JP2015169506A - Target tracking radar device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve problems with a case of implementing target tracking using a phased array antenna that tracking of a transverse target tends to fail since beams are radiated in a time division fashion and an increase in the number of times of radiation causes a reduction in search speed and a delay in the search of a new target.SOLUTION: A beam distributor 8 increases the number of times of radiation of tracking beams only for a target determined to be a transverse target by a transverse target determination unit 7 on the basis of a target Doppler frequency calculated by a target frequency calculation unit 6, thereby reducing tracking observation intervals and improving the followability of tracking. Furthermore, if the transverse target determination unit 7 determines that a target deviates from a transverse target state, the beam distributor 8 decreases the number of times of radiation of tracking beams to mitigate search speed reduction.

Description

  The present invention relates to a target tracking radar apparatus that tracks a target.

In a conventional radar apparatus, a time interval when a target is repeatedly irradiated with a target is shortened for a target whose position estimation error or prediction error is enlarged or a target determined as an emergency target based on the approach speed. Beam control is performed (for example, refer to Patent Documents 1 and 2).
In the conventional radar apparatus, the tracking of the target tracking is ensured by reducing the beam scanning for the purpose of searching and increasing the ratio of the beam scanning of all tracking targets.

JP-A 61-86671 Japanese Patent Laid-Open No. 2000-2760

In a radar device that simultaneously tracks and searches for a target using a phased array antenna, an estimation error / prediction error is required to improve target tracking in response to individual tracking states of multiple targets to be tracked. Beam control that distributes the number of observations to a target with a large or a target with a high approach speed is required.
However, conventionally, there has been no disclosure of specific measures for improving the followability with respect to a traversing target that moves in the lateral direction in which tracking is most easily canceled.

For a traversing target whose target cannot be detected by the pulse Doppler radar, the target is lost and tracking is canceled by irradiating the beam until the target can be detected. In the conventional multi-target tracking by the radar device of the phased array antenna, since the beam is irradiated in time division, there is a problem that the beam irradiation interval is extended and the traversing target is easily lost.
In addition, in conventional beam control, it has been practiced to increase the priority and shorten the beam irradiation interval for targets with high threats and high threats, and targets with large prediction errors. For easy traversing targets, raising the priority of beam irradiation has not been realized, and there has been a problem that tracking is easily canceled.

  On the other hand, if the number of times of beam irradiation with respect to the tracking target is increased in order to improve the tracking followability, there is a problem that the search speed within the scanning range decreases and the detection of the new target becomes slow.

  The present invention has been made to solve such a problem, and determines whether or not the target is in a traversing state from the target Doppler frequency, and performs beam irradiation with respect to the traversing target preferentially. It is an object of the present invention to provide a target tracking radar device that can improve tracking of a target.

  A target tracking radar apparatus according to the present invention includes a transmitter, a phased array antenna that radiates a signal from the transmitter to an external space, and a receiver that detects a reception signal received by the phased array antenna. A signal processing unit that detects a target signal that is a reflected signal at a target from the received signal, a frequency calculation unit that calculates a Doppler frequency of the target signal, and the target based on the Doppler frequency, A traversing target determiner that determines whether or not the traversing state moves laterally with respect to a straight line connecting the phased array antenna, and a beam distributor that controls the beam pointing of the phased array antenna And when the target is in the traversing state according to the judgment of the traversing target determiner, the beam distributor A control command to increase the number of directing the beam to a certain target, and outputs to the phased-array antenna

  According to the target tracking radar apparatus according to the present invention, by determining the traversing target based on the target Doppler frequency, the tracking of the traversing target can be canceled by increasing the number of beam pointing with respect to the traversing target. There is an inhibitory effect. Further, when the traversing target state is escaped, there is an effect of reducing the search speed by decreasing the number of beam pointing with respect to the target.

