The method of suppressing interference in the area of side lobes of the radar antenna and device for its implementation

 

The invention relates to the field of radar and can be used to improve the reliability of reception overlapping in time of the signals from multiple targets while suppressing signals in the lateral direction. The technical result is the suppression of noise in linear signal processing. The method of suppressing interference in the area of side lobes of the radar antenna based on the reception of the primary signal and the compensation signal, the summation of the primary and the compensation signal, and the summed signal is subjected to amplification, filtering processing, detection and comparison with a threshold, with modulation compensation signal phase starts at the zero value of the weighting coefficient, which is then increased to a value at which the level of impulse noise in the filtered signal becomes less than the threshold value, in this case, to avoid suppression of the useful signal, the combined signal after amplification is divided into primary and compensatory, then simultaneously subjected a divided signal filter processing and detection, determine their value, and comparing the received signal with a threshold. The noise suppression device in the field of the e blocks, the adder, the processing unit, modulator, and the processing unit contains an amplifier, a coherent filter, the first detector, the threshold unit, controlled phase shifter, a coherent filter, a second detector and myCitadel. 2 C. p. F.-ly, 4 Il.

The invention relates to the field of radar and is an improvement of the invention under the application №4528815/09 (method and apparatus), a positive solution P-28232 from 25.12.90,

The known method and device to increase the noise immunity of the radar in relation to simulation noise acting on the lateral lobes of the antenna directional diagram (BOTTOM).

The essence of this method lies in the fact that you accept the basic and compensatory signals, adjusting the amplitude of the compensation signal by multiplying by a weighting factor and summed with the main signal, while before summing modulate the phase of the compensation signal in the range from 0 to 360periodic law(t) with period not exceeding the duration of the impulse noise. After summation perform filter processing, detection and comparison with a threshold, with modulation compensation signal pasover impulse noise in the filtered sum signal becomes less than the threshold value. When the filter processing is performed by amplifying the signal, amplitude limiting and matched filtering.

Thus, signals received by the main antenna are received by the adder without distortion, and the signals received compensation antenna before entering the adder distorted due to the modulation phase. As a result, the phase of the signal at the output of the adder will be distorted and the extent of this distortion depends on the ratio of the signal levels of the main and compensation. When receiving a signal from the lateral direction with a corresponding value of the weighting factor set depending on the noise level and the acceptable level of false alarm, the signal level of the compensation antenna will be higher than the signal of the main antenna and the phase of the total signal will be determined largely by the phase of the distorted signal, with the result that he will be depressed when the filter processing.

The operation of the known method is performed by a known device (Fig.1) for the specified application, containing basic and compensatory antenna connected to the signal inputs of the respective receiving units 1 and 2, the outputs of which are connected to the input of the adder 3, the output of which is connected to the input of ucen to the second input of the receiving unit 2 of the compensation channel, and a third input receiving unit 2 is connected to the output of the entire device.

The processing unit (Fig.2) contains a connected in series broadband amplifier 6, the inlet of which is an input processing device, the limiter 7, consistent filter 8, a detector 9, and a threshold device 10 whose output is the output of the entire device.

The processing unit uses the operation constraints. How hard limit signals with subsequent processing in narrowband (agreed) the filter is effective in suppressing signals with a structure different from the structure of the working signal, including at the expense of distortion of its phases. It is especially effective when using signals with vnutripolostnoe modulation (phase or frequency).

However, it has a significant deficiency is a significant loss of range of detection of multiple targets due to the overlap in time of reflected signals and the phase change patterns of the total signal.

With increasing duration of the echo signal in a restrictive cascade, resulting in the phase coding RLS becomes more vulnerable to partial overlap of the echo signals in time. Due to the effect of suppression of the weak is otnositelnogo overlap, if after level matched filtering has a detector with a fixed threshold detection (Excerpt from "Handbook of radar systems" Ed. by M. of SKOLNIK, T. 3., - M.: Owls.Radio, 1979, S. 173).

