JPH06289130A - Monopulse radar device - Google Patents

Abstract

PURPOSE:To make the judgement of a plurality of targets being equal in a distance and a velocity and the continuation of a stable tracking process to one target possible by adding a plural target detector inside a tracking error detector and an extent computing function to an angular error detector. CONSTITUTION:A tracking error detector 7 is provided with a plural target detector 7d to detect a plurality of targets (two targets) existing in an azimuth direction or a high angle direction inside an antenna beam, and a function for computing an extent (extension in angular direction of a plurality of targets) being the imaginary part of a monopulse ratio is newly added to an angular error detector 7c. Whether the number of targets existing inside the antenna beam is more than 2 or not is judged by a detector 7d. When two targets exist inside the same beam, and moreover ones own machine follows the target, the antenna beam is pointed in an angular direction where the half of the width of beam is added to an angle error obtain by the detector 7c and a present beam directional angle, and the positions of the two targets can be known by computing the angle error of only one target.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a monopulse radar device technology.

[0002]

2. Description of the Related Art FIG. 7 shows a conventional monopulse radar device. In the figure, 1 is an antenna that radiates a transmitted wave in a space in a specific direction and receives a reflected wave, 2 is a beam controller that controls the beam direction of the antenna, 3 is an exciter that generates a transmitted wave, and 4 is a A circulator for supplying a signal from the transmitting section to the antenna and supplying a received signal to the receiving and detecting section, 5 is a receiver for converting the received signal into a digital video received signal, and 6a is a digital video received signal output from the receiver 5 From the above, a range bin number calculator for determining the target distance, 6b is a Doppler bin number calculator for determining the target speed from the digital video received signal output from the receiver 5, and 6 is the range bin number calculator 6a and the Doppler bin number calculator. A target detector having a detector 6b, 7a is a distance error detector for calculating a range error from the digital video reception signal output from the receiver 5, and 7b is A speed error detector for calculating a Doppler error from the digital video reception signal of the receiver 5 output, 7c is a real part of the monopulse ratio from the monopulse sum channel and the monopulse difference channel of the digital video reception signal of the receiver 5 output. A conventional angle error detector for calculating a certain angle error, 7 is a conventional tracking error detector having the distance error detector 7a, the velocity error detector 7b and the conventional angle error detector 7c, 8
Is a target information processor that processes target information obtained by signal processing, sends a control signal to the exciter 3 and sends beam pointing angle data to the beam controller 2, and 9 denotes the target detector 6, which is conventional. Tracking error detector 7 and target information processor 8
And a signal processor 10 having a display unit for displaying the target information output from the target information processor 8.

The conventional monopulse radar device is constructed as described above. FIG. 8 is a flow chart showing the processing of the conventional monopulse radar device. In the figure, 11
Is the execution process of the search process, and 12 is the process of the target detector 6, which determines whether the signal S detected in the state of the search process 11 exceeds the threshold λ _T , that is, the target to be tracked is detected. Indicates whether it has been done. 1
Reference numeral 3 indicates that, when the determination in 12 is No, the search process is continued and the feedback is returned to the determination in 12 again. Reference numeral 14 indicates that when the determination in 12 above is Yes, the antenna beam is directed in the direction in which the target exists, and the target tracking process by the monopulse is executed. Reference numeral 15 denotes the conventional angle error detector 7 when the target tracking processing of 14 is executed.
Directing the antenna beam from the angle error θ _E , which is the real part of the monopulse ratio obtained by signal processing in c, and the current beam directivity angle θ to the direction of θ + θ _E , which is the exact position where the target exists. Indicates. By this processing, the tracking state is maintained.

Incidentally, for example, as shown in FIG. 9, it is assumed that the antenna gain in the monopulse system is represented as 24 for the monopulse sum channel and 25 for the monopulse difference channel. However, the horizontal axis shows the angle deviation from the boresight axis, that is, the angle error, normalized by the beam width of the antenna beam (unit is the beam width),
The vertical axis represents the relative value of the antenna gain with the maximum value being 1. At this time, since the tracking process is generally executed within the beam width shown by 26, the antenna gain G Σ of the monopulse sum channel and the antenna gain GΔ of the monopulse difference channel are as shown in FIG. As 29, using the position θ _T of the single target 28 viewed from the reference axis 27 and the current beam pointing angle θ viewed from the reference axis 27,
It is expressed by the following approximate expression.

[0005]

[Equation 1]

[0006]

[Equation 2]

At this time, the conventional angle error detector 7c is used.
The angle error θ _E obtained in the signal processing in
The received signal of the monopulse sum channel is Σ, the received signal of the monopulse difference channel is Δ, and the monopulse ratio is Δ / Σ.
In addition, Re [] indicates the real part in [], and is calculated by the following equation.

