Height measuring device, height measuring method, height measuring program

Abstract

To measure a height of an object with simple and inexpensive radars.SOLUTION: A height measurement device measures a height of an object by using a plurality of radars. In the radar, measurement accuracy in a horizontal direction is set to be higher than measurement accuracy in a vertical direction in order to measure a linear distance to the object. The height measurement device includes a recording section, a signal identification section, and a calculation section. The recording section pre-records information on a horizontal plane coordinate and a height for each radar. The signal identification section outputs, for each radar, object information obtained by combining a linear distance to the object, azimuth information, and time information based on a detection signal, the azimuth information, and the time information. The calculation section obtains an object position candidate being the combination of the horizontal plane coordinate with the height without causing inconsistency in pieces of object information obtained from the radars within a time range where a difference of the time information is pre-fixed, and outputs at least the obtained height.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a height measurement device, a height measurement method, and a height measurement program for measuring the height of an object using a plurality of radars. [Background technology]

[0002] Among the widely available radars is a search radar that rotates an antenna horizontally with a narrow directivity in the horizontal direction and a relatively wide directivity in the vertical direction (fan beam pattern), and is used, for example, in marine radar. Because it has a wide directivity in the vertical direction, it is suitable for monitoring the surrounding situation without identifying the target. However, since the information obtained is two-dimensional, it is not possible to grasp the altitude information of flying objects, etc. One height measurement technique using radar is the pencil beam method (Non-Patent Document 1). In this method, a pencil beam with narrow directivity in the vertical direction is formed, and this is scanned electronically or mechanically to measure the elevation angle of the target object relative to the radar and determine the height. In order to form a pencil beam, the antenna dimensions must be large in both the horizontal and vertical directions, resulting in a large device. One height measurement technique using a fan beam is the V-beam method (Non-Patent Document 1). This method forms a V-shaped fan beam with two antennas, and measures the height of the target object from the measurement results obtained from each antenna and the geometric relationship between the two antennas. As a solution to this problem, Patent Document 1 shows a height measurement technology that utilizes the rocking motion of the device when it is mounted on a ship, etc. Also, Patent Document 2 shows a multistatic height measurement technology that uses multiple transmitting stations and one receiving station. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2002-122659 A [Patent Document 2] Japanese Patent Application Publication No. 11-125674 [Non-patent literature]

[0004] [Non-Patent Document 1] Shinichi Ito, "Basic Theory of Radar Systems," Corona Publishing, November 2015. Summary of the Invention [Problem to be solved by the invention]

[0005] Antennas with fan beam patterns are simple and inexpensive, but cannot measure altitude. Height measurement technology using fan beams has the problem of large-scale hardware configuration, such as the need for two antennas to make the beam V-shaped. The technology in Patent Document 1 has the problem that the application environment is limited. The technology in Patent Document 2 requires a transmitter / receiver with high phase stability because the phase is used to estimate altitude. The present invention has been made in consideration of the above circumstances, and has an object to measure the altitude of an object using a simple and inexpensive radar. [Means for solving the problem]

[0006] The height measuring device of the present invention uses multiple radars to measure the height of an object. The radar includes an antenna, a rotating unit, and a time information unit, and is set to have a higher horizontal measurement accuracy than a vertical measurement accuracy, and measures the linear distance to the object. The antenna transmits and receives radio waves and outputs a detection signal. The rotating unit rotates the antenna and outputs antenna direction information. The time information unit outputs the time information. The height measuring device includes a recording unit, a signal discrimination unit, and a calculation unit. The recording unit records horizontal coordinates and altitude information for each radar in advance. The signal discrimination unit outputs object information for each radar, which combines a linear distance to the object, direction information, and time information, based on the detection signal, direction information, and time information. The calculation unit determines object position candidates that are combinations of horizontal coordinates and altitudes where the difference in time information is within a predetermined time range and there is no contradiction between the object information obtained from the multiple radars, and outputs at least the determined altitude. Effect of the Invention

