JPH0755915A - Active phased array radar - Google Patents

Abstract

PURPOSE:To improve searching and tracking data rates by altering a search scanning system to a horizontal scanning, and employing a variable search data rate different according to an angle of attack. CONSTITUTION:A program editor 900 edits beam scanning specifications at each angle-of-attack beam scanning stage, and calculates a scanning time. Further, the editor 900 edits tracking beam scanning specifications, and calculates a scanning time. A data rate setter 910 sets number of times of scanning a search beam at each angle of attack, and sets total number of the tracking beams. A beam scanning scheduler 920 edits a time assignment of the beam scanning, and calculates a scanning time. A beam scanning program and the assignment are stored in a memory 830 and written in a time management table 840. A beam control computer 810 sets a scanning schedule for horizontally scanning the search beam at each angle of attack according to the program stored in the memory 830, receives tracking information of a target to be input from a tracking computer 700, and sets the scanning schedule of the tracking beam.

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 multi-functional radar device 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 device, not only improvement of detection performance but also improvement of clutter suppression performance and interference wave suppression performance is an important issue. Is being developed and put into practical use as a multifunctional three-dimensional radar device capable of solving the above problems.

That is, in general, it is necessary to irradiate more energy in order to increase the detection distance of the radar, but there is a physical limit in increasing the transmission power and the antenna gain, and the limit has already been reached. The reality is that it has reached.

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

Since the transmission / reception module can be solidified by the remarkable development of the semiconductor manufacturing technology in recent years, the solidified transmission / reception module is arranged in a one-to-one correspondence with each antenna element of the array antenna. An active phased array antenna having a configuration can be easily realized.

Further, due to remarkable progress in digital signal processing technology and high-speed signal processing devices, real-time processing of complex complex number correlation operation has become possible. However, if this is applied to an active phased array radar, microwaves in a specific direction can be obtained. By continuously irradiating a plurality of signals and subjecting a plurality of reflected signals to digital filtering, the detection distance is improved, and the target signal to clutter power ratio (S / C) or the target signal to interfering wave power ratio (S / C) is increased. J) can be greatly improved.

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

Specifically, since the degree of freedom of the time resource is increased by adopting the two-dimensional electronic scanning, if the time resource is effectively used, the number of transmission hits (continuous in a specific direction can be obtained without changing the physical condition). The number of microwave pulses to be applied can be easily increased. As a result, the detection distance improves, but as a result of the increase in the number of transmission hits, multiple reflected signals from the target are obtained, so high-speed digital signal processing is applied to it.
By the correlation signal processing, unnecessary signals such as clutter and interfering waves can be separated from the target and suppressed.

The active phased array radar currently in practical use is basically constructed as shown in, for example, FIG. 3, and performs searching and tracking by forming and scanning a beam by computer control. is there.

In FIG. 3, the N × M element antennas (111 to 1MN) are connected to the N × M T / R (transmission / reception) modules (211 to 2MN) in a one-to-one correspondence. The N × M T / R modules have the same configuration, and as indicated by 211, a transmission circuit 2111, a circulator 2112, a reception circuit 2113, and a control circuit 2.
114 is provided, and the M number of N sets is a set of M beam transmission lines (301 to 30M) corresponding to the beam combiner 400, the excitation pulse generator 410, and the antenna controller 420. Signal transmission / reception is performed, and a predetermined beam is formed on the N × M element antennas to exert a radar radio wave transmission / reception function.

For beam forming, the beam control computer 810 indicates the beam forming direction, and the beam forming direction is set by the timing controller 80.
The antenna controller 420 received via 0 transmits the microwave rotation phase to the control circuit 2114 in the N × M T / R modules (211 to 2MN) via the M signal transmission paths (301 to 30M). The antenna controller 420 transmits the amount of (phase shift) and the amount of power attenuation, and each T / R module transmits the antenna controller 420.
A control circuit (2114) that receives these control signals from
However, the phase shift amount is applied to the transmission circuit (2111) during transmission, and the phase shift amount and the attenuation amount are applied to the reception circuit (2113) during reception.

