JP2014240752A - Radar device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radar device capable of preventing the generation of a radar false image due to the generation or reflection of useless power even when there exists a radio wave obstacle within an observation range, and simplifying the installation process.SOLUTION: A radar device 10 includes: a satellite signal tracking part 12a for tracking each of a plurality of GPS satellites; an orbit data acquisition part 12c for acquiring the data of the orbit of each of the GPS satellites; and a mask range setting part 15 for calculating coordinates where the satellite signal tracking part 12a have been unable to track the plurality of GPS satellites and coordinates where the satellites have appeared in coordinates determined by an azimuth angle and elevation angle with the installation position as a reference for each orbit, and for setting a range surrounded by segments connecting the respective coordinates as a radio wave transmission stop range for stopping the transmission of a radio wave.

Description

  The present invention relates to a radar apparatus that observes, for example, weather.

The weather radar observes rainfall conditions by transmitting radio waves around 360 degrees with a relatively low altitude as an observation target. Conventionally, for example, when a weather radar is installed on the roof of a building, if there are high-rise buildings or forests (hereinafter referred to as “radio wave obstacles”) within the observation range of the weather radar, the radio wave transmitted from the weather radar is Since it is reflected by an object, there is a problem in that wasteful power is generated and an image of a target (radar false image) that does not actually exist within the observation range is generated.
As a means for solving this problem, a weather radar device described in Patent Document 1 is known. Patent Document 1 describes an antenna, an azimuth angle driving mechanism that varies the azimuth angle by rotating the antenna around a vertical axis, an elevation angle driving mechanism that varies the elevation angle of the antenna, and an azimuth angle driving mechanism. An azimuth angle control circuit that outputs azimuth angle data so that the antenna rotates at a constant speed, and an elevation angle control circuit that has an elevation angle storage table that stores elevation angles previously associated with each azimuth angle are provided.

  With this configuration, the one disclosed in Patent Document 1 is such that the elevation angle control circuit obtains elevation angle data corresponding to the azimuth angle data obtained in advance at the observation point where the weather is observed from the elevation angle storage table, and obtains the obtained data from the elevation angle drive mechanism. In the direction where there are high-rise buildings, forests, etc. (hereinafter referred to as “radio-wave obstacles”), the elevation angle is increased to prevent generation of wasted power and radar false images due to reflections. ing.

Japanese Patent Laid-Open No. 10-104356

  However, in the device described in Patent Document 1, it is necessary to obtain in advance for each observation point an azimuth where a radio wave obstacle exists and an elevation angle for avoiding the radio wave obstacle, so that the installation process of the apparatus becomes complicated. There was a problem.

  The present invention has been made to solve the conventional problems, and can prevent generation of useless power and radar false images due to reflection even when there is a radio wave obstacle in the observation range. An object of the present invention is to provide a radar device that can facilitate the installation process.

A radar apparatus according to the present invention is a radar apparatus that is installed at a predetermined installation position and receives an echo of a radio wave transmitted toward a target, and is a satellite tracking unit that tracks each of a plurality of satellites included in the global positioning system. Orbit data acquisition means for acquiring the orbit data of each satellite, and a concentric circle centered on the intersection with the intersection of the cross intersection line indicating each direction of east, west, north, and south and the intersection of the cross intersection line directly above the installation position In the two-dimensional coordinates representing the elevation angle in step 2, the coordinates at which the satellite tracking means can no longer track the satellite and the coordinates at which the satellite appeared are obtained for each orbit, and within the range surrounded by the line segment connecting the coordinates. Radio wave transmission stop range setting means for setting the radio wave transmission stop range for stopping the transmission of the radio wave;
It has the composition provided with.

  With this configuration, in the radar apparatus of the present invention, the radio wave transmission stop range setting unit automatically sets the radio wave transmission stop range by obtaining each coordinate for each orbit where the satellite tracking unit can no longer track a plurality of satellites. Unlike the conventional ones, it is not necessary to previously obtain the azimuth in which a radio wave obstacle exists and the elevation angle for avoiding the radio wave obstacle for each observation point. Therefore, the radar apparatus of the present invention can prevent generation of useless electric power or generation of a false radar image due to reflection even when there is a radio wave obstacle in the observation range, and can facilitate the installation process. .

  The radar apparatus according to the present invention further includes a radio wave transmission stop range updating unit that updates the radio wave transmission stop range at predetermined time intervals.

  With this configuration, the radar apparatus of the present invention can update the radio wave transmission stop range as needed or periodically.

