JP2596334B2 - Active phased array radar - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an active phased array radar, that is, a multifunctional radar apparatus combining two-dimensional electronic scanning with an active phased array antenna and high-speed digital signal processing.

[0002]

2. Description of the Related Art As is well known, in a radar apparatus, it is important to improve not only detection performance but also clutter suppression performance and interference wave suppression performance. Active phased array radars have such problems. Is being developed and put into practical use as a multifunctional three-dimensional radar device that can solve the above problem.

That is, in general, it is necessary to irradiate more energy in order to increase the radar detection range, but there is a physical limit to increase the transmission power and antenna gain, and the limit has already been reached. That is the fact.

However, in a radar device having an active phased array antenna, a beam is synthesized by controlling the amplitude and phase of a microwave for each antenna element.
A two-dimensional electronic scanning method that forms and scans a beam in a two-dimensional space of azimuth and elevation by controlling the amplitude and phase is possible, and forms a beam with a high degree of freedom in the irradiation direction and directional characteristics by controlling the amplitude and phase. And time resources can be used effectively. That is, it is possible to easily adopt a measure for irradiating more energy without increasing the transmission power and the antenna gain.

[0005] Here, the remarkable development of the semiconductor manufacturing technology in recent years has made it possible to solidify the transmitting / receiving module. Therefore, the solidified transmitting / receiving module is arranged in one-to-one correspondence with each antenna element of the array antenna. An active phased array antenna having a configuration can be easily realized.

Also, remarkable progress in digital signal processing technology and high-speed signal processing devices has enabled real-time processing of complex complex correlation operations. However, if this is applied to an active phased array radar, microwaves can be transmitted in a specific direction. By continuously irradiating a plurality of reflected signals and performing digital filter processing on a plurality of reflected signals, thereby improving a detection distance and a target signal-to-clutter power ratio (S / C) or a target signal-to-interference wave power ratio (S / C). J) can be greatly improved.

[0007] In short, an active phased array radar uses an active phased array antenna.
It can be said that this is a multifunctional three-dimensional radar device that can greatly improve the detection performance and the suppression performance of clutter and interference waves by combining the two-dimensional electronic scanning and the high-speed digital signal processing.

More specifically, the adoption of two-dimensional electronic scanning increases the degree of freedom of time resources. If the time resources are effectively used, the number of transmission hits (continuously in a specific direction) can be maintained without changing physical conditions. (The number of microwave pulses to be irradiated) can be easily increased. As a result, the detection distance is improved, but as a result of the increase in the number of transmission hits, a plurality of reflected signals from the target are obtained, and high-speed digital signal processing is applied thereto,
Unwanted signals such as clutter and interference waves can be separated from the target and suppressed by the correlation signal processing.

The active phased array radar currently being put into practical use is basically configured as shown in FIG. 3, for example, and performs search and tracking by forming and scanning a beam under computer control. is there.

In FIG. 3, N × M element antennas (111 to 1MN) are connected to N × M T / R (transmit / receive) modules (211 to 2MN) in a one-to-one correspondence. The N × M T / R modules have the same configuration, and as shown in 211, a transmission circuit 2111, a circulator 2112, a reception circuit 2113, and a control circuit 2111.
114, and M of which N is one set is a beam combiner 400, an excitation pulse generator 410, an antenna controller 420, and a corresponding one of M signal transmission paths (301 to 30M). Signal transmission / reception is performed, and a predetermined beam is formed on the N × M element antennas, thereby exhibiting a function of transmitting and receiving radar radio waves.

In the beam forming, the beam control computer 810 indicates the beam forming direction and sends it to the timing controller 80.
The antenna controller 420 received through the M.0 transmits the rotation phase of the microwave to the control circuit 2114 in the N × M T / R modules (211 to 2MN) via the M signal transmission paths (301 to 30M). (Phase shift) amount and the amount of power attenuation are transmitted, and the antenna controller 420
Control circuit (2114) receiving these control signals from
However, at the time of transmission, the phase shift amount is given to the transmission circuit (2111), and at the time of reception, the phase shift amount and the attenuation amount are given to the reception circuit (2113).

The transmission signal (pulsed microwave signal) is
The excitation pulse generator 410 generates an instruction from the beam control computer 810 via the timing controller 800 and the pulse expander 510. The M signal transmission path (3
01 to 30M) to the transmission circuits 2111 in the N × M T / R modules (211 to 2MN).

