JP2017003386A - Radar device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radar device capable of easily determining whether or not a target veers.SOLUTION: A radar device performs transmission and reception of a wave and rotates a radar antenna in a horizontal plane, for detecting the surrounding of an own device (radar device). The radar device comprises a Doppler velocity calculation part for calculating Doppler velocity of the target with respect to the own device (radar device) on each of plural points, based on detection information (reception data) obtained from each of the plural points of the single target. The radar device uses the Doppler velocities (V,V) detected on each of the plural points (i,j) of the single target, for determining whether or not the target veers.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a radar apparatus for detecting the surroundings of its own apparatus. More specifically, the present invention relates to a configuration for detecting another target that has changed needles in a radar apparatus.

  2. Description of the Related Art Conventionally, a radar device that detects the surroundings of its own device by transmitting and receiving radio waves while rotating a radar antenna in a horizontal plane is known. Patent Documents 1 and 2 disclose this type of radar apparatus.

  The radar apparatus disclosed in Patent Document 1 is configured to be able to obtain information on whether another target (for example, another ship) is approaching or moving away using the Doppler velocity.

  The radar apparatus disclosed in Patent Documents 2 and 3 tracks one target (for example, another ship), so that the Doppler speed of the target acquired during one scan in which the radar antenna makes one rotation and the previous one scan. The rate of change of the Doppler speed of the target acquired during this period is calculated to determine whether the target has changed.

  Further, the radar apparatus of Patent Document 4 also calculates the rate of change of the Doppler velocity between the previous frame (corresponding to the previous one scan) and the current frame (corresponding to the current one scan), and whether the target is changing. It is the structure which judges whether or not.

JP 2013-178206 A Japanese Patent No. 5415145 Japanese Patent No. 5196971 Japanese Patent No. 2930841

  However, the radar device disclosed in Patent Document 1 cannot detect a target that has changed its course. Further, in the configurations of Patent Documents 2 to 4, although it is possible to detect whether or not the target has changed, at least one radar antenna rotates to determine whether or not the target has changed. It took time equivalent to one scan. Further, when detecting the Doppler velocity for one point of the target at a certain time, the detection information obtained from the one point is detected from the detection information obtained from many other surrounding points. It was technically difficult to discriminate and extract.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a radar apparatus capable of determining in a short time whether or not a target has changed.

Means and effects for solving the problems

  The problems to be solved by the present invention are as described above. Next, means for solving the problems and the effects thereof will be described.

  According to an aspect of the present invention, a radar apparatus having the following configuration is provided. That is, this radar apparatus detects the surroundings of its own apparatus by transmitting and receiving radio waves while rotating the radar antenna in a horizontal plane. The radar apparatus includes a Doppler velocity calculation unit that calculates Doppler velocity of the target with respect to the own device at each of the plurality of points from detection information obtained from the plurality of points of one target. Then, the radar apparatus determines whether or not the target has changed using the Doppler velocity calculated at each of the plurality of points of the one target.

  Accordingly, it is possible to determine in a short time whether or not the target is changing its needle, using the Doppler velocities detected at a plurality of points of one target. Thereby, the information useful for the user for preventing the collision with the target can be provided.

  The radar device preferably has the following configuration. That is, the radar apparatus further includes a direction determination unit and a needle change determination unit. The direction determination unit calculates an actual velocity vector at each of a plurality of points of the one target from the Doppler velocity, and determines whether or not the directions of the actual velocity vectors at the respective points are substantially the same. To do. The needle change determination unit determines that the target has changed if the directions of the respective actual velocity vectors are different.

  Thereby, it is possible to easily determine whether or not the target has changed using a direct indicator related to the change of the actual speed vector.

  In the radar apparatus, it is preferable that the needle change determination unit determines that the target is traveling straight if the directions of the actual speed vectors are substantially the same.

  Thereby, it is possible to easily determine whether or not the target is moving straight, using a direct index related to the change in the direction of the actual speed vector.

  The radar device preferably has the following configuration. That is, when the direction determination unit considers a first point that is one point among a plurality of points of the one target and a second point that is a plurality of points other than the first point. Assuming that the target has not changed, an angle formed by an actual velocity vector of the first point with respect to a line segment connecting the first point and the own device for each of the second points. Is calculated based on the Doppler speed at the first point and the Doppler speed at the second point. The orientation determination unit evaluates variations between the plurality of angles.