[0007] According to the height measuring device of the present invention, the height of an object can be measured with at least two radars using antennas with fan beam patterns, which makes it possible to measure the height of an object with a simple and inexpensive radar. [Brief description of the drawings]

[0008] [Figure 1] FIG. 2 is a diagram showing a configuration example when the height measuring device of the first embodiment is used. [Diagram 2] FIG. 4 is a diagram showing a process flow of the height measurement method according to the first embodiment. [Diagram 3] FIG. 1 shows the directivity of an antenna having a fan beam pattern. [Figure 4] A diagram showing how multiple radars detect a single target. [Diagram 5] A diagram showing the relationship between altitude candidates and horizontal distance when the straight-line distance to the target object is the same. [Figure 6] A diagram showing horizontal coordinates based on target information obtained from two radars plotted on a horizontal plane. [Figure 7] A diagram showing the case where there are two objects with the same bearing and straight-line distance from the radar. [Figure 8] A diagram showing the horizontal plane when there are two objects with the same orientation from the radar. [Figure 9] A diagram showing horizontal coordinates based on target information obtained from two radars when there are two targets plotted on a horizontal plane. [Figure 10] FIG. 13 is a diagram showing a configuration example in which a height measuring device according to the first modified example is used. [Figure 11] FIG. 11 is a diagram showing a process flow of a height measurement method according to the first modified example. [Figure 12] A diagram showing how two radars detect one target. [Figure 13] A diagram showing the relationship between the altitude of an object and its horizontal distance. [Figure 14] A diagram showing what happens when there are two intersection points on a horizontal plane. [Figure 15] A diagram showing what happens when there are two straight-line distances to an object obtained from a radar. [Figure 16] FIG. 2 is a diagram showing an example of the functional configuration of a computer. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment of the present invention will be described in detail. Note that components having the same functions are given the same reference numbers and duplicated explanations will be omitted. EXAMPLES

[0010] FIG. 1 shows an example of the configuration when the height measuring device of the first embodiment is used. FIG. 2 shows the processing flow of the height measuring method of the first embodiment. FIG. 3 is a diagram showing the directivity of an antenna having a fan beam pattern. FIG. 3(A) shows an example of the shape of a directional beam on a horizontal plane. In this figure, the horizontal plane is shown using the X-axis and the Y-axis. For example, the X-axis may be defined as the east-west direction, and the Y-axis may be defined as the north-south direction. FIG. 3(A) shows an example of a directional beam directed in the Y-axis direction. FIG. 3(B) shows an example of the shape of a directional beam on a vertical plane. The horizontal axis is the Y-axis, and the vertical axis is the Z-axis. In this figure, the Z-axis is the vertical direction.

[0011] The height measuring device 100 of the first embodiment includes a plurality of radars 2001, . . . , 200 N The altitude of the target is measured using the radar 200. Here, N is an integer of 2 or more, and n is an integer of 1 to N. n The height measuring device 100 includes an antenna 210, a rotating unit 220, and a time information unit 230. The antenna 210 is set so that the directivity is higher in the horizontal direction than in the vertical direction, and measures the linear distance to the target object. For example, an antenna having a fan beam pattern as shown in FIG. 3 may be used. The antenna 210 includes an antenna unit 211 and a transmitting / receiving unit 212, and the antenna unit 211 transmits and receives radio waves, and the transmitting / receiving unit 212 outputs a detection signal. The transmitting / receiving unit 212 receives azimuth information from the rotating unit 220 (described later), receives time information from the time information unit 230, and transmits the detection signal, azimuth information, and time information to the height measuring device 100.

[0012] Rotation unit 220 has motor 221 and rotation control unit 222. Rotation unit 220 rotates the antenna in the horizontal direction by controlling motor 221 so that the angular velocity or angle is specified by rotation control unit 222. Furthermore, rotation control unit 222 outputs azimuth information of antenna 210. "Rotating the antenna" means both rotating the entire antenna 210 and rotating only antenna unit 211. In other words, it is sufficient if the emission direction of radio waves can be rotated in the horizontal direction.

