JP2000162315A - Radar apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radar apparatus of a high observation accuracy by directly calculating an antenna orientation angle and a PRF(pulse repetition frequency) set value from a position coordinate of an observation target and a position coordinate of an airframe. SOLUTION: The radar apparatus is constituted of an airframe 1, an antenna 2 mounted to the airframe 1, a navigation satellite signal-receiving machine 3, a radar computer 4, an antenna-controlling machine 5, a navigation satellite 6, a database 8 and an observation antenna 9. By the control of the antenna- controlling machine 5, the database converts a latitude and a longitude of an observation target to a position coordinate having an origin at a global center adopted by the navigation satellite, and the radar computer obtains a target vector for the observation target seen from the airframe, so that an orientation vector of the observation antenna is agreed with the target vector.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to satellites, aircraft,
The present invention relates to a radar device mounted on a flying object such as an airship and a balloon to observe the earth.

[0002]

2. Description of the Related Art FIG. 5 is a view for explaining a conventional radar device. In FIG. 5, reference numeral 1 denotes a flying object flying above the earth, and 2 denotes a flying object mounted on the flying object 1 and shows position information of the flying object. An antenna 3 for receiving a signal, a navigation satellite signal receiver 3 for processing a signal received by the antenna 2 and analyzing position coordinates, and a receiving unit 4 for receiving position information from the navigation satellite signal receiver 3 and changing observation parameters. Radar calculator to calculate,
Reference numeral 5 denotes an antenna controller that receives antenna pointing information from the radar computer 4 and changes the pointing direction of the observation antenna. 6 denotes an orbital position that generates a radio wave for measuring a distance using a radio wave propagation time. Known navigation satellites,
7 is the earth, 9 is the observation antenna, 11 is the observation target, 12
Is a flying object altitude, 13 is a point directly below the flying object, 14 is an antenna directional angle, 15 is a distance between the flying object and the observation target, and 16 is a distance between a point directly below the flying object and the observation target.

In a conventional radar device, a navigation satellite signal receiver 3 calculates the position coordinates of the flying object 1 from radio waves transmitted from a navigation satellite 6 received by an antenna 2 and transmits the coordinates to a radar computer 4. The radar computer 4 calculates the flying object's ground altitude 12 obtained from the difference between the distance from the center of the earth and the earth's radius from the position coordinates, the point 13 directly below the flying object, and the observation target 11.
The antenna directivity angle 14 is calculated from the distance 16 obtained from the (fixed target) latitude and longitude information, and transmitted to the antenna controller 5. The antenna controller 5 performs control so that the observation target 11 is captured by the radar by matching the current directional angle of the observation antenna 9 with the target antenna directional angle 14.

[0004]

Among the conventional radar devices, the flying object height calculated by the radar calculator is constant irrespective of the latitude immediately below the flying object, but the actual flying object height is the ellipsoid of the earth. There is a problem that the antenna directivity angle cannot be calculated with sufficiently high accuracy because it changes high near the two poles and low near the equator depending on the effect. Also PR
F (PulseRepetition Frequency
Since the set value of cy) depends on the distance between the flying object and the observation target, an error in the antenna directional angle causes an error in the distance between the flying object and the observation target, thereby deteriorating the set value of the PRF. For this reason, the conventional radar apparatus has a problem that it is necessary to measure a distance and an angle from the reference point of the position coordinates clearly set on the ground to the satellite and correct the flying object altitude.

A radar apparatus according to the present invention has been made in order to solve the above-mentioned problems, and uses an antenna directional angle and a PR based on the position coordinates of an observation target and the position coordinates of a flying object.
By directly calculating the installation value of F, a radar device with high observation accuracy is provided. In addition, a radar device with high observation accuracy is provided by performing position coordinate calculation using an earth ellipsoid model for an observation target whose position coordinates are unknown.