  That is, even if the Doppler velocities obtained at a plurality of points of one target are directly compared, it is difficult to determine whether or not the target has changed. In this regard, according to the above-described configuration, an indicator of the direction of the actual velocity vector at each of a plurality of points of one target (more precisely, a line segment connecting the first point and the device itself, It is possible to determine whether or not the target has changed the needle directly and simply using the actual velocity vector at the first point and the index formed by the angle.

  In the radar apparatus, the Doppler velocity at each of a plurality of points of the one target is calculated during one scan in which the radar antenna makes one rotation, and whether or not the target has changed its needle. Is preferably determined.

  Thus, in the past, it was determined whether or not the target has changed by tracking the target over a plurality of scans to detect a change in Doppler speed. In this configuration, only one scan is performed. It is possible to know whether or not the target has changed its needle, and it is possible to detect the changing of the needle more quickly.

  In the radar apparatus, it is preferable that the plurality of points of the one target is three points or more.

  Accordingly, the needle change can be detected with high accuracy by comprehensively considering the Doppler speeds at three or more points of one target.

  The radar device preferably has the following configuration. That is, the radar apparatus further includes a display unit that displays a result of detecting the surroundings of the radar apparatus as a radar image. When it is determined that the target has not changed, the display unit displays a display representing the target in a predetermined manner at a corresponding portion of the radar image. On the other hand, when it is determined that the target has changed, a display indicating the target is displayed in a different form from the predetermined form at a corresponding portion of the radar image.

  As a result, by displaying the target that has changed the needle on the radar image in a different manner from the target that has not changed the needle, the user viewing the radar image on the display unit pays attention to the target that has changed. It becomes easy and the monitoring burden with respect to the target around a user can be reduced.

  In the radar apparatus, it is preferable that a tracking process is performed on the target that has been determined to have changed.

  Thereby, it is possible to prevent a collision with the target by tracking the target that has been changed and paying attention to the subsequent movement.

  In the radar apparatus, it is preferable to predict the course of the target after using the determination as to whether or not the target has changed.

  Thereby, the subsequent course of the target can be predicted using the determination as to whether or not the target has changed, and a collision with the target can be reliably prevented.

1 is a block diagram showing an overall configuration of a radar apparatus according to an embodiment of the present invention. Explanatory drawing which shows the relationship between the Doppler speed of each point and an actual speed vector when it is assumed that the target (other ship) is going straight ahead.

  Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing an overall configuration of a radar apparatus 11 according to an embodiment of the present invention.

  A radar apparatus 11 of this embodiment shown in FIG. 1 is a ship radar provided in a ship such as a fishing boat, and is mainly used for detecting a target such as another ship. The radar device 11 will be schematically described. The radar device 11 detects the surroundings of the own device (own ship) by transmitting and receiving radio waves while rotating the radar antenna 1 in a horizontal plane.

  As shown in FIG. 1, the radar apparatus 11 of this embodiment includes an antenna unit 21 and a signal processing unit 22.

  The antenna unit 21 is attached to a predetermined position on the ship. The antenna unit 21 includes a radar antenna 1, a detection unit 2, and an A / D conversion unit 3.

  The radar antenna 1 can radiate a signal (pulsed radio wave) having a sharp directivity and is configured to receive an echo (reflected signal) from a target around the device. The radar antenna 1 is configured to be able to rotate 360 ° in a horizontal plane, and is configured to repeatedly transmit and receive radio waves while changing the transmission direction of pulsed radio waves (changing the angle of the radar antenna 1). With this configuration, it is possible to detect a target around the own device (own ship) over 360 °. In the following description, the operation from the transmission of a pulsed radio wave to the transmission of the next pulsed radio wave is called “sweep”, and the operation of rotating the radar antenna 1 360 ° while transmitting / receiving radio waves is “ Sometimes called “scan”.

  The detector 2 detects and amplifies the signal received by the radar antenna 1 and outputs the received signal to the A / D converter 3.

  The A / D converter 3 samples the analog received signal input from the detector 2 and converts it into digital data consisting of a plurality of bits (hereinafter also referred to as “received data”).

  The signal processing unit 22 includes a sweep memory 4, a binarization processing unit 5, a target relative coordinate estimation unit 61, a pulse Doppler processing unit 17, a Doppler velocity calculation unit 18, an orientation determination unit 63, and a needle change determination. A unit 64, an image memory 7, an image processing unit 8, and a display 9 are provided.

