting means for detecting a received signal exceeding the first threshold value, and by the first and second threshold detecting means. Received signal is inputted, the received signal is subjected to one-in-two test processing, and the one-in-two tester that detects the detection result of one in two as a target signal. A radar apparatus comprising: 4. A transmitter that outputs a transmission signal, an antenna that receives a reflected wave corresponding to the transmission signal, a receiver that receives and processes the reflected wave received by the antenna, and a reception processing that is performed by the receiver. A first threshold detecting means for receiving a received signal of one adjacent beam to the received signal and detecting a received signal exceeding a first threshold value higher than a reference value determined by a false alarm probability; A received signal of the other beam adjacent to the received signal is input and detected by a second threshold detecting means for detecting a received signal exceeding the first threshold value, and by the first and second threshold detecting means. Receiving the received signal, and performing N test processing during 2
A medium N tester and a detection signal of one in two of the two middle N testers are inputted, and a detection signal of one in two exceeding a second threshold value set higher than the first threshold value is detected. A third threshold detecting means, and a synthesizer for receiving a detection signal of the third threshold detecting means or a detection signal of two out of two of the one-in-two tester, and outputting any one of the detection signals as a target signal A radar apparatus comprising: 5. A transmission frequency control means for varying a frequency of a transmission signal output from the transmitter, wherein a frequency difference is provided between the adjacent beams. Item 5. The radar device according to any one of Items 4. 6. A transmitter for outputting a transmission signal, an antenna for receiving a reflected wave corresponding to the transmission signal, a receiver for receiving and processing the reflected wave received by the antenna, and a receiver for receiving and processing the reflected wave. A threshold detection means for detecting a reception signal exceeding a threshold value higher than a reference value determined by a false alarm probability for each scan, and a reception signal for each scan detected by the threshold detection means. And a N-in-M tester that performs an N-in-M test process on the received signal for each scan and detects the N-in-M detection signal as a target signal. 7. A transmitter for outputting transmission signals having different pulse widths, an antenna for receiving a reflected wave corresponding to the transmission signal, a receiver for receiving and processing the reflected wave received by the antenna, and the receiver A threshold signal detecting means for detecting a received signal exceeding a threshold value higher than a reference value determined by a false alarm probability, and a pulse width detected by the threshold detecting means. The received signal is input, the N-in-M test process is performed on the received signal for each pulse width, and the N-in-M detection signal that detects the N-in-M detection signal as a target signal.
A radar device comprising a tester. 8. A transmitter that outputs a transmission signal, an antenna that receives a reflected wave corresponding to the transmission signal, a receiver that receives and processes the reflected wave received by the antenna, and a reception processing that is performed by the receiver. Threshold signal detecting means for receiving a received signal which has been input and exceeding a set threshold value, a distance calculating means for calculating a distance to a target by a detection signal of the threshold detecting means, and a distance calculating means for calculating the distance to a target. A pulse width control unit for setting a pulse width of a transmission signal output from the transmitter according to the distance to the target. 9. A detection signal of any one of the threshold detection means, the one-in-two tester, the synthesizer, or the N-in-M tester is input for each scan, and the N out of M detection signals of these scans are input. The radar apparatus according to any one of claims 2 to 4, further comprising an inter-scan verifier that performs a verification process and outputs a detection signal of N out of M as a target signal.