JP2020027063A - Radar target detection device and radar target detection program - Google Patents

Abstract

To extract targeted reception intensity after eliminating reception intensity due to background reflection and clutter in all directions seen from a radar system in an almost same manner without needing a mechanism for driving an orientation direction of an antenna in response to a tilt of the radar system even if the radar system is tilted to the ground surface and/or the sea surface.SOLUTION: The amount of attenuation of the entire reception intensity is increased more as the orientation direction of a transmission/reception beam is tilted toward the ground surface and/or the sea surface, and on the other hand, the amount of the attenuation of the entire reception intensity is decreased more as the orientation direction of the transmission/reception beam is separated from the ground surface and/or the sea surface. A Doppler and angle measurement processing result is corrected in accordance with a tilt angle in the orientation direction of the transmission/reception beam.SELECTED DRAWING: Figure 3

Description

  The present disclosure relates to a technique for removing a signal due to clutter and extracting a signal due to a target.

  2. Description of the Related Art Conventionally, there is a technique for removing a signal due to clutter and extracting a signal according to a target (for example, refer to Patent Document 1). Here, the shorter the distance from the radar device, the higher the reception intensity due to the background reflection. Therefore, the shorter the distance from the radar device, the greater the attenuation of the entire reception intensity. Then, the reception intensity due to the background reflection is removed, and further, the reception intensity due to the clutter is removed, and thus the reception intensity due to the target is extracted.

  FIG. 1 shows a conventional receiving intensity attenuation method. As shown in the upper part of FIG. 1, before the attenuation of the entire reception intensity, the reception intensity of the clutter and the target is superimposed on the reception intensity of the background reflection, and the reception intensity of the clutter and the target superimposed on the reception intensity of the background reflection. Is larger than the display threshold, and the clutter and the target are displayed on the radar display device. As shown in the middle part of FIG. 1, the shorter the distance from the radar device, the greater the attenuation of the entire reception intensity. As shown in the lower part of FIG. 1, after the attenuation of the entire reception intensity, the reception intensity due to the clutter and the target is separated from the reception intensity due to the background reflection, the reception intensity due to the clutter is smaller than the display threshold, and the clutter is a radar display device. , The reception intensity of the target is greater than the display threshold, and the target is displayed on the radar display device.

Japanese Patent No. 6061588

FIG. 2 shows a conventional method of attenuating the reception intensity at the front and rear sides. As shown in the first stage of FIG. 2, when the flying object F on which the radar system is mounted is inclined forward by an angle θ _{F, the} direction of the transmission / reception beam BB on the rear side is changed to the ground and / or sea level L. , The transmission direction of the transmission / reception beam BF on the front side is directed to the ground and / or the sea surface L.

With reference to the second stage in FIG. 2, a description will be given before the attenuation of the entire reception intensity. On the rear side, the reception intensity by the clutter and the flying object FB is superimposed on the reception intensity by the background reflection, the reception intensity by the clutter and the flying object FB superimposed on the reception intensity by the background reflection is larger than the display threshold, and the clutter and the flying object FB It is displayed on the radar display device. In the forward direction, the reception intensity by the clutter and the flying object FF is superimposed on the reception intensity by the background reflection, the reception intensity by the clutter and the flying object FF superimposed on the reception intensity by the background reflection is larger than the display threshold, and the clutter and the flying object FF It is displayed on the radar display device. Since the flying body F is inclined by an angle theta _F in the forward direction, the reception intensity of the background reflection and clutter at the front, higher than the reception strength by the background reflection and clutter at the back.

  The attenuation of the entire reception intensity will be described using the third stage in FIG. Even at the front and the rear, the shorter the distance from the radar system, the greater the attenuation of the entire reception intensity.

With reference to the fourth stage of FIG. 2, a description will be given of the state after the reception intensity of the entire signal has attenuated. At the rear, the reception intensity by the clutter and the flying object FB is separated from the reception intensity by the background reflection, the reception intensity by the clutter is smaller than the display threshold, the clutter is not displayed on the radar display device, and the reception intensity by the flying object FB is the display threshold. Larger, the flying object FB is displayed on the radar display. In front, the reception intensity of the clutter and the flying vehicle FF is separated from the reception intensity of the background reflection, the reception intensity of the flying vehicle FF is larger than the display threshold, the flying vehicle FF is displayed on the radar display device, and the reception intensity of the clutter is also displayed Above the threshold, clutter is also displayed on the radar display. This is flying body F is inclined by an angle theta _F in a forward direction, because the attenuation of the overall reception strength is the same in the front and rear. Therefore, it is conceivable to make the directivity direction of the antenna horizontal in response to the inclination of the flying object F. However, a driving mechanism for the antenna is required, and the device configuration of the radar system is complicated. When the driving speed of the antenna is lower than the inclination speed of the flying object F, the display screen of the radar display device becomes difficult to see.

  Therefore, in order to solve the above-described problem, the present disclosure requires a mechanism that drives the pointing direction of the antenna in response to the inclination of the radar device even if the radar device is inclined with respect to the ground and / or the sea surface. An object of the present invention is to extract the reception intensity due to the target after removing the reception intensity due to the background reflection and the clutter in almost all the directions as viewed from the radar apparatus.

  In order to solve the above-mentioned problem, the more the directivity direction of the transmission / reception beam is directed to the ground and / or the sea surface, the larger the attenuation of the entire reception intensity is, while the more the directivity direction of the transmission / reception beam is away from the ground and / or the sea surface, It was decided to reduce the amount of attenuation of the entire reception intensity. Then, the result of the Doppler and angle measurement processing is corrected according to the inclination angle of the directivity direction of the transmission / reception beam.

  Specifically, the present disclosure relates to a radar inclination information acquisition unit that acquires radar inclination information regarding an inclination angle of a transmission / reception antenna of the radar device with respect to the ground and / or the sea surface, and the radar using a reflecting object that is short in distance from the radar device. In order to attenuate the reception intensity of the radar apparatus more greatly, the amount of attenuation of the reception intensity of the radar apparatus is increased based on the radar tilt information, as the direction of the transmission / reception beam of the radar apparatus is directed toward the ground and / or the sea surface. A radar reception intensity attenuator for reducing the amount of attenuation of the reception intensity of the radar device as the direction of the transmission / reception beam of the radar device becomes farther from the ground and / or the sea surface; and the radar output by the radar reception intensity attenuator. Suppress radar reflection intensity from the ground and / or sea surface based on Doppler processing in the reception intensity of the device A Doppler / angle measurement processing unit that measures a moving speed of a target moving with respect to the ground and / or the sea surface, and measures the direction in which the target moves with respect to the ground and / or the sea surface based on angle measurement processing. A radar target detection device comprising:

  Further, the present disclosure provides a radar tilt information obtaining step of obtaining radar tilt information regarding a tilt angle of a transmission / reception antenna of the radar device with respect to the ground and / or the sea surface, and reception of the radar device by a reflecting object whose distance from the radar device is short. In order to attenuate the reception intensity of the radar device, the attenuation amount of the reception intensity of the radar device is increased as the direction of the transmission / reception beam of the radar device is directed toward the ground and / or the sea surface based on the radar tilt information. A radar reception intensity attenuation step for reducing the attenuation of the reception intensity of the radar device as the directivity direction of the transmission / reception beam of the device becomes farther from the ground and / or the sea surface; and reception of the radar device output in the radar reception intensity attenuation step. In intensity, based on the Doppler process, the radar response from the ground and / or sea level Doppler and angle measurement processing that suppresses the intensity, measures the moving speed of a target moving with respect to the ground and / or the sea surface, and measures the direction in which the target moves with respect to the ground and / or the sea surface based on the angle measurement processing And a step for causing the computer to execute the steps sequentially.