It is a figure explaining the structure of the target tracking radar apparatus which concerns on Embodiment 1 of this invention. It is a figure explaining a beam control system in case there are a plurality of targets in the target tracking radar device concerning Embodiment 1 of this invention. It is a figure explaining a beam control system in case there are a plurality of targets in the target tracking radar device concerning Embodiment 1 of this invention. It is a figure explaining the beam control system in case there exists a transverse target in the target tracking radar apparatus which concerns on Embodiment 1 of this invention. It is a figure explaining the beam control system in case there exists a transverse target in the target tracking radar apparatus which concerns on Embodiment 1 of this invention. It is a figure explaining the beam control system when a transverse target is canceled in the target tracking radar apparatus concerning Embodiment 1 of this invention. It is a figure explaining the beam control system when a transverse target is canceled in the target tracking radar apparatus concerning Embodiment 1 of this invention. It is a figure for demonstrating the target tracking radar apparatus which concerns on Embodiment 2 of this invention.

Embodiment 1 FIG.
Hereinafter, the target tracking radar apparatus according to Embodiment 1 of the present invention will be described with reference to the drawings.
FIG. 1 is a diagram showing a configuration of target tracking radar apparatus 100 according to the first embodiment. The target tracking radar apparatus 100 includes a phased array antenna 1 (referred to as “phased array antenna 1”), a transmitter 2, a receiver 3, a signal processing unit 4, a data processing unit 5, and a beam distributor 8. The data processing unit 5 includes a target frequency calculator 6 and a traversing target determiner 7.
The phased array antenna 1 is an antenna capable of directing a beam in an arbitrary direction instantaneously by beam scanning control.
In FIG. 1, the high-frequency pulse signal generated by the transmitter 2 is radiated to the external space via the phased array antenna 1. In response to a beam scanning control command from the beam distributor 8, the phased array antenna 1 scans the entire scanning region with a pencil beam having a beam width θ and performs target tracking by performing beam scanning on the registered target. Unlike the mechanically driven antenna, the phased array antenna 1 can perform random beam scanning.
When the reflected signal from the target is received by the phased array antenna 1, the received signal is input to the receiver 3. The received signal detected by the receiver 3 is sent to the signal processing unit 4 where the signal processing unit 4 detects the target signal.
Inside the data processing unit 5, it is determined whether or not the detected target is a traversing target. The target frequency calculation unit 6 of the data processing unit 5 calculates the frequency of the detected target signal. The traversing target determination unit 7 determines whether the target corresponds to the traversing state by comparing the calculated target Doppler frequency of the target signal with the frequency of the ground serving as the background of the target.
When the traversing target determination unit 7 determines that the traversing state is present, the beam distributor 8 that has received the determination result instructs the phased array antenna 1 to perform a beam scanning control command 90 so as to increase the number of beam directing operations with respect to the traversing target. Is sent out.

2-7 is a figure explaining the beam control method of the target tracking radar apparatus 100 which concerns on this Embodiment.
2 and 3 are diagrams for explaining a beam control method in the case where all of a plurality of targets initially move in the direction of the own machine 12. 4 and 5 are diagrams for explaining a beam control method in the case where one of a plurality of targets is a traversing target that moves laterally with respect to the direction toward the aircraft 12. FIGS. 6 and 7 are diagrams for explaining a beam control method in the case where the traversing target is eliminated and all of the plural targets are straight ahead targets that move in the direction of the aircraft 12.

In FIG. 2, the target tracking radar device 100 mounted on the own device 12 scans the scanning region and performs three target trackings of the first target 9, the second target 10, and the third target 11. . The first target 9, the second target 10, and the third target 11 are, for example, flying objects.
In FIG. 2, the first target 9, the second target 10, and the third target 11 are each flying toward the own aircraft 12 at the shortest distance.

FIG. 3 is a diagram showing a beam scanning order 50 of the phased array antenna 1 executed by the target tracking radar apparatus 100 in the situation of FIG.
In the beam scanning order 50 of FIG. 3, T1 is the tracking process for the first target 9, T2 is the tracking process for the second target 10, T3 is the tracking process for the third target 11, and S is the time for executing the search process. Indicates a band. At this time, the beam distributor 8 scans in the order of scanning of the first target 9, scanning of the scanning area, scanning of the second target 10, scanning of the scanning area, scanning of the third target 11, and scanning of the scanning area. Is output to the phased array antenna 1.
That is, the beam distributor 8 sequentially activates the target 1 beam irradiation 15, the target 2 beam irradiation 16, and the target 3 beam irradiation 17 after the search beam irradiation 18, as shown in FIG. To control the beam directing.

