JP2747360B2 - Tracking radar device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Overview] Fast Fourier Transform (FFT: Fast Fourier T
A tracking radar device having a function of radiating radio waves to a target at each pulse repetition frequency (PRF) while detecting a target by removing clutter by a ransform circuit and detecting a target. When calculating the PRF based on the predicted value output from the follower in order to avoid the blind caused by the overlap of the frequency and the PRF, the purpose is to find the optimal PRF by a simple calculation. Different weights are set for the radar range cells in the distance direction and the speed direction for each of them, and a weighting memory in which the weights are stored is provided.In the PRF calculation circuit, the distance prediction value and the speed prediction obtained by the follower are calculated. Weighting is performed using the weight of the weighting memory based on the value, and the PRF having the largest weight is selected and extracted from the plurality of PRFs.

[Industrial applications]

The present invention removes clutter from a received radio wave by an FFT circuit, detects a target, and tracks a target.
The present invention relates to a tracking radar device having a function of emitting a radio wave to a target for each F.

Use radar to detect and track a moving target such as an aircraft, and when radiating radio waves to the target for each PRF, avoid blinds caused by overlapping of the target Doppler frequency and the PRF To calculate the PRF based on the predicted value output from the follower. Therefore, it is necessary to perform such PRF calculation easily and reliably.

[Conventional technology]

FIG. 5 shows a block diagram of an example of the conventional art. In the same figure, after the reflected wave from the target is received by the antenna 11,
Both the distance signal and the angle signal are phase-detected by the receiver 12, and components (clutter) near an integral multiple of the PRF by the FFT circuit 13.
After being removed, distance measurement and angle measurement are performed by the target detection circuit 14, and the target is detected. The follower 15 predicts a distance Rp to the target based on information from the target detection circuit 14.
And the target speed prediction value p is calculated, and the target is tracked.
On the other hand, the PRF is calculated by the PRF calculation circuit 16 as described later,
The transmitter 17 transmits a radio wave based on the PRF from the PRF calculation circuit 16 and radiates it to the space via the antenna 11.

Here, since the so-called blind occurs when the target Doppler frequency overlaps with the vicinity of an integral multiple of the PRF, in order to avoid this, the target Doppler frequency is calculated from the speed prediction value p calculated by the follower 15 in the PRF calculation circuit 16. Calculate,
Based on this, a PRF that does not cause blinds is calculated.

[Problems to be solved by the invention]

In the above-described conventional example, the PRF calculation in the PRF calculation circuit 16 is performed using only the speed prediction value p obtained by the follower 15, so that the optimum PRF cannot be calculated very accurately, and the system design is limited. There was a problem. Further, the PRF calculation circuit 16 performs a complicated calculation using the predicted speed value p, and thus has a problem that a large-scale calculation circuit is required. Therefore, it is conceivable that a more optimal PRF can be obtained by performing the PRF calculation using both the distance prediction value Rp and the speed prediction value p. However, the calculation in the PRF calculation circuit 16 becomes more complicated as it is, and practically Not inconvenient.

The present invention, when calculating the PRF based on the predicted value output from the follower to avoid blind caused by the overlap of the target Doppler frequency and the PRF, it is possible to find the optimal PRF by a simple calculation It is an object of the present invention to provide a tracking radar device that can perform the tracking.

[Means for solving the problem]

FIG. 1 shows a principle diagram of the present invention. The present invention relates to a receiver 12
The clutter is removed from the received signal obtained in the above, the target is detected by the target detecting circuit 14, and the target is predicted by the follower 15 to track the target, while the PRF calculation circuit is used by using the predicted value. The PRF is calculated and taken out at 20, and is applied to a tracking radar device for transmitting a transmission signal based on the PRF from the transmitter 17. In the figure, reference numeral 21 denotes a weighting memory for setting different weights for radar range cells in a distance direction and a speed direction for each of a plurality of different PRFs and storing the same. In the present invention, the PRF operation circuit 2
At 0, weighting is performed using the weight of the weighting memory 21 based on the predicted distance value and the predicted speed value obtained by the follower 15, and the PRF having the largest weight is selected and extracted from a plurality of PRFs.

[Action]

In the present invention, weight data is set for a plurality of PRFs, and weighting is performed using the weight data based on the distance prediction value and the speed prediction value.
Compared to a conventional system that does not use weight data, it can be easily implemented and requires a simple configuration of an arithmetic circuit. Further, since weighting data is set for both the distance direction and the speed direction and weighting is performed based on both the distance prediction value and the speed prediction value, a conventional example in which calculation is performed using only one prediction value is performed. The optimal PRF can be calculated more accurately than.

〔Example〕

FIG. 2 is a block diagram of one embodiment of the present invention, in which the same components as those in FIG. 5 are denoted by the same reference numerals. In FIG. 2, reference numeral 20 denotes a PRF calculation circuit which calculates the PRF using the predicted distance value Rp and the predicted speed value p output from the follower 15. Two
Reference numeral 1 denotes a weighting memory, which stores a distance direction weight and a velocity direction weight for each of a plurality of PRFs as described later. Other configurations are the same as those of the conventional example shown in FIG.

Here, FIG. 3 shows an example of the distance direction weight and the speed direction weight stored in the memory 21. Regarding the distance direction weights, as shown in FIG. 6A, PRF0, PRF1, PRF2,.
Fn has an individual PRF (repetition frequency), and weights “0”, “1”, “2”... Are set for each radar range cell in the direction of the distance R (proportional to time). On the other hand, as for the velocity direction weight, as shown in FIG.
For example, frequencies 0 to PRF are assigned weights “0”, “2”, “4”, “6”.
Assigned as "8", "6", "4", "2", "0", as a result, for example, PRF1 to PRF3 have "0", "2" for each radar range cell in the speed (proportional to frequency) direction. "4"
Weights “6”, “8”, “6”,... Are set.