[0006]

According to a first aspect of the present invention, there is provided a radar device which flies over the earth, an antenna mounted on the above-mentioned flying object and receiving a signal indicating position information of the flying object,
A navigation satellite signal receiver that processes signals received by the antenna to analyze position coordinates, a radar calculator that calculates observation parameters for an observation target, receives antenna pointing information from the radar computer, and determines the pointing direction of the observation antenna. A database that consists of a plurality of navigation satellites whose on-orbit positions are known, which generates a radio wave for measuring the distance using the antenna controller to be changed and radio wave propagation time, and stores the position coordinates of the observation target Directional vector for the observation target viewed from the flying object is obtained from the position coordinates of the observation target and the position coordinates of the flying object, and control is performed so that this directional vector matches the directional vector of the observation antenna. It has an antenna controller.

A radar device according to a second aspect of the present invention is a flying object flying over the earth, an antenna mounted on the flying object and receiving a signal indicating position information of the flying object, and a signal processing means for processing a signal received by the antenna. A navigation satellite signal receiver that analyzes coordinates, a radar computer that receives satellite position coordinates from the navigation satellite signal receiver, and calculates observation parameters for observation targets, and a radio wave for measuring distance using radio wave propagation time Generating a plurality of navigation satellites whose on-orbit positions are known, and comprising a database that stores the position coordinates of the observation target, from the position coordinates of the observation target and the position coordinates of the projectile, Analyze the distance between observation targets and PR of the transmission signal output from the observation antenna
A radar calculator for calculating F from the distance is provided.

A radar device according to a third aspect of the present invention is a flying object flying over the earth, an antenna mounted on the flying object and receiving a signal indicating positional information of the flying object, and a signal processing means for processing a signal received by the antenna. A navigation satellite signal receiver that analyzes coordinates, a radar computer that receives satellite position information from the navigation satellite signal receiver and calculates observation parameters for observation targets, and a radio wave for measuring distance using radio wave propagation time A database consisting of a plurality of navigation satellites whose on-orbit positions are known, and having a database storing the equatorial radius and polar radius of the earth ellipsoid model, and a database for observation targets whose position coordinates are unclear. Calculates the position coordinates using the earth ellipsoid model in the inside, and uses the distance between the projectile and the observation target analyzed from the position coordinates of the projectile to output from the observation antenna. The PRF of the transmission signal that is obtained by including a radar computer that calculated from the distance.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. 1 is a configuration diagram showing a first embodiment of the present invention, in which 1 is a flying object flying over the earth, 2 is mounted on the flying object 1,
An antenna for receiving a signal indicating position information of a flying object, a navigation satellite signal receiver for processing a signal received by the antenna 2 and analyzing position coordinates, and a position coordinate from the navigation satellite signal receiver 3 Is a radar calculator for calculating observation parameters, 5 is an antenna controller for receiving antenna directivity information from the radar computer 4 and changing the directivity of the observation antenna, and 6 is a radio wave propagation time. A plurality of navigation satellites whose on-orbit positions are known for generating radio waves for measurement, 7 is the earth, 8 is a database storing position coordinates of observation targets, 9 is an observation antenna, 10 is a vector indicating the observation target, 11 is an observation target. In the figure, the navigation satellite signal receiver 3 processes the signal received by the antenna 2, calculates the position coordinates of the flying object 1 in the coordinate system adopted by the navigation satellite 6, and transmits it to the radar computer 4. Further, the database 8 has conversion data for replacing the terrestrial latitude and longitude information with the coordinate system adopted by the navigation satellite 6, and converts the latitude and longitude of the designated observation target into the position in the coordinate system adopted by the navigation satellite 6. The coordinates are converted and transmitted to the radar computer 4. The radar computer 4 performs a calculation for replacing the position coordinates of the observation target with the position vector of the observation target in the coordinate system centered on the flying object 1 and transmits the result to the antenna controller 5 as the target vector 10. The antenna controller 5 directs the observation antenna 9 toward the observation target 11 by controlling the directional vector of the observation antenna 9 to coincide with the target vector 10.

