JP6231267B2 - Radar receiver - Google Patents

Description

  The present invention relates to a radar receiver that can detect target movement with high sensitivity.

  Radar measurement technology detects targets with low reflection intensity such as distant targets and small targets, so it can increase the size of the antenna and increase the transmission output. In addition, the scan correlation technology described below ( For example, Patent Document 1) can be used.

  In a normal scan correlation technique, a plurality of past scan images and a current scan image are weighted and averaged. Therefore, the signal level of the target having a high correlation between the scanned images is increased, while the clutter component having a low correlation between the scanned images is suppressed. That is, the signal-to-noise ratio (hereinafter referred to as SN (Signal to Noise) ratio) is improved. However, for a stationary target, the correlation is high and the signal level of the target is high, and the target is clearly visible, but for a moving target, the correlation is low and the signal level of the target is low. The trajectory that the target has moved remains thin or disappears.

  In the scan correlation technology for moving targets, the current position of the target is estimated based on the past scan image, and the display position of the target is corrected to the current position of the target in the past scan image. A plurality of past scan images whose display positions have been corrected and the current scan image are weighted and averaged. Therefore, the SN ratio of the target is improved for both the stationary target and the moving target.

JP 2012-103197 A

  However, in the conventional scan correlation technique corresponding to a moving target, the target SN ratio is improved for a target that performs constant-velocity linear motion because the current position estimation accuracy is high. For targets that perform curved motion, the target position's current position estimation accuracy is low, so improvement in the signal-to-noise ratio of the target cannot be expected, and the target's trajectory remains thin or the target's display disappears. There was a thing.

  Therefore, in order to solve the above-described problems, the present invention aims to prevent the SN ratio of a target from being deteriorated even in a target that performs a motion other than a constant velocity linear motion in a radar measurement technique using scan correlation. To do.

  In order to achieve the above objective, scan correlation images generated using conventional scan correlation technology for moving targets, and current scan correlation images generated without using normal scan correlation technology and scan correlation technology for moving targets The scanned image was superimposed and displayed.

  Specifically, the present invention includes a reflection radar signal reception unit that receives a reflection radar signal, a scan image generation unit that generates a scan image based on the reflection radar signal received by the reflection radar signal reception unit, Based on the past scan image generated by the scan image generation unit, the movement vector calculation unit that calculates the movement vector of the target and estimates the current position of the target, and the past image generated by the scan image generation unit In the scan image, the target display position correction unit that corrects the display position of the target in the past scan image to the current position of the target estimated by the movement vector calculation unit, and the scan image generation unit A scan correlation process is performed on the current scan image and the past scan image in which the target display position correction unit corrects the display position of the target. The scan correlation image generation unit that generates the scan correlation image, the current scan image generated by the scan image generation unit, and the scan correlation image generated by the scan correlation image generation unit are superimposed. And a scan image superimposed display unit for displaying the radar image.

  According to this configuration, even if the trajectory of the target remains thin in the scan correlation image or the display of the target disappears, the signal level of the target can be prevented from being deteriorated in the scan superimposed image.

  Further, in the present invention, the scan image generation unit suppresses a clutter component in the generated current scan image, and the scan image superimposed display unit includes the current image in which the scan image generation unit suppresses the clutter component. A radar receiver that superimposes and displays a scan image and the scan correlation image generated by the scan correlation image generation unit.

  According to this configuration, it is possible to suppress the clutter component in the scan superimposed image without degrading the signal level of the target (SNR improvement).

  Further, according to the present invention, the scan image superimposing display unit stores a preset distance threshold, and the scan image generation unit generates a short-distance region whose distance from the own apparatus is shorter than the distance threshold. The current scan image and the scan correlation image generated by the scan correlation image generation unit are displayed in a superimposed manner, and for a long-distance region whose distance from the device is longer than the distance threshold, the scan image generation unit The radar receiver according to claim 1, wherein the current scan image in which a clutter component is suppressed or the current scan image generated by the scan image generation unit is displayed.

  According to this configuration, in a long-distance region where the speed of the target is seemingly slow, it is possible to reduce the processing load on the entire scan image without executing the moving target-corresponding scan correlation process.

  In the radar measurement technique using scan correlation, the present invention can prevent the SN ratio of a target from deteriorating even for a target that performs a motion other than a uniform linear motion.

It is a figure which shows the structure of the radar receiver of this invention. It is a figure which shows the 1st scan image superimposed display method. It is a figure which shows the 2nd scan image superimposed display method. It is a figure which shows the 3rd scan image superimposed display method.

  Embodiments of the present invention will be described with reference to the accompanying drawings. The embodiments described below are examples of the present invention, and the present invention is not limited to the following embodiments.

(Radar receiver)
First, the configuration of the radar receiver will be described. The configuration of the radar receiver of the present invention is shown in FIG. The radar receiver R includes a reflected radar signal receiver 1, a scan image generator 2, a scan image storage 3, a movement vector calculator 4, a target display position correction unit 5, a scan correlation image generator 6, and a scan image superimposed display. And a clutter component suppression unit 8.