  The sweep memory 4 is a buffer memory that can store received data for one sweep in real time. In the sweep memory 4, received data sampled during one sweep is stored in chronological order. Accordingly, the distance r to the echo source corresponding to the received data can be obtained based on the read address when the received data is read from the sweep memory 4. Although not shown, data indicating which direction the radar antenna 1 is currently facing with respect to the bow (antenna angle) is output from the radar antenna 1. Therefore, when reading the received data from the sweep memory 4, the position of the echo source corresponding to the received data can be obtained in polar coordinates.

  The binarization processing unit 5 performs binarization by comparing the signal level of the sweep memory 4 with a predetermined binarization threshold value. Specifically, the binarization processing unit 5 outputs data (for example, “1”) indicating that “there is a target” when the signal level is equal to or higher than the binarization threshold. On the other hand, when the signal level is less than the binarization threshold, data indicating that “there is no target” (for example, “0”) is output.

  The target relative coordinate estimation unit 61 evaluates the continuity on the plane of the binarized data input from the binarization processing unit 5, and it is determined that “there is a target” collectively. After extracting the existing data, the coordinates of a plurality of points in one target are obtained. That is, since the data collected spatially is considered to indicate an echo from one target, the target relative coordinate estimation unit 61 selects a continuous region determined to be “having the target” as one target. Consider it a mark. The target relative coordinate estimation unit 61 extracts a plurality of points from the obtained continuous region under appropriate conditions, and outputs the coordinates of the points to the pulse Doppler processing unit 17. These points are used as points of interest for detecting a target needle change. Note that, from the viewpoint of reliably detecting the change of needle, it is preferable that the plurality of points to be extracted be points to some extent apart from one target (for example, a plurality of points including both ends of the target).

  The pulse Doppler processing unit 17 and the Doppler velocity calculation unit 18 obtain the Doppler frequency by the pulse Doppler (pulse pair) method, and calculate the Doppler velocity of the target based on the Doppler frequency.

  The pulse Doppler processing unit 17 calculates a Doppler frequency at each of a plurality of points of one target extracted by the target relative coordinate estimation unit 61. Specifically, the phase change between the echo carrier wave in the current sweep and the echo carrier wave in the immediately preceding sweep at each of a plurality of points is obtained. Then, based on this phase change, the Doppler frequency at each of the plurality of points is calculated. After calculating the Doppler frequency, the pulse Doppler processing unit 17 outputs the Doppler frequency to the Doppler velocity calculation unit 18.

  The Doppler velocity calculation unit 18 calculates the relative velocity at each of a plurality of points from the relational expression between the Doppler frequency and the relative velocity. The relative velocity calculated here is the relative velocity between the own device and the target in the radiation direction component of the radio wave from the own device (own ship) (the relative speed in the linear distance direction between the target and the own device), That is, the Doppler speed. Here, the Doppler speed at each of a plurality of points (attention points) of the target detected by the Doppler speed calculation unit 18 is output to the direction determination unit 63.

The direction determination unit 63 substantially calculates an actual velocity vector at each of the plurality of points of the target based on the Doppler velocity at each of the plurality of points of the target, and the plurality of points. It is determined whether or not the directions of the actual speed vectors are the same. Specifically, the direction determination unit 63 first assumes that the target is moving straight without changing its course (that is, the actual velocity vectors at each of a plurality of points of the target have the same direction, and Under the assumption that they have the same length), based on the Doppler velocities at each of the plurality of points of the target, an operation for _obtaining a value of a common index (α _{ij to be} described later) is performed. It is determined whether or not the index value obtained from the speed is more than a threshold value. If the variation is less than the threshold value, it means that the above assumption is correct. Therefore, the direction determination unit 63 determines that the directions of the actual speed vectors are substantially the same. On the other hand, if the variation is equal to or greater than the threshold value, it means that the above assumption is incorrect. Therefore, the direction determination unit 63 determines that the directions of the actual speed vectors are not the same (different). The direction determination unit 63 outputs the determination result thus obtained to the needle change determination unit 64. The details of the calculation and processing performed by the orientation determination unit 63 will be described later.

  The needle change determination unit 64 determines whether or not the target has changed. Specifically, the needle changing determination unit 64 determines that the target is moving straight if the direction of the actual velocity vector at each of the plurality of points of the target is substantially the same. On the other hand, if the direction of the actual velocity vector at each of the plurality of points of the target is different, it is determined that the target has changed. The needle change determination unit 64 outputs a determination result as to whether or not each target has changed its needle to the image processing unit 8.