Now, it is assumed that the target is detected and the follower 15 outputs a predicted distance value Rp as shown in FIG. 4 (A) and a predicted speed value p as shown in FIG. 4 (B). Since the weights as shown in FIG. 3 are stored in the weighting memory 21, in the PRF operation circuit 20, as shown in FIG.
Is weighted with “6” and PRF3 is weighted with “2”, while as for the velocity direction, as shown in FIG. 3B, PRF1 is weighted with “8”, PRF2 is weighted with “4”, and PRF3 is weighted with “2”. Done. On the basis of such weighting, PRF calculation of PRF1 ... 4 + 8 = 12 PRF2 ... 6 + 4 = 10 PRF3 ... 2 + 2 = 4 is performed.
RF1 is selected. Similarly, if the distance prediction value is Rp 'and the speed prediction value p', PRF2 is selected by the calculation of PRF1 ... 1 + 4 = 5 PRF2 ... 3 + 6 = 9 PRF3 ... 1 + 4 = 5.

When two PRFs having the maximum value are obtained as a result of the PRF calculation, depending on the application of the radar, for example, one of the two weights in the distance direction is selected, or the weight in the speed direction is selected. What is necessary is just to select the larger one.

The PRF calculated and selected in this way is
, And a radio wave based on the PRF is transmitted and radiated into space via the antenna 11. In this case, since the PRF calculation is performed by performing weighting based on the predicted value, the calculation can be easily realized as compared with the case where the PRF calculation is performed based only on the predicted value, and the distance predicted value Rp and Since the PRF calculation is performed using both the speed prediction value p, the optimum PRF can be calculated more accurately than a system that performs the PRF calculation using only the speed prediction value p. Further, by setting the weighting method according to the application of the radar to be used, the optimum PRF can be obtained for various different systems.

In some cases, only the distance prediction value (or only the speed prediction value) may be used depending on the use of the radar. In this case, the distance prediction value Rp (or the speed prediction value p) obtained by the follower 15 is used. What is necessary is just to select a PRF by weighting. For example, in a system in which only the distance prediction value needs to be used, in the example shown in FIG.
In a system in which F2 is selected and only the speed prediction value needs to be used, in the example shown in FIG.
Is selected.

〔The invention's effect〕

As described above, according to the present invention, since the PRF calculation is performed by performing weighting based on the predicted value, the calculation can be easily performed as compared with the case where the PRF calculation is performed based only on the predicted value. , It requires only an arithmetic circuit with a simple configuration,
Also, since the PRF calculation is performed using both the distance prediction value and the speed prediction value, the optimal PRF calculation is more accurately performed than a system that performs the PRF calculation using only the speed prediction value.
Can be calculated.

[Brief description of the drawings]

FIG. 1 is a principle diagram of the present invention, FIG. 2 is a block diagram of one embodiment of the present invention, FIG. 3 is a diagram for explaining weights in a distance direction and a speed direction in the present invention, and FIG. FIG. 5 is a block diagram illustrating an example of a conventional technique. In the figure, 11 is an antenna, 12 is a receiver, 13 is an FFT circuit, 14 is a target detection circuit, 15 is a follower, 17 is a transmitter, 20 is a PRF calculation circuit, and 21 is a weighting memory.

Claims (3)

(57) [Claims] 1. A target detection circuit (14) for detecting a target by removing clutter from a reception signal obtained by a receiver (12) and obtaining a predicted value of the target by a follower (15). While tracking the target, the pulse repetition frequency (PRF) calculation circuit (20) calculates and extracts the optimum PRF using the predicted value, and transmits a transmission signal based on the PRF from the transmitter (17). In the tracking radar device, different weights are set for the radar range cells in the distance direction for each of a plurality of different PRFs, and a weighting memory (21) storing the different weights is provided. In the PRF calculation circuit (20), Weighting is performed using the weight of the weighting memory (21) based on the distance prediction value (Rp) obtained by the follower (15), and
A tracking radar device, wherein a PRF having the largest weight is selected and extracted from the PRF. 2. A target detection circuit (14) for detecting a target by removing clutter from a received signal obtained by a receiver (12) and obtaining a predicted value of the target by a follower (15). While tracking the target, a PRF calculation circuit (20) calculates and extracts a PRF using the predicted value, and transmits a transmission signal based on the PRF from a transmitter (17). For each of the different PRFs, a different weight is set for the radar range cell in the velocity direction and a weighting memory (21) storing the different weights is provided. In the PRF calculation circuit (20), the follower (15) Weighting is performed using the weight of the weighting memory (21) based on the speed prediction value (p) obtained in step (1), and the PRF having the largest weight is selected and taken out from the plurality of PRFs. Tracking radar device. 3. A target detection circuit (14) for detecting a target by removing clutter from a reception signal obtained by a receiver (12), and obtaining a predicted value of the target by a follower (15). While tracking the target, a PRF calculation circuit (20) calculates and extracts a PRF using the predicted value, and transmits a transmission signal based on the PRF from a transmitter (17). For each of the different PRFs, a different weight is set for each radar range cell in the distance direction and the velocity direction, and a weighting memory (21) storing the different weights is provided. In the PRF calculation circuit (20), Distance predicted value (Rp) and speed predicted value (p) obtained by the follower (15)
A tracking radar device for performing weighting using the weight of the weighting memory (21) based on the PRF, and selecting and extracting the PRF having the largest weight from the plurality of PRFs.