  According to these configurations, even if the radar apparatus is inclined with respect to the ground and / or the sea surface, the radar apparatus does not need a mechanism for driving the pointing direction of the antenna in response to the inclination of the radar apparatus. In addition, the reception intensity due to the target can be extracted after removing the reception intensity due to the background reflection and the clutter in almost all the directions. Then, the Doppler / angle measurement processing can be performed after removing the reception intensity due to the background reflection and the clutter.

  Further, according to the present disclosure, the Doppler / angle measurement processing unit corrects suppression of radar reflection intensity from the ground and / or the sea surface based on the radar tilt information in the Doppler processing, and applies the correction to the ground and / or sea surface. A radar target detection device that corrects the moving speed of a target that moves relative to the ground, and in the angle measurement processing, corrects the direction in which the target moves relative to the ground and / or the sea surface based on the radar inclination information. It is.

  According to this configuration, even if the radar device is inclined with respect to the ground and / or the sea surface, the inclination of the radar device can be reduced without requiring a mechanism for driving the pointing direction of the antenna in response to the inclination of the radar device. It is possible to correct the result of Doppler / angle measurement processing as if it were not present.

  Specifically, the present disclosure relates to a radar inclination information acquisition unit that acquires radar inclination information regarding an inclination angle of a transmission / reception antenna of the radar device with respect to the ground and / or the sea surface, and the radar using a reflecting object that is short in distance from the radar device. In order to attenuate the reception intensity of the radar apparatus more greatly, the amount of attenuation of the reception intensity of the radar apparatus is increased based on the radar tilt information, as the direction of the transmission / reception beam of the radar apparatus is directed toward the ground and / or the sea surface. A radar reception intensity attenuator for reducing the amount of attenuation of the reception intensity of the radar device as the direction of the transmission / reception beam of the radar device becomes farther from the ground and / or the sea surface; and the radar output by the radar reception intensity attenuator. Radar reflections from small targets based on smoothing along distance and azimuth at the receiving intensity of the device Degrees suppressed, on the basis of the angle measuring process, a radar target detection apparatus characterized by comprising: a smoothing-angle measuring unit for measuring the presence direction of a large target, a.

  Further, the present disclosure provides a radar tilt information obtaining step of obtaining radar tilt information regarding a tilt angle of a transmission / reception antenna of the radar device with respect to the ground and / or the sea surface, and reception of the radar device by a reflecting object whose distance from the radar device is short. In order to attenuate the reception intensity of the radar device, the attenuation amount of the reception intensity of the radar device is increased as the direction of the transmission / reception beam of the radar device is directed toward the ground and / or the sea surface based on the radar tilt information. A radar reception intensity attenuation step for reducing the attenuation of the reception intensity of the radar device as the directivity direction of the transmission / reception beam of the device becomes farther from the ground and / or the sea surface; and reception of the radar device output in the radar reception intensity attenuation step. In intensity, based on a smoothing process along distance and azimuth, Suppressed radar reflection intensity, based on the angle measuring process, a radar target detection program for executing a smoothing-angle measuring process step of measuring the presence direction of a large target, a turn to the computer.

  According to these configurations, even if the radar apparatus is inclined with respect to the ground and / or the sea surface, the radar apparatus does not need a mechanism for driving the pointing direction of the antenna in response to the inclination of the radar apparatus. In addition, the reception intensity due to the target can be extracted after removing the reception intensity due to the background reflection and the clutter in almost all the directions. Then, after removing the reception intensity due to the background reflection and the clutter, the smoothing / angle measurement processing can be executed.

  Further, the present disclosure is the radar target detection device, wherein the smoothing / angle measurement processing unit corrects the direction in which a large target exists in the angle measurement process based on the radar tilt information. .

  According to this configuration, even if the radar device is inclined with respect to the ground and / or the sea surface, the inclination of the radar device can be reduced without requiring a mechanism for driving the pointing direction of the antenna in response to the inclination of the radar device. As a result, it is possible to correct the angle measurement processing result.

  In addition, the present disclosure further includes a radar altitude information acquisition unit that acquires radar altitude information relating to the altitude of a transmitting / receiving antenna of the radar apparatus from the ground and / or the sea surface, wherein the radar reception intensity attenuating unit includes the radar inclination information. , Based on the radar altitude information, the altitude of the transmitting / receiving antenna of the radar device is set to the ground and / or The lower the sea level, the quicker the attenuation of the reception intensity of the radar apparatus with respect to the increase in the distance from the radar apparatus to the reflecting object, while the height of the transmitting / receiving antenna of the radar apparatus is higher from the ground and / or the sea surface. As the distance from the radar device to the reflecting object increases, the decrease in the attenuation of the reception intensity of the radar device gradually decreases. A radar target detection apparatus according to claim Rukoto.

  According to this configuration, even when the radar apparatus is at an arbitrary altitude from the ground and / or the sea surface, the background reflection and the reception intensity due to clutter are almost similarly removed in all directions as viewed from the radar apparatus, and the target The reception intensity can be extracted.

  Further, the present disclosure also relates to an attenuation that associates a tilt angle of a transmission / reception antenna of the radar device with respect to the ground and / or the sea surface, a distance from the radar device to a reflecting object, and a relationship between an attenuation of reception intensity of the radar device. An attenuation table storing unit for storing an amount table, wherein the radar reception intensity attenuating unit sets the direction of the transmission / reception beam of the radar apparatus to the ground and / or the ground based on the radar tilt information and the attenuation table. The attenuation of the reception intensity of the radar device is increased as it faces the sea surface, while the attenuation of the reception intensity of the radar device is decreased as the direction of the transmission / reception beam of the radar device is away from the ground and / or the sea surface. A radar target detection apparatus characterized in that:

  According to this configuration, by storing the attenuation amount table before the operation of the radar device, the attenuation amount of the entire reception intensity can be immediately set when the radar device is tilted.

  In this manner, the present disclosure provides a radar apparatus that can be tilted with respect to the ground and / or sea surface without needing a mechanism to drive the pointing direction of the antenna in response to the tilt of the radar apparatus. After substantially removing the reception intensity due to the background reflection and the clutter in all the directions seen, the reception intensity due to the target can be extracted.

FIG. 6 is a diagram showing a conventional receiving intensity attenuation method. FIG. 4 is a diagram illustrating a method of attenuating reception intensity in the front and rear according to the related art. FIG. 1 is a diagram illustrating a configuration of a radar system according to a first embodiment. It is a figure showing the contents of the attenuation amount table of a 1st embodiment. It is a flowchart which shows the procedure of the clutter removal of 1st Embodiment. FIG. 3 is a diagram illustrating a method of attenuating reception intensity in front and rear according to the first embodiment. FIG. 3 is a diagram illustrating a method of attenuating reception intensity in front and rear according to the first embodiment. It is a figure showing the composition of the radar system of a 2nd embodiment. It is a figure showing the contents of the attenuation amount table of a 2nd embodiment. It is a flowchart which shows the procedure of the clutter removal of 2nd Embodiment. FIG. 11 is a diagram illustrating a method of attenuating reception intensity at low altitude and high altitude according to the second embodiment. FIG. 2 is a diagram illustrating a configuration of a Doppler / angle measurement processing unit according to the present disclosure. 13 is a flowchart illustrating a procedure of Doppler and angle measurement processing according to the present disclosure. FIG. 11 is a diagram illustrating a procedure of Doppler and angle measurement processing according to the present disclosure. FIG. 11 is a diagram illustrating the details of Doppler correction based on an inclination angle according to the present disclosure. FIG. 11 is a diagram illustrating the details of angle measurement correction based on the tilt angle according to the present disclosure. FIG. 3 is a diagram illustrating a configuration of a smoothing / angle measurement processing unit according to the present disclosure. 13 is a flowchart illustrating a procedure of a smoothing / angle measurement process according to the present disclosure. FIG. 11 is a diagram illustrating a procedure of a smoothing / angle measurement process according to the present disclosure.