  The image memory 7 is configured to be able to store a raster format two-dimensional image. With this configuration, the received data output from the sweep memory 4 is output to the address after the address is calculated to indicate the position on the plane of the target that has emitted (reflected) the echo. As a result, the received data is plotted on the two-dimensional image, and as a result, a raster image in the form of a raster image showing the state of the target around the device itself is generated.

  The image processing unit 8 generates a radar image for display based on the received data stored in the image memory 7 and superimposes the estimated motion information of the target on the radar image. For example, the image processing unit 8 blinks only a mark indicating a target that has been changed, or displays it in a color different from that of another target (a target that has not been changed). Thereby, it becomes easy for the user to pay attention to the subsequent movement of the target whose course has been changed (the course is being changed), and the monitoring burden on the target around the user can be reduced.

  The display 9 as a display unit is configured as a known raster scan type display device, for example, and displays the result of detecting the surroundings of the device as a radar image. The display device 9 is configured to be able to display a composite image reflecting the processing result of the image processing unit 8 as a radar image.

  Next, processing performed by the orientation determination unit 63 will be described in detail with reference to FIG. FIG. 2 is an explanatory diagram showing the relationship between the Doppler speed at each point and the actual speed vector when it is assumed that the target (other ship) is traveling straight.

As described above, the direction determination unit 63 calculates the value of the common index (α _ij ) based on the Doppler velocity at each of the plurality of points of the target, and performs the process of evaluating the variation.

In the following description, the position of the own device is defined as point O (polar coordinates (0, 0)). In addition, one of the plurality of points of the target for which the Doppler velocity calculation unit 18 has calculated the Doppler velocity is set as a point i, and the other one of the plurality of points is set as a point j. An angle formed by the line segment iO and the line segment jO is defined as θ _ij .

The Doppler velocity of the target at the point i is represented by V _i ^d , and the Doppler velocity of the target at the point j is represented by V _j ^d . Further, the actual velocity vector of the target at the point _i is represented by V _i , and the actual velocity vector of the target at the point j is represented by V _j . Note that the Doppler speed is positive when approaching the own device (own ship) from the target (other ship).

Further, the angle formed by the line segment iO with respect to the actual velocity vector V _i of the target at the point i is α _ij, and the angle formed by the line segment jO with respect to the actual velocity vector V _j of the target at the point j is Let α _j . These angles α _ij and α _j are set to −π ≦ α ≦ π with the counterclockwise direction being positive when the point on the target (other ship) side is the starting point.

Here, V _i ^d , V _j ^d , and θ _ij can be acquired by normal processing of the radar apparatus 11 (so-called Doppler radar), while V _i , V _j , α _ij , and α _j are directly It cannot be obtained and the following calculation is required.

Here, when the magnitude | V _i | of the actual velocity vector V _i at the point i is expressed using V _i ^d and α _ij , the following expression (1) is obtained.

Further, when the magnitude | V _j | of the actual velocity vector V _{j at} the point j is expressed using V _j ^d and α _j , Expression (2) is obtained.

Here, the direction determination unit 63 performs subsequent calculations and processing on the assumption that the target is traveling straight. If the target is going straight, the actual velocity vector of the target will be the same at any point on the target, so the magnitude of the actual velocity vector V _i of the target at point i and the point j The actual velocity vector V _j of the target is equal. That is, when it is assumed that the target is traveling straight, Equation (3) is established.

Further, if the target is moving straight, the actual velocity vector of the target is the same at any point on the target. Therefore, the direction of the actual velocity vector V _i of the target at the point i and the point j The direction of the actual velocity vector V _j of the target at is equal. That is, when it is assumed that the target is traveling straight, Equation (4) is established.

Substituting the expression representing | V _i | in Expression (1) and the expression representing | V _j | in Expression (2) into Expression (3), and then expressing α _j in Expression (4). When substituted, it becomes like Formula (5).

式（７）より、α_ijを求めることができる。 When the above equation (5) is transformed using the trigonometric addition theorem (6), the following equation (7) is obtained.

Α _ij can be obtained from equation (7).

Although the above is the calculation for one point j, in this embodiment, the point j is an arbitrary plurality of points (n points, where n ≧ 2) on the target, and each point j The value of the angle α _ij formed by the line segment iO with respect to the actual velocity vector V _i of the target at i is obtained. Therefore, the value of the angle α _ij can be obtained by the number (n) of points j (α _i1 ,..., Α _ij ,..., Α _in ). Further, if considered substantially, the angle α _ij can be said to be a common index at a plurality of points j affected by the actual velocity vector at the point i and the actual velocity vector at the point j.

