scholarly journals SIMULATION MODELING OF THE INTERFERENCE IMMUNITY OF THE RADARS OPERATING WITH COMPRESSED SIGNAL

2020 ◽  
Vol 8 (12) ◽  
pp. 799-804
Author(s):  
Sevdalin Ivanov Spassov ◽  
Keyword(s):  
Simulation Modeling ◽  
Pulse Compression ◽  
Matched Filter ◽  
Chirp Signal ◽  
Interference Immunity ◽  
Matched Filters ◽  
Matlab Software ◽  
Interference Signals

The immunity to the interference of a radar operating with a pulse compression signal is an important feature. The matched filter is one of the elements of the radar, providing resistance to interference. A model of a matched filter to chirp signal has synthesized using the Simulink tool of the Matlab software. Two types of interference signals have fed to the matched filter input, and the output signals are measured. The matched filters degree of suppression against these two interference signals has been assessed. Inferences about the interference immunity of the radars operating with compressed signals have been made.

scholarly journals JAMMINGIMMUNITYRESEARCH OF A RADAR OPERATING WITH BARKER CODED PHASE MODULATED SIGNAL

2020 ◽  
Vol 8 (12) ◽  
pp. 738-743
Author(s):  
Sevdalin Ivanov Spassov ◽  
Keyword(s):  
Pulse Compression ◽  
Matched Filter ◽  
Interference Immunity ◽  
Matched Filters ◽  
Compression Technique ◽  
Matlab Software ◽  
Interference Signals

The matched filter is one of the most important elements in the pulse compression technique. Pulse compressed signal enhances the interference immunity of a radar operating with such a signal. A model of the matched filter for a Barker coded phase modulated signal was synthesized using the Simulink tool of the Matlab software. Interference signals were feed to the input of the matched filter and output signals were measured. The matched filters degree of suppression of these interference signals was assessed. Conclusions were made about the jamming immunity of radars operating with Barker coded phase modulated signal.

scholarly journals JAMMINGIMMUNITY RESEARCH OF A RADAR OPERATING WITH CHIRP SIGNAL

2020 ◽  
Vol 8 (12) ◽  
pp. 731-737
Author(s):  
Sevdalin Ivanov Spassov ◽  
Keyword(s):  
Pulse Compression ◽  
Matched Filter ◽  
Chirp Signal ◽  
Matched Filters ◽  
Compression Technique ◽  
Matlab Software ◽  
Interference Signals

Pulse compressed signal enhances the jamming immunity of a radar operating with such a signal. The matched filter is one of the most important elements in the pulse compression technique. A model of a matched filter for a chirp signal was synthesized using the Simulink tool of the Matlab software. Interference signals were feed to the input of the matched filter and output signals were measured. The matched filters degree of suppression of these interference signals was assessed. Conclusions were made about the jamming immunity of radar operating with chirp signal.

scholarly journals CHIRP FILTER JAMMING IMMUNITY RESEARCH

2021 ◽  
Vol 9 (01) ◽  
pp. 966-971
Author(s):  
Sevdalin Ivanov Spassov ◽  
Keyword(s):  
Pulse Compression ◽  
Matched Filter ◽  
Chirp Signal ◽  
Echo Signal ◽  
Matched Filters ◽  
Compression Technique ◽  
Matlab Software

The pulse compression technique uses a matched filter to extract an echo signal in the radars receiver. A model of a matched filter for a chirp signal was synthesized using the Simulink Tool of the MATLAB software. Pulse jamming and chirp jamming signals were feed to the input of the matched filter. The output signals were measured. The matched filters degree of suppression of these jamming signals was assessed. Conclusions were made about the jamming immunity of a radar operating with a Chirp matched filter.

scholarly journals A Truncated Matched Filter Method for Interrupted Sampling Repeater Jamming Suppression Based on Jamming Reconstruction