[0008]

[Equation 3]

Next, returning to FIG. 8, reference numeral 21 denotes a judgment as to whether or not the tracking process currently being executed is interrupted (break) due to a small received S / N ratio or the like. 22 indicates that when the determination in 21 is No, the target tracking process is continuously executed and is fed back to the process in 15 described above.
Reference numeral 23 indicates that the tracking process is stopped and the search process is executed when the determination at 21 is Yes.

[0010]

In the processing of the conventional monopulse radar device as described above, as shown in FIG.
When the own device 29 is executing the target tracking process using the monopulse radar, if there are two targets 31 and 32 having the same distance and velocity in the antenna beam 30, the conventional angle error detector 7c is used. Is calculated by
The angle error θ _E obtained by the mathematical expression 3 indicates the accurate position of the single target, but the “Philip L.
Bogler, Detecting the Pres
enceof Target Multiplicity
y. IEEE Transactions on Ae
loss and Electronic Sy
stems, AES-22, 2 (Mar. 1986),
197-203. As stated in “etc., above 2 goals 31, 3
The centroid of 2 was shown, and the centroid position did not show an accurate value due to the difference in the target S / N ratio, and tracking was unstable.

Therefore, in the processing of the conventional monopulse radar device, since it is impossible to detect the two targets 31 and 32 existing in the antenna beam 30 and having the same distance and velocity, the display 10 actually shows the above. Despite the presence of the two targets 31 and 32, only one target was displayed as a false target in the direction of the centroid, and the tracking was unstable.

Further, as shown in FIG. 12, the two targets 3 in the antenna beam 30 are tracked during the target tracking.
When 1 and 32 gradually increase the distance between each other, the aircraft 29 continues to direct the beam in the direction of the centroid of the two targets 31, 32, and finally, the two targets 31, 32.
Are two targets 33, 34 outside the antenna beam 30, respectively.
As a result, the position of the aircraft 29 was changed, and the own aircraft 29 had stopped (broken) the tracking process.

The present invention has been made to solve the above problems. When two targets having the same distance and velocity are present in the antenna beam, the presence of the two targets is determined and stable tracking is performed. This is a device that has a transition process, and angle information for only one target (angle error)
In order to obtain a device having a process capable of separating multiple targets.

Further, another embodiment of the present invention is made to solve the above problems, and when there are two targets having the same distance and velocity in the antenna beam, the existence of the two targets is confirmed. An apparatus having a process of making a determination and shifting to stable tracking, and further obtaining an apparatus having a process capable of obtaining angle information (angle error) of two targets and executing the tracking process for the two targets as well. Is intended.

[0015]

In order to achieve the above objects, a monopulse radar device according to the present invention comprises:
An angle error detector in a tracking error detector in a conventional signal processor calculates an imaginary part of a monopulse ratio, that is, an extent, which is necessary to determine the existence of multiple targets (two targets) in an antenna beam. A function is added, and further, a multi-target detector for determining the existence of a plurality of targets (two targets) in the antenna beam is newly added in the tracking error detector in the signal processor. Then, a means for determining that there are multiple targets in the antenna beam is applied, and when multiple targets (two targets) having the same distance and speed are present in the antenna beam, the beam pointing angle is set to the azimuth direction.
Alternatively, the beam is controlled so that the angle information (angle error) of only one target can be obtained by intentionally shifting in the elevation direction.

Further, in another embodiment of the monopulse radar device according to the present invention, in order to achieve the above object, an antenna is provided in an angle error detector in a tracking error detector in a conventional signal processor. The function of calculating the imaginary part of the monopulse ratio, that is, the extent necessary to determine the existence of multiple targets (two targets) in the beam is added, and
In the tracking error detector in the signal processor, a multi-target detector for determining the presence of multiple targets (two targets) in the antenna beam is newly added. Then, a means for determining that there are multiple targets in the antenna beam is applied, and multiple targets (2 targets) having the same distance and velocity in the antenna beam are applied.
If the existence of a beam is recognized, the beam allocation angle is intentionally shifted in the azimuth direction or the elevation direction so that only one target exists in the antenna beam, and the beam allocation in time division is performed by the target number. Then, the beam is controlled so that the angle information (angle error) of a plurality of targets can be obtained.

[0017]

According to one embodiment of the present invention, during the target tracking process using the monopulse radar, a plurality of target detectors are newly added in the tracking error detector in the signal processor, and By adding the function of calculating the extent to the angle error detector in the tracking error detector, it is possible to determine that there are two targets existing in the antenna beam and having the same distance and velocity. Further, by recognizing the existence of the plurality of targets (two targets) and controlling the beam pointing angle, the angle error of only one target can be obtained and the stable tracking process can be continued.