  At this time, since the phased array antenna 1 performs target tracking in the order of the first target 9, the second target 10, and the third target 11, the time interval for performing the tracking processing of the first target 9 is shown in FIG. It becomes the time of Ta shown.

  FIG. 4 is a diagram illustrating a state in which one of the three targets illustrated in FIG. 2 is a traversing target. An example of the movement locus of the first target 9 is represented by a broken locus 9a. As shown by the locus 9a, the first target 9 that has approached the direction of the own device 12 takes a locus that approaches the direction of the own device 12 again after changing its traveling direction at a certain timing. In FIG. 4, the first target 9 is in a traversing state in which the first target 9 moves in a direction transverse to the straight line connecting the aircraft 12 and the first target 9. The target that is in the rampant state is called a rampant target. The second target 10 and the third target 11 continue to fly toward the own aircraft 12 without changing the traveling direction.

  At this time, the phased array antenna 1 of the target tracking radar apparatus 100 executes a tracking beam scan 13 for tracking the searched target and a search beam scan 14 for searching for the target.

FIG. 5 is a diagram showing a beam scanning order 51 of the phased array antenna 1 executed by the target tracking radar apparatus 100 in the situation of FIG. Similar to the situation of FIG. 2, the target tracking radar apparatus 100 executes the tracking process and the scanning area search process for each of the three targets, but the beam distributor 8 according to the present embodiment is The scan of the target 9, the scan of the scan area, the scan of the second target 10, the scan of the second target 10, the scan of the first target 9, the scan of the scan area, the scan of the third target 11, Following the scanning of the target 11 of 3, the scanning of the first target 9, the scanning of the scanning region, and a beam scanning control command for scanning in order are output to the phased array antenna 1.
That is, when the tracking target (here, the first target 9) becomes a traversing target, the beam distributor 8 detects the traversing target after the search beam irradiation 18 in the scanning range as shown in FIG. The beam irradiation 15 to the first target 9 is activated every time before the beam irradiation 18 to perform the beam irradiation. As shown in FIG. 5, the beam irradiation 16 on the second target 10 of the other target and the beam irradiation 17 on the third target 11 direct the tracking beam in the order shown in FIG.

  Thus, since the beam irradiation 15 is activated every time for the traversing target (first target 9) to perform the beam irradiation, the time interval for performing the tracking process of the first target 9 is the time Tb shown in FIG. Thus, the time can be shorter than Ta shown in FIG. Thereby, it can suppress that tracking is canceled with respect to a traversing target.

  Next, FIG. 6 shows a state in which the traversing target (first target 9) shown in FIG. 4 continues to move, escapes from the traversing target state, and flies linearly toward the aircraft 12. Yes.

FIG. 7 is a diagram showing a beam scanning order 52 of the phased array antenna 1 in the situation of FIG. As shown in FIG. 7, when the first target 9 is out of the traversing target state, the beam distributor 8 issues a beam scanning control command for reducing the number of times of activation of the tracking beam for the first target 9 to the phased array antenna 1. Output to.
That is, the beam distributor 8 starts the target 1 beam irradiation 15, the target 2 beam irradiation 16, and the target 3 beam irradiation 17 in order after the search beam irradiation 18 as shown in FIG. The beam directing is controlled so that there is no difference in the number of activations due to.

Thus, the target tracking radar apparatus according to the present embodiment changes the beam scanning order based on whether or not the tracking target is a traversing target.
When the tracking target is a traversing target, the beam irradiation time interval for the target is shortened and the number of beam irradiations is increased, so tracking is also performed for the traversing target that is most likely to be missed during the tracking process. The reliability of target tracking can be improved without canceling.

Embodiment 2. FIG.
In the first embodiment, the data processing unit 5 determines whether or not the target is a traversing target by comparing the calculated target Doppler frequency of the target signal with the frequency of the ground that is the background of the target. Is determined to be in a traversing state, the beam distributor 8 increases the number of beam pointing with respect to the traversing target.
In the present embodiment, the timing for increasing the number of beam pointing with respect to the traversing target is adjusted.

