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JP-2026075189-A - Radar device, clutter suppression method, and clutter suppression program

JP2026075189AJP 2026075189 AJP2026075189 AJP 2026075189AJP-2026075189-A

Abstract

[Challenge] To detect targets more reliably while suppressing rain clutter. [Solution] The radar device comprises a transmitting unit that transmits radio waves to a detection target area, a receiving unit that receives reflected waves that have been reflected by the radio waves in the detection target area, a calculation unit that calculates a clutter fit degree, which is an index indicating the possibility that the reflected waves are rain clutter, based on the degree of phase agreement of the reflected waves in the azimuth direction, a correction unit that performs crosswind correction to correct the clutter fit degree by taking into account the influence of wind direction on the clutter fit degree, and a suppression unit that performs suppression processing to suppress the rain clutter based on the crosswind corrected clutter fit degree. [Selection Diagram] Figure 1

Inventors

  • 藤村 拓矢

Assignees

  • 古野電気株式会社

Dates

Publication Date
20260508
Application Date
20241022

Claims (11)

  1. A radar device for detecting targets in a target area, A transmitting unit that transmits radio waves to the detection target area, A receiving unit that receives reflected waves reflected in the detection target area of the aforementioned radio waves, A calculation unit calculates a clutter fit score, which is an index indicating the possibility that the reflected wave is rain clutter, based on the degree of phase agreement of the reflected wave in the azimuthal direction. A correction unit that performs crosswind correction to correct the clutter fit by taking into account the effect of wind direction on the clutter fit, A radar device comprising: a suppression unit that performs suppression processing to suppress rain clutter based on the crosswind-corrected clutter fit.
  2. The calculation unit calculates the clutter fit for each reflection position of the reflected wave in the detection target area, The radar apparatus according to claim 1, wherein the correction unit, in the crosswind correction, creates a first velocity histogram which is a histogram of the Doppler velocity of the reflection position in a first region of a predetermined size, and corrects the clutter fit corresponding to the reflection position in the first region if the peak width of the first velocity histogram satisfies a predetermined condition.
  3. The calculation unit calculates the clutter fit for each reflection position of the reflected wave in the detection target area, The radar apparatus according to claim 1 or 2, wherein the correction unit calculates the difference between the maximum and minimum values of the intensity of the reflected wave in a second region of a predetermined size in the crosswind correction, and corrects the clutter fit corresponding to the reflection position in the second region if the difference satisfies predetermined conditions.
  4. The calculation unit calculates the clutter fit for each reflection position of the reflected wave in the detection target area, The radar apparatus according to any one of claims 1 to 3, wherein the correction unit, in the crosswind correction, creates a cumulative histogram of the intensity of the reflected wave in a third region of a predetermined size, and corrects the clutter fit corresponding to the reflection position in the third region if the slope of the cumulative histogram satisfies a predetermined condition.
  5. The correction unit further performs moving target correction on the clutter fit to distinguish between the rain clutter and the reflected waves at the moving target. The radar device according to any one of claims 1 to 4, wherein the suppression unit performs the suppression process based on the moving target-corrected clutter fit.
  6. The calculation unit calculates the clutter fit for each reflection position of the reflected wave in the detection target area, The radar device according to claim 5, wherein the correction unit, in the correction of a moving target, creates a second velocity histogram which is a histogram of the Doppler velocities of a plurality of reflection positions in the detection target area, extracts the reflection positions having a Doppler velocity within a predetermined velocity range determined based on the peak of the second velocity histogram, and corrects the clutter fit corresponding to the reflection positions excluding the extracted reflection positions.
  7. The radar apparatus according to claim 6, wherein the correction unit creates a second velocity histogram of the Doppler velocities of the plurality of reflection positions, excluding the reflection position whose clutter fit is less than or equal to a predetermined value.
  8. The radar apparatus according to claim 6 or 7, wherein the correction unit sets a threshold using the Doppler velocity of the reflection position and the IIR filter, and creates a second velocity histogram of the Doppler velocities of the plurality of reflection positions, excluding the reflection position having a Doppler velocity greater than or equal to a predetermined value than the threshold.
  9. If the clutter fit is greater than a predetermined reference value, the suppression unit, in the suppression process, uses an IIR filter to subtract a suppression threshold set using a predetermined filter coefficient from the amplitude of the reflected wave. The radar apparatus according to any one of claims 1 to 8, wherein, when the clutter fit is less than or equal to the reference value, the suppression unit, in the suppression process, uses an IIR filter to subtract a suppression threshold adjusted according to the magnitude of the clutter fit from the amplitude of the reflected wave.
  10. A method for suppressing clutter in a radar device that detects targets in a target area, A radio wave is transmitted to the aforementioned detection target area, The radio waves are received from the reflected waves that have been reflected in the detection target area. Based on the degree of phase agreement of the reflected wave in the azimuthal direction, a clutter fit index, which is an indicator of the likelihood that the reflected wave is rain clutter, is calculated. Crosswind correction is performed to adjust the clutter fit, taking into account the effect of wind direction on the clutter fit. A clutter suppression method comprising performing a suppression process to suppress rain clutter based on the crosswind-corrected clutter fit.
  11. A clutter suppression program used in a radar device for detecting targets in a target area, The process of transmitting radio waves to the detection target area, The process of receiving the reflected wave that was reflected in the detection target area of the aforementioned radio wave, A process for calculating a clutter fit score, which is an index indicating the likelihood that the reflected wave is rain clutter, based on the degree of phase agreement of the reflected wave in the azimuthal direction, A process to perform crosswind correction to correct the clutter fit by taking into account the effect of wind direction on the clutter fit, A clutter suppression program for causing a computer to perform a suppression process to suppress the rain clutter based on the crosswind-corrected clutter fit.