It should be added, that a significant overlap of strong and weak signals weak can be completely suppressed, but there is a mutual suppression and two equal signals. Therefore, in modern radar nonlinear processing is replaced by a linear one.

The use of amplitude limiting filter in the processing of this method will lead to mutual suppression overlapping in time of the signals received primary antenna, even in the complete absence of signal in the compensation channel.

Thus, a disadvantage of the known method of suppressing interference in a region of the lateral lobes of radar antenna is in the reception deteriorates overlapping signals from multiple targets.

The purpose of the additional invention is to eliminate the mentioned drawback, namely, providing reception of overlapping time working signals of the main directions while maintaining the effect of suppressing signals the lateral direction.

This objective is achieved in that in the method according to the patent application "Method submitted at the reception of the primary signal and the corrected amplitude and phase modulated in the range from 0 to 360periodic law(t) kompozicionnogo signal, summing them, according to the invention the filter processing performed by the gain simultaneous processing in the agreed filters the main signal and the recovered through an additional modulation in the range from 360 to 0periodic law 2-(t) the compensation signal, and upon detecting define their relationship, decide on the presence of a signal, if the level of the main signal exceeds the level of the compensation signal is not less than the threshold value.

That is, the objective is achieved by the fact that instead of suppressing signal from the lateral direction in the limiter, where does amplified sum signal of the main channel and distorted due to phase modulation in the range from 0 to 360according to the law1(t)=(t) the compensation signal, the combined signal after amplification is divided into main and compensation by restoring the signal phase compensation signal by phase modulation within 360-0according to the lawThe objective is also achieved by the fact that in the known device, containing basic and compensatory radar antenna connected to the signal inputs of the respective receiving units whose outputs are connected to inputs of the adder, the output of which is connected to the input of the processing unit and the modulator, the output of which is connected to the control input of the phase of the output signal of the compensation of the receiving unit, and the control input amplitude compensation of the receiving unit is connected to the output processing unit according to the invention the second output of the modulator is connected to the second input of the processing unit, which contains connected in series amplifier, which input is the first input of the processing unit, consistent filter, the detector subtractive device, a threshold device whose output is the output of the entire device, and connected in series controlled phase shifter, the first input of which is the second input of the processing unit and the second connected his device.

In Fig.1 presents a functional diagram of the device of the prototype of Fig.2 is a diagram of a known processing unit of Fig.3 is a functional diagram of the device of Fig.4 diagram of the proposed processing unit.

The proposed device (Fig.3) provides basic and compensatory antenna connected to the signal inputs of the respective receiving units 1 and 2, the outputs of which are connected with the inputs of the adder 3, the output of which is connected to the first input of the processing unit 4, the output of which is the output of the entire device and the modulator 5, the first output of which is connected to the second input of the receiving unit 2, and the second output to the second input of the processing unit 4, in addition, a third input receiving unit 2 is connected to the output of the entire device.

The processing unit (Fig.4) contains connected in series amplifiers 6, consistent filter 8, a detector 9, subtractive device 11, a threshold device 10 whose output is the output of the entire device, and connected in series controlled phase shifter 12, the first input of which is connected to the first input of the processing unit and the second input to the second output of the modulator 5, a coherent filter 13, a detector 14, the output of which is connected with the second input visiteuse the block 1, the adder 3, a coherent filter 8 and the detector 9 is supplied to the first input of subtractive device 11. The signal received compensation antenna through the receiver unit 2, which with the help of the modulator 5 distort its phase structure by phase modulation according to the law1(t)=(t), after passing through the adder 3 and the controlled phase shifter 12, where restore its phase structure by phase modulation according to the law2(t)=2-(t), and through soglasovanny filter 13, a detector 14 is supplied to the second input of subtractive device 11. The signal from the subtractive device arrives at the threshold output device 10.

In different situations the device performs the following operations.