  Embodiments of the present disclosure will be described with reference to the accompanying drawings. The embodiments described below are examples of the present disclosure, and the present disclosure is not limited to the following embodiments. In the specification and the drawings, components having the same reference numerals indicate the same components.

(Clutter removal of the first embodiment)
FIG. 3 shows the configuration of the radar system of the first embodiment. The radar system R includes a radar transmitting / receiving device 1, a radar target detecting device 2, a radar display device 3, and a tilt / azimuth detecting device 4. The radar transmitting and receiving apparatus 1 includes a waveform generator 11, a radar transmitter 12, a circulator 13, antennas 14-1 and 14-2, a motor driver 15, a rotary shaft motor 16, an azimuth rotary shaft 17, and a radar attenuator 18-1. , 18-2 and radar receivers 19-1 and 19-2. The radar target detection device 2 includes an inclination / azimuth information acquisition unit 21, an attenuation table storage unit 22, a reception intensity attenuation unit 23, a Doppler / angle measurement unit 24, and a smoothing / angle measurement unit 25. The radar target detection device 2 can be realized by installing a radar target detection program described later with reference to FIGS.

  The radar transmission unit 12 uses the waveform generation unit 11, the circulator 13, and the antenna 14-1 to transmit an irradiation signal to the target and the clutter. The radar receiving units 19-1 and 19-2 use the antennas 14-1 and 14-2, respectively, and receive reflected signals from a target and clutter. Each of the radar attenuators 18-1 and 18-2 attenuates the greater the reception intensity of the radar transmission / reception device 1 due to a reflecting object that is closer to the radar transmission / reception device 1. The reason why two reception systems are provided is to perform angle measurement processing using a phase monopulse or the like.

  The azimuth rotation shaft 17 is a drive mechanism for rotating the antennas 14-1 and 14-2 in the azimuth direction. The rotation shaft motor 16 is a motor that rotates the azimuth rotation shaft 17. The motor drive unit 15 is a control unit that drives the rotating shaft motor 16. Although the radar transmitting and receiving apparatus 1 includes the azimuth rotation axis 17 and the rotation axis motor 16, it is not necessary to include the roll axis and the pitch axis, and the roll axis motor and the pitch axis motor for the reasons described later.

  The Doppler / angle measurement processing unit 24 executes Doppler / angle measurement processing described later with reference to FIGS. The smoothing and angle measurement processing unit 25 executes a smoothing and angle measurement process described later with reference to FIGS.

  The tilt / azimuth detecting device 4 includes tilt information on the tilt angles of the antennas 14-1 and 14-2 of the radar transmitting / receiving device 1 with respect to the ground and / or the sea surface, and information of the antennas 14-1 and 14-2 of the radar transmitting / receiving device 1. And azimuth information about the azimuth direction. Examples of the inclination / azimuth detection device 4 include a combination of a gyro device that detects an inclination angle in a roll direction and a pitch direction, and a sensor device of an azimuth rotation axis 17 that detects an azimuth direction.

  The tilt / azimuth information acquisition unit 21 includes tilt information on the tilt angles of the antennas 14-1 and 14-2 of the radar transmitting / receiving device 1 with respect to the ground and / or the sea surface, and the antennas 14-1 and 14-2 of the radar transmitting / receiving device 1. And the azimuth information on the azimuth direction of. The attenuation table storage unit 22 stores the inclination angles of the antennas 14-1 and 14-2 of the radar transmission / reception device 1 with respect to the ground and / or the sea surface, the distance from the radar transmission / reception device 1 to the reflecting object, and the reception intensity of the radar transmission / reception device 1. And an attenuation amount table that associates the relationship with the attenuation amount.

  The reception intensity attenuator 23 controls the radar attenuators 18-1 and 18-2 after setting the attenuation of the reception intensity of the radar transmitting and receiving apparatus 1 based on the inclination information and the attenuation amount table. Specifically, the reception intensity attenuating unit 23 increases the attenuation of the reception intensity of the radar transmission / reception device 1 as the direction of the transmission / reception beam of the radar transmission / reception device 1 is directed toward the ground and / or the sea surface. On the other hand, the reception intensity attenuating unit 23 reduces the attenuation of the reception intensity of the radar transmission / reception device 1 as the transmission direction of the transmission / reception beam of the radar transmission / reception device 1 becomes farther from the ground and / or the sea surface.

  First, a step of storing the attenuation amount table before the operation of the radar transmitting and receiving apparatus 1 will be described. FIG. 4 shows the contents of the attenuation amount table of the first embodiment. As a general rule, the shorter the distance from the radar transmitting / receiving device 1, the greater the attenuation of the entire reception intensity.

A description will be given of a case where the transmission and reception beam has a directivity direction parallel to the ground and / or the sea surface and the inclination angle of the transmission and reception beam is θ ₂ = 0. Based on the direction dependence of the transmission and reception beam gain and the inclination angle of the transmission and reception beam θ ₂ = 0, (1) set the attenuation of the entire reception intensity in the vicinity of the radar transmission and reception device 1 to A ₂ , and (2) the maximum distance from the radar transceiver device 1 for performing the attenuation of the entire reception intensity is set to R _2, (3) (attenuation amount a of the whole of the reception intensity) [alpha] 1 / (distance R from the radar transceiver device 1) ^d Set to. Here, the index d may be about 4 in consideration of a radar equation, or about 2 in consideration of in-plane reflection on the ground and / or sea.

A case will be described in which the transmitting and receiving beams are directed to the ground and / or the sea surface, and the inclination angle of the transmitting and receiving beams is θ ₁ <0. On the basis of the direction dependency of the transmission / reception beam gain and the transmission / reception beam tilt angle θ ₁ <0, (1) the attenuation of the entire reception intensity near the radar transmission / reception device ₁ is set to A1, and (2) the maximum distance from the radar transceiver device 1 for performing the attenuation of the entire reception intensity is set to R _1, (3) (attenuation amount a of the whole of the reception intensity) [alpha] 1 / (distance R from the radar transceiver device 1) ^d Set to ^-δ . Here, the attenuation _{A 1} is greater than the attenuation _{A 2,} the maximum distance _{R 1} is greater than the maximum distance _{R 2,} exponent d-[delta], smaller exponent d.

A description will be given of a case where the transmission and reception beam is directed away from the ground and / or the sea surface and the inclination angle of the transmission and reception beam is θ ₃ > 0. Based on the tilt angle theta _3> 0 in the gain of the directional dependence and transmitting and receiving beams of transmitting and receiving beams, (1) the attenuation of the overall strength of the received signal in the vicinity of the radar transceiver device 1 is set to A _3, (2) the maximum distance from the radar transceiver device 1 for performing the attenuation of the entire reception intensity is set to R _{3, (3)} (attenuation amount a of the whole of the reception intensity) [alpha] 1 / (distance R from the radar transceiver device 1) d ^{+ [delta]} Set to. Here, the attenuation _{A 3} is smaller than the attenuation amount _{A 2,} the maximum distance _{R 3} is shorter than the maximum distance _{R 2,} exponent d + [delta], larger exponent d.