The following transmission / reception operations are performed in each T / R module. Since each T / R module has the same configuration and performs the same operation, in the case of the T / R module 211, the transmitting circuit 2111 gives the input microwave signal a phase rotation as instructed by the control circuit 2114. ,
The signal is output to the element antenna 111 via the circulator 2112. As a result, a predetermined beam is formed in the two-dimensional space of the azimuth and the elevation angle of the search airspace, and the microwave signal is emitted to the search airspace.

The receiving circuit 2113 converts the microwave signal received by the element antenna 111 into a circulator 21.
12, and gives the same attenuation and phase rotation as instructed by the control circuit 2114 to the signal transmission path 3.
01 to the beam combiner 400. That is, in the beam combiner 400, N × M element antennas (1
(11 to 1 MN) are combined.

The combined microwave signal is supplied to a receiver 50
At 0, the signal is converted to a predetermined intermediate frequency signal, band-pass filtered so that only signals within the reception band determined by design pass, and then phase-detected based on the reference signal.

The phase-detected signal is supplied to an A / D converter 60
The signal is digitized at 0 and compressed by correlation processing at a pulse compressor 610 to become a narrow pulse signal.
Enter 20.

The signal processor 620 performs correlation processing on the input narrow pulse signal, removes unnecessary signals such as clutter and detects a target signal, and displays the processed video signal on the man-machine interface 710. To the tracking computer 700.

The tracking computer 700 performs a tracking process on the detected target signal, displays the result on the man-machine interface 710, and also controls the beam control computer 810.
Give to.

The beam control computer 810 reads the corresponding beam scanning program data from the beam scanning program memory 830 based on the radar mode information selected by the man-machine interface 710, and reads the corresponding time management data from the time management table 840. Is read out, and the specifications of the instantaneous search beam scanning (that is, the scan schedule of the search beam) are edited according to the time signal from the timer 820, and the edited data is given to the timing controller 800.

Further, the beam control computer 810 receives the information on the target being tracked from the tracking computer 700, determines the priority of the target to be scanned with the tracking beam every time based on a predetermined priority rule, and scans the search beam. In the meantime, the tracking beam scanning specifications are sequentially edited and allocated to the time slot predetermined in the time management data, that is, the scanning schedule of the tracking beam is set and supplied to the timing controller 800.

The timing controller 800 receives the search and tracking beam scanning control data from the beam control computer 810, sends a beam scanning control signal to the antenna controller 420, and controls the radar of the signal processor 620 and the like. A control signal and a timing signal such as a transmission pulse width, the number of transmission hits, and a distance range for signal processing are transmitted to each device constituting the apparatus.

As a result, the search beam is scanned in the search space in the vertical direction (that is, the elevation direction) for each direction, and the tracking beam scan is performed between the search beam scans.

[0023]

As described above, the conventional multifunctional radar in the process of practical use obtains a plurality of pieces of information by effectively utilizing time resources with increased degrees of freedom by employing two-dimensional electronic scanning. And apply high-speed digital signal processing to it, so that detection performance, clutter suppression performance,
We succeeded in greatly improving the interference suppression performance.

However, since all of these radar performances are achieved by increasing the number of transmission hits, the search time is significantly increased if further improvement is to be made. At this time, the search scan is a method of scanning the search beam in the elevation direction for each azimuth and sequentially moving the scan beam in the azimuth direction. Therefore, the time interval of the search beam irradiating the target existing at substantially the same elevation angle ( This is called “search data rate”, and as a result, the time required for first detecting the target that has entered the radar search airspace and the tracking update time interval (this is called “tracking data rate”) ) Is prolonged.

The present invention has been made in view of such a problem, and an object of the present invention is to maintain an excellent detection capability, a clutter suppression capability, an interference wave suppression capability, and the like of a conventional multi-function radar while preventing an intrusion target. An object of the present invention is to provide an active phased array radar capable of greatly improving initial detection capability and tracking capability.

[0026]

In order to achieve the above object, an active phased array radar according to the present invention has the following configuration. That is, the active phased array radar of the present invention is a radar device that combines two-dimensional electronic scanning with an active phased array antenna and high-speed digital signal processing; scanning the search beam horizontally at a different frequency for each elevation angle; Means for editing a beam scanning program for scanning a tracking beam in a direction designated by a preset time slot between scans by setting a search beam scanning frequency independently for each elevation angle. It is characterized by having.