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

The following transmission / reception operation is performed in each T / R module. Since each T / R module has the same configuration and operates with the same content, in the case of the T / R module 211, the transmission 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 elevation of the search area, and the microwave signal is applied to the search area.

The receiving circuit 2113 receives the microwave signal received by the element antenna 111 and circulator 21.
The signal is transmitted via the signal transmission line 3 via the signal transmission line 3 and the attenuation and the phase rotation as instructed by the control circuit 2114.
01 to the beam combiner 400. That is, in the beam combiner 400, N × M element antennas (1
The microwave signals received by (11 to 1MN) are combined.

The combined microwave signal is received by the receiver 50.
At 0, the signal is converted to a predetermined intermediate frequency signal, band-pass filtered so that only the signal within the reception band defined by the design passes, and then phase detection is performed based on the reference signal.

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

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

The tracking computer 700 performs tracking processing on the detected target signal, displays the result on the man-machine interface 710, and at the same time, 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 the corresponding time management data from the time management table 840. Is read out, and the specifications of the search beam scanning every moment (that is, the search beam scanning schedule) are edited according to the time signal from the timer 820, and the edited specifications are given to the timing controller 800.

The beam control computer 810 receives the tracking target information from the tracking computer 700 and momentarily determines the priority of the target to be scanned with the tracking beam based on a predetermined priority rule, and the search beam scanning is performed. In the meantime, the tracking beam scanning specifications are sequentially edited and assigned to the predetermined time slots in the time management data, that is, the tracking beam scanning schedule is set and given to the timing controller 800.

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

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

[0023]

As described above, the multi-functional radar in the process of practical use in the related art obtains a plurality of information by effectively utilizing the time resource having an increased degree of freedom by adopting the two-dimensional electronic scanning. By applying high-speed digital signal processing to it, detection performance, clutter suppression performance,
We succeeded in greatly improving the interference wave suppression performance.

However, since all of these radar performances are achieved by increasing the number of transmission hits, if further improvement is attempted, the search time will greatly increase. At this time, the search scanning is a method in which the search beam is scanned in the elevation direction for each azimuth and sequentially moved in the azimuth direction, so that the time interval of the search beam irradiating the target existing at substantially the same elevation angle ( This is called the "search data rate", and as a result, the time required to first detect the target that has entered the radar search airspace and the tracking update time interval (this is called the "tracking data rate"). ) Is long.

The present invention has been made in view of such a problem, and an object thereof is to maintain the excellent detection ability, clutter suppression ability, interference wave suppression ability, etc. of the conventional multi-function radar while maintaining the intrusion target. It is to provide an active phased array radar capable of significantly improving the initial detection ability and the tracking ability.

[0026]

In order to achieve the above object, the active phased array radar of 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; the search beam is scanned horizontally with 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 scannings by independently setting the frequency of search beam scanning for each elevation angle; It is characterized by that.

[0027]

Next, the operation of the active mine active phased array radar of the present invention having the above construction will be described. As described above, the conventional search system adopted by the radar device scans the search beam in the elevation direction for each azimuth,
Since it is a method of moving it in the azimuth direction one by one, the search time becomes longer when searching the search space uniformly, 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 for each elevation angle within a certain angle range within 180 ° in the horizontal direction (azimuth direction). Moreover, a beam can be instantaneously formed in the horizontal direction within that 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 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, and the search is performed at a high search data rate in the air space where the target is intruding from the outside (for example, low elevation angle area), and other air spaces (for example, high elevation area) The inside is designed to search at a low search data rate.

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

As described above, according to the present invention, since the search data rate in the priority search area can be set high and the search data rate in the tracking continuation area can be set low, the search data rate can be increased instead, so that the total search can be performed. 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 an embodiment of the present invention. As shown in the figure, according to the present invention, in the multifunctional radar in the practical process shown in FIG. 3, as a means for editing a beam scanning program, a program editor 900, a data rate setting device 910, a beam scanning scheduler 920, and a monitor. A display unit 930 is added, the edited beam scanning program and time management data are set in the beam scanning program memory 830 and the time management table 840, and the beam control computer 810 performs control operation for realizing the active phased array radar according to the present invention. Is done.