  Next, the step of immediately setting the attenuation of the entire reception intensity when the radar transmitting and receiving apparatus 1 is tilted will be described. FIG. 5 shows a procedure for removing clutter according to the first embodiment. FIGS. 6 and 7 show a method of attenuating the reception intensity at the front and rear of the first embodiment.

As shown in the first stage of FIG. 6, when the flying object F on which the radar system is mounted is inclined forward by the angle θ _{F, the} direction of the transmission / reception beam BB on the rear side is changed to the ground and / or sea level L. , The transmission direction of the transmission / reception beam BF on the front side is directed to the ground and / or the sea surface L.

With reference to the second stage in FIG. 6, a description will be given before the attenuation of the entire reception intensity. On the rear side, the reception intensity by the clutter and the flying object FB is superimposed on the reception intensity by the background reflection, the reception intensity by the clutter and the flying object FB superimposed on the reception intensity by the background reflection is larger than the display threshold, and the clutter and the flying object FB It is displayed on the radar display device 3. In the forward direction, the reception intensity by the clutter and the flying object FF is superimposed on the reception intensity by the background reflection, the reception intensity by the clutter and the flying object FF superimposed on the reception intensity by the background reflection is larger than the display threshold, and the clutter and the flying object FF It is displayed on the radar display device 3. Since the flying body F is inclined by an angle theta _F in the forward direction, the reception intensity of the background reflection and clutter at the front, higher than the reception strength by the background reflection and clutter at the back.

The attenuation of the entire reception intensity will be described using the third stage in FIG. Tilt-azimuth information acquisition unit 21 acquires gradient information about the inclination angle theta _F (step S1). The reception intensity attenuator 23 refers to the attenuation table shown in FIG. 4 (step S2), and sets the attenuation of the entire reception intensity based on the inclination information and the attenuation table (step S3).

The rear inclination angle of the transmitting and receiving beams BB is + theta _F. Therefore, the attenuation amount of the entire reception intensity when the inclination angle of the transmission / reception beam is θ ₃ (= + θ _F ) in the attenuation amount table shown in FIG. 4 is referred to. Then, (1) the attenuation amount of the entire reception intensity near the radar transmission / reception device 1 is set to A _B (= A ₃ ), and (2) the maximum value from the radar transmission / reception device 1 that attenuates the entire reception intensity. The distance is set to R _B (= R ₃ ), and (3) (the attenuation amount A of the entire reception intensity) ∝1 / (the distance R from the radar transmitting and receiving apparatus 1) is set to ^{d + δ} .

The forward inclination angle of the reception beam BF is - [theta] _F. Therefore, in the attenuation amount table shown in FIG. 4, the attenuation amount of the entire reception intensity when the inclination angle of the transmission / reception beam is θ ₁ (= −θ _F ) is referred to. Then, (1) the attenuation amount of the entire reception intensity near the radar transmission / reception device 1 is set to A _F (= A ₁ ), and (2) the maximum amount of attenuation from the radar transmission / reception device 1 that attenuates the entire reception intensity. The distance is set to R _F (= R ₁ ), and (3) (the attenuation amount A of the entire reception intensity) ∝1 / (the distance R from the radar transmitting and receiving apparatus 1) ^d−δ .

  With reference to the fourth stage in FIG. 6, a description will be given of the state after the entire reception intensity has been attenuated. The Doppler / angle measurement processing section 24 and / or the smoothing / angle measurement processing section 25 execute respective processing.

  At the rear, the reception intensity by the clutter and the flying object FB is separated from the reception intensity by the background reflection, the reception intensity by the clutter is smaller than the display threshold, the clutter is not displayed on the radar display device 3, and the reception intensity by the flying object FB is displayed. The flying object FB that is larger than the threshold value is displayed on the radar display device 3. Also in front, the reception intensity by the clutter and the flying object FF is separated from the reception intensity by the background reflection, the reception intensity by the clutter is smaller than the display threshold, the clutter is not displayed on the radar display device 3, and the reception intensity by the flying object FF is displayed. The flying object FF larger than the threshold value is displayed on the radar display device 3.

The inclination angle theta _F of the aircraft F is constantly changing. Therefore, when the clutter removal processing is continued (NO in step S4), steps S1 to S3 are repeated. On the other hand, when ending the clutter removal processing (YES in step S4), the clutter removal program is ended.

Here, the change frequency of the inclination angle theta _F of the aircraft F is considered to be small compared to the rotation frequency of the antenna 14-1 and 14-2 (several Hz). Therefore, it is not necessary to execute steps S1 to S4 many times in one rotation cycle of the antennas 14-1 and 14-2.

In the rotation period P1 of the antenna 14-1 and 14-2, the inclination angle theta _F of the aircraft F is small in the positive direction, slightly larger set than rear attenuation of overall received signal strength at the front. In the rotation period P2 of the antenna 14-1 and 14-2, the inclination angle theta _F of the aircraft F is large in the positive direction is set sufficiently larger than the rear the attenuation of overall received signal strength at the front. In the rotation period P3 antennas 14-1 and 14-2, a tilt angle theta _F of the aircraft F is 0, set equal attenuation of overall received signal strength at the front and rear. In the rotation period P4 antennas 14-1 and 14-2, significantly to the inclination angle theta _F is the negative direction of the aircraft F, set sufficiently larger than the forward attenuation of overall received signal strength at the rear. In the rotation period P5 antennas 14-1 and 14-2, reduce the inclination angle theta _F is the negative direction of the aircraft F, slightly larger set than forward the attenuation of overall received signal strength at the rear.

  In the first embodiment, before the operation of the radar transmitting and receiving apparatus 1, an attenuation amount table is stored in advance. Here, as a first modified example, during operation of the radar transmitting and receiving apparatus 1, the entire reception is performed so that the degree of attenuation of the receiving intensity due to clutter and background reflection is substantially the same in all directions viewed from the radar transmitting and receiving apparatus 1. The intensity attenuation may be feedback-controlled. Alternatively, as a second modified example, when the radar transmitting and receiving apparatus 1 is operated, the attenuation amount of the entire reception intensity is reduced according to the state of the ground and / or the sea surface L (for example, the wave height, wavelength, and wave speed at the sea surface). You may do machine learning.

(Clutter removal of the second embodiment)
FIG. 8 shows the configuration of the radar system of the second embodiment. The radar system R includes a tilt / altitude / azimuth detecting device 4 ′ instead of the tilt / azimuth detecting device 4. The radar target detection device 2 includes an inclination / altitude / azimuth information acquisition unit 21 ′ instead of the inclination / azimuth information acquisition unit 21. The radar target detection device 2 can be realized by installing a radar target detection program described later with reference to FIGS.

  The inclination / altitude / azimuth detection device 4 ′ includes the inclination information on the inclination angles of the antennas 14-1 and 14-2 of the radar transmission / reception device 1 with respect to the ground and / or the sea surface, and the radar transmission / reception device 1 from the ground and / or the sea surface. , And azimuth information on the azimuth directions of the antennas 14-1 and 14-2 of the radar transmitting and receiving apparatus 1 are generated. As the inclination / altitude / azimuth detecting device 4 ', a gyro device for detecting an inclination angle in a roll direction and a pitch direction, an altitude measuring device using a radar, and a sensor device for an azimuth rotation axis 17 for detecting an azimuth direction And the like.