2021 ◽  
Vol 14 (1) ◽  
pp. 97
Author(s):  
Lu Lu ◽  
Meiguo Gao
Keyword(s):  
Time Delay ◽  
Theoretical Analysis ◽  
Numerical Simulations ◽  
Frequency Modulation ◽  
Pulse Compression ◽  
Matched Filter ◽  
Filter Method ◽  
Matched Filters ◽  
Digital Radio ◽  
Real Target

Interrupted sampling repeater jamming (ISRJ) is becoming more widely used in electronic countermeasures (ECM), thanks to the development of digital radio frequency memory (DRFM). Radar electronic counter-countermeasure (ECCM) is much more difficult when the jamming signal is coherent with the emitted signal. Due to the intermittent transmission feature of ISRJ, the energy accumulation of jamming on the matched filter shows a ‘ladder’ characteristic, whereas the real target signal is continuous. As a consequence, the time delay and distribution of the jamming slice can be obtained based on searching the truncated-matched-filter (TMF) matrix. That is composed of pulse compression (PC) results under matched filters with different lengths. Based on the above theory, this paper proposes a truncated matched filter method by the reconstruction of jamming slices to suppress ISRJ of linear frequency modulation (LFM) radars. The numerical simulations indicate the effectiveness of the proposed method and validate the theoretical analysis.

scholarly journals Coherent Pulse-Compression Lidar Based on 90-Degree Optical Hybrid

Sensors ◽  
2019 ◽  
Vol 19 (20) ◽  
pp. 4570 ◽  
Author(s):  
Jing Yang ◽  
Bin Zhao ◽  
Bo Liu
Keyword(s):  
Phase Difference ◽  
Amplitude Modulation ◽  
Detection Probability ◽  
Pulse Compression ◽  
Random Phase ◽  
Local Oscillator ◽  
Chirp Signal ◽  
Lidar System ◽  
Coherent Pulse

A coherent pulse-compression lidar system based on a 90-degree optical hybrid is demonstrated in this paper. In amplitude modulation (AM) mode, the returned RF chirp signal will be influenced by a random phase difference between local oscillator and echo light, causing fluctuations in the ranging results, and as a result the detection probability is small. By using the 90-degree optical hybrid, two orthogonal complementary signals are obtained to stabilize the result so as to increase the detection probability. We performed an experiment to measure the distance of a white printed wall which is about 65 m away from the system. The detection probability increased from 65% to 99.88%, and the precision is improved from 0.42 m to 0.27 m.

scholarly journals Multiclass Radio Frequency Interference Detection and Suppression for SAR Based on the Single Shot MultiBox Detector

Sensors ◽  
2018 ◽  
Vol 18 (11) ◽  
pp. 4034 ◽  
Author(s):  
Junfei Yu ◽  
Jingwen Li ◽  
Bing Sun ◽  
Jie Chen ◽  
Chunsheng Li
Keyword(s):  
Radio Frequency ◽  
Pulse Compression ◽  
Radio Frequency Interference ◽  
Single Shot ◽  
Separation Problem ◽  
Underdetermined Blind Source Separation ◽  
Time Frequency ◽  
Interference Signals ◽  
Novel Method ◽  
Short Time

Radio frequency interference (RFI) is known to jam synthetic aperture radar (SAR) measurements, severely degrading the SAR imaging quality. The suppression of RFI in SAR echo signals is usually an underdetermined blind source separation problem. In this paper, we propose a novel method for multiclass RFI detection and suppression based on the single shot multibox detector (SSD). First, an echo-interference dataset is established by randomly combining the target signal with various types of RFI in a simulation, and the time–frequency form of the dataset is obtained by utilizing the short-time Fourier transform (STFT). Next, the time–frequency dataset acts as input data to train the SSD and obtain a network that is capable of detecting, identifying and estimating the interference. Finally, all of the interference signals are exactly reconstructed based on the prediction results of the SSD and mitigated by an adaptive filter. The proposed method can effectively increase the signal-to-interference-noise ratio (SINR) of RFI-contaminated SAR echoes and improve the peak sidelobe ratio (PSLR) after pulse compression. The simulated experimental results validate the effectiveness of the proposed method.

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