JP2003066138A - Tracking radar - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tracking radar that can keep tracking of such a target that has a large angular velocity and moves to the outside of an angular coverage area of a phased array. SOLUTION: A target is detected by a target detector 7 from a reception signal that is received by a phased array antenna, and a target positional information is computed by an angle measurement computer 8. According to the computed target positional information, a driving control signal for tracking the target is generated by a tracking processor 9, and the phased array antenna is driven through a driving controller 12. Furthermore, a driving angular information for driving the phased array antenna in accordance with the driving control signal is estimated and computed by a driving angle computer 14.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tracking radar using a phased array antenna, and more particularly to a tracking radar having a driving function capable of driving in at least one of the azimuth direction and the elevation angle direction.

[0002]

2. Description of the Related Art Conventionally, a tracking radar shown in FIG. 8 is known as a tracking radar using a phased array antenna. The basic operation of the conventional tracking radar shown in FIG. 8 will be described below. First, the transmission signal generated by the transmitter 5 is supplied to the power distribution combiner 3 via the circulator 4, and the transmission signal distributed by the power distribution combiner 3 is supplied to the phase shifters 2-1 to 2-K. Supplied. During this period, the beam scanning angle (θs) output from the tracking processor 9 described later is supplied to the scanning controller 11, and the phase shifters 2-1 to 2-K whose phases are controlled according to the beam scanning angle (θs).
Is fed to the phased array antenna composed of the antenna elements 1-1 to 1-K, a transmission beam is formed and spatially radiated.

This transmission signal is reflected by the target object, is incident on the antenna elements 1-1 to 1-K, is supplied as a reception signal to the phase shifters 2-1 to 2-K, and the phase shifter 2-1. ~ 2
After the phase is controlled by -K, the signal is combined by the power dividing / combining unit 3, frequency-converted by the receiver 6 via the circulator 4, and then A / D converted and I / Q quadrature detection. This signal is target-detected by the target detector 7 when the signal strength exceeds the threshold level, and the target-detected signal is subjected to the angle-measuring operation by the angle-measuring calculator 8 to obtain the angle-measuring error angle with respect to the beam scanning angle (θs). (ΘE) is obtained. In the tracking processor 9, the next target position is predicted and calculated by the tracking filter based on the angle measurement error angle (θE), set in the scan controller 11, and the target position information is displayed on the display 10.

Here, when the phased array antenna is used, for a target object that moves beyond its angular coverage (the angular range in which the target can be followed by beam scanning),
It is necessary to drive the phased array antenna. Therefore, when the target object moves beyond the set angle range, the drive control signal output from the tracking processor 9 is input to the drive unit 13 via the drive controller 12, and the phased array antenna is output. It is driven in at least one of the azimuth direction and the elevation direction. An angle detector 131 is built in the drive unit 13, and the drive angle of the phased array antenna detected by the angle detector 131 is used as angle data (θM) via the drive controller 12 to follow the follower 9
Entered in.

[0005]

In the conventional tracking radar having the function of controlling the drive of the phased array antenna, the drive angle error becomes large when the drive control is performed at a large angular velocity, and the target tracking when the drive angle error becomes larger than the beam width. There was a problem of losing things.

Therefore, in order to continue following the target,
It was necessary to reduce the rotation speed. Hereinafter, the processing content of the tracking processor 9 will be described in detail. In the tracking processor 9,
Based on the previous beam scanning angle θs (n-1) and the previous side angle error angle θE (n-1) calculated by the angle measuring calculator 8, the present target predicted position θp (n) is obtained,

[Equation 1]   θp (n) = θs (n-1) + θE (n-1) (1) It is output to the display unit 10.

Then, the tracking processor 9 at the time n based on the current target predicted position θp (n) at the time n and the previous and previous previous angle data (θM) detected by the angle detector 131. Obtain the beam scanning angle (θs (n)),

## EQU00002 ## .theta.s (n) =. Theta.p (n)-{. Theta.M (n-1)-. Theta.M (n-2)} (2) Output to the scan controller 11. The angle detector 13
Since there is a delay time until the angle data (θ M) detected by 1 is input to the follow-up processor 9 via the drive controller 12, the angle data at time (n-2) and (n-1). The moving angle is calculated from the above, and is treated as the moving angle at time n.

On the other hand, when the phased array antenna starts to rotate or stops, transient characteristics due to the moment of inertia of the antenna system act, so that the moving angle (θM) of the drive unit 13 per time detected by the angle detector 131 is detected. ) Is different. Therefore, in the conventional tracking radar, it is necessary to set the driving rotation speed to a low speed so that the transient characteristics when the rotation is started or stopped is negligible with respect to the beam width. For this reason, it was not possible to maintain the tracking of the target object having a large angular velocity and moving out of the angular coverage of the phased array antenna.