[0013] The time information unit 230 outputs time information. The time information unit 230 may synchronize the transmission and reception of radio waves from the antenna 210 or may match the time information by communicating with the time information unit 230 of another radar. The time information unit 230 may also operate based on external time information such as GPS. In this case, it is possible to synchronize the transmission and reception of radio waves from the antenna 210 without communicating with the time information unit 230 of another radar.

[0014] The height measuring device 100 includes a recording unit 190, a signal discrimination unit 110, and a calculation unit 120. The height measuring device 100 may also include a trajectory estimation unit 130 and a speed estimation unit 140. The recording unit 190 previously stores radars 2001, ..., 200 N The horizontal coordinates and altitude information for each point are recorded. Examples of horizontal coordinates include latitude and longitude, but this is not limited to these. For example, a Cartesian coordinate system may be set on the horizontal plane of the farm, and horizontal coordinates may be expressed as distance from the origin. Examples of altitude include sea level, but this is not limited to these. For example, the height of a point on the farm may be used as the base, and the point may be expressed as the difference in altitude from the base.

[0015] The height measurement device 100 includes radars 2001, . . . , 200 N The signal identification unit 110 receives the detection signal, direction information, and time information from the radars 2001, . . . , 200 NFor each time, the signal discrimination unit 110 outputs object information that combines the straight-line distance to the object, the direction information, and the time information based on the detection signal, the direction information, and the time information (S110). If the recording unit 190 has recorded a combination of the horizontal plane coordinates and altitude of the object in the past in association with the time information, the signal discrimination unit 110 may estimate the straight-line distance to the object and the direction information at the specified time based on the detection signal, the direction information, and the time information, and use the estimated information as object information. The signal discrimination unit 110 may also predict the area of ​​the object based on the detection signal, and include the information on the area of ​​the object in the object information.

[0016] The calculation unit 120 calculates the time information of a plurality of radars 2001, . . . , 200, each of which has a difference in time information within a predetermined time range. N The calculation unit 120 first calculates a candidate object position that is a combination of horizontal plane coordinates and altitudes that do not cause any contradiction between the object information obtained from the radars 2001, . . . , 200, and outputs at least the calculated altitudes (S120). N From the object information obtained from the above, object position candidates, which are candidates for combinations of horizontal coordinates and altitude, are obtained. After that, the calculation unit 120 selects object position candidates that do not cause contradictions, and obtains combinations of horizontal coordinates and altitude of the object. "No contradictions" means that the difference between the combinations of horizontal coordinates and altitude is within the range of error (tolerance) when compared.

[0017] Here, we will explain "the difference in time information is within a predetermined time range." Figure 4 shows how multiple radars detect one target object. This figure shows the state of the horizontal plane, with the horizontal axis being the X axis and the vertical axis being the Y axis. In Figure 4, each radar 200 n A line is drawn from the radar to the target. nSince the antenna 210 rotates, the timing at which the two radars 2001 and 2002 detect one target differs. In other words, the time at which the radar 2001 detects the target and the time at which the radar 2002 detects the target do not exactly match in most cases. Therefore, the calculation unit 120 may determine a time difference of approximately one rotation of the antenna 210 as "within a predetermined time range" and process the information as being detected at the same time. Note that, if the signal identification unit 110 estimates the straight-line distance and directional information to the target at the specified time and sets the information as target information, the "within a predetermined time range" may be shorter than the time difference of approximately one rotation of the antenna 210.