According to another embodiment of the present invention,
During target tracking processing using the monopulse radar, a new multiple target detector is added to the tracking error detector in the signal processor, and an extent is added to the angle error detector in the tracking error detector in the conventional signal processor. By adding the calculation function, it is possible to determine that there are two targets existing in the antenna beam and having the same distance and velocity. Further, by recognizing the existence of the plurality of targets (two targets) and controlling the beam pointing angle, the angle error of the two targets can be obtained, and stable tracking processing can be continued for the two targets. .

[0019]

【Example】

Embodiment 1 FIG. 1 shows an embodiment of the present invention. In the figure, 1 to 6, 7a, 7b, 8 and 10 are exactly the same as the above conventional device. 7c is a conventional angle error detector 7c
In the above, only the angle error which is the real part of the monopulse ratio is calculated from the monopulse sum channel and the monopulse difference channel of the digital video reception signal which is the output of the receiver 5, but the extent which is the imaginary part of the monopulse ratio is newly added. It is an angle error detector with a function to calculate. Reference numeral 7d denotes an angle error calculated by the angle error detector 7c (in the case of multiple targets, the centroid is the center of gravity of those targets) and an extent indicating the spread of the multiple targets (in the case of a single target, 0). From "Philip
L. Bogler, Detecting thePr
Essence of Target Multipli
city. IEEE Transactions on
Aerospace and Electronic
Systems, AES-22, 2 (Mar. 198).
6), 197-203. Is a multi-target detector that detects a plurality of targets (two targets) existing in the azimuth direction or the elevation direction in the antenna beam by using the method described in ", etc., where the centroid B and the extent C are It is calculated by the following formula, provided that the two targets exist at the positions of θ ₁ and θ ₂ respectively when viewed from the reference axis, and the amplitudes of the reflected signals from the 2 targets are V ₁ and V ₂ , and the monopulse sum channel and the monopulse It is assumed that the antenna gains of the difference channels are represented by the equations 1 and 2, respectively, and the beam pointing angle viewed from the reference axis is θ.
[] Indicates the imaginary part in [].

[0020]

[Equation 4]

[0021]

[Equation 5]

[0022]

[Equation 6]

Next, returning to FIG. 1, 7 is a tracking error detector having a distance error detector 7a, a velocity error detector 7b, an angle error detector 7c and a plurality of target detectors 7d, and 9 is a target detector 6, This is a signal processor having a tracking error detector 7 and a target information processor 8.

The processing in the monopulse radar device configured as described above will be described based on a flow chart. In FIG. 2, 11 to 15 and 21 to 23 are exactly the same processes as those of the conventional device. 16 is the multiple target detector 7d
The process of determining whether the target number n _T existing in the antenna beam is 2 or more, which is detected in 1. 17 includes two targets 31 in the antenna beam 30 as shown in FIG.
If 32 is present and the determination in 16 is Yes, as shown in FIG. 3, the angle error obtained by the angle error detector 7c during tracking of the target by the own device 29 (in this case, the two target centroids). Θ _E and the beam width θ _BW of the antenna beam 30 at the current beam pointing angle θ
Angle plus half, _{ie, θ + θ E + θ BW} /
Showing that the antenna beam is directed in the direction of 2,
Indicates that the angle error of only the target 31 is calculated and its position is known by the processing of 17 above. Reference numeral 19 indicates that the antenna beam is directed in the direction of the angle error θ _E. Reference numeral 20 indicates that, when the determination at 22 is No, the target tracking processing is continuously executed and the processing proceeds to processing 19.

Embodiment 2 Next, another embodiment of the present invention will be described. FIG. 4 shows the configuration of the device, and FIG. 5 shows the processing of the device. In FIG. 4, 3 to 10 are exactly the same as those of the device of the first embodiment. Reference numeral 35 is a phased array antenna that instantaneously radiates a transmitted wave in a space in a specific direction and receives a reflected wave, and 2 is a beam that controls the beam direction of the phased array antenna 35 by phase control of the phased array antenna module. It is a controller.
In FIG. 5, 11 to 23 are exactly the same as the processing of the first embodiment. Reference numerals 34 and 35 are processes that make use of the characteristics of the high-speed scan of the phased array antenna. Since the conventional antenna used in the first embodiment has a time loss due to beam scanning, the processes shown in processes 17 and 18 in FIG. Goal 3 of 3
Although the angle information was obtained by directing the beam only to 1, the phased array antenna has the characteristic that the time loss due to the beam scanning can be ignored. direction of the target 32, i.e. phased array antenna the antenna beam θ + θ _E -θ _BW / 2
The beam is also directed in the direction of so that the angle information of both the targets 31 and 32 can be obtained.

[0026]

Since the present invention is constructed as described above, it has the following effects.

Even if a plurality of targets (two targets) having the same distance and velocity are present in the antenna beam, the target information (only one target in the monopulse radar device of the first embodiment) is obtained by the optimum beam pointing control. The position can be obtained, and the target information (position) can be obtained by separating the two targets with the monopulse radar device of the second embodiment. Therefore, improvement in tracking accuracy can be expected, and it becomes possible to display an accurate target position on the display.

Further, as a conventional method of separating multiple targets, RA is used.
M processing (Raid Assessment Mode)
There is a so-called target, which separates multiple targets by distance difference or speed difference, and it was not possible to separate multiple targets having the same distance and speed. It is possible to separate multiple targets with the same value. Further, although the RAM processing is performed manually, the present invention does not increase the load on the pilot because it is automatically performed.

Even in the situation shown in FIG. 9, the tracking of the two targets is maintained.

[Brief description of drawings]

FIG. 1 is a diagram showing a monopulse radar device according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a process of the monopulse radar device according to the first embodiment of the present invention.

FIG. 3 is a diagram showing beam orientation in the first embodiment of the present invention.

FIG. 4 is a diagram showing a monopulse radar device according to a second embodiment of the present invention.

FIG. 5 is a diagram showing a process of a monopulse radar device according to a second embodiment of the present invention.

FIG. 6 is a diagram showing beam orientation in the second embodiment of the present invention.

FIG. 7 is a diagram showing a conventional monopulse radar device.

FIG. 8 is a diagram showing a process of a conventional monopulse radar device.

FIG. 9 is a diagram showing antenna gains of a monopulse sum channel and a monopulse difference channel of a monopulse radar.

FIG. 10 is a diagram showing a case where a single target exists in an antenna beam.

FIG. 11 is a diagram showing a case where two targets are present in the antenna beam.

FIG. 12 is a diagram showing one flight example of two targets when two targets are present in the antenna beam.

[Explanation of symbols]

 1 Antenna 2 Beam Controller 3 Exciter 4 Circulator 5 Receiver 6 Target Detector 6a Range Bin Number Calculator 6b Doppler Bin Number Calculator 7 Tracking Error Detector 7a Distance Error Detector 7b Velocity Error Detector 7c Angle Error Detector 7d Multiple Target detector 8 Target information processor 9 Signal processor 10 Display 35 Phased array antenna

Claims (2)

[Claims] 1. An antenna for radiating a transmitted wave in a space of a specific direction and receiving a reflected wave, a beam controller for controlling the direction of the beam of the antenna, an exciter for generating the transmitted wave, and an antenna for the antenna. A circulator that supplies a signal from the transmission unit and a reception signal to the reception detection unit, a receiver that converts the reception signal into a digital video reception signal, a range bin number calculator that determines the target distance, and a target speed , A target detector having the range bin number calculator and the Doppler bin number calculator, a range error detector for calculating a range error from the digital video received signal, and a Doppler signal from the digital video received signal. A velocity error detector for calculating an error, and a monopulse sum channel and a monopulse difference channel of the above digital video reception signal From this, an angle error detector that calculates the angle error that is the real part of the monopulse ratio and an extent (expansion in the angular direction of multiple targets) that is the imaginary part of the monopulse ratio, and the presence of multiple targets in the antenna beam is determined. A multi-target detector, a tracking error detector having the distance error detector, the velocity error detector, the angle error detector, and the multi-target detector, and the exciter for processing the target information obtained by signal processing. From the target information processor, which sends a control signal to the beam controller and sends beam pointing angle data to the beam controller, a signal processor having the target detector, a tracking error detector and a target information processor, and the target information processor. A monopulse radar device comprising: a display for displaying output target information. 2. A phased array antenna that instantaneously radiates a transmitted wave to a space in a specific direction and receives a reflected wave, and phase control of a phased array antenna module,
A beam controller for controlling the direction of the beam of the phased array antenna, an exciter for generating a transmission wave, a signal is supplied from the transmission unit to the phased array antenna, and a circulator for supplying a reception signal to a reception detection unit, A receiver for converting the received signal into a digital video received signal, a range bin number calculator for determining the target distance, a Doppler bin number calculator for determining the target speed, the range bin number calculator and the Doppler bin number calculator. A target detector having, a range error detector for calculating a range error from the digital video received signal, a velocity error detector for calculating a Doppler error from the digital video received signal, and a monopulse sum channel of the digital video received signal From the monopulse difference channel, the angle part, which is the real part of the monopulse ratio, , An angle error detector that calculates the extent that is the imaginary part of the monopulse ratio, a multi-target detector that determines the existence of multiple targets in the antenna beam, the distance error detector, the velocity error detector, and the angle error A tracking error detector having a detector and multiple target detectors, and target information for processing target information obtained by signal processing, sending a control signal to the exciter, and sending beam pointing angle data to the beam controller. A processor, and a signal processor having the target detector, the tracking error detector and a target information processor,
A monopulse radar device comprising: a display for displaying target information output from the target information processor.