JPS63132187A - Device for indicating mobile target - Google Patents

Abstract

PURPOSE:To reduce clutters which are left unerased and to facilitate the discrimination of a mobile body by setting a proper feedback coefficient for plural areas formed by frictionizing the distance and azimuth of a radar detection range according to the clutter state. CONSTITUTION:A data input circuit 1 outputs an azimuth setting signal 11 indicating the azimuths of plural areas and a range setting signal 10 indicating the distances, and a feedback coefficient setting signal 12 wherein response characteristic coefficients corresponding to the areas are set is outputted at the same time. Further, when an azimuth signal consisting of a reference azimuth signal 6 and an incremental pulse 7 is inputted to a range azimuth gate generator 2, an azimuth angle is discriminated and when a distance signal consisting of a zero-range trigger 8 and a range clock 9 is inputted, the distance from a reference point is decided. Then a range azimuth gate signal 13 generated with those azimuth signal and distance signal is outputted by the generator 13, and this and the setting signal 12 are used to obtain a feedback control signal 14, which is sent to an MTI erasing circuit 4.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application) The present invention is directed to the MT I (Maring Tar) of radar.
getIndicator) The present invention relates to a cancellation circuit, and particularly relates to a moving target indicating device that effectively displays a moving target while suppressing radar clutter in each region.

(Prior Art) Conventionally, the MTI cancellation circuit of this type of radar sets several types of feedback coefficients in advance, and calculates the degree of clutter-1 of a fixed target signal in the field, that is, the degree of clutter remaining in the field by PPI (Plan Po5i-). tion
(Indication) The circuit was designed to observe on the device and select only the feedback coefficients that are least likely to remain undisappeared.

(Problems to be Solved by the Invention) The conventional MTI cancellation circuit described above is a circuit that selects only the feedback coefficient of one type of cancellation in the radar detection range.
A moving target is detected while suppressing reflected waves from a fixed target, and there is a drawback in that the only ability to detect this moving target is with a certain detection sensitivity.

By the way, even if the target is a fixed target, the detection status will fluctuate due to frequency fluctuations such as radar staro or coho signals, antenna scanning, and the influence of the wind on the fixed target itself. It is generally well known that it can be detected equivalently.

Therefore, conventional MT! Since the erasing circuit has only a fixed speed response characteristic, it has the disadvantage that some clutter can be sufficiently suppressed and some may remain, depending on the clutter within the radar detection range. Further, if the above-mentioned response characteristic is set to a lower value, almost all clutter can be eliminated, but on the other hand, there is a contradictory problem in that the identifiability of the moving target is reduced.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a moving target indicating device that effectively eliminates clutter without reducing the detection accuracy of a moving target.

(Means for Solving the Problems) In order to solve the above-mentioned problems and achieve the above objects, the present invention provides means to eliminate reflected waves from a fixed target based on the MT signal of the MTI cancellation circuit. Along with erasing oppression,
A reflected wave from a moving target existing within the monitoring area is input to a detection unit to detect the moving target according to the deviation of the Doppler frequency, and the detection is performed using a monitoring signal consisting of an azimuth signal and a distance signal from a reference point. a moving target indicating device for instructing and displaying the position of a moving target on a display unit, comprising area specifying means for dividing the monitoring area into a plurality of areas, specifying each of the divided areas and outputting an area specifying signal; response designating means for designating a detection sensitivity value of the detection unit to a value corresponding to each of the regions and outputting a response designation signal; and adding the region designation signal to the monitoring signal to output a range azimuth gate signal. A range azimuth gate generator, and a feedback control circuit that outputs a feedback control signal for assigning the detection sensitivity value to each region based on the range azimuth gate signal and the response designation signal. , the MT canceling circuit outputs the feedback control signal by adding it to the MTI signal, and suppresses and cancels reflected waves from the fixed target according to a detection sensitivity value set for each region. It is characterized by

(Example) Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram showing one embodiment of the present invention.

Reference numeral 1 denotes a data input circuit, which incorporates an area specifying means and a response specifying means. The area setting and response designation by the data input circuit 1, that is, the assignment of the feedback coefficient to the MTI erasure time #t4 are performed by the range setting signal 10. It is set by the azimuth setting signal 11 and the feedback coefficient setting signal 12. Selection of the clutter region is performed by the range azimuth gate signal 13 from the range azimuth gate generator 2. This range azimuth gate generator 2 receives an azimuth angle reference signal (
Azinth Reference Pulse:A
P R) 6 and incremental pulse signal (Azi
Nuth Char+ge Pu-! se:ACP>
When a direction signal consisting of 7 and a distance signal consisting of a zero range trigger 8 and a range clock 9 are input, an area designation signal consisting of a range setting signal 10 and an azimuth setting signal 11 is added corresponding to the above-mentioned direction signal and distance signal. Then, a range azimuth gate signal 13 is output. This range azimuth gate signal 13 is the range setting signal 10 of the data input circuit 1.
and a gate signal according to the azimuth setting signal 11,
The signal is sent to the feedback control circuit 3. The feedback control circuit 3 receives a response designation signal sent from the data input circuit 1, that is, a feedback coefficient setting signal 1, for the region selected by the range azimuth gate signal 13.
2, a feedback coefficient is given to each region and output as a feedback control signal 14 to the MTI erasure circuit 4. MT! The erasing circuit 4 selects the coefficient value specified by the feedback control signal 14 from among several types of feedback coefficients selected in advance, which corresponds to the selected area.