FIG. 8 is a diagram showing a configuration of the target tracking radar apparatus 101 according to the second embodiment.
A target tracking radar apparatus 101 according to Embodiment 2 includes a phased array antenna 1, a transmitter 2, a receiver 3, a signal processing unit 4, a data processing unit 5b, and a beam distributor 8b.
The data processing unit 5 b includes a target frequency calculator 6, a traversing target determiner 7, and a target frequency change rate calculator 20. Thus, in the present embodiment, the target frequency change rate calculator 20 is added. In addition, the same number is attached | subjected about the structure of the same function as Embodiment 1, and the description is abbreviate | omitted.

Next, the operation of the data processing unit 5b according to the present embodiment will be described.
The target frequency calculation unit 6 in the data processing unit 5b calculates the frequency of the target signal detected in the same manner as in the first embodiment.
The traversing target determination unit 7 determines whether the target corresponds to the traversing state by comparing the target Doppler frequency of the target signal calculated by the target frequency calculating unit 6 with the frequency of the ground serving as the target background.
Further, in the present embodiment, the target frequency change rate calculator 20 calculates the time change rate of the target Doppler frequency calculated by the target frequency calculation unit 6, and supplies the calculated target Doppler frequency change rate to the beam distributor 8b. Output.
The beam distributor 8b compares the rate of change of the target Doppler frequency with a predetermined value. When the rate of change of the target Doppler frequency is equal to or greater than the predetermined value, the beam distributor 8b determines that the change in the target pointing direction is fast. Thus, the beam orientation of the phased array antenna is controlled so as to increase the timing of increasing the number of beam orientations with respect to the traversing target. In addition, when the rate of change of the target Doppler frequency is smaller than a predetermined value, it is determined that the change in the target directivity direction is gradual and the timing for increasing the number of beam directing times for the traversing target is also delayed. Controls the beam orientation of the array antenna.

  As described above, the target tracking radar apparatus according to the present embodiment includes the target frequency change rate calculator that calculates the change rate of the target Doppler frequency. Accordingly, it is possible to adjust the timing for increasing the number of beam pointing with respect to the traversing target in accordance with the operation speed at which the target is directed in the horizontal direction, making it difficult to cancel tracking and improving the reliability of target tracking.

  DESCRIPTION OF SYMBOLS 1 Phased array antenna, 2 Transmitter, 3 Receiver, 4 Signal processing part, 5, 5b Data processing part, 6 Target frequency calculator, 7 Traversal target judgment unit, 8, 8b Beam distributor, 9 1st target ( Traversing target), 10 second target (straight forward target), 11 third target (straight forward target), 12 own machine, 13 tracking beam scanning, 14 search beam scanning, 15 target 1 beam irradiation, 16 target 2 beam irradiation, 17 Target 3 beam irradiation, 18 Search beam irradiation, 19 Target 1 (straight), 20 Target frequency change rate calculator, 50, 51, 52 Beam scanning order, 90 Beam scanning control command, 100 101 Target tracking radar device, Ta, Tb Observation interval.

Claims (3)

A transmitter,
A phased array antenna that radiates the signal from the transmitter to external space;
A receiver for detecting a received signal received by the phased array antenna;
A signal processing unit for detecting a target signal that is a reflected signal at a target from the received signal;
A frequency calculation unit for calculating a Doppler frequency of the target signal;
A traversing target determiner that determines, based on the Doppler frequency, whether the target is in a traversing state in which the target moves in a direction transverse to a straight line connecting the target and the phased array antenna;
A beam distributor for controlling the beam orientation of the phased array antenna;
A target tracking radar device comprising:
The beam distributor, when the target is in the traversing state as determined by the traversing target determiner, sends a control command to increase the number of times the beam is directed to the target in the traversing state, the phased array A target tracking radar device characterized by outputting to an antenna. The beam distributor, when the traversing target determination unit determines that the target that has been in the traversing state is no longer in the traversing state, issues a control command to reduce the number of times the beam is directed toward the target. The target tracking radar apparatus according to claim 1, wherein the target tracking radar apparatus outputs the signal to an antenna. A Doppler frequency change rate calculator for calculating a change rate of the Doppler frequency;
The beam splitter sends a control command for increasing a timing for increasing the number of times of directing a beam to the target in the traversing state when the rate of change is larger than a predetermined value. When the rate of change is smaller than a predetermined value, a control command for delaying the timing of increasing the number of times the beam is directed to the target in the traversing state is output to the phased array antenna. The target tracking radar apparatus according to claim 1, wherein:

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