[0018] The calculation unit 120 of the first embodiment includes a coordinate calculation unit 122 and a position comparison unit 125. The coordinate calculation unit 122 predetermines a plurality of altitude candidates, and for each object information and each altitude candidate, calculates horizontal plane coordinates when the altitude of the object is the altitude candidate. Through this process, the coordinate calculation unit 122 calculates a plurality of object position candidates, which are combinations of horizontal plane coordinates and altitude (S122). FIG. 5 shows the relationship between altitude candidates and horizontal distances when the straight-line distances to the object are the same. The horizontal axis is the direction of the straight line extending from the radar 2001 in FIG. 4, and the vertical axis is the altitude. h1(0) is the altitude of the radar 2001, and h(1), h(2), h(3), and h(4) are examples of the predetermined altitude candidates. R1(t) is the straight-line distance to the object at time t (more precisely, a predetermined time range expressed by time t).

[0019] L1(t,1) is the horizontal distance from radar 2001 for altitude candidate h(1) at time t, L1(t,2) is the horizontal distance from radar 2001 for altitude candidate h(2) at time t, L1(t,3) is the horizontal distance from radar 2001 for altitude candidate h(3) at time t, and L1(t,4) is the horizontal distance from radar 2001 for altitude candidate h(4) at time t. For example, when it is necessary to take the radius of the Earth into consideration, L1(t,m) can be found as follows:

number

number

[0020] Then, based on the direction information, the horizontal plane coordinates (X1(t,1),Y1(t,1)),(X1(t,2),Y1(t,2)),(X1(t,3),Y1(t,3)),(X1(t,4),Y1(t,4)) corresponding to L1(t,1),L1(t,2),L1(t,3),L1(t,4) are determined.

[0021] Similarly, horizontal distances L2(t,1), L2(t,2), L2(t,3), and L2(t,4) from the radar 2002 are also calculated. Then, horizontal coordinates (X2(t,1), Y2(t,1)), (X2(t,2), Y2(t,2)), (X2(t,3), Y2(t,3)), and (X2(t,4), Y2(t,4)) are calculated.

[0022] The position comparison unit 125 compares a plurality of radars 2001, . . . , 200 NThe radar 2001 compares the object position candidates obtained from the object information obtained from the radar 2002, selects an object position candidate that does not cause a contradiction, and obtains a combination of the horizontal plane coordinates and altitude of the object (S125). FIG. 6 shows a diagram in which horizontal plane coordinates based on the object information obtained from the radar 2001 and the radar 2002 are plotted on a horizontal plane. In the case of FIG. 6, it can be seen that the horizontal plane coordinates of (X1(t,2),Y1(t,2)) and (X2(t,2),Y2(t,2)) are close to each other. As described above, the detection time of the radar 2001 and the detection time of the radar 2002 do not exactly match, and the radar itself has an error. There is also a difference between the actual altitude and the altitude candidate. Therefore, it is sufficient to comprehensively consider these errors and select an object position candidate that does not cause a contradiction (the error is within an acceptable range). Therefore, in the case of FIG. 6, the position comparison unit 125 determines h(2) as the altitude of the object. The horizontal plane coordinates may be selected from either (X1(t,2),Y1(t,2)) or (X2(t,2),Y2(t,2)), or the average may be used as the horizontal plane coordinates, or a weighted average taking into account the difference between the time information included in the object information and the time t may be used as the horizontal plane coordinates.

[0023] FIG. 7 shows a case where two objects have the same direction and linear distance from the radar 2001. FIG. 8 shows a horizontal plane state where two objects have the same direction from the radar 2001. FIG. 9 shows a diagram in which horizontal plane coordinates based on object information obtained from the radar 2001 and the radar 2002 are plotted on a horizontal plane. In the case of FIG. 9, it can be seen that the horizontal plane coordinates of (X1(t,2),Y1(t,2)) and (X2(t,2),Y2(t,2)) are close to each other, and the horizontal plane coordinates of (X1(t,4),Y1(t,4)) and (X2(t,4),Y2(t,4)) are close to each other. In this way, among the multiple object position candidates obtained from one object information, there may be multiple object position candidates that do not cause any contradiction with the object position candidates obtained from the object information obtained from another radar. In this case, it is sufficient to determine that the object exists at the position of the multiple object position candidates.

[0024] When the height measuring device 100 also includes the trajectory estimation unit 130, the recording unit 190 records the obtained combination of horizontal coordinates and altitude of the object in association with time information. Then, the trajectory estimation unit 130 obtains the trajectory of the object based on the combination of horizontal coordinates and altitude of the object recorded in the recording unit 190 and the time information. When the height measuring device 100 also includes the speed estimation unit 140, the moving speed of the object can be obtained from the trajectory and the time information. Furthermore, when the trajectory estimation unit 130 estimates the trajectory after two objects are close to each other, if the object information includes information on the area of ​​the object, the trajectory estimation unit 130 may estimate the trajectory taking into account the area. Furthermore, when the speed estimation unit 140 is also included, the trajectory may be estimated taking into account the moving speed.

[0025] According to the height measuring device of the first embodiment, if there are at least two radars using antennas with fan beam patterns, the height of the target object can be measured. Therefore, the height of the target object can be measured with a simple and inexpensive radar. For example, when flying a drone in an area such as a farm, if radars using antennas with fan beam patterns are placed at two or more locations on the farm, the horizontal coordinates and altitude of the drone can be confirmed simply and inexpensively. Furthermore, with the height measuring device of the present invention, even when two or more drones are used, the horizontal coordinates and altitude of each drone can be confirmed. Furthermore, when a pencil beam is used, there is a problem that it takes time to monitor a wide area because the beam is thin. However, with the height measuring device of the first embodiment, it is possible to simultaneously monitor the situation of a wide area without identifying the target object using an antenna with a fan beam pattern and obtain the position information of the identified target in three dimensions (horizontal coordinates and altitude). [Variation 1]

[0026] Fig. 10 shows an example of the configuration when the height measuring device of the modified example 1 is used. Fig. 11 shows the processing flow of the height measuring method of the modified example 1. The calculation unit 120 of the height measuring device 100 of the first embodiment comprises a coordinate calculation unit 122 and a position comparison unit 125. The calculation unit 121 of the height measuring device 101 of the modified example 1 comprises a coordinate candidate calculation unit 123, an altitude calculation unit 124 and a position comparison unit 125. The only difference is the calculation unit, and the other configurations are the same as those of the height measuring device 100. The processing flow is also different only in calculation step S121, and the other processing flows are the same.

[0027] Similarly to the calculation unit 120, the calculation unit 121 also calculates the time information of a plurality of radars 2001, . . . , 200, each of which has a difference in time information within a predetermined time range. N The calculation unit 121 first calculates a candidate object position that is a combination of horizontal plane coordinates and altitudes that do not cause any contradiction between the object information obtained from the multiple radars 2001, . . . , 200 N The calculation unit 121 then selects object position candidates that are free of contradictions, and calculates combinations of horizontal coordinates and altitudes of the objects. In other words, the basic processing concept is the same, but the specific processing described below is different.

[0028] The calculation unit 121 includes a coordinate candidate calculation unit 123, an altitude calculation unit 124, and a position comparison unit 125. The coordinate candidate calculation unit 123 calculates the altitude of a plurality of radars 2001, . . . , 200 N From the azimuth information of the object information obtained from the radar, horizontal plane coordinate candidates that are candidates for the horizontal plane coordinates of the object are obtained (S123). FIG. 12 shows how one object is detected by two radars. In FIG. 12, the horizontal plane coordinate candidates are (X(t,1), Y(t,1)). N If you draw a straight line based on the azimuth information of the object information obtained from the azimuth information, it will intersect near the object. If there are three or more straight lines, they will not intersect exactly at one point, but the average value of the intersection points can be used as a candidate for the horizontal coordinates of the object.