Description

This disclosure relates to a radar device, a clutter suppression method, and a clutter suppression program. Techniques have been developed to suppress rain clutter in echo images generated by radar devices. For example, Patent Document 1 (International Publication No. 2020/039797) discloses the following echo data processing device: The echo data processing device comprises a first threshold calculation unit that calculates a first threshold based on the distribution of echo data intensity for each position in the distance direction from the device's position; a second threshold calculation unit that calculates a second threshold consisting of values adapted to the change in echo data intensity in the distance direction; and a threshold determination unit that determines a threshold for clutter suppression for each position in the distance direction using the first and second thresholds. International Publication No. 2020/039797 Figure 1 is a diagram showing the configuration of a radar device according to an embodiment of the present disclosure.Figure 2 shows an example of a detection target area of a radar device according to an embodiment of the present disclosure.Figure 3 shows an example of the procedure for calculating the vector match degree by the signal processing unit in a radar device according to an embodiment of the present disclosure.Figure 4 shows an example of the clutter fit calculated by the signal processing unit in the radar device according to the embodiment of this disclosure.Figure 5 shows an example of the procedure for creating a histogram by the signal processing unit in a radar device according to an embodiment of the present disclosure.Figure 6 shows an example of a velocity histogram created by the signal processing unit in a radar device according to an embodiment of the present disclosure.Figure 7 shows an example of an intensity histogram created by the signal processing unit in a radar device according to an embodiment of the present disclosure.Figure 8 shows an example of the cumulative frequency distribution of an intensity histogram created by the signal processing unit in a radar device according to an embodiment of the present disclosure.Figure 9 shows an example of a reflection position to which a detection target flag has been assigned by the signal processing unit in the radar device according to the embodiment of this disclosure.Figure 10 shows an example of the clutter fit after crosswind correction by the signal processing unit in a radar device according to an embodiment of the present disclosure.Figure 11 shows an example of a reflection position to which a mask flag has been assigned by the signal processing unit in a radar device according to an embodiment of the present disclosure.Figure 12 shows an example of a reflection position to which a mask flag has been assigned by the signal processing unit in a radar device according to an embodiment of the present disclosure.Figure 13 shows an example of a reflection position to which a mask flag has been assigned by the signal processing unit in a radar device according to an embodiment of the present disclosure.Figure 14 shows an example of a velocity histogram created by the signal processing unit in a radar device according to an embodiment of the present disclosure.Figure 15 shows an example of a reflection position to which a rain flag has been assigned by the signal processing unit in the radar device according to the embodiment of the present disclosure.Figure 16 shows an example of a reflection position that has been flagged by the signal processing unit in a radar device according to an embodiment of the present disclosure.Figure 17 shows an example of the clutter fit after moving target correction by the signal processing unit in a radar device according to an embodiment of the present disclosure.Figure 18 is a flowchart showing the operation procedure when a radar device according to an embodiment of the present disclosure displays an echo image.Figure 19 is a flowchart showing the operation procedure when a radar device according to an embodiment of the present disclosure sets a suppression threshold.Figure 20 is a flowchart showing the operation procedure when a radar device according to an embodiment of the present disclosure performs crosswind correction.Figure 21 is a flowchart showing the operation procedure when a radar device according to an embodiment of the present disclosure performs moving target correction. [Configuration and Basic Operation] Figure 1 is a diagram showing the configuration of a radar device according to an embodiment of the present disclosure. Referring to Figure 1, the radar device 101 comprises a transmitting unit 11, a transmitting antenna 12, a receiving antenna 13, a receiving unit 14, a signal processing unit 15, a display processing unit 16, and a storage unit 17. The radar device 101 is mounted on a ship 1. The signal processing unit 15 is an example of a calculatio