Subsequently, the direction determination unit 63 compares the index values α _i1 ,..., Α _in obtained from the respective Doppler velocities, and determines whether or not there is a variation of the values over a threshold value. If the variation _in α _i1 ,..., Α _in is less than the threshold value, it is determined that the above assumptions are correct and the directions of the actual speed vectors are substantially the same. On the other hand, if the variation of α _i1 ,..., Α _in is greater than or equal to the threshold value, it is determined that the direction of the actual speed vector is not the same (different) because the above assumption is incorrect.

In the present embodiment, the direction determination unit 63 determines that the direction of the actual speed vector is substantially the same when the variation of the index values α _i1 ,..., Α _in is greater than or equal to the threshold, and the actual speed when the variation is less than the threshold. It is determined that the direction of the vector is different. However, theoretically, even when the directions of the actual velocity vectors are the same and are different in magnitude, the index values α _i1 ,..., Α _in can vary. However, the fact that the direction of the actual velocity vector is the same and differs in magnitude at a plurality of points of one target means that the target expands and contracts in a certain direction, so it is difficult to think in practice. Therefore, when the index values α _i1 ,..., Α _in vary, it can be said that there is no practical problem even if the direction of the actual speed vector is evaluated to be different.

  In this way, the direction determination unit 63 substantially calculates the actual speed vector at each of a plurality of points of one target (another ship, etc.), and the actual speed at each of the plurality of points. It is determined whether or not the directions of the vectors are the same. Then, the needle change determination unit 64 determines whether or not the target has changed using the result determined by the direction determination unit 63.

As can be seen from FIG. 2, the Doppler velocities obtained at each of a plurality of points of one target have different directions and sizes, and each of the plurality of points of one target detected by the radar device 11. Even if the Doppler velocities are directly compared, it is difficult to determine whether or not the target has changed. In this respect, the direction determination unit 63 of the present embodiment substantially directly and simply uses the target of the direction of the actual velocity vector at each of a plurality of points of one target. It can be determined whether or not the needle has changed. Strictly speaking, in the calculation and processing performed by the orientation determination unit 63 in this embodiment, one point i (first point) among a plurality of points of one target and a plurality of points of the target are calculated. When considering the point j (second point) that is n points other than the point i, it is assumed that the target has not changed, and for each point j, the point i The angle α _ij formed by the actual velocity vector V _{i at the} point i with respect to the line iO connecting the device is calculated based on the Doppler velocity at the point i and the Doppler velocity at the point j, and the variation is calculated. By evaluating, it can be determined whether or not the target has changed.

As described above, the radar apparatus 11 of the present embodiment detects the surroundings of its own apparatus (radar apparatus 11) by transmitting and receiving radio waves while rotating the radar antenna 1 in a horizontal plane. The radar apparatus 11 detects the Doppler velocity of the target with respect to the target apparatus (radar apparatus 11) at each of the plurality of points from detection information (received data) obtained from the plurality of points of one target. The Doppler speed calculation unit 18 is provided. Then, using the Doppler velocities (V _i ^d , V _j ^d ,...) Detected at a plurality of points (i, j,...) Of the one target, the target is changed to a needle. Judge whether or not.

As a result, the target is changed by using Doppler velocities (V _i ^d , V _j ^d ,...) Detected at a plurality of points (i, j,...) Of one target. It can be easily determined whether or not. As a result, information useful for the user (for example, information indicating the presence of a dangerous target such as a large ship changing its course) can be easily provided.

  In particular, the Doppler velocity at each of a plurality of points (i, j,...) Of one target can be detected during one scan in which the radar antenna 1 is rotated once. Then, it is possible to determine whether or not the target has changed using the Doppler velocities at a plurality of points (i, j,...) Detected during this one scan.

  Thus, conventionally, by tracking a target over a plurality of scans and detecting a change in Doppler speed, it has been determined whether or not the target has changed needles. By doing so, it is possible to know whether or not the target has changed the needle by only one scan, and it becomes possible to detect the changing of the needle more quickly.

  The preferred embodiment of the present invention has been described above, but the above configuration can be modified as follows, for example.

  In the above embodiment, it is assumed that at least three points are included in a plurality of points (attention points used for detecting a change of needle) of one target, but the number of attention points may be arbitrary. That is, the number of points of interest is preferably 3 or more, and is preferably 4 or more from the viewpoint of improving the detection accuracy of the changing needle.