[0029] The altitude calculation unit 124 calculates the altitude of the object for each piece of object information and for each horizontal coordinate candidate, thereby calculating an object position candidate that is a combination of the horizontal coordinate and the altitude (S124). Fig. 13 shows the relationship between the altitude of the object and the distance on the horizontal plane. The horizontal distance L1(t,1) can be calculated from the horizontal coordinate candidate (X(t,1), Y(t,1)) and the horizontal coordinate of the radar 2001. The altitude h(t,1) can be calculated from the straight-line distance R1(t,1) to the object and the horizontal distance L1(t,1), taking into account whether or not the radius of the earth needs to be taken into account.

[0030] The position comparison unit 125 compares the position of a plurality of radars 2001, . . . , 200 N The object position candidates obtained from the object information obtained from the above are compared, an object position candidate that does not cause any contradiction is selected, and a combination of the horizontal coordinates and altitude of the object is obtained (S125).

[0031] In the case of the calculation unit 121, since the horizontal plane coordinates are first obtained and then the altitude is obtained, it is theoretically considered that there will be no contradiction between the object position candidates. However, when there are two or more objects in the same direction, it is necessary to select an object position candidate that does not cause a contradiction. FIG. 14 shows a state in which there are two intersections on the horizontal plane. FIG. 15 shows a state in which there are two straight-line distances to the object obtained from the radar 2001. In FIG. 15, the straight-line distance R1(t,1) and the straight-line distance R1(t,2) are the same distance. In this case, there are two object information pieces obtained from the radar 2001. However, in reality, there may be three objects. Whether there are two or three objects can be determined by selecting an object position candidate that does not cause a contradiction, taking into consideration the object information obtained from the other radar 2002.

[0032] The height measuring device of the first modification can achieve the same effect as that of the first embodiment. Therefore, according to the height measuring device of the present invention, the height of an object can be measured with at least two radars using antennas with fan beam patterns. Therefore, the height of an object can be measured with a simple and inexpensive radar.

[0033] [Programs, recording media] The processing of the height measuring device described above can be carried out by loading a program for executing each step of the above method into the recording unit 2020 of the computer 2000 shown in FIG. 16, and operating the control unit 2010, input unit 2030, output unit 2040, display unit 2050, etc.

[0034] The program describing the processing contents can be recorded on a computer-readable recording medium, which may be, for example, a magnetic recording device, an optical disk, a magneto-optical recording medium, a semiconductor memory, or any other type of recording medium.

[0035] The program may be distributed, for example, by selling, transferring, lending, etc. portable recording media such as DVDs and CD-ROMs on which the program is recorded. Furthermore, the program may be distributed by storing the program in a storage device of a server computer and transferring the program from the server computer to other computers via a network.

[0036] A computer that executes such a program, for example, first stores the program recorded on a portable recording medium or the program transferred from a server computer in its own storage device. Then, when executing a process, the computer reads the program stored in its own recording medium and executes a process according to the read program. As another execution form of the program, the computer may directly read the program from the portable recording medium and execute a process according to the program, or may execute a process according to the received program each time a program is transferred from the server computer to the computer. The above-mentioned process may be executed by a so-called ASP (Application Service Provider) type service that realizes a processing function only by issuing an execution instruction and obtaining a result, without transferring a program from the server computer to the computer. Note that the program in this embodiment includes information used for processing by an electronic computer and equivalent to a program (data that is not a direct command to the computer but has a nature that specifies the processing of the computer, etc.).