Next, processing in the flying object according to the first embodiment of the present invention will be described with reference to FIG. In the figure, 1 is a flying object flying over the earth, 2 is an antenna mounted on the flying object 1 and receives a signal indicating position information of the flying object, and 3 is a position coordinate obtained by processing a signal received by the antenna 2. 4 is a radar computer that calculates observation parameters, 5 is an antenna controller that receives antenna pointing information from the radar computer 4 and changes the direction of the observation antenna, and 6 is radio wave propagation. A plurality of navigation satellites, whose on-orbit positions are known, which generate radio waves for measuring distances using time, 8 is a database storing position coordinates of observation targets, and 9 is an observation antenna. In the figure, satellite data from a navigation satellite 6 received by an antenna 2 is sent to a navigation satellite signal receiver 3. As processing 1, the navigation satellite signal receiver 3 calculates the position coordinates of the flying object 1 from the satellite data and transmits the calculated coordinates to the radar computer 4. Processing 2
In the database 8, the latitude and longitude of the observation target are converted into position coordinates and transmitted to the radar computer 4. In process 3, the radar computer 4 performs a vector calculation for replacing the position coordinates of the observation target from the database 8 with a vector for the observation target in the coordinate system centered on the flying object 1, and transmits the vector to the antenna controller 5. In process 4, the antenna controller 5 controls the current directional vector of the observation antenna 9 so as to coincide with the target vector calculated in process 3, so that the antenna can be directed to the observation target. As an example, the target vector R￣ when the position coordinate of the flying object 1 is h, the latitude of the observation target is φ, the longitude is θ, and the position coordinate is 1 is expressed as follows.

[0011]

(Equation 1)

Embodiment 2 FIG. FIG. 1 is a block diagram showing a second embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a flying object flying over the earth, and 2 is mounted on the flying object 1 and receives a signal indicating positional information of the flying object. An antenna 3 is a navigation satellite signal receiver that processes signals received by the antenna 2 to analyze position coordinates, and a radar computer 4 receives position coordinates from the navigation satellite signal receiver and calculates observation parameters. 5 is an antenna controller that receives the antenna pointing information from the radar computer and changes the pointing direction of the observation antenna. 6 is an antenna controller that generates a radio wave for measuring a distance using a radio wave propagation time. A plurality of known navigation satellites, 7 is the earth, 8 is a database storing the position coordinates of the observation target and the earth ellipsoid model, 9 is an observation antenna, 10 is a vector indicating the observation target, and 11 is a viewfinder. It is the target. In the figure, the navigation satellite signal receiver 3 has an antenna 2
, And calculates the position coordinates of the flying object 1 in the coordinate system adopted by the navigation satellite 6, and transmits the coordinates to the radar computer 4. Further, the database 8 stores the latitude on the ground,
It has conversion data for replacing the longitude information with the coordinate system adopted by the navigation satellite 6, converts the latitude and longitude of the designated observation target into position coordinates in the coordinate system adopted by the navigation satellite 6, and transmits the coordinates to the radar computer. . The radar computer 4 performs a calculation for replacing the position coordinates of the observation target with the position vector of the observation target in a coordinate system centered on the flying object 1, and obtains a scalar quantity to determine the distance between the flying object 1 and the observation target 11. Calculate and calculate PRF.

Next, processing in the flying object according to the second embodiment of the present invention will be described with reference to FIG. In the figure, 1 is a flying object flying over the earth, 2 is an antenna mounted on the flying object 1 and receives a signal indicating position information of the flying object, and 3 is a position coordinate obtained by processing a signal received by the antenna 2. 4 is a radar computer that calculates observation parameters, 5 is an antenna controller that receives antenna pointing information from the radar computer, and changes the direction of the observation antenna, and 6 is the radio wave propagation time , A plurality of navigation satellites whose on-orbit positions are known that generate radio waves for measuring distances, 8 is a database storing position coordinates of observation targets, and 9 is an observation antenna. In the figure, satellite data from a navigation satellite 6 received by an antenna 2 is sent to a navigation satellite signal receiver 3. As processing 1, the navigation satellite signal receiver 3 calculates the position coordinates of the flying object 1 from the satellite data and transmits the calculated coordinates to the radar computer 4. As processing 2, the latitude and longitude of the observation target are converted into position coordinates in the database 8 and transmitted to the radar computer 4. Processing 3
In the radar computer 4, the vector for the observation target in the coordinate system centered on the flying object 1 is obtained from the position coordinates of the observation target from the database 8 and the vector value is converted into a scalar quantity to obtain the distance between the flying object and the observation target. Calculate the distance. In process 4, the radar computer 4 calculates the PRF from the distance calculated in process 2 above. By repeating the above processes 1 to 4, the PRF fluctuating due to the ellipsoidal effect of the earth can be set to an optimum value. As an example, when the position coordinate of the flying object 1 is h, the latitude of the observation target is φ, the longitude is θ, and the position coordinate is l, the PRF is:
It is selected from a range satisfying the following conditions 1-3.