The present invention has been made in view of the above,
It is an object of the present invention to provide a tracking radar capable of maintaining tracking even of a target object having a large angular velocity and moving outside the angular coverage of the phased array.

[0010]

The invention according to claim 1 is
In order to solve the above problems, in a tracking radar having a driving means for driving a phased array antenna composed of a plurality of element antennas and a phase shifter, a target for detecting a target object from a reception signal received by the phased array antenna. Detecting means, angle measurement calculating means for calculating target position information of the target detected by the target detecting means, and drive for following the target according to the target position information calculated by the angle measuring calculation means. Tracking processing means for generating a control signal and outputting it to the driving means, and the following processing by predictively calculating drive angle information for driving the phased array antenna according to the drive control signal generated by the tracking processing means. The gist is that the driving angle calculation means for outputting to the means is provided.

According to a second aspect of the present invention, in order to solve the above-mentioned problems, the tracking processing means is configured such that the target position information calculated by the angle measuring calculation means has a predetermined angle within the tracking coverage area of the phased array antenna. It is provided with a judging means for judging whether or not the range is exceeded, and when the target position information exceeds a predetermined angle range, outputting the drive control signal so as to maintain the tracking of the target in the tracking coverage area. Use as a summary.

In order to solve the above-mentioned problems, the drive angle calculating means calculates the transient characteristic of the drive angle at the time of starting and stopping the rotation of the drive means of the phased array antenna by using an equation or time. The point is to have it as a table.

According to a fourth aspect of the present invention, in order to solve the above problems, a drive angle detecting means for detecting a drive angle of the phased array antenna and a drive angle of the phased array antenna detected by the drive angle detecting means are used. On the basis of,
The gist of the present invention is to include a correction unit that corrects the drive angle information calculated by the drive angle calculation unit.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. (First Embodiment) FIG. 1 is a block diagram showing a configuration of a tracking radar according to a first embodiment of the present invention.

In FIG. 1, the transmitter 5 periodically generates a transmission signal and supplies it to the circulator 4, and
It is supplied to the power distribution combiner 3 via the circulator 4. The power distribution / combiner 3 distributes the transmission signal and supplies it to the phase shifters 2-1 to 2-K. During this period, the scan controller 11 that receives the beam scanning angle (θs) output from the tracking processor 9 described later controls the phase shifters 2-1 to 2-K in accordance with the beam scanning angle (θs). And the phase shifter 2-1
~ 2-K the transmission signal output from the antenna element 1-1
A 1-K phased array antenna is fed to form a transmission beam for spatial radiation.

This transmission signal is reflected by the target object, is incident on the antenna elements 1-1 to 1-K, and is supplied to the phase shifters 2-1 to 2-K as reception signals. Phase shifter 2-1 to
In 2-K, the phase of the received signal is controlled and the power distribution combiner 3
To the signal synthesizing unit, and after performing frequency conversion by the receiver 6 via the circulator 4, A / D conversion and I
/ Q Quadrature detection. This signal performs target detection when the signal strength exceeds the threshold level set by the target detector 7, and the target detected signal is the angle measuring calculator 8
At, the angle measurement calculation is performed to obtain the angle measurement error angle (θE) with respect to the beam scanning angle (θs). In the tracking processor 9, the next target position is predicted and calculated by the tracking filter based on the angle measurement error angle (θE), the beam scanning angle (θs) is set in the scanning controller 11, and the target position information (θp) is set. Is displayed on the display device 10.

Here, when the phased array antenna is used, for a target object that moves beyond its angular coverage (the angular range in which the target can be followed by beam scanning),
It is necessary to drive the phased array antenna. Therefore, when the target object moves beyond the set angle range, the drive control signal output from the follow-up processor 9 is input to the drive unit 13 via the drive controller 12 to drive the phased array antenna. It drives in at least one of the azimuth direction and the elevation direction.

The drive unit 13 has an angle detector 131 built therein, and the drive angle of the phased array antenna detected by the angle detector 131 is the angle data (θM).
) Is input to the drive controller 12. Specifically, the tracking processor 9 determines whether or not the target position information calculated by the angle measuring calculator 8 exceeds a reference angular range within the tracking coverage of the phased array antenna.
The tracking processor 9 continues to follow a target object that exceeds the angular coverage of the phased array antenna by drive control. Therefore, when there is a target object that moves beyond a preset angular range, a drive control signal is output. A drive start command is output as, while a stop command is output as a drive control signal when the target object moves within a preset angle range.