[0037] In addition, in this embodiment, the present device is configured by executing a predetermined program on a computer, but at least a part of the processing contents may be realized by hardware. [Explanation of symbols]

[0038] 100,101 Height measuring device 110 Signal discrimination unit 120,121 Calculation part 122 Coordinate calculation part 123 Coordinate candidate calculation section 124 Altitude calculation section 125 Position comparison section 130 Trajectory estimation section 140 Speed ​​estimation section 190 Recording section 200 n Radar 210 Antenna 211 Antenna section 212 Transmitter / receiver section 220 Rotating part 221 Motor 222 Rotation control section 230 Time information section

Claims

1. A height measuring device that measures the altitude of an object using a plurality of radars that measure the linear distance to the object, and whose horizontal measurement accuracy is set higher than its vertical measurement accuracy, comprising: The radar includes: an antenna for transmitting and receiving radio waves and outputting a detection signal; a rotation unit that rotates the antenna and outputs azimuth information of the antenna; a time information unit that outputs time information; Equipped with The height measuring device is A recording unit that records information on horizontal coordinates and altitude for each of the radars in advance; a signal identification unit that outputs, for each of the radars, target information that combines a linear distance to a target, the direction information, and the time information based on a detection signal, the direction information, and the time information; A calculation unit that finds target position candidates that are combinations of horizontal coordinates and altitudes where the difference in time information between target information obtained from a plurality of radars within a predetermined time range falls within an error range, and outputs at least the found altitude. Equipped with The calculation unit is a coordinate calculation unit that predetermines a plurality of altitude candidates, and calculates horizontal coordinates for each of the object information and each of the altitude candidates when the altitude of the object is the corresponding altitude candidate, thereby determining a plurality of object position candidates that are combinations of horizontal coordinates and altitudes; a position comparison unit that compares the object position candidates obtained from the object information obtained from a plurality of radars, selects an object position candidate that is within an error range, and obtains a combination of the horizontal coordinates and altitude of the object; have A height measuring device characterized by:

2. 2. The height measuring device according to claim 1, If there are multiple object position candidates determined from one object information that are within the error range of the object position candidates determined from object information obtained from another radar, it is determined that an object exists at the position of the multiple object position candidates. A height measuring device characterized by:

3. 3. The height measuring device according to claim 1, The signal identification unit The area of ​​the object is also predicted based on the detection signal, and the object information also includes information on the area. A height measuring device characterized by:

4. The height measuring device according to any one of claims 1 to 3, the recording unit records the obtained combination of the horizontal coordinates and the altitude of the object in association with time information; A trajectory estimation unit that determines the trajectory of an object based on a combination of the horizontal coordinates and altitude of the object recorded in the recording unit and time information. Also equipped A height measuring device characterized by:

5. 5. The height measuring device according to claim 4, A speed estimation unit that calculates the moving speed of the object from the trajectory and time information. Also equipped A height measuring device characterized by:

6. A height measurement method for measuring the height of an object using a plurality of radars that measure a linear distance to the object, the horizontal measurement accuracy being set higher than the vertical measurement accuracy, comprising: The radar includes: an antenna for transmitting and receiving radio waves and outputting a detection signal; a rotation unit that rotates the antenna and outputs azimuth information of the antenna; a time information unit that outputs time information; Equipped with The height measurement method includes: The horizontal coordinates and altitude information for each radar are recorded in advance, a signal identification step of outputting, for each of the radars, target information combining a linear distance to a target, the direction information, and the time information based on a detection signal, the direction information, and the time information; A calculation step of determining object position candidates that are combinations of horizontal coordinates and altitudes in which the difference in time information between object information obtained from a plurality of radars within a predetermined time range falls within an error range, and outputting at least the determined altitude. having The calculation step comprises: a coordinate calculation step of determining a plurality of altitude candidates in advance, and determining a horizontal coordinate for each of the object information and each of the altitude candidates when the altitude of the object corresponds to the altitude candidate, thereby determining a plurality of object position candidates which are combinations of the horizontal coordinate and the altitude; a position comparison step of comparing the object position candidates obtained from the object information obtained from a plurality of radars, selecting an object position candidate that is within an error range, and obtaining a combination of the horizontal coordinate and the altitude of the object; Run A height measuring method comprising:

7. A height measuring program for causing a computer to function as the height measuring device according to any one of claims 1 to 5.

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