[0027]

Next, the operation of the mooring mine active phased array radar of the present invention having the above configuration will be described. As described above, the search scanning method employed by the conventional radar apparatus scans the search beam in the elevation direction for each direction,
Since it is a method of sequentially moving the azimuth in the azimuth direction, if the search space is uniformly searched, the search time becomes longer, and the time interval of the search beam irradiating the target existing at almost the same elevation angle (search data rate) ) Becomes longer.

On the other hand, as is well known, in an active phased array antenna, for example, even in a planar array antenna, beam scanning can be performed in the horizontal direction at each elevation angle within a certain angle range within 180 ° in the horizontal direction (azimuth direction). In addition, a beam can be instantaneously formed in the horizontal direction within the angle range. Therefore, for example, when a cylindrical active phased array antenna is used, instantaneous horizontal scanning can be performed for each elevation angle in an arbitrary azimuth angle range within an azimuth angle range of 360 °.

Therefore, in the present invention, the search scanning method is changed from the conventional scanning in the elevation direction to the scanning in the horizontal direction.
A variable search data rate that differs depending on the elevation angle is adopted. A search is performed at a high search data rate in an air space where a target enters from outside (for example, a low elevation area), and other air areas (for example, a high elevation area) The inside can be searched at a low search data rate.

As a result, in an air space where first detection is important, a target that has entered the search air space can be immediately detected for the first time, and tracking can be established in a short time. The invading target eventually enters an airspace with a low search data rate, but since it has already tracked, it can emit a tracking beam based on the priority determination and maintain a high tracking data rate.

As described above, according to the present invention, the search data rate can be set high in the important search area and the search data rate can be set low in the tracking continuation area, and the tracking data rate can be increased instead. Search and tracking performance can be improved without increasing time.

[0032]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an active phased array radar according to one embodiment of the present invention. As shown in the figure, according to the present invention, in the multifunctional radar in the process of commercialization shown in FIG. 3, as a means for editing a beam scanning program, a program editor 900, a data rate setting unit 910, a beam scanning scheduler 920, and a monitor are used. A control operation for adding an indicator 930, setting the edited beam scanning program and time management data in the beam scanning program memory 830 and the time management table 840, and causing the beam control computer 810 to realize the active phased array radar according to the present invention. Is performed.

That is, the beam scanning program memory 83
0 and the contents of the time management table 840 are appropriately changed in actual operation, unlike the multifunction radar in the process of practical use shown in FIG. Also, the control operation performed by the beam control computer 810 is different. Further, the active phased array antenna may be of a planar type, but this embodiment assumes an omnidirectional, for example, cylindrical type.

Accordingly, in FIG. 1, the parts related to the present invention should originally have different reference numerals, but these basic operations can be similarly understood. For convenience of explanation, FIG. Like the other components of the multifunction radar in the process of being converted, the same reference numerals and names are given. Hereinafter, a description will be given mainly of a portion according to the present invention.

The program editor 900 includes a beam elevation angle,
It has input means for setting beam scanning parameters such as search distance range, transmission pulse width, number of transmission hits, transmission repetition cycle, etc., and edits these beam scanning parameters for each elevation beam scanning step, as well as for each elevation beam. Is calculated. Further, the beam scanning specifications of the tracking beam, which is the adaptive beam scanning, are edited, and the scanning time per tracking beam is calculated. These are temporarily stored, and the data rate setting unit 910 and the beam scanning scheduler 920
Given to.

The data rate setting unit 910 has input means for independently setting the search data rate for each elevation step, and sets the number of times the search beam is scanned within the total beam scanning time for each elevation angle. In addition, the time required to scan the beam in the search airspace once, that is, the total number of tracking beams to be scanned within the scan time is set. These are provided to the beam scan scheduler 920.

The beam scanning scheduler 920 of each elevation search beam scanning time (T _S · n: n is the elevation beam number of steps, hereinafter the same), the tracking beam scanning time (T _t), the search beam scanning count for each elevation ( Based on K _S · n) and the number of tracking beam scans (K _t ), each beam scan is assigned on the time axis, and the time schedule of the beam scan is edited and the scan time is calculated.

The beam scanning program and the time schedule edited by the above procedure are displayed on the monitor display 930.
Corrections can be made if necessary, and final confirmation can be made. The finally completed beam scanning program and time schedule after modification are written into the beam scanning program memory 830 and the time management table 840 by operating a predetermined key.