FIG. 2 is an example showing the velocity response when the clutter spectrum distribution and feedback coefficient are changed. FIG. 2(a) is a characteristic diagram showing an example of the standard setting velocity response 14b of the MT eraser circuit 4, and FIG. 3(b) is a characteristic diagram showing a low speed target for the characteristics of FIG. 3(a). A characteristic diagram showing a velocity response 15b that suppresses the response of an object and increases loss of a high-velocity target;
FIG. 3(C) is a characteristic diagram showing a velocity response 16b that speeds up the response of low-velocity targets and reduces loss of high-velocity targets with respect to the characteristics of FIG. 3(a). FIG. 3 is a response area setting diagram in which the velocity response value is set for each area.

The present invention will be described in detail with reference to FIGS. 2 and 3.

In the data input circuit 1, as shown in FIG.
A range setting signal 10 indicating distance is output. Further, the data input circuit 1 outputs a feedback coefficient setting signal 12 by specifying coefficients indicating characteristics of the response corresponding to the above-mentioned regions a, b, and c. To explain specifically,
A response characteristic 14b is specified for area a, a response characteristic 15b is specified for area S, and a response characteristic 16b is specified for area C. When the range azimuth gate generator 2 receives an azimuth signal consisting of an azimuth reference signal 6 and an incremental pulse 7, the range azimuth gate generator 2 uses the azimuth reference signal 6 to generate the number of incremental pulses 7 output for each predetermined azimuth angle, with the north azimuth as a reference. The azimuth from the north is determined according to the direction. The range azimuth gate generator 2 also includes a zero range trigger 8 and a range clock 9.
When a distance signal consisting of is input, the distance from the reference point is determined. The position of the moving target existing within the monitoring area shown in FIG. 3 is indicated on a display section (not shown) using the monitoring signal consisting of the azimuth signal and the distance signal. The range azimuth gate generator 2 also receives a region designation signal, that is, a range setting signal 1.
0 and the azimuth setting signal 11 are input, the azimuth angle and distance of each of the designated areas a, b, and c are determined, and these areas a, b.

The range azimuth gate signal 13 is output by adding the azimuth signal and distance signal corresponding to C to the above-mentioned monitoring signal. The feedback control circuit 3 receives the range azimuth gate signal 1
3 and a feedback coefficient setting signal 12, a feedback control signal 14 is outputted to select the above-mentioned specified response characteristic, that is, the detection attitude value for each of the regions a, b, and c. The MTI erasure circuit 4 adds the feedback control signal 14 to the MTI signal 5b and outputs it. As a result, the reflected waves from the fixed target are suppressed and eliminated according to the coefficients set for each region, that is, the response characteristics, and the moving targets are detected using the response characteristics set for each region. To be more specific, in the region a shown in FIG. 3, the moving target is detected using the response characteristic 14b shown in FIG. In the region, a moving target is detected using the response characteristic 15b in FIG.
Suppress and erase. Similarly, in region C, a moving target is detected using the response characteristic 16b in FIG. 2(C), and clutter 16a is suppressed and eliminated using the same response characteristic.

(Effects of the Invention) As explained above, according to the present invention, appropriate feedback coefficients are set for a plurality of regions in which distance and direction are each subdivided, depending on the clutter situation within the radar detection range. This makes it possible to suppress clutter in accordance with the radar installation field, sufficiently reduce the amount of clutter left behind in radar PPI control, and facilitate the identification of moving objects on the clutter.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing the configuration of an embodiment of the present invention, and Fig. 2 is an example of the relationship between the clutter spectrum and velocity response when the feedback coefficient of the MTI canceler (double canceler with feedback) is changed. FIG. 3 is a diagram showing an example of a display screen of a PPI device to which the present invention is applied. DESCRIPTION OF SYMBOLS 1...Data input circuit, 2...Range azimuth gate generator, 3...Feedback control circuit, 4...
MTl erasure circuit, 5... coherent input signal, 6.
... Direction reference signal, 7... Incremental pulse,
8...Zero range trigger, 9...Range clock,
10... Range setting signal, 11... Azimuth setting signal, 12... Feedback coefficient setting signal, 13...
・Range azimuth gate signal.

Claims (1)

[Claims] Based on the MTI signal of the MTI cancellation circuit, the reflected waves from the fixed target are suppressed and canceled, and the reflected waves from the moving targets within the monitoring area are input to the detection section to detect the deviation of the Doppler frequency. The moving target indicating device detects the moving target according to a reference point, and instructs and displays the position of the detected moving target on a display unit using a monitoring signal consisting of an azimuth signal and a distance signal from a reference point, an area specifying means for dividing into areas and outputting an area specifying signal by specifying each divided area; and specifying a detection sensitivity value of the detection section to a value corresponding to each area and outputting a response specifying signal. a range azimuth gate generator that adds the area designation signal to the monitoring signal and outputs a range azimuth gate signal; a feedback control circuit that outputs a feedback control signal for assigning a value to each region, and the MTI elimination circuit adds the feedback control signal to the MTI signal and outputs it, A moving target indicating device that suppresses and eliminates reflected waves from the area according to a detection sensitivity value set for each region.