The drive control signal (drive start command and stop command) output from the follow-up processor 9 is distributed to two systems,
One drive control signal is input to the drive unit 13 via the drive controller 12 to drive the phased array antenna. Drive angle calculator 14 to which the other drive control signal is input
Calculates the movement angle data (dθM) corresponding to the movement angle of the drive unit 13 and outputs it to the tracking processor 9.

Next, the configuration will be described with reference to the block diagram of the drive angle calculator 14 shown in FIG. The reference signal n generated by the reference signal generator 141 and the tracking processor 9
The drive control signals (drive start command and stop command) output from the address generator 143 are input to the address generator 143. The address generator 143 has a counter that counts the reference signal n, and starts counting the reference signal n from 0, for example, after the drive control signal is cleared at the low level and switched to the high level, and its output is used as the address ADD. In addition to outputting to the time table 145, the read signal OE is output almost in synchronization with this address ADD.

The address ADD output from the address generator 143 and the read signal OE are sent to the time table 145.
The time table 145 outputs the movement angle data (dθM) to the follow-up processor 9. Movement angle data (dθM) stored in the timetable 145
Is data that considers transient characteristics when the drive unit 13 starts and stops rotating.

Next, the block diagrams shown in FIGS. 1 and 2 and FIG.
The operation of the tracking radar according to the present embodiment will be described with reference to the graph of the movement angle data shown in FIG. The transmission signal periodically generated by the transmitter 5 is supplied to the power distribution combiner 3 via the circulator 4, and the transmission signal is distributed by the power distribution combiner 3 to shift the phase shifters 2-1 to 2-K. Is supplied to.

During this period, the phase shifters 2-1 to 2-K are received by the scanning controller 11 which receives the beam scanning angle (θs) output from the tracking processor 9 according to the beam scanning angle (θs).
Is phase-controlled, and the transmission signals output from the phase shifters 2-1 to 2-K are fed to the antenna elements 1-1 to 1-K to form a transmission beam and spatially radiate.

This transmission signal is reflected by the target object, is incident on the antenna elements 1-1 to 1-K, and is supplied to the phase shifters 2-1 to 2-K as reception signals. Then, the received signals are phase-controlled by the phase shifters 2-1 to 2-K, are supplied to the power distribution / combiner 3 to be combined, and are frequency-converted by the receiver 6 via the circulator 4 and then A / D.
Transformed and I / Q quadrature detected. This signal is subjected to target detection by the target detector 7 when the signal intensity exceeds the threshold level, and the angle of the detected target signal is calculated by the angle measuring calculator 8 to measure the angle with respect to the beam scanning angle (θs). An error angle (θE) is obtained.

In the tracking processor 9, the next target position is predicted and calculated by the tracking filter based on the angle measurement error angle (θE), and the beam scanning angle (θs) is output to the scanning controller 11. , Target position information (θp) is displayed on the display 1
Displayed at 0. As described above, since it is necessary to drive the phased array antenna for a target object that moves beyond the angular coverage (angle range where the target can be followed by beam scanning) of the phased array antenna, the target object is When moving beyond the set angle range,
The drive control signal output from the tracking processor 9 is input to the drive unit 13 via the drive controller 12 and drives the phased array antenna in at least one of the azimuth direction and the height direction.

The tracking processor 9 determines whether or not the target position information calculated by the angle measuring calculator 8 moves from inside the tracking coverage area of the phased array antenna to outside the tracking coverage area and exceeds a reference angular range. . When there is a target object that moves beyond the preset angle range, a drive start command is output as a drive control signal, while when the target object moves within the preset angle range, it stops as a drive control signal. A command is output.

The drive control signal (drive start command and stop command) output from the follow-up processor 9 is distributed to two systems,
One drive control signal is input to the drive unit 13 via the drive controller 12 to drive the phased array antenna. The other drive control signal is input to the address generator 143 provided in the drive angle calculator 14. In the address generator 143, when the drive control signal is cleared at the low level and switched to the high level, the counter starts counting from 0, and the address ADD and the read signal OE are output to the time table 145.

In the time table 145, the address AD
According to D and the read signal OE, movement angle data (dθM
) Is sequentially read and output to the tracking processor 9, as shown in FIG.

The tracking processor 9 obtains the beam scanning angle (θs (n)) at the time n based on the target predicted position θp (n) at the time n and the movement angle data (dθM).

