JPH0450788A - Radar signal processor - Google Patents

Abstract

PURPOSE:To prevent misdetection at the time of the target automatic detection of constant wrong warning probability (CFAF), etc., by substituting the range bin of a disturbing radio wave or a nearby range bin with a noise level when there is the disturbing radio wave. CONSTITUTION:Signals which are received by a radar antenna and an auxiliary antenna and outputted from a precedent-stage signal processor 4 through respec tive receivers are three channels Ch of a sum signal SIGMA, an azimuth difference signal B, and a high-low difference signal E and SLBCh. A comparator 12 comparates SIGMACh obtained by the multiplication 10 between the SLBCh and a threshold coefficient k9, SLBCh, and a noise level m11 and outputs 1 (or true) when SIGMA < k.SLB and SLB > m to obtain their AND result 13. Then noise controller 14 judges that a disturbing radio wave enters the range bin when the AND result is 1, substitute the data of the range bin or nearby range bin with the noise level m11, and performs the switching 15 of the connection to the output side of a controller 14. Consequently, a misdetection can be prevented at the time of the automatic detection of a target by a post-stage signal processor 6.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a radar signal processing device that automatically detects a target such as an aircraft.

[Conventional technology]

FIG. 3 is a block diagram of a conventional radar signal processing device. In the figure, (1) is a radar antenna that can continuously change the angle of elevation while rotating, (2) is an auxiliary antenna that receives interference waves such as jamming coming from side lobes, and (3) is a receiver that converts microwave signals from the radar antenna (1) and auxiliary antenna (2) into electrical signals, and (4) is a receiver that converts unnecessary signals such as di-clutter etc. contained in the electrical signals from the receiver (3). MT to suppress! .

The front-stage signal processing device (16) performs pulse compression, etc., and detects and compares the amplitudes of the radar antenna (1) and auxiliary antenna (2) signals from the front-stage signal processing device (4), and prevents interference such as jamming. Determine the presence or absence of radio waves,
If there is a jamming signal, there is a jamming removal device that blanks the data of that range pin or that range pin and nearby range pins. (6) performs automatic target detection processing such as CFAR on the signal from the jamming removal device. The second stage signal processing device (7) is the second stage signal processing device (6
This is a display device that displays the processing results from ) on a PPI scope or the like.

FIG. 4 is a diagram illustrating the operation of the jamming removal device (16) of the conventional radar signal processing device configured as described above. The signal from the radar antenna (1) from the front-stage signal processing device (4) has three channels, and the sum signal (hereinafter Σ
It's called a channel. ), bearing difference signal (hereinafter referred to as Bearir
It is called +g (B) channel. ) and a height difference signal (hereinafter referred to as Elevation (E) channel). In addition, the signal from the auxiliary antenna (2) from the front stage signal processing device (4) is 5LB (Side Lobe Bl).
Anker) signal (hereinafter referred to as SLB channel). (8) is an amplitude detector that detects the amplitude of each signal of the Σ channel and SLB channel, and (9) is an SL signal.
a threshold coefficient that controls the amplitude value of the B channel;
(10) is the multiplier that multiplies the SLB channel signal and the threshold coefficient (11) is the noise level which is the minimum value of the amplitude of the radar signal processing device, (12) is the signal of the Σ channel and the multiplier (10) This is a comparator that compares the output of the SLB channel and the noise level (11), and outputs 1 (or true) when the following conditions are satisfied.

Σ<k-8LB SLB>m Here, Σ: E channel amplitude: Threshold coefficient SLB: SLB channel amplitude m: Noise level (13) is an AND circuit that performs AND of the output of the comparator (12) , (17) is a blanking controller that blanks the data of the range pin or the range pins nearby when the output of the AND circuit (13) is 1, and outputs O to the B channel, the E channel, and the Σ channel. , (15) is an interlocking switch that switches the connection to the blanking controller (17) when the output of the AND circuit (13) is 1.

FIG. 5 is a diagram illustrating antenna patterns of the radar antenna (1) and the auxiliary antenna (2) of the radar signal processing device configured as described above. Radar antenna (1)
The antenna pattern is a pattern that concentrates and radiates energy in a specific direction.

It consists of a main lobe and several side lobes. On the other hand, the antenna pattern of the auxiliary antenna (2) has a constant wide width over the entire area radiated by the radar antenna (1), and the side lobe level of the radiation intensity of the radar antenna (1) is made up of which beams.

FIG. 6 is a diagram illustrating the operating principle of the jamming removal device (16) of the radar signal processing device configured as described above. For example, when jamming comes from the target and side lobes, in the Σ channel, the target received by the main lobe and the jamming received by the side lobes have amplitude characteristics as shown in FIG. 6(a). Similarly, in the SLB channel, targets and jamming received by the auxiliary antenna (2) with constant radiation intensity are shown in Figure 6 (
The amplitude characteristics are as shown in b). The presence or absence of jamming is determined based on the amplitude values of these Σ channels and SLB channels, and if there is jamming, the data of that range pin or that range pin and nearby range pins is output.
By doing so, an output as shown in FIG. 6(C) is obtained.

[Problem to be solved by the invention]

In the above radar signal processing device, when jamming or other interference radio waves enter from side lobes, all data on the mixed range pin or the range pin and nearby range pins are blanked and set to O, so the subsequent stage signal Blanked data, that is, O, is entered into the reference cell range pin of the CFAR processed by the processing device (6), and the CFAR threshold level becomes low, causing Pfa(
Probability of false alarm
There was a problem that this led to an increase in the probability of false alarm (m: false alarm probability).