[0014]

(Equation 2)

Embodiment 3 FIG. 1 is a configuration diagram showing a third embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a flying object flying over the earth, and 2 is mounted on the flying object 1 and receives a signal indicating position information of the flying object. An antenna 3 is a navigation satellite signal receiver for processing signals received by the antenna 2 to analyze position coordinates, and a radar computer 4 is for receiving position coordinates from the navigation satellite signal receiver 3 and calculating observation parameters. Reference numerals 4 and 5 denote antenna controllers which receive antenna pointing information from the radar computer and change the pointing direction of the observation antenna. 6 denotes an on-orbit which generates radio waves for measuring a distance using radio wave propagation time. A plurality of navigation satellites whose positions are known, 7 is the earth, 8 is a database storing the position coordinates of the observation target and the equator radius and polar radius of the earth ellipsoid model, 9 is an observation antenna, and 10 is an observation target. Be a vector, 11 is an observation target. In the figure, the navigation satellite signal receiver 3 processes the signal received by the antenna 2, calculates the position coordinates of the flying object 1 in the coordinate system adopted by the navigation satellite 6, and transmits it to the radar computer 4. Further, the database 8 transmits data on the latitude and longitude on the ground and the corresponding equatorial radius and polar radius of the earth ellipsoid model to the radar computer. The radar computer 4 converts the latitude and longitude of the observation target into position coordinates in a coordinate system adopted by the navigation satellite 6 based on the information, and converts the position coordinates of the observation target into the flying object 1.
The distance between the flying object 1 and the observation target 11 is calculated by calculating the scalar quantity by calculating the position vector of the observation target in the coordinate system centered on
Is calculated.

Next, processing in the flying object according to the third embodiment of the present invention will be described with reference to FIG. In the figure, 1 is a flying object flying over the earth, 2 is an antenna mounted on the flying object 1 and receives a signal indicating position information of the flying object, and 3 is a position coordinate obtained by processing a signal received by the antenna 2. 4 is a radar computer that calculates observation parameters, 5 is an antenna controller that receives antenna pointing information from the radar computer 4 and changes the direction of the observation antenna, and 6 is radio wave propagation. A plurality of navigation satellites, whose on-orbit positions are known, which generate radio waves for measuring distances using time, 8 is a database storing position coordinates of observation targets, and 9 is an observation antenna. In the figure, satellite data from the navigation satellite 6 received by the antenna 2 is sent to the navigation satellite receiver 3. As processing 1, the navigation satellite receiver 3 calculates the position coordinates of the flying object from the satellite data and transmits it to the radar computer 4. As processing 2, the database 8 selects the latitude and longitude of the observation target and the optimal equatorial radius and polar radius of the earth ellipsoid model, and transmits them to the radar computer 4. Radar computer 4 as processing 3
Calculates the position coordinates of the observation target from the latitude and longitude from the database 8, obtains a vector for the observation target in a coordinate system centered on the flying object 1, and converts the vector value into a scalar quantity to observe the flying object. Calculate the distance between the targets. In process 4, the radar computer 4 calculates the PRF from the distance calculated in process 2 above. Processing 1 above
It is possible to set the PRF that fluctuates due to the ellipsoidal effect of the earth to an optimum value by repeatedly performing steps 4 to 4.
As an example, the PRF when the position coordinate of the flying object 1 is h, the latitude of the observation target is φ, the longitude is θ, and the position coordinate is 1 is selected from a range satisfying the following conditions 1 to 3.

[0017]

(Equation 3)

[0018]

According to the first aspect of the present invention, the pointing control of the observation antenna is performed based on the position coordinates of the flying object and the position coordinates of the observation target in the coordinate system adopted by the navigation satellite. There is an effect that directivity control of the antenna can be performed without being affected.