  The present invention can prevent generation of useless electric power or generation of a false radar image due to reflection even when there is a radio wave obstruction within the observation range, and can further facilitate the installation process. An apparatus can be provided.

It is a figure which shows the example of installation in one Embodiment of the radar apparatus which concerns on this invention. It is a block block diagram in one Embodiment of the radar apparatus which concerns on this invention. It is a figure which shows the satellite number of the GPS satellite observed in Tokyo in one Embodiment of the radar apparatus which concerns on this invention. It is the figure which represented the result which the satellite signal tracking part and the orbit data acquisition part monitored for 24 hours in one Embodiment of the radar apparatus based on this invention with the sky coordinate. It is a figure which shows an example of the mask range which the mask range setting part set in one Embodiment of the radar apparatus which concerns on this invention. It is a flowchart of the main routine in one Embodiment of the radar apparatus which concerns on this invention. It is a flowchart of the mask range setting process in one Embodiment of the radar apparatus which concerns on this invention. It is explanatory drawing of the setting of an electromagnetic wave transmission stop area in one Embodiment of the radar apparatus which concerns on this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  First, the configuration of an embodiment of a radar apparatus according to the present invention will be described. An example in which the radar apparatus according to the present invention is applied to a weather radar will be described.

  As shown in FIG. 1, the radar apparatus 10 according to the present embodiment is installed on the roof of a building 1, for example. It functions as a weather radar to observe. There is a building 2 in the vicinity of the building 1, and conventionally, a part of the radio wave transmitted from the radar device 10 hits the building 2 and is reflected, so that a false image is generated in the radar device 10 due to useless power and reflection. End up. The radar apparatus 10 according to the present embodiment can solve this problem.

  A block diagram of the radar apparatus 10 is shown in FIG. As shown in FIG. 2, the radar apparatus 10 includes a GPS (Global Positioning System) receiver 11, a signal analysis apparatus 12, a tracking data storage unit 13, an orbit data storage unit 14, a mask range setting unit 15, and a mask range storage unit 16. A radar control unit 17, a drive control device 18, a signal processing device 19, and a radar antenna 20.

  The radar apparatus 10 includes a microcomputer including a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and an input / output circuit to which various interfaces are connected. The microcomputer realizes the function of the radar apparatus 10 by causing a CPU to execute a control program stored in advance in a ROM.

  The GPS receiver 11 is connected to the GPS antenna 11a. The signal analysis device 12 includes a satellite signal tracking unit 12a, a current position acquisition unit 12b, and an orbit data acquisition unit 12c. The drive control device 18 includes an azimuth angle drive unit 18a and an elevation angle drive unit 18b.

  The GPS receiver 11 receives an RF (Radio Frequency) signal including a unique satellite signal component transmitted from each GPS satellite, which is a kind of positioning satellite, via the GPS antenna 11 a and outputs the RF (Radio Frequency) signal to the signal analysis device 12. It is like that. The RF signal includes a navigation message from each GPS satellite. The navigation message includes orbit data (ephemeris, almanac, etc.) of each GPS satellite necessary for positioning calculation and various correction data, and is repeatedly broadcast at a predetermined frame rate.

  The satellite signal tracking unit 12a tracks (traces) a unique satellite signal component output by each GPS satellite from the RF signal received by the GPS receiver 11 for each GPS satellite. The position of each GPS satellite is represented by sky coordinates based on the current position of the radar apparatus 10 based on a satellite tracking signal that tracks each GPS satellite. Here, the satellite signal tracking unit 12a constitutes satellite tracking means according to the present invention. The sky coordinates will be described later.

  The current position acquisition unit 12b acquires information on the current position where the radar apparatus 10 is installed, for example, information on latitude, longitude, height, and current time, from the RF signal received by the GPS receiver 11. Yes.

  The orbit data acquisition unit 12c acquires predicted orbit data of each GPS satellite predicted from the RF signal received by the GPS receiver 11. This orbit data acquisition unit 12c constitutes orbit data acquisition means according to the present invention.

  The tracking data storage unit 13 stores the satellite tracking signal of each GPS satellite tracked by the satellite signal tracking unit 12a as tracking data expressed in sky coordinates.

  The trajectory data storage unit 14 stores the predicted trajectory data acquired by the trajectory data acquisition unit 12c.

  The mask range setting unit 15 sets a mask range that is a range in which transmission of radio waves is stopped in the sky coordinates. The mask range setting unit 15 constitutes a radio wave transmission stop range setting unit according to the present invention. Further, the mask range constitutes a radio wave transmission stop range according to the present invention.

  The mask range storage unit 16 stores mask range data in which the mask range set by the mask range setting unit 15 is represented by sky coordinates.

  The radar control unit 17 performs control related to the operation of the entire radar apparatus 10. Specifically, the radar control unit 17 outputs a drive signal to the drive control device 18 and causes the drive control device 18 to drive the radar antenna 20. The radar control unit 17 reads the mask range data from the mask range storage unit 16 and controls the signal processing device 19 so as not to transmit radio waves within the mask range. Further, the radar control unit 17 outputs a control signal to the signal analysis device 12, and causes the signal analysis device 12 to acquire tracking data, current position data, and orbit data appropriately or periodically as necessary. . The radar control unit 17 constitutes a radio wave transmission stop range updating unit according to the present invention.

  The azimuth angle drive unit 18a includes, for example, a rotation gear attached to a vertical axis that rotates the radar antenna 20, a motor that rotates the rotation gear, and a rotary encoder that outputs a pulse indicating the rotation position of the rotation gear. The radar antenna 20 is rotated about the vertical axis in accordance with the drive signal from the radar control unit 17 so that the direction of the radar antenna 20 is varied.

  The elevation angle drive unit 18b includes a reversible motor, for example, and varies the elevation angle of the radar antenna 20 in accordance with a drive signal from the radar control unit 17.

  Although not shown, the signal processing device 19 includes a radar transmission signal generation unit, a local oscillator, a radio wave transmission unit, a radio wave reception unit, and the like. The signal processing device 19 generates a radar transmission signal, receives the radar transmission signal reflected by the object as a radar reception signal, and each time the radar antenna 20 rotates 360 degrees around the vertical axis, Video data is output.

  The radar antenna 20 is configured to receive a radar reception signal including a reflected wave from a target as a target signal component by emitting a radar transmission signal from the signal processing device 19 in a certain direction. The distance from the radar antenna 20 to the target is obtained from the time difference between the reception time of the radar reception signal including the target signal component and the transmission time of the radar transmission signal corresponding to the radar reception signal. Further, the direction of the target is obtained from the direction of the radar antenna 20 when a radar transmission signal corresponding to the radar reception signal is transmitted.

  Next, functions of the satellite signal tracking unit 12a and the orbit data acquisition unit 12c of the signal analysis device 12 will be described.

  FIG. 3 is a diagram showing, as an example, the number of GPS satellites observed in Tokyo every hour from 0:00 to 24:00. As shown in FIG. 3, the number of satellites fluctuates in the range from 6 to 11. The satellite signal tracking unit 12a and the orbit data acquisition unit 12c monitor all observable GPS satellites over, for example, 24 hours.

  FIG. 4 shows the results of 24-hour monitoring by the satellite signal tracking unit 12a and the orbit data acquisition unit 12c in two-dimensional coordinates (sky coordinates). The sky coordinates represent the elevation angle in a concentric circle centering on the intersection with the crossing line indicating each direction of east, west, north, and south, and the intersection of the crossing line directly above the installation position of the radar apparatus 10. Specifically, the direction of the azimuth in the sky coordinates is set such that the north azimuth is 0 degree, the east azimuth is 90 degrees, the south azimuth is 180 degrees, and the west azimuth is 270 degrees. In terms of how to express the elevation angle in the sky coordinates, the horizontal line is 0 degrees and the position just above the installation position is 90 degrees.

  As shown in FIG. 4, the orbit data of the four GPS satellites 101 to 104 are shown in the sky coordinates. Here, in order to make the explanation easy to understand, the number of satellites to be observed by the satellite signal tracking unit 12a and the orbit data acquisition unit 12c is four. The GPS satellites 101 to 104 constitute a satellite according to the present invention. In the illustrated orbit data, the solid line indicates the tracking orbit data 111, 112, 113a, 113b, 114a, and 114b obtained by the satellite signal tracking unit 12a tracking each GPS satellite. On the other hand, in the illustrated orbit data, a broken line indicates predicted orbit data 121 to 124 of each GPS satellite acquired by the orbit data acquisition unit 12c. In addition, the arrow shown on the tracking orbit data represents the traveling direction of each GPS satellite.

  In FIG. 4, for the GPS satellite 101, tracking orbit data 111 and predicted orbit data 121 are connected at a point 131. This point 131 indicates a position on the sky coordinate where the satellite signal tracking unit 12a can no longer track the GPS satellite 101, and is hereinafter referred to as an “annihilation point”.

  Next, with respect to the GPS satellite 102, the tracking orbit data 112 and the predicted orbit data 122 are connected at the vanishing point 132.