  The inclination / altitude / azimuth information acquisition unit 21 ′ includes inclination information on the inclination angles of the antennas 14-1 and 14-2 of the radar transmission / reception device 1 with respect to the ground and / or the sea surface, and a radar transmission / reception device from the ground and / or the sea surface. The altitude information on the altitude of the first antennas 14-1 and 14-2 and the azimuth information on the azimuth directions of the antennas 14-1 and 14-2 of the radar transmitting and receiving apparatus 1 are acquired. The attenuation table storage unit 22 according to the second embodiment includes, in addition to the attenuation table storage unit 22 according to the first embodiment, tilt angles of the antennas 14-1 and 14-2 of the radar transmitting and receiving apparatus 1 with respect to the ground and / or the sea surface; Altitudes of the antennas 14-1 and 14-2 of the radar transmitting / receiving device 1 from the ground and / or the sea surface, a relationship between a distance from the radar transmitting / receiving device 1 to the reflecting object, and an attenuation of the reception intensity of the radar transmitting / receiving device 1, Is stored.

  The reception intensity attenuator 23 of the second embodiment sets the attenuation of the reception intensity of the radar transceiver 1 based on the inclination information, the altitude information, and the attenuation table in addition to the reception intensity attenuator 23 of the first embodiment. Then, the radar attenuation units 18-1 and 18-2 are controlled. Specifically, it is assumed that the reception intensity attenuating unit 23 determines that the direction of the transmission / reception beam of the radar transmission / reception device 1 is directed to the ground and / or the sea surface. At this time, as the altitude of the antennas 14-1 and 14-2 of the radar transmitting and receiving apparatus 1 is lower from the ground and / or the sea surface, the reception intensity attenuating unit 23 performs the radar for increasing the distance from the radar transmitting and receiving apparatus 1 to the reflecting object. The attenuation of the reception intensity of the transmission / reception device 1 is reduced quickly. On the other hand, as the altitude of the antennas 14-1 and 14-2 of the radar transmitting and receiving apparatus 1 is higher from the ground and / or the sea surface, the reception intensity attenuating unit 23 performs the radar for increasing the distance from the radar transmitting and receiving apparatus 1 to the reflecting object. The attenuation of the reception intensity of the transmission / reception device 1 is gradually reduced.

  First, a step of storing the attenuation amount table before the operation of the radar transmitting and receiving apparatus 1 will be described. FIG. 9 shows the contents of the attenuation amount table according to the second embodiment. As a general rule, the shorter the distance from the radar transmitting / receiving device 1, the greater the attenuation of the entire reception intensity.

The transmission and reception beam is directed to the ground and / or the sea surface, the inclination angle of the transmission and reception beam is θ ₁ <0, and the height of the antennas 14-1 and 14-2 is substantially equal to the ground and / or the sea surface. _{The case} when the number is ₁ will be described. Based on the direction dependency of the gain of the transmission / reception beam, the inclination angle θ ₁ <0 of the transmission / reception beam, and the altitude H _{1 of the} antennas 14-1 and 14-2, (1) the overall reception intensity near the radar transmission / reception device 1 set the amount of attenuation a _1, (2) the maximum distance from the radar transceiver device 1 for performing the attenuation of the entire reception intensity is set to R _1, (3) (attenuation amount a of the whole of the reception intensity) alpha 1 / (distance R from radar transmitting / receiving device 1) ^d−δ is set. Here, the attenuation A shown in the left column of FIG. 9 is the same as the attenuation A shown in the left column of FIG.

Orientation of the transmit and receive beams are directed to the ground and / or sea surface, with the inclination angle of the transmit and receive beams are theta _{1 <0,} lower the altitude ground and / or sea antennas 14 - 1 and 14 - 2 H ₂ Is described. Based on the direction dependency of the gain of the transmission / reception beam, the inclination angle θ ₁ <0 of the transmission / reception beam, and the altitude H _{2 of the} antennas 14-1 and 14-2, (1) the overall reception intensity near the radar transmission / reception device 1 Is set to A ₁ ′, (2) the maximum distance from the radar transmitting / receiving device 1 that attenuates the entire reception intensity is set to R ₁ ′, and (3) (the attenuation A of the entire reception intensity is set). ) ∝1 / (distance R from radar transmitting / receiving device 1) ^d−δL . Here, the attenuation A ₁ ′ is smaller than the attenuation A ₁ , the maximum distance R ₁ ′ is longer than the maximum distance R ₁ , and the index d−δL is smaller than the index d−δ. The reason will be described later with reference to FIG.

Orientation of the transmit and receive beams are directed to the ground and / or sea surface, with the inclination angle of the transmit and receive beams are theta _{1 <0,} a high H ₃ from altitude ground and / or sea antennas 14-1 and 14-2 Is described. Based on the direction dependence of the transmission and reception beam gain, the transmission and reception beam tilt angle θ ₁ <0, and the altitude H _{3 of the} antennas 14-1 and 14-2, (1) the overall reception intensity near the radar transmission and reception device 1 Is set to A ₁ ″, (2) the maximum distance from the radar transmitting / receiving device 1 that attenuates the entire reception intensity is set to R ₁ ″, and (3) (the attenuation A of the entire reception intensity is set). ) ∝1 / (distance R from radar transmitting / receiving device 1) ^d−δH . Here, the amount of attenuation A ₁ ″ is smaller than the amount of attenuation A ₁ ′, the maximum distance R ₁ ″ is longer than the maximum distance R ₁ ′, and the index d−δH is smaller than the index d−δL. The reason will be described later with reference to FIG.

  Next, the step of immediately setting the attenuation of the entire reception intensity when the radar transmitting and receiving apparatus 1 is tilted will be described. FIG. 10 shows a procedure for removing clutter according to the second embodiment. FIG. 11 shows a method of attenuating the reception intensity at the low altitude and the high altitude according to the second embodiment.

As shown in the first stage of FIG. 11, when the flying object F on which the radar system is mounted is tilted forward by the angle θ _F , the forward direction of the transmission / reception beam BD is changed to the ground and / or sea level L. Turn to. When the flying object F on which the radar system is mounted flies at a low altitude H _L (high altitude H _H ), the directivity of the transmission / reception beam BD on the front side is short distance (far distance) from the radar system in the horizontal direction. At a distance) across the ground and / or sea level L.

  With reference to the second stage in FIG. 11, a description will be given before the attenuation of the entire reception intensity. At a low altitude, the reception intensity of the clutter and the target T is superimposed on the reception intensity of the background reflection, the reception intensity of the clutter and the target T superimposed on the reception intensity of the background reflection is larger than the display threshold, and the clutter and the target T are displayed in radar. It is displayed on the device 3. Even at a high altitude, the reception intensity by the clutter and the target T is superimposed on the reception intensity by the background reflection, the reception intensity by the clutter and the target T superimposed on the reception intensity by the background reflection is larger than the display threshold, and the clutter and the target T are displayed in radar. It is displayed on the device 3. Here, the intensity of the received signal due to the background reflection at a low altitude is higher than the intensity of the received signal due to the background reflection at a high altitude. The signal received by the ground and / or sea clutter at a low altitude is higher in intensity but shorter in distance than the signal received by the ground and / or sea clutter at a high altitude.

With reference to the third stage in FIG. 11, an explanation will be given of the attenuation amount of the entire reception intensity. Gradient, altitude, azimuth information acquisition unit 21 'obtains the inclination information relating to the inclination angle theta _F, and altitude information about the altitude H, a (step S1'). The reception intensity attenuator 23 refers to the attenuation amount table shown in FIG. 9 (step S2), and sets the attenuation amount of the entire reception intensity based on the inclination information, the altitude information, and the attenuation amount table (step S3 ′). ).