According to the second aspect, since the PRF is calculated from the position coordinates of the flying object and the position coordinates of the observation target in the coordinate system adopted by the navigation satellite, the PRF is calculated without being affected by the ellipsoidal effect of the earth. This has the effect that the observation parameters can be set.

According to the third aspect, the present invention can be realized with limited information such as a database of the relation between the equator radius, the polar radius, the latitude, and the longitude of the earth ellipsoid model determined for each area on the earth, and the longitude. Since the PRF is calculated from the position coordinates of the flying object and the position coordinates of the observation target in the coordinate system adopted by the navigation satellite, the observation parameters can be set without being affected by the ellipsoidal effect of the earth. There is.

[Brief description of the drawings]

FIG. 1 is a first embodiment of a radar device according to the present invention;
FIG.

FIG. 2 is a first embodiment of a radar device according to the present invention;
It is a figure which shows the process in the flying object in FIG.

FIG. 3 is a second embodiment of the radar device according to the present invention;
It is a figure which shows the process in the flying object in FIG.

FIG. 4 is a third embodiment of the radar device according to the present invention;
It is a figure which shows the process in the flying object in FIG.

FIG. 5 is a diagram showing a conventional radar device.

[Explanation of symbols]

1 projectile, 2 antenna, 3 navigation satellite signal receiver,
4 Radar calculator, 5 antenna controller, 6 navigation satellite, 7 earth, 8 database, 9 observation antenna, 10 target vector, 11 observation target, 12 flying object altitude, 13 flight object lower point, 14 antenna directivity angle,
15 Spacecraft-distance between observation targets, 16 Point just below spacecraft-
Distance between observation targets.

Claims (3)

[Claims] Claims: 1. A flying object flying over the earth,
An antenna for receiving a signal indicating position information of the flying object,
A navigation satellite signal receiver that processes signals received by the antenna to analyze position coordinates, a database that stores position coordinates of observation targets on the earth, a radar calculator that calculates observation parameters for the observation targets, an antenna from the radar computer An antenna controller that receives directional information and changes the directional direction of the observation antenna, and a plurality of navigation satellites with known on-orbit positions that generate radio waves for measuring distance using radio wave propagation time In the configured radar device, the radar computer receives the position coordinates of the observation target held in the database and the position coordinates of the flying object from the navigation satellite signal receiver, obtains a directivity vector for the observation target viewed from the flying object, A feature is provided that controls the directional vector so that it matches the directional vector of the observation antenna. Radar device that. 2. A flying object flying over the earth,
An antenna for receiving a signal indicating position information of the flying object,
A navigation satellite signal receiver that processes signals received by the antenna to analyze position coordinates, a database that stores position coordinates of observation targets on the earth, a radar calculator that calculates observation parameters for the observation targets, and a radio wave propagation time. In a radar device comprising a plurality of navigation satellites having known orbital positions for generating radio waves for measuring a distance by using the radar computer, the radar computer receives position coordinates of an observation target in a database and receives navigation satellite signals. The distance between the flying object and the observation target is analyzed based on the position coordinates of the flying object from the aircraft, and the PRF (PRF) of the transmission signal output from the observation antenna is analyzed.
ulse Repetition Frequency
a radar device having means for calculating y) from the distance. 3. A flying object that flies over the earth,
An antenna for receiving a signal indicating position information of the flying object,
A navigation satellite signal receiver that processes signals received by the above antenna to analyze position coordinates, a database that stores various equatorial radii and polar radii of a spheroid that serves as an earth ellipsoid model, and calculates observation parameters for observation targets A radar computer that generates a radio wave for measuring a distance by using a radio wave propagation time, and is configured by a plurality of navigation satellites whose on-orbit positions are known, wherein the radar computer receives a navigation satellite signal. Means for calculating the distance between the flying object analyzed from the position coordinates of the flying object from the aircraft and the observation target using an earth ellipsoid model held in the database and calculating the PRF of the transmission signal output from the observation antenna from the distance. A radar device comprising: