JPS58113776A - Signal processor of search radar - Google Patents

Abstract

PURPOSE:To output exactly target information from a signal processor at all times, by controlling turn-on and turn-off of a bearing correcting circuit in accordance with a switching instruction of moving target indicating video and normal video, and an integral on and off insturction. CONSTITUTION:Radar video passes through a hardware part of a quantitizing circuit 3a of a signal processing circuit 3, a sweep correlating circuit 3b, a bearing correcting circuit 32, etc., and is applied to a scan correlating circuit 3c of a software part. As for this circuit 32, its turn-on and turn-off are controlled by a controlling circuit 31 to which a switching instruction M of moving target indication (MTI) and NORMAL which executes no MTI indication, and a switching signal as to whether integral processing to increase the signal amplitude is executed or not are applied. As a result, in an MTT-processed area (m) including a clutter area (c) of a short distance an integral processing is not executed, a bearing is not corrected, the correction is executed in a NORMAL area (n), and in a long-distance, the bearing is corrected by whether the integration is executed or not, and bearing information of a target generating no delayed error caused by the integral processing is outputted at all times.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a signal processing device for a searcher.

In general, in search radars and the like, the radar receiver is equipped with a video integration function for the purpose of target detection ability, radar interference wave removal, and the like. In recent years, in addition to visual monitoring, IT
Automatic target detection and tracking processing using computers, etc. is popular, and it can be said that the future is toward full automation, but automatic detection and tracking is not possible because the center value of the target direction may shift due to processing delays due to the integration effect when it comes to video that has undergone integral processing. It was not used as a video.

1i is an example of a radar device equipped with a conventional video integration function.
Shown in Figure 81.

In the figure, (1) is the antenna, (2) is M T I
(Moving1'arget Irxiicator
; (3) is a signal processing device with automatic target detection and tracking functions; A child conversion circuit (3m), a sweep correlation circuit (3b) that performs sweep phase open processing on the output of this child conversion circuit (31m), and a sweep correlation circuit (3b) that performs sweep phase open processing on the output of this child conversion circuit (31m).
It is comprised of a scan correlation circuit (3C) that performs scan correlation processing on the output of (b) and outputs target position information. Also, (4) is an instruction device, which is a receiving device (
2) MT that instructs to turn on/off the MTI function.
It provides an I/NORMAL switching command M and an integral on/off command I.

Although the operation of the radar is well known and does not require explanation, the output signal of the receiving device and the signal processing device will be explained in detail as they relate to the present invention.

The output signal V of the receiver [(2) is generally an MTI-processed video (hereinafter referred to as MTI
video) and video that is not subjected to MTI processing (hereinafter referred to as normal video) are switched and output depending on the clutter situation.

To speed up your understanding, PPI (PlanP) shown in Figure 2
ositicm Indicator) Replace it on the scope and show the situation. In the figure, C is the clutter region, m is the MTI suppression area that is intense in this region C, and D is delayed by the repetition period T of this MTI signal pulse, multiplied by the feedback coefficient gk, and returned to obtain the output OUT as the sum of the two. Feedback integration is often used, and MT
Integration is not applied to I video, but only to normal video.

Here, talking about video integration, when the target integral input TI shown in Figure 4 is input corresponding to the antenna pattern, the signal amplitude increases due to the integral effect, but due to the response characteristics of the integral, the target integral output A side effect is that an azimuth deviation of 12 peak values occurs.

Using a video signal with such characteristics, a signal processing device performs quantization, sweep correlation processing, and scan correlation processing to automatically detect and track a target.
Generally, quantization, sweep correlation processing, and correction are performed in hardware, while scan correlation processing is performed in software. Here, it is a common practice to receive and pass information such as the distance and direction of one square signal at the connection part between the hardware and the software.

Now, assuming that MTI video and normal video are switched depending on the clutter situation and integration is applied to normal video, there is a shift S in the azimuth center value due to the processing delay of the integration effect for normal video region n. Therefore, the orientation information will not match between the MTI video processing and the normal video processing, which is disadvantageous.

In addition, target detection and tracking by the radar equipment also uses the secondary radar reception signal and takes cross-correlation with the -order radar, so the central azimuth value is due to the processing delay of the integral effect on the primary radar side. The deviation is also inconvenient from the viewpoint of target detection and tracking, and azimuth deviation occurs due to integration on/off.
It is inconvenient for history that nothing happens.

Since the conventional search radar signal processing device is configured as described above, it has the disadvantage that the integrated input video signal is also processed as is, and accurate direction detection cannot be performed due to deviation of the direction center value. Ta.

This invention was made to eliminate the drawbacks of the conventional ones as described above, and when transferring target position information from the signal processing device's software to the software, By correcting the deviation amount of the azimuth center 4dl and not making the correction for targets in areas that are not integrated, the signal can be processed even if there is a deviation in the azimuth center value due to integration in the video to be processed. It is an object of the present invention to provide a signal processing device for a search radar in which a correct value can be obtained as target azimuth information outputted from the processing device, and an integrally processed video can also be used as an automatically detected and tracked video.

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 5 shows a signal processing device for a search radar according to an embodiment of the present invention, and in the figure, the antenna (1j, receiving device 1121, and indicating device (4) in FIG. 1 are omitted).

In the morning, the MTI/NORMAL switching command M and the integral on/off command I are input, and when video integration is turned on in the normal video area, a control circuit that issues a correction command, @ is a signal from this control circuit Cl1l. This is a correction circuit that performs direction correction on the output of the sweep correlation circuit (3b) according to a correction command. Further, the other component circuits (31) (3C) of the signal processing device Wt (31) operate exactly the same as the conventional ones.

Next, the operation will be explained.

The control circuit (9) receives M T I / from the indicating device (4).
In response to the NORMAL switching command M and the integral on/off command I4, a control signal for determining whether or not to correct the azimuth center value shift cover by integrating the target azimuth information, that is, a correction on/off signal is generated and output. This correction on/off signal is a signal that turns off the entire area when integration is off, and turns off correction in the MTI video area and turns correction on in the normal video area when integration is on. Therefore, to explain using Fig. 2, the clutter area C at a short distance does not require azimuth correction because it is an area where integration is off because it has been subjected to MTI processing, and the clutter area C at a long distance is a normal video area n. , when integration is on, azimuth correction is on, and when integration is off, azimuth correction is off.

Through such an operation, the target azimuth information transferred to the scan correlation circuit (3C) is correct even if there is a deviation in the azimuth center value due to integration in the video signal. will be obtained.

Since the direction of the cross-correlation between the -order radar signal and the secondary radar signal is also corrected in the integral range, the conventional melting point can be eliminated.

As described above, according to the present invention, it is possible to automatically switch the azimuth center value deviation amount due to video integration in the search radar between the video integration application area and the non-use area to turn the correction on/off. This has the advantage that automatic target detection and tracking can be performed normally even when video/integration is on.

[Brief explanation of drawings]

Figure M1 is a block diagram showing an example of a conventional search radar, Figure 2 is a diagram showing the PPI display screen of the device in Figure 1, Figure 3 is an equivalent circuit diagram showing video integration operation, and Figure 4 is a diagram showing video integration. FIG. 5 is a diagram showing a signal processing device for a search radar according to an embodiment of the present invention. (3)...Signal processing device, (3b)...Swive correlation circuit, (3C)...Scan correlation circuit, Inc.
・Control circuit, country...correction circuit. Note that the same reference numerals in the figures indicate the same or equivalent parts. Agent Shin Kuzuno - Figure 1 Figure 2 Figure 3 Figure 5 Figure 3

Claims (1)

[Claims] 1) a sweep correlation circuit that performs sweep correlation processing on a video input of moving target indication (hereinafter referred to as M''I'l) processed MTI video or normal video that has not been processed with MTI; A correction circuit that performs azimuth correction for correcting the deviation of the azimuth center value due to video integration in response to a correction command on the output; a scan correlation circuit that performs scan correlation processing on the output of this correction circuit; A signal processing device for a search radar, comprising: a control circuit which receives a normal video switching command and a video integration on/off command and applies the correction command to the correction circuit in a normal video recording area.