  The reflection radar signal receiving unit 1 receives a reflection radar signal. The scan image generation unit 2 generates a scan image based on the reflection radar signal received by the reflection radar signal reception unit 1. The scan image storage unit 3 stores the scan image generated by the scan image generation unit 2.

  The movement vector calculation unit 4 calculates a movement vector of the target based on the past scan image generated by the scan image generation unit 2 and stored in the scan image storage unit 3, and estimates the current position of the target. For example, the movement vector calculation unit 4 uses a three-dimensional Fourier transform to calculate a locus of a straight line of a target in a three-dimensional coordinate space composed of two-dimensional space coordinates and one-dimensional time coordinates. In the target display position correction unit 5, the movement vector calculation unit 4 estimates the display position of the target in the past scan image in the past scan image generated by the scan image generation unit 2 and stored in the scan image storage unit 3. The current position of the target is corrected.

  The scan correlation image generation unit 6 performs a scan correlation process on the current scan image generated by the scan image generation unit 2 and the past scan image whose target display position correction unit 5 has corrected the display position of the target. Thus, a scan correlation image is generated. For example, the scan correlation image generation unit 6 performs weighted addition averaging of the current scan image and a plurality of past scan images.

  The clutter component suppressing unit 8 suppresses clutter components in the reflected radar signal received by the reflected radar signal receiving unit 1. For example, the clutter component suppression unit 8 suppresses the clutter component using STC (Sensitivity Time Control).

  As a first scan image superposition display method, the scan image superposition display unit 7 superimposes and displays the current scan image generated by the scan image generation unit 2 and the scan correlation image generated by the scan correlation image generation unit 6. Details will be described later with reference to FIG.

  As a second scan image superposition display method, the scan image superimposition display unit 7 superimposes the current scan image in which the clutter component suppression unit 8 suppresses the clutter component and the scan correlation image generated by the scan correlation image generation unit 6. It may be displayed. Details will be described later with reference to FIG.

  The scan image superimposition display unit 7 stores a preset distance threshold as a third scan image superimposition display method, and a near distance region in which the distance from the own apparatus is shorter than the distance threshold and the distance from the own apparatus The scan image superimposed display method may be made different in a short-distance region longer than the distance threshold. Details will be described later and in FIG.

  That is, the first or second scan image superimposed display method is applied to a short-distance region whose distance from the own device is shorter than the distance threshold. For a long distance region where the distance from the own device is longer than the distance threshold, the current scan image in which the clutter component suppression unit 8 suppresses the clutter component or the current scan image generated by the scan image generation unit 2 is displayed.

  By the way, in the conventional scan correlation technique corresponding to a moving target, the trajectory of the target may remain thin or the display of the target may disappear. Therefore, in the first to third scan image superposition display methods, a scan correlation image generated using a conventional scan correlation technique corresponding to a moving target, a normal scan correlation technique, and a scan correlation corresponding to a moving target. The current scan image generated without using technology is displayed in a superimposed manner.

  Here, the first to third scan image superposition display methods are related to whether or not the trajectory of the target remains thin or the display of the target disappears in the conventional scan correlation technique for moving target correspondence. However, it may be applied only when the trajectory of the target remains thin or the display of the target disappears in the conventional scan correlation technique corresponding to a moving target.

(First scan image superposition display method)
A first scan image superimposed display method is shown in FIG. The scan image generation unit 2 calculates the past target position TP and the past clutter component CP in the past scan image SP. The movement vector calculation unit 4 calculates a movement vector V based on the past track P in the past scan image SP, and estimates the current target position based on the past target position TP and the movement vector V. . The target display position correction unit 5 corrects the position of the target from the past target position TP to the corrected target position TC in the past scan image SC after the target display position correction.

  The scan image generation unit 2 calculates the current target position TL and the current clutter component CL in the current scan image SL. In the past scan image SC and the current scan image SL after the target display position correction, the past clutter component CP and the current clutter component CL have no correlation, and the target that performs acceleration motion or curved motion is the current Since the estimation accuracy of the target position is low, the corrected target position TC and the current target position TL are different from each other.

  The scan correlation image generation unit 6 performs a scan correlation process on the past scan image SC and the current scan image SL after the target display position correction. In the scan correlation image SA, the clutter component is suppressed, and the locus of the target remains thin or the display of the target disappears.

  The scan image superimposing display unit 7 superimposes and displays the scan correlation image SA and the current scan image SL. In the scan correlation superimposed image SS, the display of the target improves the SN ratio as the current target position TL, while the current clutter component CL remains.

  As described above, in the first scan image superimposed display method, even if the target trajectory remains thin or the target display disappears in the scan correlation image SA, the target correlation is displayed in the scan correlation superimposed image SS. The display can improve the signal level as the current target position TL.