[Equation 3]   θs (n) = θp (n) -dθM (n) (3) The beam scanning angle (θs) is output to the scanning controller 11.

The effect of this embodiment is that the drive control for detecting the target from the received signal received by the phased array antenna, calculating the target position information, and following the target according to the target position information. A signal is generated to drive the phased array antenna, and the drive angle information for driving the phased array antenna is predicted and calculated according to this drive control signal, so that the drive angular velocity generated when the phased array antenna is drive-controlled Even when the change is larger than the beam width of the beam spatially radiated by the phased array antenna, the drive angle can be estimated with high accuracy, and the target being tracked is not lost from the angle coverage, and the phased array antenna can be used. Since it can be driven to rotate at high speed, it moves with a large angular velocity. Covered the angle of the phased array antenna can be maintained tracking in the region.

Further, it is determined whether the target position information exceeds a predetermined angle range from within the tracking range of the phased array antenna. If the target position information exceeds the predetermined angle range, the target object within the tracking range is determined. By outputting the drive control signal so as to maintain the tracking of the phased array antenna, the phased array antenna can be rotationally driven at high speed without losing sight of the tracked target object within the angular coverage area. Further, the drive angle can be predicted by reading out the transient characteristics of the drive angle at the time of starting and stopping the rotation of the drive unit 13 of the phased array antenna from the time table and using the read characteristic.

(Second Embodiment) The configuration of the tracking radar according to the second embodiment of the present invention is the same as the configuration of the tracking radar according to the first embodiment shown in FIG. The feature of this embodiment is that the drive angle calculator 14 has
A timer (not shown) for measuring the following timing t,
A ROM (not shown) that stores a calculation program, a RAM (not shown) that temporarily stores control data,
A CPU (not shown) for calculating the movement angle data (dθM) according to the calculation program is provided.

RO provided inside the drive angle calculator 14
M is an arithmetic expression for obtaining movement angle data (dθM),

[Mathematical formula-see original document] d [theta] M = [theta] '= a + bt + ct ^ 2 + dt ^ 3 + (4) is stored as an arithmetic program. The coefficients a, b, c, d are coefficients determined by the motor characteristics and the moment of inertia of the motor provided for driving the phased array antenna.

Next, the operation of the tracking radar according to the present embodiment will be described with reference to the block diagram shown in FIG. 1 and the arithmetic expression of the movement angle data shown in FIG. In this embodiment, the operation of the drive angle calculator 14 will be described by omitting the same parts as those described in the first embodiment.

The drive angle calculator 14 monitors the drive control signals (drive start command and stop command) output from the follow-up processor 9, and when the drive control signal becomes low level, the timer becomes 0. After being cleared and the drive control signal is switched from the low level to the high level, the timer starts the tracking timing t.

Immediately after the drive control signal is output from the tracking processor 9, that is, the tracking timing t is 0 <t.
When <t1, the coefficient a = 0 and the coefficients b, c, and d are treated as constant values with respect to the coefficients a, b, c, and d shown in Expression (4). On the other hand, when the tracking timing t is t1 <t, the coefficients a, b, c, and d shown in the equation (4) are treated as coefficient a = constant value and coefficient b = c = d = 0.

The effect of this embodiment is that, in addition to the effect of the first embodiment, the transient characteristic of the drive angle at the time of starting and stopping the rotation of the drive unit 13 of the phased array antenna is calculated from an arithmetic expression. Thus, the drive angle can be predicted.

(Third Embodiment) FIG. 5 is a block diagram showing the structure of a tracking radar according to a third embodiment of the present invention. A feature of this embodiment is that a drive angle calculator 15 is provided instead of the drive angle calculator 14 used in the first embodiment. Inside the drive angle calculator 15, an integrator 151 that obtains an integrated value θM 1 from the movement angle data (dθM) output from the timetable 145 and an angle data (θM 0) detected by the angle detector 131 are used. A subtracter 153 for subtracting the integrated value θM 1 to obtain a correction angle (θM 0-θM 1) and a corrected angle data (dθMh) by adding the movement angle data (dθM) and the correction angle (θM 0-θM 1). ) Is newly provided.

Next, the block diagrams shown in FIGS. 5 and 6 and FIG.
The operation of the tracking radar according to the present embodiment will be described with reference to the graph of the movement angle data shown in FIG. In the present embodiment, the operation of the drive angle calculator 15 will be described by omitting the same parts as those described in the first embodiment.

The drive control signals (drive start command and stop command) output from the follow-up processor 9 are drive angle calculators 15.
The address ADD and the read signal OE are input to the address generator 143 provided in the address generator 143, are cleared when the drive control signal is low level and are switched to the high level, and counting is started from 0 by the counter.
Is output to.