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 those in the multi-functional radar in the practical process shown in FIG. Also, the control operation performed by the beam control computer 810 is different. Further, the active phased array antenna may be a planar type, but in this embodiment, an omnidirectional, for example, cylindrical type is assumed.

Therefore, the parts according to the present invention in FIG. 1 should originally have different signs, but since their basic operations can be understood in the same manner, in FIG. Like other components in the multifunctional radar in the process of being converted, the same symbols and names are given. Hereinafter, the description will focus on the part relating to the present invention.

The program editor 900 calculates the beam elevation angle,
It has input means for setting beam scanning specifications such as search range, transmission pulse width, number of transmission hits, and transmission repetition period, and edits these beam scanning specifications for each elevation beam scanning step, and also for each elevation beam. Calculate the scan time of. Further, the beam scanning specifications of the tracking beam that is adaptive beam scanning are edited, and the scanning time per tracking beam is calculated. These are temporarily stored, and the data rate setter 910 and the beam scanning scheduler 920 are also stored.
Given to.

The data rate setting unit 910 has an input means capable of 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 within the search space by one round, 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 scans the search beam for each elevation angle (T _S · n: n is the number of elevation beam steps, the same applies below), the tracking beam scanning time (T _t ), and the number of search beam scans for each elevation angle ( Based on K _S · n) and the number of tracking beam scans (K _t ), each beam scan is allocated on the time axis, the beam scan time interval is edited, and the scan time is calculated.

The beam scanning program and time schedule edited by the above procedure are displayed on the monitor display 930.
Modifications can be made if necessary, and a final confirmation can be made. The beam scanning program and the time division, which have been corrected and finally completed, are written in the beam scanning program memory 830 and the time management table 840 by a predetermined key operation.

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

[0040]

[Table 1]

Table 2 shows an example of setting 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 time interval for beam scanning. Since the search in the horizontal plane is performed collectively for each elevation angle, different variable search data rates can be realized for each elevation angle. To be understood.

Thus, the beam control computer 810 searches for the search beam horizontally for each elevation angle according to the search beam scanning frequency set for each elevation beam in the beam scanning program edited and set in the beam scanning program memory 830. In addition to setting a beam scanning schedule, a tracking beam that scans the tracking beam in a preset time slot during search beam scanning based on a target priority information input from the tracking computer 700 and a predetermined priority rule is received. Since the scan schedule is set, the search data rate is high in the air space (for example, low elevation angle area) where the target is intruding from the outside, and the low search data rate is in other air areas (for example, high elevation angle area). You can search with.

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

In short, according to the present invention, the search data rate in the priority search area can be set high, and the search data rate can be set low in the tracking continuation area. Instead, the tracking data rate can be set high, so that the total search time can be shortened. It can improve search and tracking performance without expansion.

[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 variable type search data that varies depending on the elevation angle is used. Adopting the rate, the air space where the target enters from the outside (for example, low elevation angle area)
It is possible to search at a high search data rate in the inside and at a low search data rate in the other airspace (for example, high elevation angle area), so it is excellent in the conventional multi-functional radar device in the practical process. It is possible to improve the search data rate and the tracking data rate at the same time while maintaining the functions and performances.

[Brief description of drawings]

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

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

FIG. 3 is a configuration block diagram of an active phased array radar in the process of practical application in the related art.

[Explanation of symbols]

 111-1MN element antenna 211-2MN T / R module 301-30M signal transmission line 400 beam combiner 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 setter 920 Beam scanning scheduler 930 Monitor display 2111 Transmission circuit 2112 Circulator 2113 Receiving circuit 2114 Control circuit

[Procedure amendment]

[Submission date] February 21, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be amended] Claims

[Correction method] Change

[Correction content]

[Claims]

Claims (1)

[Claims] 1. A radar device combining two-dimensional electronic scanning with an active phased array antenna and high-speed digital signal processing; the search beam is horizontally scanned at different frequencies for each elevation angle, and is preset between search beam scans. Means for editing a beam scanning program for scanning the tracking beam in the direction designated by the specified time slot by independently setting the frequency of the search beam scanning for each elevation angle. Active phased array radar.