  In the above embodiment, the target in which the needle change is detected is configured to be displayed in a different form (for example, in a different color), but instead, it is triggered by the detection of the target needle change. The target may be automatically set as a target of the tracking process, and the target may be displayed in a mode different from the normal time. As the tracking process, for example, known target tracking (TT) may be used, but is not limited thereto. In this way, by detecting a target that has changed its course and automatically tracking it, it becomes easier for the user to focus on subsequent movements, and the ship's own ship collides with the target (other ship). Can be prevented.

  Instead of the above embodiment, the subsequent course of the target may be predicted using the degree to which the target has changed. In that case, for example, it is possible to adopt a configuration in which the subsequent course calculated using the degree of change of the needle is displayed on the radar image. Alternatively, in addition to this, if the target has not changed, it is predicted that the target will continue to travel straight thereafter, and the speed of the target is calculated using equation (1). The predicted course may be acquired and displayed on the radar image.

  In the above embodiment, the Doppler frequency is obtained by the pulse Doppler method, and the Doppler velocity of the target is calculated based on the Doppler frequency. However, the method of calculating the Doppler velocity is not limited to this. For example, instead of calculating the Doppler velocity, the Doppler velocity may be directly calculated only by echoes obtained in one sweep without calculating the Doppler frequency.

  Although the radar apparatus of the above embodiment is a ship radar apparatus provided in a ship such as a fishing boat, the radar apparatus of the present invention is not limited to a ship, and for example, instead of this, for an aircraft The present invention can also be applied to other radar devices.

Doppler velocity of a target in one radar antenna 6 target motion estimator 11 radar system 62 Doppler velocity calculation unit 63 orientation determining unit 64 veering determination unit V _i Doppler velocity of the target object at the point ^d i V _j ^d point j theta _ij line iO and goods angle alpha _j segment actual velocity vector alpha _ij line iO and V _i of the target object is formed in the actual velocity vector V _j point j of characteristic at an angle V _i points i line segments jO forms angle between jO and V _j

Claims (9)

In a radar device that detects the surroundings of its own device by transmitting and receiving radio waves while rotating the radar antenna in a horizontal plane,
From the detection information obtained from a plurality of points of one target, comprising a Doppler speed calculation unit that calculates a Doppler speed of the target with respect to the device at each of the plurality of points,
A radar apparatus, wherein a Doppler velocity calculated at each of a plurality of points of the one target is used to determine whether or not the target has changed. The radar apparatus according to claim 1,
A direction determining unit that calculates an actual velocity vector at each of a plurality of points of the one target from the Doppler velocity, and determines whether or not the directions of the actual velocity vectors are substantially the same;
A needle change determination unit that determines that the target has changed if the direction of each actual velocity vector is different,
A radar apparatus, further comprising: The radar apparatus according to claim 2,
The radar change determining unit determines that the target is moving straight if the directions of the respective actual velocity vectors are substantially the same. The radar apparatus according to claim 2 or 3,
The orientation determination unit
When considering a first point that is one point among a plurality of points of the one target and a second point that is a plurality of points other than the first point,
Assuming that the target has not changed, for each of the second points, an angle formed by the actual velocity vector of the first point with respect to a line segment connecting the first point and the own device. , Based on the Doppler velocity at the first point and the Doppler velocity at the second point,
The radar apparatus according to claim 1, wherein the orientation determination unit evaluates variations between the plurality of angles. The radar apparatus according to any one of claims 1 to 4, wherein
The Doppler velocity at each of a plurality of points of the one target is calculated during one scan in which the radar antenna makes one rotation, and it is determined whether or not the target has changed. Radar device. A radar device according to any one of claims 1 to 5,
The radar apparatus according to claim 1, wherein the plurality of points of the one target is three or more points. The radar apparatus according to any one of claims 1 to 6,
A display unit for displaying a result of detecting the surroundings of the device as a radar image;
The display unit
When it is determined that the target has not changed, a display representing the target is displayed in a predetermined manner at a corresponding position in the radar image,
A radar apparatus, wherein when it is determined that the target has changed, a display representing the target is displayed in a different form from the predetermined form at a corresponding portion of the radar image. The radar apparatus according to any one of claims 1 to 7,
A radar apparatus characterized in that a tracking process is performed on the target that is determined to have changed needles. The radar apparatus according to any one of claims 1 to 8,
A radar apparatus characterized by predicting a subsequent course of the target using a determination as to whether or not the target has changed.

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