At a low altitude, the inclination angle of the transmission / reception beam BD is-[theta] _F , and the altitude of the antennas 14-1 and 14-2 is _HL . Therefore, in the attenuation amount table shown in FIG. 9, the inclination angle of the transmission / reception beam is θ ₁ (= −θ _F ), and the altitude of the antennas 14-1 and 14-2 is H ₂ (= H _L ). At some point, the amount of attenuation of the entire reception strength is referred to. Then, (1) the attenuation amount of the entire reception intensity near the radar transmission / reception device 1 is set to A _L (= A ₁ ′), and (2) the attenuation from the radar transmission / reception device 1 that attenuates the entire reception intensity. The maximum distance is set to R _L (= R ₁ ′), and (3) (the attenuation amount A of the entire reception intensity) ∝1 / (the distance R from the radar transmitting and receiving apparatus 1) ^d−δL .

Is a high altitude, inclination angles of the transmit and receive beam BD is - [theta] _F, high antenna 14-1 and 14-2 are _{H H.} Therefore, in the attenuation amount table shown in FIG. 9, the inclination angle of the transmission / reception beam is θ ₁ (= −θ _F ), and the altitude of the antennas 14-1 and 14-2 is H ₃ (= H _H ). At some point, the amount of attenuation of the entire reception strength is referred to. Then, (1) the attenuation amount of the entire reception intensity near the radar transmission / reception device 1 is set to A _H (= A ₁ ″), and (2) the attenuation from the radar transmission / reception device 1 that attenuates the entire reception intensity. The maximum distance is set to R _H (= R ₁ ″), and (3) (attenuation amount A of the entire reception intensity) ∝1 / (distance R from radar transmitting / receiving device 1) ^d−δH .

  With reference to the fourth stage in FIG. 11, a description will be given of the state after the reception strength of the entire signal has attenuated. The Doppler / angle measurement processing section 24 and / or the smoothing / angle measurement processing section 25 execute respective processing.

  At low altitude, the reception intensity by the clutter and the target T is separated from the reception intensity by the background reflection, the reception intensity by the clutter is smaller than the display threshold, the clutter is not displayed on the radar display device 3, and the reception intensity by the target T is the display threshold. Larger, the target T is displayed on the radar display device 3. Even at a high altitude, the reception intensity by the clutter and the target T is separated from the reception intensity by the background reflection, the reception intensity by the clutter is smaller than the display threshold, the clutter is not displayed on the radar display device 3, and the reception intensity by the target T is the display threshold. Larger, the target T is displayed on the radar display device 3.

The inclination angle θ _F and the altitude H of the flying object F change every moment. Therefore, when the clutter removal processing is continued (NO in step S4), steps S1 'to S3' are repeated. On the other hand, when ending the clutter removal processing (YES in step S4), the clutter removal program is ended.

Here, the change frequency of the inclination angle theta _F and altitude H of the aircraft F is considered to be small compared to the rotation frequency of the antenna 14-1 and 14-2 (several Hz). Therefore, in one rotation cycle of the antennas 14-1 and 14-2, it is not necessary to execute steps S1 'to S4 many times as in FIG.

  In the second embodiment, before the operation of the radar transmitting and receiving apparatus 1, an attenuation amount table is stored in advance. Here, as a first modified example, during operation of the radar transmitting and receiving apparatus 1, the entire reception is performed so that the degree of attenuation of the receiving intensity due to clutter and background reflection is substantially the same in all directions viewed from the radar transmitting and receiving apparatus 1. The intensity attenuation may be feedback-controlled. Alternatively, as a second modified example, when the radar transmitting and receiving apparatus 1 is operated, the attenuation amount of the entire reception intensity is reduced according to the state of the ground and / or the sea surface L (for example, the wave height, wavelength, and wave speed at the sea surface). You may do machine learning.

(Doppler and angle measurement processing of the present disclosure)
The Doppler / angle measurement processing unit 24 of the radar target detection device 2 according to the first and second embodiments will be described. FIG. 12 illustrates a configuration of the Doppler / angle measurement processing unit according to the present disclosure. The procedure of the Doppler / angle measurement processing of the present disclosure is shown in the flowchart of FIG. 13 and the reception signal of FIG. The Doppler / angle measurement processing unit 24 receives signals from the Doppler processing units 241-1 and 241-2, the ground / sea surface removal units 242-1 and 242-2, the target detection unit 243, the angle measurement processing unit 244, and the radar display output unit 245. Be composed.

  Building B (lower in height than flying vehicle F1), flying vehicle F2 (higher in height than flying vehicle F1), and other terrain, in order of decreasing distance, in front of flying vehicle F1 as its own aircraft. Assume that H (altitude is almost equal to the flying object F1) and rain area C (altitude higher than the flying object F1) exist.

  The Doppler processing units 241-1 and 241-2 receive the received signals of the antennas 14-1 and 14-2 after the clutter removal, respectively. In the received signals of the antennas 14-1 and 14-2 after the clutter is removed, the clutter near the flying object F1 is suppressed.

  The Doppler processing units 241-1 and 241-2 measure the target moving speed based on the reception signals of the antennas 14-1 and 14-2 after the clutter is removed, respectively. Then, the ground / sea surface removing units 242-1 and 242-2 suppress the radar reflection intensity from the ground and / or the sea surface based on the reception signals of the antennas 14-1 and 14-2 after the Doppler processing, respectively. . Further, the Doppler processing units 241-1 and 241-2 measure the moving speed of the target moving with respect to the ground and / or the sea surface, respectively, based on the reception signals of the antennas 14-1 and 14-2 after the Doppler processing. (Step S11). In the reception signals of the antennas 14-1 and 14-2 after the Doppler processing, the reflection intensity from the building B and the topography H, which are fixed targets, is suppressed. Then, the reflection intensity from the flying object F2 as the moving target is maintained. The rain area C, which is a moving target but also a spatially widening target, is determined to be other than the target to be detected.

  The target detection unit 243 measures the distance of the target moving with respect to the ground and / or the sea surface based on the reception signal of the antenna 14-2 after the Doppler processing. In the received signal of the antenna 14-2 after the detection of the target, the distance of the flying object F2 as the moving target is measured. The angle measurement processing unit 244 measures the direction in which the target moves with respect to the ground and / or the sea surface based on the reception signals of the antennas 14-1 and 14-2 after the Doppler processing (step S12). In the received signals of the antennas 14-1 and 14-2 after the angle measurement processing, the elevation angle of the flying object F2 which is the moving target (the elevation angle of the flying object F2 is positive because the elevation of the flying object F2 is higher than the elevation of the flying object F1). Is measured).

  The radar display output unit 245 obtains information on the moving speed of the target moving with respect to the ground and / or the sea surface from the Doppler processing units 241-1 and 241-2, obtains information on the distance from the target detection unit 243, Elevation information is acquired from the angle measurement processing unit 244, altitude and azimuth information is acquired from the inclination / altitude / azimuth information acquisition unit 21 ', and these information are output to the radar display device 3 (step S13). . When the Doppler / angle measurement process is to be continued (NO in step S14), steps S11 to S13 are repeated. On the other hand, when the Doppler / angle measurement processing ends (YES in step S14), the Doppler / angle measurement processing program ends.

  Here, the Doppler processing units 241-1 and 241-2 correct the target moving speed based on the radar inclination information. Then, the ground / sea surface removing units 242-1 and 242-2 correct the suppression of the radar reflection intensity from the ground and / or the sea surface based on the radar inclination information. Further, the Doppler processing units 241-1 and 241-2 correct the moving speed of the target moving with respect to the ground and / or the sea surface based on the radar inclination information (provided in step S11).