Table 1 shows an example of specifications for setting the elevation beam scanning and the tracking beam scanning. A beam scanning program in which the search beam scanning frequency is set independently for each elevation angle is edited.

[0040]

[Table 1]

Table 2 shows setting examples of the number of search beam scans and the number of tracking beam scans for each elevation angle.

[0042]

[Table 2]

FIG. 2 shows an example of setting the timetable of the beam scanning. Since the search in the horizontal plane is performed collectively for each elevation angle, a variable search data rate different for each elevation angle can be realized. Understood.

Thus, the beam control computer 810 causes the beam scanning program edited in the beam scanning program memory 830 to scan the beam horizontally at each elevation angle in accordance with the search beam scanning frequency set for each elevation beam. In addition to setting the beam scanning schedule, receiving the tracking information of the target input from the tracking computer 700, the tracking beam is scanned in the preset time slot during the search beam scanning based on the predetermined priority rule. Since the scan schedule is set, a search is performed at a high search data rate in an air space where a target enters from outside (for example, a low elevation area), and a low search data rate is used in other air areas (for example, a high elevation area). Will be able to search.

As a result, in an air space where first detection is important, a target that has entered the search air space can be immediately detected for the first time, and tracking can be established in a short time. The invading target eventually enters an airspace with a low search data rate, but since it has already tracked, it can emit a tracking beam based on the priority determination and maintain a high tracking data rate.

In short, in the present invention, the search data rate in the important search area can be set high, the search data rate can be set low in the tracking continuation area, and the tracking data rate can be increased instead. Searching and tracking performance can be improved without magnification.

[0047]

As described above, in the active phased array radar of the present invention, the search scanning method is changed from the conventional scanning in the elevation direction to the scanning in the horizontal direction, and the variable search data differs depending on the elevation angle. In the airspace where the target enters from outside (for example, low elevation area)
The search is performed at a high search data rate, and the search is performed at a low search data rate in other airspaces (for example, a high elevation angle area). This has the effect of improving the search data rate and the tracking data rate while maintaining the same functions and performance.

[Brief description of the drawings]

FIG. 1 is a configuration block diagram of an active phased array radar according to one embodiment of the present invention.

FIG. 2 is a time chart of an example of setting a time division of beam scanning according to the present invention.

FIG. 3 is a block diagram showing the configuration of a conventional active phased array radar in the process of practical use.

[Explanation of symbols]

 111 to 1 MN element antenna 211 to 2 MN T / R module 301 to 30 M signal transmission line 400 beam synthesizer 410 excitation pulse generator 420 antenna controller 500 receiver 510 pulse expander 600 A / D converter 610 pulse compressor 620 signal Processor 700 Tracking computer 710 Man-machine interface 800 Timing controller 810 Beam control computer 820 Timer 830 Beam scanning program memory 840 Time management table 900 Program editor 910 Data rate setting unit 920 Beam scanning scheduler 930 Monitor display 2111 Transmission circuit 2112 circulator 2113 Receiving circuit 2114 Control circuit

Claims (3)

(57) [Claims] 1. A radar apparatus that combines two-dimensional electronic scanning with an active phased array antenna and high-speed digital signal processing; scanning a search beam horizontally at a different frequency for each elevation angle, and presetting between search beam scans. Means for editing a beam scanning program for scanning the tracking beam in the direction designated in the designated time slot by independently setting the frequency of search beam scanning for each elevation angle. Active phased array radar. 2. The active phased device according to claim 1,
In the array radar; the editing means is
Edit the beam scanning specifications for each elevation beam step,
Calculating the scanning time for each elevation beam,
Edit the beam scanning specifications and scan for each tracking beam
First means for calculating the interval; the first hand
The output of the step and the search data rate for each input elevation step
Scans the search beam within the total beam scan time
Set the number of times to perform for each elevation angle and scan the search airspace once
Set the total number of tracking beams to be scanned within the time required for
Second means based on the output of the first and second means.
Search beam scanning time for each elevation angle, tracking beam scanning
Number of search beam scans, tracking beam scans for each interval and elevation angle
Edit beam scan timetable and calculate scan time
And a third means for calculating
Act on the output of the first and third means;
An active phased array radar characterized by the following. 3. The active phased device according to claim 2,
In an array radar, the output of the first and third means
Fourth means for displaying force and enabling corrective operation;
Active phased array
Da.