This invention has been made to solve the above problems.2 A jamming removal compensation device (5 ), and is a radar signal processing device that aims to prevent erroneous detection during automatic target detection in the subsequent signal processing device (6).

[Means to solve the problem]

The radar signal processing device according to the present invention detects interference such as jamming from a signal obtained through a radar antenna, a receiver, and a pre-stage signal processing device, and a signal obtained via an auxiliary antenna, a receiver, and a pre-stage signal processing device. determine the presence or absence of
It has a jamming removal compensation device that replaces range pin data with interference radio waves with noise level, a subsequent signal processing device that automatically detects targets, and a display device that displays the results.

[Effect]

In this invention, interference radio waves such as jamming coming in from side lobes are compared with signals from the radar antenna and 9 judgments are made, and the data of the range pin where the interference radio waves are present or the range pin and nearby range pins is replaced with the noise level. CFAR of the subsequent signal processing device
This makes it possible to prevent false detection when automatically detecting a target.

〔Example〕

FIG. 1 is a configuration diagram showing one embodiment of this invention (1)
- (4), (6), and (7) are completely the same as the above-mentioned conventional device. (5) detects and compares the amplitude of the radar antenna (1) and auxiliary antenna (2) signals from the previous stage signal processing device (4), determines the presence or absence of jamming radio waves, and determines whether there is a range pin or This is a jamming removal compensation device that replaces the data of the range pin and nearby range pins with a noise level.

FIG. 2 is a diagram showing the internal configuration of the jamming removal compensation device (5). A signal received by a radar antenna (1), passed through a receiver (3), and outputted from a pre-stage signal processing device (4) is composed of three channels, Σ, B, and E. Also,
The signal received by the auxiliary antenna (2), passed through the receiver (3), and outputted from the previous stage signal processing device (4) is an SLB channel. (8) is an amplitude detector that detects the amplitude of each signal of the Σ channel and the SLB channel, and (9) is a threshold coefficient that controls the amplitude value of the SLB channel.

(10) is a multiplier that multiplies the amplitude data of the SLB channel by the threshold coefficient, (11) is the noise level (12) which is the minimum value of the amplitude of this radar signal processing device.
compares the signal of the Σ channel and the output of the multiplier (10), and also compares the signal of the SLB channel with the noise level (11
), and when the following conditions are satisfied, 1(
or true).

Σ<k -5LB SLB>m Here, Σ: The amplitude of the Σ channel: Threshold coefficient SLB: The amplitude of the SLB channel m: Noise level (13) is the logic that performs the logical product of each output of the comparator (12) The product circuit (14) determines that interference radio waves are mixed in the range pin when the output of the AND circuit (13) is 1, and replaces the data and noise level of that range pin or the range pins nearby. Noise controller, (15) is when the output of AND circuit (13) is 1
This is an interlocking switch that switches the connection to the output side of the noise controller (14) when

In the radar signal processing device configured as described above, instead of blanking the data of the range pin where interference radio waves such as jamming coming in from the side lobe exist, or the range pin and neighboring range pins, the data is adjusted based on the noise level. By replacing it, it becomes possible to prevent erroneous detection when automatically detecting a target by the subsequent signal processing device (6).

〔Effect of the invention〕

As explained above, this invention automatically detects a target such as a CFAR by replacing the range pin where interference radio waves such as jamming coming from side lobes are present or the range pin and nearby range pins with a noise level. In this case, there is no omission in the take of the reference cell range pin, which has the effect of preventing erroneous detection.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a diagram showing an embodiment of the invention, and FIG. 3 is a diagram showing a detailed block diagram of the jamming removal compensation device. FIG. 1 is a diagram showing a conventional radar signal processing device. FIGS. 5 and 6(a) to 6(c) are diagrams for explaining the operation of a conventional radar signal processing device. In the figure, (1) is a radar antenna, (2) is an auxiliary antenna, (3) is a receiver, (4) is a front-stage signal processing device,
(5) is a jamming removal compensation device, (6) is a post-stage signal processing device, (7) is a display device, (8) is an amplitude detector, (9) is a
) is the threshold coefficient, (10) is the multiplier. (11) is the noise level, (12) is the comparator, (1
3) is an AND circuit, (14) is a noise controller, (1
5) is an interlocking switch, (16) is a jamming removal device, and (17) is a blanking controller. In addition, in FIG. 1, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Claims] A radar antenna that can change the angle of elevation while rotating, an auxiliary antenna that receives interference waves such as jamming coming from side lobes, a receiver that receives signals from this radar antenna and the auxiliary antenna, and this receiver. MTI (MovingTarg)
A pre-stage signal processing device that performs clutter suppression processing, such as a moving target indicator (e.g., moving target indicator), detects the amplitude of the radar antenna and auxiliary antenna signals from this pre-stage signal processing device, and compares the signals to determine the presence or absence of jamming radio waves. , a jamming removal compensation device that replaces the data of the range pin or the range pins in the vicinity of that range pin with a noise level when there is a jamming radio wave, and a CFAR (Cons.
tantFalseAlarmRate: A post-stage signal processing device that performs automatic target detection processing such as constant false alarm probability), and a processing result from this post-processing device is
(anPositionIndicator) A radar signal processing device characterized by comprising a display device for displaying on a scope or the like.