(Second scan image superimposed display method)
A second scan image superimposed display method is shown in FIG. When the second scan image superimposed display method is compared with the first scan image superimposed display method, the past scan image SP, the past scan image SC after the target display position correction, the current scan image SL, and the scan correlation image SA are compared. Are the same, but the current scan image SR and scan correlation superimposed image SS after clutter component suppression are different. Below, a different part is demonstrated.

  The clutter component suppression unit 8 suppresses the current clutter component CL in the current scan image SR after the clutter component suppression, and extracts the current target position TL.

  The scan image overlay display unit 7 superimposes and displays the scan correlation image SA and the current scan image SR after the clutter component suppression. In the scan correlation superimposed image SS, the display of the target improves the SN ratio as the current target position TL, and the current clutter component CL disappears.

  Thus, in the second scan image superimposed display method, in the scan correlation superimposed image SS, the display of the target can improve the signal level as the current target position TL, and the current clutter component CL is suppressed. can do.

(Third scan image superimposed display method)
A third scan image superimposed display method is shown in FIG. The inside of the distance area boundary TH is called a short distance area, and the outside of the distance area boundary TH is called a long distance area. When the third scan image superimposed display method is compared with the first and second scan image superimposed display methods, the short distance region processing method is the same, but the long distance region processing method is different. Below, a different part is demonstrated.

  The scan image generation unit 2 calculates the target position TN and the current clutter component CL of the short distance area in the short distance area of the current scan image SL, and the target position of the long distance area in the long distance area. TF and the current clutter component CL are calculated. In the short distance region, the same processing as that of the first and second scan image superimposed display methods is executed.

  Scan correlation processing is not executed in the long-distance region. The scan image superimposing display unit 7 may display the current scan image generated by the scan image generation unit 2 as the current scan image SF1 in the long distance region in the long distance region. The scan image superimposing display unit 7 may display the current scan image in which the clutter component suppression unit 8 suppresses the clutter component in the long distance region as the current scan image SF2 in the long distance region.

  As described above, in the third scan image superposition display method, in the far distance area where the speed of the target is apparently slow, the scan correlation process is not performed, and the entire scan image including the short distance area and the far distance area is combined. The processing burden can be reduced.

  The radar receiver according to the present invention is particularly applicable for the purpose of detecting not only a stationary target but also a moving target such as a ship radar and an aeronautical radar.

R: radar receiver 1: reflected radar signal receiver 2: scan image generator 3: scan image storage 4: movement vector calculator 5: target display position corrector 6: scan correlation image generator 7: scan image superposition Display unit 8: Clutter component suppression unit SP: Past scan image SL: Current scan image SC: Past scan image after target display position correction SA: Scan correlation image SS: Scan correlation superimposed image SR: After clutter component suppression Current scan image SF1: current scan image SF2 in the long-distance area: current scan image TP after suppression of clutter components in the long-distance area: past target position TL: current target position TC: corrected object Target position TF: Target position TN in the long distance area: Target position CP in the short distance area CP: Past clutter component CL: Current clutter component TH: Distance Area boundary P: Past wake V: motion vector

Claims (3)

A reflection radar signal receiving unit for receiving the reflection radar signal;
Based on the reflection radar signal received by the reflection radar signal reception unit, a scan image generation unit that generates a scan image;
Based on the past scan image generated by the scan image generation unit, a movement vector calculation unit that calculates a movement vector of the target and estimates a current position of the target;
In the past scan image generated by the scan image generation unit, the target display position for correcting the display position of the target in the past scan image to the current position of the target estimated by the movement vector calculation unit. A correction unit;
By performing scan correlation processing on the current scan image generated by the scan image generation unit and the plurality of past scan images whose target display position correction unit has corrected the display position of the target, scan correlation is performed. A scan correlation image generation unit for generating an image;
When the motion represented by the movement vector of the target is an acceleration motion or a curved motion, the target trajectory remains thin or the display of the target disappears, and the current scan image generated by the scan image generation unit And a scan image superposition display unit that superimposes and displays the scan correlation image generated by the scan correlation image generation unit,
A radar receiver characterized by comprising: The scan image generation unit suppresses a clutter component in the generated current scan image,
The scan image superimposition display unit superimposes and displays the current scan image in which the scan image generation unit suppresses clutter components and the scan correlation image generated by the scan correlation image generation unit. Item 2. The radar receiver according to Item 1. The scanned image superimposed display unit stores a preset distance threshold,
For the short distance region where the distance from the own device is shorter than the distance threshold, the current scan image generated by the scan image generation unit and the scan correlation image generated by the scan correlation image generation unit are displayed in a superimposed manner. ,
For a long-distance region where the distance from the device is longer than the distance threshold, the current scan image in which the scan image generation unit suppresses clutter components or the current scan image generated by the scan image generation unit is displayed. The radar receiver according to claim 1 or 2.

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