  Next, for the GPS satellite 103, the tracking orbit data 113a and the predicted orbit data 123 are connected at the disappearance point 133, and the predicted orbit data 123 and the tracking orbit data 113b are connected at the point 134. This point 134 indicates the position on the sky coordinates where the satellite signal tracking unit 12a becomes able to track again after the GPS satellite 103 cannot be tracked, and is hereinafter referred to as an “appearance point”. A GPS satellite that cannot be observed when the satellite signal tracking unit 12a and the orbit data acquisition unit 12c start observation also is referred to as an “appearance point”.

  Next, regarding the GPS satellite 104, the tracking orbit data 114a and the predicted orbit data 124 are connected at the disappearance point 135, and the predicted orbit data 124 and the tracking orbit data 114b are connected at the appearance point 136.

  Next, the function of the mask range setting unit 15 will be described. The mask range setting unit 15 sets the mask range from the entire range represented by the sky coordinates based on the disappearance points 131 to 133 and 135 and the appearance points 134 and 136 shown in FIG.

  Specifically, as shown in FIG. 5, the mask range setting unit 15 connects the vanishing points 131 and 135 shown in FIG. 4 along the elevation direction to obtain a line segment 141. Similarly, the mask range setting unit 15 connects the vanishing points 132 and 133 shown in FIG. 4 along the azimuth direction and connects the arc 142, and the appearance points 134 and 136 along the elevation direction as the connection line 143. obtain. As a result, the mask range setting unit 15 sets a region within the range (shaded portion) surrounded by the line segments 141 to 143 and the horizontal line as a mask range, and stores the coordinate data of the mask range in the mask range storage unit 16. To do. The mask range in this example is a range in which the azimuth is from 65 degrees to 135 degrees and the elevation angle is from 0 degrees to 50 degrees.

  Instead of the mask range shown in FIG. 5, the mask range setting unit 15 sequentially connects the disappearance points 131, 135, 132, 133, and the appearance points 134, 136 shown in FIG. By connecting 136 and the extinction point 131 with line segments, the setting of the mask range can be simplified with the range enclosed by these line segments as the mask range.

  Next, the operation of the radar apparatus 10 according to the present embodiment will be described with reference to FIGS.

  As shown in FIG. 6, the mask range setting unit 15 executes a mask range setting process (step S20). That is, as shown in FIG. 7, the GPS receiver 11 receives an RF signal including a navigation message transmitted from each GPS satellite via the GPS antenna 11a (step S21). The GPS receiver 11 outputs the received RF signal to the signal analysis device 12.

  The signal analyzer 12 analyzes the RF signal (step S22). Specifically, the satellite signal tracking unit 12a tracks the unique satellite signal component output by each GPS satellite from the RF signal received by the GPS receiver 11 for each GPS satellite, and acquires tracking data expressed in the sky coordinates. To do. In addition, the current position acquisition unit 12b acquires information on the current position of the radar device 10 from the RF signal received by the GPS receiver 11. Further, the orbit data acquisition unit 12c acquires predicted orbit data of each GPS satellite to be predicted from the RF signal received by the GPS receiver 11, and uses the predicted orbit data as sky coordinates.

  The satellite signal tracking unit 12a stores the tracking data in the tracking data storage unit 13, and the orbit data acquisition unit 12c stores the orbit data in the orbit data storage unit 14 (step S23). The current position acquisition unit 12 b outputs information on the current position to the mask range setting unit 15.

  The mask range setting unit 15 determines whether 24 hours have elapsed since the start of observation of the GPS satellite (step S24). In step S24, the mask range setting unit 15 returns to step S21 if it has not determined that 24 hours have elapsed since the start of observation of GPS satellites, and masks if it has determined that 24 hours have elapsed since the start of observation of GPS satellites. A range is set (step S25), mask range data indicating the set mask range is stored in the mask range storage unit 16 (step S26), and the process returns to the main routine.

  Returning to FIG. 6, the radar control unit 17 reads the mask range data from the mask range storage unit 16 (step S11).

  The radar control unit 17 reads a preset elevation angle value from a memory (not shown), transmits a control signal to the elevation angle drive unit 18b, and causes the elevation angle drive unit 18b to set the elevation angle of the radar antenna 20 (step S12).

  The radar control unit 17 sets a radio wave transmission stop section in which radio wave transmission is stopped at the set elevation angle based on the mask range data (step S13). This will be specifically described with reference to FIG.

  FIG. 8 shows a mask range 151 drawn on the sky coordinates. For example, when the elevation angle is set to 45 degrees, the radar control unit 17 stops the radio wave transmission stop section 152 that stops the transmission of radio waves in the section indicated by the dotted line in the range in which the arc indicating the elevation angle of 45 degrees is included in the mask range 151. And the section indicated by the solid line is set as the radio wave transmission permission section 153.

