JP2844643B2 - Target tracking method - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a target tracking method using a primary search radar for a surface-to-surface target and an air-to-air target, and more particularly to a target tracking method for improving a target correlation method.

[Prior Art] Conventionally, target tracking by a primary search radar has been a position correlation method based on a predicted target position and a position (direction, distance) of a target (proto) detected by signal processing. That is, based on the position update by the α-β tracker, a tracking gate centered on the predicted target position of the next scan is created, and the position correlation of whether the position of the target (plot) detected by the signal processing is within the gate is performed. doing. Further, when a plurality of targets exist in the tracking gate (multi-correlation), the target closest to the predicted position is set as the correlation target.

[Problem to be Solved] The above-described conventional correlation method for target tracking by the primary search radar is performed only by position correlation in the case of multi-correlation, in particular, even if the target target exists in the tracking gate, the target target position can be determined. There is a problem in that a false correlation occurs between a near pseudo target and an erroneous target, and when the target starts turning or exercises with a large change in acceleration, tracking becomes impossible.

The present invention has been made in view of the above-described problems, and has as its object to provide a target tracking method capable of eliminating a cross-correlation between a pseudo target and an erroneous target and reducing the cause of a failure in tracking.

[Means for Solving the Problems] In order to achieve the above object, a target tracking method of the present invention comprises:
Utilizing that the received power of the primary search radar is proportional to the target effective reflection area as shown in the following radar equation, the target correlation algorithm performs amplitude correlation in addition to position correlation.

Pr = {Pt · Gt · Ar / (4π) 2 · R 4} · σ where, Pr: the reflected wave received power Pt: Radar transmission output Gt: transmitting antenna gain Ar: receive antenna effective area R: Distance sigma: target Is the effective reflection area of

That is, in the target tracking method according to the present invention, the amplitude information is extracted at the same time as the target detection of the signal processing, the amplitude data is edited and sent to the tracking unit as the target information, and the amplitude after the position correlation is performed in the target tracking correlation. It has the function of performing value correlation and determining the final correlation target.

In order to extract the amplitude information, the LOG video signal output from a logarithmic (LOG) amplifier for the radar video is gated and picked up at the timing of the leading edge of the target detection by the sliding window method to obtain the amplitude information.

The amplitude information is edited together with the position information (azimuth and distance) obtained by the target detection and transmitted to the tracking unit.

For tracking, a tracking gate is opened centered on the predicted target position, position correlation is performed based on whether or not a detected target exists in the gate, and for the target with correlation, the amplitude data of the system target and the target amplitude data are compared. And
If the difference is within a predetermined value, the correlation is determined. If the difference is equal to or more than the predetermined value, the correlation is not determined even if the position correlation is obtained.

When the correlation is determined, the amplitude data of the system target is replaced and updated with the amplitude data of the target. In this case, the update is performed only when the continuous n-scan amplitude data increases and decreases in the same direction.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of one embodiment of the present invention, and FIG. 2 is an explanatory view showing the operation. Primary radar video 100 is L
It enters the OG amplifier 10 and outputs a LOG video signal 101. LOG
The video signal 101 is digitized by the AD converter 11, and the radar video signal converted into the CFAR by the constant alarm rate (CFAR) circuit 12 is sent to the target detection system and the amplitude data extraction circuit 20.

As the target detection system, the average value is calculated by the average value detection circuit 13, the threshold value is set by the threshold circuit 15, and the presence or absence of a hit is detected by the hit detection circuit 14. For the hits for each sweep, the target position (azimuth and distance) is detected by the target detection circuit 16 by a sliding window method, and is sent to the target information editing circuit 30 as target position data 110.

On the other hand, CFAR output,
With the LOG video data as input, the amplitude data of the target is recorded by the hit detection gate signal 102 of the target detection system and the leading edge detection gate signal 103 of the sliding window detection, and sent to the target information editing circuit 30 as target amplitude data 110. .