FIG. 15 shows the details of Doppler correction based on the tilt angle according to the present disclosure. The x and y directions are within a horizontal plane, and the z direction is a vertical direction. the origin of the xyz coordinate, present aircraft F1 is own apparatus, in a direction shifted by theta _F from + y-axis direction in the elevation direction, reception beam BF flight body F1 is directed. On the + y-axis, there is an aircraft F2, which is another aircraft, and the relative speed V of the aircraft F2 to the aircraft F1 is oriented in a direction deviated by φ _{V in the} horizontal plane from the + y-axis direction.

Then, among the relative speed V of the aircraft F2 for aircraft F1, Doppler velocity of aircraft F2 as seen from the flying object F1 is, Vcosfai _{V (where} direction. Away when viewed from the aircraft F1) should be . However, in a direction shifted by theta _F from + y-axis direction in the elevation direction, reception beam BF flight body F1 is directed. Therefore, among the Doppler velocity Vcosfai _V of the aircraft F2 seen from aircraft F1, Doppler velocity of aircraft F2 that is actually measured is, Vcosφ _V cosθ _F (provided that the direction away when viewed from the aircraft F1.) And turn into. Therefore, based on the Doppler velocity Vcosφ _V cosθ _F of aircraft F2 that is actually measured, as the Doppler velocity of the aircraft F2 corrected after the _{fact, Vcosφ V cosθ F / cosθ F} = Vcosφ V ( where aircraft F1 In the direction away from you).

  Then, the angle measurement processing unit 244 corrects the direction in which the target that moves with respect to the ground and / or the sea surface is present based on the radar tilt information (provided in step S12).

FIG. 16 shows the details of the angle measurement correction based on the tilt angle according to the present disclosure. The x and y directions are within a horizontal plane, and the z direction is a vertical direction. the origin of the xyz coordinate, present aircraft F1 is own apparatus, in a direction shifted by theta _F from + y-axis direction in the elevation direction, reception beam BF flight body F1 is directed. An aircraft F2, which is another aircraft, exists in a direction shifted from the + y-axis direction by the θ _{true value in the} elevation direction.

Then, the elevation angle of the flying object F2 as viewed from the flying object F1 should be a _true θ value. However, in a direction shifted by theta _F from + y-axis direction in the elevation direction, reception beam BF flight body F1 is directed. Therefore, elevation of the aircraft F2 seen from aircraft F1 that is actually measured is becomes theta _measurement = theta _{true value} - [theta] _F. Therefore, based on the elevation angle theta _measured in aircraft F2 seen from aircraft F1 that is actually measured, as the elevation angle of the aircraft F2 seen from aircraft F1 corrected after the fact, theta _{true value} = theta _measuring + theta _F Should be measured. In FIG. 15, a case is considered where the elevation angle of the flying object F2 viewed from the flying object F1 is 0. However, unlike FIG. 15, even when the elevation angle of the flying body F2 viewed from the flying body F1 is not 0, the elevation angle of the flying body F2 viewed from the flying body F1 is measured (see FIG. 16). The Doppler velocity of the flying object F2 as viewed from the flying object F1 may be measured (refer to FIG. 15, but the elevation angle of the flying object F2 as viewed from the flying object F1 is also taken into consideration).

(Smoothing and angle measurement processing of the present disclosure)
The smoothing / angle measurement processing unit 25 of the radar target detection device 2 according to the first and second embodiments will be described. FIG. 17 illustrates the configuration of the smoothing / angle measurement processing unit according to the present disclosure. The procedure of the smoothing / angle measurement processing of the present disclosure is shown in the flowchart of FIG. 18 and the received signal of FIG. The smoothing and angle measurement processing unit 25 includes smoothing processing units 251-1 and 251-2, a target detection unit 252, an angle measurement processing unit 253, and a radar display output unit 254.

  Building B (lower in height than flying vehicle F1), flying vehicle F2 (higher in height than flying vehicle F1), and other terrain, in order of decreasing distance, in front of flying vehicle F1 as its own aircraft. Assume that H (altitude is almost equal to the flying object F1) and rain area C (altitude higher than the flying object F1) exist.

  The smoothing processing units 251-1 and 251-2 receive the received signals of the antennas 14-1 and 14-2 after clutter removal, respectively. In the received signals of the antennas 14-1 and 14-2 after the clutter is removed, the clutter near the flying object F1 is suppressed.

  The smoothing processing units 251-1 and 251-2 respectively perform smoothing processing (within a predetermined distance and azimuth range) on the reception signals of the antennas 14-1 and 14-2 after the clutter removal along the distance and the azimuth. Average processing). Then, the smoothing processing units 251-1 and 251-2 respectively suppress the radar reflection intensity from the small target in the received signals of the antennas 14-1 and 14-2 after the smoothing processing (step S21). . In the reception signals of the antennas 14-1 and 14-2 after the smoothing processing, the reflection intensity from the flying object F2, which is a small target, is suppressed. Then, the reflection intensity from the large-scale target, the building B, the terrain H, and the rain area C is maintained.

  The target detection unit 252 measures the distance of a large target based on the received signal of the antenna 14-2 after the smoothing processing. In the reception signal of the antenna 14-2 after the detection of the target, the distance between the building B, the topography H, and the rain area C, which are large targets, is measured. The angle measurement processing unit 253 measures the direction in which the large target exists based on the received signals of the antennas 14-1 and 14-2 after the smoothing processing (step S22). In the signals received by the antennas 14-1 and 14-2 after the angle measurement processing, the elevation angles of the large target, the building B, the terrain H, and the rainy area C (because the altitude of the building B is lower than the altitude of the flying object F1) The elevation angle of the building B is negative.The elevation angle of the terrain H is substantially equal to the elevation angle of the flying object F1, and the elevation angle of the terrain H is almost 0. The elevation angle of the rain area C is higher than the elevation angle of the flying object F1. , The elevation angle of the rain area C is positive.).

  The radar display output unit 254 acquires distance information from the target detection unit 252 for a large target, acquires elevation information from the angle measurement processing unit 253, and acquires altitude information from the tilt / altitude / azimuth information acquisition unit 21 '. And information on the azimuth angle is obtained, and the information is output to the radar display device 3 (step S23). Then, when the smoothing / angle measurement process is continued (NO in step S24), steps S21 to S23 are repeated. On the other hand, when ending the smoothing / angle measurement processing (YES in step S24), the smoothing / angle measurement processing program is ended.

  Here, the angle measurement processing unit 253 corrects the direction in which the large target exists based on the radar tilt information (the proviso of step S22).

FIG. 16 shows the details of the angle measurement correction based on the tilt angle according to the present disclosure. The x and y directions are within a horizontal plane, and the z direction is a vertical direction. the origin of the xyz coordinate, present aircraft F1 is own apparatus, in a direction shifted by theta _F from + y-axis direction in the elevation direction, reception beam BF flight body F1 is directed. An aircraft F2, which is another aircraft, exists in a direction shifted from the + y-axis direction by the θ _{true value in the} elevation direction.

Then, the elevation angle of the flying object F2 as viewed from the flying object F1 should be a _true θ value. However, in a direction shifted by theta _F from + y-axis direction in the elevation direction, reception beam BF flight body F1 is directed. Therefore, elevation of the aircraft F2 seen from aircraft F1 that is actually measured is becomes theta _measurement = theta _{true value} - [theta] _F. Therefore, based on the elevation angle theta _measured in aircraft F2 seen from aircraft F1 that is actually measured, as the elevation angle of the aircraft F2 seen from aircraft F1 corrected after the fact, theta _{true value} = theta _measuring + theta _F Should be measured.