1. When the operating signal in the region of the main lobe signal of the main channelgo through the adder 3, the amplifier 6, a coherent filter 8, a detector 9 and the first input of subtractive device 11 is formed a signal. This same output signal from the amplifier 6 is supplied and the input 1 of the phase shifter 12, where its phase structure will be destroyed due to vasanam the filter 13 (because the signal of the main channel will no longer be consistent with the filter 13 and the second input of the counting device 11 is formed a signal. At the same time, a working signal will be received and the compensation antenna with

As in the known device it will go to the 2nd input of the adder 2 with modulation phase by law1=(t). Since the phase structure is destroyed, then through a consistent filter 8 it will not work. But the same phase modulated signal at the output of the phase shifter 12 will receive an additional phase shift2(t)=2-(t), so that the total additional phase shift compensation signal is equal to

=1(t)+2(t)=2,

i.e., the phase structure of the compensation signal will be restored at the entrance soglasovannogo filter 13. As a result, the signal for the main direction adopted by the compensation antenna in the filter 13 will not be depressed and the second input of the subtracting 11 will be the received signal UQCbut due to condition (1) we get that

i.e., subtraction of the signal UGSsignal UQCin the device 1 the er.

2. In the area of side lobes of the antenna operates interference with the structure of the working signal. In this case, the signals of the main channeland countervailingwill be approximately equal to

Next, the processes in the device will be completely analogous to that discussed in paragraph 1, except that instead of the condition (1) will satisfy the condition (3). Then, instead of the condition (2) we get

and output device 11 by subtracting fromsignal level UQCbe established signal level less than threshold level Uothreshold device 10, i.e.

Thus, when linear signal processing, including matched filtering (in which there is compression of the signal and therefore, the separation in time overlapping uncompressed signals from multiple targets), there is rejection of signals from the lateral direction, and receive overlapping signals from multiple targets.

Claims

1. The method of suppressing interference in the area of side lobes of the radar antenna based on the reception of the primary signal and compensatoire phase in the range from 0 to 360periodic law(t), the summation of the primary and the compensation signal, and the summed signal is subjected to amplification, filtering processing, detection and comparison with a threshold, with modulation compensation signal phase starts at the zero value of the weighting coefficient, which is then increased to a value at which the level of impulse noise in the filtered signal becomes less than the threshold value, characterized in that to avoid suppression of the useful signal, the combined signal after amplification is divided into the main and compensating, by restoring the signal phase compensation signal by phase modulation within 360-0according to the law2(t)=2-(t), then simultaneously subjected a divided signal filter processing and detection, determine their value, and comparing the received signal with the threshold.

2. The noise suppression device in the area of side lobes of the radar antenna, containing basic and compensatory radar antenna, connected respectively to the signal inputs of the respective and, the output which is the output device and connected to the control input of the amplitude compensation unit admission, to the input of the phase control which is connected to the modulator output, and the processing unit contains an amplifier, the input of which is the entrance to the block and connected in series consistent filter and the detector, the threshold block whose output is the output device, wherein an additional output of the modulator is connected to an input of the processing unit, and a processing unit connected in series introduced additional controlled phase shifter, a coherent filter, detector and myCitadel, to the other input of which is connected to the output of the detector, and the output connected to the input of the threshold unit, the first input is additionally controlled phase shifter is an additional input of the processing unit and to the second input of the controlled phase shifter connected to the output of the amplifier, the other end of which is connected to the input of the matched filter.

 

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FIELD: radiolocation.

SUBSTANCE: device can be used at radiolocation stations with continuous probing signal. Device for detecting moving objects has aerial connected in series with receiver, autocompensator, detector, low frequency filter and solving unit. Device also has additional rejecter filter and one or several compensation channels each of which has aerial connected in series with receiver and rejection filter which has output connected with compensation input of autocompensator. Auotcompensator is brought between receiver of main channel and detector. Additional rejection filter is brought into feedback circuit of autocompensator.

EFFECT: improved autocompensation.

6 dwg

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