The detection target information 112 having position (azimuth, distance) information and amplitude information is input to a correlation system of a tracking algorithm. That is, the position is first input to the position correlation unit 40, and the position correlation is performed with the predicted position of the system target prediction information via the tracking gate. The target having the correlation is sent to the amplitude correlation unit 41, where the amplitude correlation is performed.

Then, a target having a correlation in both the position correlation and the amplitude correlation is determined as a target to be correlated, and the target updating unit 50 updates the position and the amplitude data by the α-β tracker. Update of amplitude data is continuous n
The logic is updated only when the increase / decrease of the scan amplitude data is in the same direction.

Further, the updated target is sent to the target predicting unit 51 to determine the target detection predicted position of the next scan, and the system target prediction information 113 is output, and is prepared for the correlation of the next scan.

For tracking water target by water radar target is military vessels, to tankers from fishing boats, the reflection cross-sectional area σ of a target there is a difference from 10 m ² to about 10,000 m ^2, the radar equation received power as described above Is proportional to the reflection cross section σ, and a difference of 20 to 30 dB is generated. Therefore, the correlation based on the amplitude data is effective.

In the case of a target turning, in the case of a multi-correlation state in which a plurality of targets are present in the tracking gate when the acceleration change is large, the target closest to the predicted target position is often not necessarily the target target. Adding correlation with amplitude data to position correlation as an algorithm improves tracking.

That is, as shown in FIG. 2 showing the relationship between the position correlation and the correlation based on the amplitude data when the multi-correlation of the tracking process exists, the target of the target B (track to be tracked) and the target A (current Tracking track). In the case of only the position correlation, the correlation is determined as the position of the nth scan of the target B (miscorrelation). Considering amplitude correlation,
The correlation is determined as the position of the nth scan of the target A (positive correlation). In FIG. 2, n, n-1, and n-2 indicate the positions of targets A and B for each scan. Also, n, n-1, n-2
The parentheses after () indicate amplitude data, and Y indicates the predicted position of the target A in the (n + 1) -th scan.

[Effects of the Invention] As described above, the present invention employs a method of performing not only the correlation of the position of the correlation algorithm but also the correlation based on the amplitude data in the target tracking of the primary search radar, thereby reducing the pseudo target and the erroneous target. This has the effect of eliminating the cross-correlation, reducing the factors that make tracking impossible, and improving tracking.

[Brief description of the drawings]

FIG. 1 is a block diagram of an embodiment of the present invention, and FIG. 2 is a conceptual diagram showing a relationship between a position correlation and a correlation based on amplitude data when there is a multi-correlation in tracking processing. 10: LOG amplifier 11: A / D converter 12: CFAR circuit 13: Average value detection circuit 14: Hit detection circuit 15: Threshold control circuit 16: Target detection circuit 20: Amplitude data extraction circuit 30: Target information editing circuit 40: Position Correlation unit 41: Amplitude correlation unit 50: Target update unit 51: Target prediction unit 100: Primary radar video 101: LOG video signal 102: Hit detection gate signal 103: Leading edge detection gate signal 110: Target amplitude data 111: Target position Data 112: Detection target information 113: System target prediction information

Claims (1)

(57) [Claims] In a target tracking method using a primary search radar sensor, a LOG for inputting a primary radar video and outputting a LOG video signal is provided.
An amplifier, a LOG video signal that is digitized and input, a constant alarm rate circuit that outputs a constant alarm rate converted radar video signal, and detects target position information based on the radar video signal, as target position data. A target detection circuit to be output, input the LOG video signal and the constant alarm rate,
An amplitude data extraction circuit that obtains amplitude data at the timing of the leading wedge of the target position detection, and inputs target position information from the target detection circuit and amplitude data from the amplitude data extraction circuit, and calculates a target predicted position and a tracking gate. The position correlation is performed through the system, the amplitude data of the system target is compared with the amplitude data of the target with respect to the correlated target, and if the difference is within a predetermined value, the correlation is determined. If the correlation is established, the tracking unit replaces the amplitude data of the system target with the amplitude data of the target target. Characteristic target tracking method.