In the time table 145, the address AD
According to D and the read signal OE, movement angle data (dθM
) Is sequentially read and output to the integrator 151, as shown in FIG.

In the integrator 151, the time table 145
The moving angle data (dθM) output from the subtracter 15
The integrated value θM 1 obtained by multiplying the correction angle (θM 0 −θM 1) output from the 3 is output to the subtractor 153. The subtractor 153 outputs the correction angle (θM 0 −θM 1) obtained by subtracting the integrated value θM 1 from the angle data (θM 0) detected by the angle detector 131 to the adder 155.

In the adder 155, as shown in FIG. 7B, the movement angle data (dθM) output from the time table 145 and the correction angle (θM 0-θM 1) are added to obtain the correction. After data (dθMh),

[Equation 5]   dθMh = dθM + θM0−θM1 (5) Is output to the tracking processor 9.

In addition to the effects of the first embodiment, the effects of the present embodiment are as follows:
Angle data (θM 0) detected by the angle detector 131
And the angle data (θ
The difference from M 1) is corrected by the subtractor 153 by the correction angle (θM 0-θM
1), and the moving angle data (dθM) output from the timetable 145 is calculated as the correction angle (θM 0-θM).
Since it is corrected periodically by using 1), the offset error can be removed from the movement angle data (dθM),
This can contribute to the improvement of the calculation accuracy of the movement angle data.

[0045]

According to the present invention, the target object is detected from the received signal received by the phased array antenna, the target position information is calculated, and the target object is tracked according to the target position information. A drive control signal for driving the phased array antenna is generated, and the drive angle information for driving the phased array antenna is predicted and calculated according to the drive control signal, so that the phased array antenna emits space spatially. Even when driving and controlling the phased array antenna at an angular velocity larger than the beam width of the beam, the drive angle can be estimated with high accuracy, and the target object being tracked is not lost from within the angle coverage,
Since it can be rotationally driven at a high speed, it is possible to maintain tracking of a target object moving with a large angular velocity within the angular coverage of the phased array antenna.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a tracking radar according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a drive angle calculator 14.

FIG. 3 is a diagram showing a graph of movement angle data output from a time table 145.

FIG. 4 is a diagram showing an arithmetic expression of movement angle data.

FIG. 5 is a block diagram showing a configuration of a tracking radar according to a third embodiment of the present invention.

FIG. 6 is a block diagram showing a configuration of a drive angle calculator 15.

FIG. 7 is a diagram showing a graph of movement angle data.

FIG. 8 is a block diagram showing a configuration of a conventional tracking radar.

[Explanation of symbols]

1-1 to 1-K Antenna element 2-1 to 2-K Phase shifter 3 Power distribution combiner 4 circulator 5 transmitter 6 receiver 7 Target detector 8 Angle measuring unit 9 Follow-up processor 10 Display 11 Scan controller 12 Drive controller 13 Drive 14,15 Driving angle calculator 131 Angle detector 141 Reference signal generator 143 address generator 145 timetable 151 integrator 153 Subtractor 155 adder

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Claims (4)

[Claims] 1. A tracking radar having a driving means for driving a phased array antenna composed of a plurality of element antennas and a phase shifter, wherein the target detecting means detects a target object from a reception signal received by the phased array antenna. An angle measurement calculation means for calculating target position information of the target detected by the target detection means; and a drive control signal for following the target according to the target position information calculated by the angle measurement calculation means. A tracking processing means for generating and outputting to the driving means, and driving angle information for driving the phased array antenna according to the driving control signal generated by the tracking processing means is predictively calculated to the tracking processing means. A tracking radar, comprising: a drive angle calculating means for outputting. 2. The tracking processing means includes a judgment means for judging whether or not the target position information calculated by the angle measurement calculation means exceeds a predetermined angle range within the tracking coverage of the phased array antenna. The tracking radar according to claim 1, wherein when the target position information exceeds a predetermined angle range, the drive control signal is output so as to maintain the tracking of the target within the tracking coverage area. 3. The drive angle calculation means has a transient characteristic of a drive angle at the time of rotation start and stop of the drive means of the phased array antenna as an arithmetic expression or a timetable. Tracking radar. 4. A drive angle detection means for detecting a drive angle of the phased array antenna, and a drive calculated by the drive angle calculation means based on the drive angle of the phased array antenna detected by the drive angle detection means. The tracking radar according to claim 1, further comprising a correction unit that corrects angle information.