  INDUSTRIAL APPLICABILITY The radar target detection device and the radar target detection program according to the present disclosure can be particularly usefully applied to a radar device mounted on a flying object, a ship, or the like, which has strong shaking.

R: radar system F, FF, FB, F1, F2: flying object T: target B: building H: terrain C: rain area BF, BB, BD: transmission / reception beam L: ground and / or sea surface 1: radar transmission / reception device 2: radar target detection device 3: radar display device 4: inclination / azimuth angle detection device 4 ': inclination / altitude / azimuth angle detection device 11: waveform generation unit 12: radar transmission unit 13: circulators 14-1 and 14-2. : Antenna 15: motor drive unit 16: rotary axis motor 17: azimuth rotation axis 18-1, 18-2: radar attenuation unit 19-1, 19-2: radar reception unit 21: tilt / azimuth information acquisition unit 21 ': Slope / altitude / azimuth information acquisition unit 22: attenuation table storage unit 23: reception intensity attenuation unit 24: Doppler / angle measurement processing unit 25: smoothing / angle measurement processing units 241-1, 241-2: Doppler Processing units 242-1 and 24 -2: ground / sea surface removal unit 243: target detection unit 244: angle measurement processing unit 245: radar display output unit 251-1, 251-2: smoothing processing unit 252: target detection unit 253: angle measurement processing unit 254: Radar display output section

Claims (8)

A radar tilt information acquisition unit configured to acquire radar tilt information regarding a tilt angle of a transmitting / receiving antenna of the radar device with respect to the ground and / or the sea surface;
On the basis of the radar tilt information, based on the radar tilt information, the direction of the transmission / reception beam of the radar device is directed toward the ground and / or the sea surface, so that the distance from the radar device to the reflection object closer to the reception intensity of the radar device is short. A radar reception intensity attenuating unit that increases the attenuation of the reception intensity of the radar device, and decreases the attenuation of the reception intensity of the radar device as the direction of the transmission / reception beam of the radar device is away from the ground and / or the sea surface. When,
In the reception intensity of the radar device output by the radar reception intensity attenuating unit, the radar reflection intensity from the ground and / or the sea surface is suppressed based on the Doppler processing, and the moving speed of the target moving relative to the ground and / or the sea surface Doppler angle measurement processing unit that measures the direction of the target that moves with respect to the ground and / or the sea surface based on the angle measurement processing,
A radar target detection device comprising: In the Doppler processing, the Doppler / angular processing unit corrects suppression of radar reflection intensity from the ground and / or the sea surface based on the radar tilt information, and moves a target moving with respect to the ground and / or the sea surface. The radar target detection according to claim 1, wherein a speed is corrected, and in the angle measurement processing, a direction in which a target that moves relative to the ground and / or the sea surface is corrected based on the radar inclination information. apparatus. A radar tilt information acquisition unit configured to acquire radar tilt information regarding a tilt angle of a transmitting / receiving antenna of the radar device with respect to the ground and / or the sea surface;
On the basis of the radar inclination information, based on the radar inclination information, the direction of the transmission / reception beam of the radar device is directed toward the ground and / or the sea surface, so that the distance from the radar device to the reflection object closer to the reception intensity of the radar device is shorter. A radar reception intensity attenuating unit that increases the attenuation of the reception intensity of the radar device, and decreases the attenuation of the reception intensity of the radar device as the direction of the transmission / reception beam of the radar device is farther away from the ground and / or the sea surface. When,
In the reception intensity of the radar device output by the radar reception intensity attenuator, the radar reflection intensity from a small target is suppressed based on a smoothing process along a distance and an azimuth. A smoothing and angle measurement processing unit for measuring the direction in which the target exists,
A radar target detection device comprising: 4. The radar target detection device according to claim 3, wherein the smoothing / angle measurement processing unit corrects a direction in which a large target exists in the angle measurement processing based on the radar tilt information. 5. A radar altitude information acquisition unit that acquires radar altitude information about the altitude of the transmitting / receiving antenna of the radar apparatus from the ground and / or the sea surface,
The radar reception intensity attenuating unit, based on the radar tilt information, when it is determined that the direction of the transmitting and receiving beams of the radar device is directed to the ground and / or sea surface, based on the radar altitude information, The lower the altitude of the transmitting / receiving antenna of the radar apparatus is from the ground and / or the sea surface, the quicker the attenuation of the reception intensity of the radar apparatus with respect to the increase in the distance from the radar apparatus to the reflecting object, The altitude of the transmitting / receiving antenna is higher from the ground and / or the sea surface, and the attenuation of the reception intensity of the radar device with respect to the increase in the distance from the radar device to the reflecting object is gradually reduced. 5. The radar target detection device according to any one of claims 1 to 4. Attenuation storing an attenuation amount table that associates an inclination angle of a transmission / reception antenna of the radar device with respect to the ground and / or the sea surface, and a relationship between a distance from the radar device to a reflecting object and an attenuation amount of the reception intensity of the radar device. An amount table storage unit,
The radar reception intensity attenuating unit, based on the radar tilt information and the attenuation amount table, reduces the attenuation of the reception intensity of the radar device as the direction of the transmission / reception beam of the radar device is directed toward the ground and / or the sea surface. On the other hand, the more the direction of the transmission / reception beam of the radar apparatus is away from the ground and / or the surface of the sea, the smaller the attenuation of the reception intensity of the radar apparatus is. A radar target detection device as described in the above. Radar inclination information acquisition step of acquiring radar inclination information relating to the inclination angle of the transmitting / receiving antenna of the radar device with respect to the ground and / or the sea surface;
On the basis of the radar tilt information, based on the radar tilt information, the direction of the transmission / reception beam of the radar device is directed toward the ground and / or the sea surface, so that the distance from the radar device to the reflection object closer to the reception intensity of the radar device is short. A radar reception intensity attenuation step of increasing the attenuation of the reception intensity of the radar device, and decreasing the attenuation amount of the reception intensity of the radar device as the direction of the transmission / reception beam of the radar device is further away from the ground and / or the sea surface. When,
In the reception intensity of the radar device output in the radar reception intensity attenuation step, the radar reflection intensity from the ground and / or the sea surface is suppressed based on Doppler processing, and the moving speed of the target moving with respect to the ground and / or the sea surface Measuring, based on the angle measurement processing, the Doppler angle measurement processing step of measuring the direction of the target moving relative to the ground and / or the sea surface,
Target detection program for causing a computer to execute in order. Radar inclination information acquisition step of acquiring radar inclination information relating to the inclination angle of the transmitting / receiving antenna of the radar device with respect to the ground and / or the sea surface;
On the basis of the radar tilt information, based on the radar tilt information, the direction of the transmission / reception beam of the radar device is directed toward the ground and / or the sea surface, so that the distance from the radar device to the reflection object closer to the reception intensity of the radar device is short. A radar reception intensity attenuation step of increasing the attenuation of the reception intensity of the radar device, and decreasing the attenuation amount of the reception intensity of the radar device as the direction of the transmission / reception beam of the radar device is further away from the ground and / or the sea surface. When,
In the reception intensity of the radar device output in the radar reception intensity attenuation step, the radar reflection intensity from a small target is suppressed based on a smoothing process along a distance and an azimuth. A smoothing and angle measurement processing step for measuring the direction in which the target exists,
Target detection program for causing a computer to execute in order.

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