  The signal processing device 19 transmits and receives radio waves (step S14). Here, the signal processing device 19 transmits radio waves in the radio wave transmission permission section 153 set in step S13, and stops transmission of radio waves in the radio wave transmission stop section 152.

  The signal processing device 19 converts the radar reception signal received by the radar antenna 20 into radar image data, and outputs it as observation data to an external device (step S15).

  The radar control unit 17 determines whether or not to update the mask range (step S16). In step S16, the radar controller 17 proceeds to step S20 if it is determined to update the mask range, and proceeds to step S14 if it is not determined to update the mask range. For example, the radar control unit 17 determines to update the mask range on a predetermined day once every month.

  As described above, the radar apparatus 10 according to the present embodiment automatically determines the mask range in which transmission of radio waves is stopped by obtaining the disappearance point and the appearance point for each trajectory based on the tracking data and the trajectory data. Since the setting unit 15 is provided, there is no need to obtain in advance, for each observation point, an azimuth where a radio wave obstacle exists and an elevation angle for avoiding the radio wave obstacle, unlike the conventional one. Therefore, the radar apparatus 10 according to the present embodiment can prevent generation of useless power and radar false images due to reflection even when there is a radio wave obstacle in the observation range, and also facilitates the installation process. Can do.

  In the above-described embodiment, the radar apparatus according to the present invention has been described as an example applied to a weather radar. However, the present invention is not limited to this and is located in a place that is easily affected by a radio wave obstacle. It can be applied to all installed radar devices, and the same effect can be obtained.

  Further, in the above-described embodiment, the example in which one mask range is set has been described. However, the present invention is not limited to this, and can be applied to the case where a plurality of mask ranges are set. An effect is obtained.

  In the above-described embodiment, the mask range setting unit 15 has been described with an example in which the mask range is set based on the disappearance points and the appearance points obtained by the four satellites. However, the present invention is not limited to this. The mask range can also be set based on only the disappearance point or the appearance point of the satellite. In this case, it is preferable to use tracking orbit data and predicted orbit data from more satellites.

  In the above-described embodiment, the GPS has been described as an example of the global positioning system. However, the present invention is not limited to this and can be applied to a global positioning system other than GPS. Similar effects can be obtained.

  As described above, the radar apparatus according to the present invention can prevent generation of useless power and radar false images due to reflection even when there is a radio wave obstacle in the observation range, and also facilitates the installation process. This is useful as a radar device for observing weather.

DESCRIPTION OF SYMBOLS 10 Radar apparatus 11 GPS receiver 11a GPS antenna 12 Signal analysis apparatus 12a Satellite signal tracking part (satellite tracking means)
12b Current position acquisition unit 12c Orbit data acquisition unit (orbit data acquisition means)
13 Tracking data storage unit 14 Orbit data storage unit 15 Mask range setting unit (radio wave transmission stop range setting means)
16 Mask range storage unit 17 Radar control unit (Radio wave transmission stop range update means)
DESCRIPTION OF SYMBOLS 18 Drive control apparatus 18a Azimuth angle drive part 18b Elevation angle drive part 19 Signal processing apparatus 20 Radar antenna 101-104 GPS satellite (satellite)
111, 112, 113a, 113b, 114a, 114b Tracking trajectory data 121-124 Predicted trajectory data 131-133, 135 Vanishing point 134, 136 Appearing point 151 Mask range (Radio wave transmission stop range)
152 Radio wave transmission stop range 153 Radio wave transmission possible range

Claims (2)

A radar device installed at a predetermined installation position and receiving an echo of a radio wave transmitted toward a target,
Satellite tracking means for tracking each of a plurality of satellites included in the global positioning system;
Orbit data acquisition means for acquiring orbit data of each satellite;
The satellite tracking means tracks the satellite in a two-dimensional coordinate system that expresses the elevation angle with a concentric circle centered on the intersection point, with the intersection of the cross intersection line indicating each direction of east, west, south, and north and the intersection point being directly above the installation position. A radio wave transmission stop range in which coordinates that cannot be obtained and coordinates at which satellites appear are determined for each orbit, and a range surrounded by a line segment connecting the coordinates is set as a radio wave transmission stop range in which the radio wave transmission is stopped Setting means;
A radar apparatus comprising:   The radar apparatus according to claim 1, further comprising: a radio wave transmission stop range updating unit that updates the radio wave transmission stop range at a predetermined time interval.

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