scholarly journals Improved ISRJ-Based Radar Target Echo Cancellation Using Frequency Shifting Modulation

Electronics ◽  
2019 ◽  
Vol 8 (1) ◽  
pp. 46 ◽  
Author(s):  
Qihua Wu ◽  
Feng Zhao ◽  
Junjie Wang ◽  
Xiaobin Liu ◽  
Shunping Xiao
Keyword(s):  
Frequency Modulation ◽  
Sampling Frequency ◽  
Measured Data ◽  
Echo Cancellation ◽  
Radar Signal ◽  
Radar Target ◽  
False Target ◽  
Ingenious Method ◽  
Real Target ◽  
Frequency Shifting

Target echo cancellation is an ingenious method that protects the target of interest (TOI) from being detected by radar. Interrupted-sampling repeater jamming (ISRJ) is a novel deception jamming method for linear frequency modulation (LFM) radar countermeasures, which has been applied in target echo cancellation recently. Compared with the conventional cancellation method, not only can the target echo be successfully cancelled at radar receiver, but a train of false targets is also produced and forms deception jamming by applying the ISRJ technique. In this paper, an improved radar target echo cancellation method based on ISRJ is proposed that utilizes an extra frequency shifting modulation on the intercepted LFM radar signal. The jammer power is more efficiently utilized by the proposed method. Moreover, more flexible multi-false-target deception jamming can be obtained by adjusting the interrupted sampling frequency. The real target remains effectively protected by the false preceding target in the presence of amplitude mismatch of cancellation signal and target echo. Numerical simulations and measured data experiments are conducted to demonstrate the effectiveness of the proposed method.

scholarly journals Neural Network-Guided Sparse Recovery for Interrupted-Sampling Repeater Jamming Suppression

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Zijian Wang ◽  
Wenbo Yu ◽  
Zhongjun Yu ◽  
Yunhua Luo ◽  
Jiamu Li
Keyword(s):  
Neural Network ◽  
Pulse Compression ◽  
Radar Signal ◽  
Echo Signal ◽  
Target Groups ◽  
The Real ◽  
Processing Gain ◽  
False Target ◽  
Target Locating ◽  
Real Target

Interrupted-sampling repeater jamming (ISRJ) is a new type of DRFM-based jamming designed for linear frequency modulation (LFM) signals. By intercepting the radar signal slice and retransmitting it many times, ISRJ can obtain radar coherent processing gain so that multiple false target groups can be formed after pulse compression (PC). According to the distribution characteristic of the echo signal and the coherence of ISRJ to radar signal, a new method for ISRJ suppression is proposed in this study. In this method, the position of the real target is determined using a gated recurrent unit neural network (GRU-Net), and the real target can be, therefore, reconstructed by adaptive filtering in the sparse representation of the echo signal based on the target locating result. The reconstruction result contains only the real target, and the false target groups formed by ISRJ are suppressed completely. The target locating accuracy of the proposed GRU-Net can reach 92.75%. Simulations have proved the effectiveness of the proposed method.

Research on Radar Target Simulator

2014 ◽  
Vol 971-973 ◽  
pp. 1726-1729
Author(s):  
Ying Liu ◽  
Dian Ren Chen ◽  
Lei Chen
Keyword(s):  
Analog Circuits ◽  
Simulation System ◽  
Host Computer ◽  
Radar Signal ◽  
Radar Target ◽  
Sampled Data ◽  
Characteristic Parameters ◽  
Target Characteristic ◽  
Radar Simulator ◽  
Simulation Signal

A radar target simulation system based on DRFM is designed in this paper ,in this system, the radar signal that is amplified and conversioned by the receive analog circuits is directly sampled by the ADC of DRFM, then the sampled data is stored in QDR2 SRAM array. When need to generate radar target simulation signal, the radar signal data is read from the QDR2 SRAM array and synthesis radar target simulation signal with the target characteristic parameters provided by the host computer. It can be widely used in various radar simulator occasions.

scholarly journals SINR- and MI-Based Maximin Robust Waveform Design

Entropy ◽  
2019 ◽  
Vol 21 (1) ◽  
pp. 33 ◽  
Author(s):  
Bin Wang ◽  
Xu Chen ◽  
Fengming Xin ◽  
Xin Song
Keyword(s):  
Parameter Estimation ◽  
Prior Information ◽  
Design Method ◽  
Waveform Design ◽  
Upper And Lower Bounds ◽  
Radar Target ◽  
Worst Case ◽  
The Real ◽  
Target Spectrum ◽  
Real Target

Due to the uncertainties of radar target prior information in the actual scene, the waveform designed based on radar target prior information cannot meet the needs of detection and parameter estimation performance. In this paper, the optimal waveform design techniques under energy constraints for different tasks are considered. To improve the detection performance of radar systems, a novel waveform design method which can maximize the signal-to-interference-plus-noise ratio (SINR) for known and random extended targets is proposed. To improve the performance of parameter estimation, another waveform design method which can maximize the mutual information (MI) between the radar echo and the random-target spectrum response is also considered. Most of the previous waveform design researches assumed that the prior information of the target spectrum is completely known. However, in the actual scene, the real target spectrum cannot be accurately captured. To simulate this scenario, the real target spectrum was assumed to be within an uncertainty range where the upper and lower bounds are known. Then, the SINR- and MI-based maximin robust waveforms were designed, which could optimize the performance under the most unfavorable conditions. The simulation results show that the designed optimal waveforms based on these two criteria are different, which provides useful guidance for waveform energy allocation in different transmission tasks. However, under the constraint of limited energy, we also found that the performance improvement of SINR or MI in the worst case for single targets is less significant than that of multiple targets.

The Future of Radar Target Enhancers

1997 ◽  
Vol 50 (2) ◽  
pp. 248-250
Author(s):  
N. Ward
Keyword(s):  
Present Status ◽  
Radar Signal ◽  
Radar Target ◽  
Radar Detection ◽  
Identifying Code ◽  
The Future ◽  
Small Craft ◽  
Further Development

The development, present status and likely application of Radar Target Enhancers are discussed. Their role in improving the effectiveness of aids to navigation and enhancing the safety of small craft is considered and their likely further development assessed.The Radar Target Enhancer (RTE) is a device which automatically transmits a signal in response to an interrogating signal received. The response from an RTE has no identifying code. The RTE only amplifies and retransmits the radar signal received, so that it has the same appearance on a display as a passive return, but is more consistent. The purpose is to improve the radar returns from navigation marks and to improve radar detection of small craft, to reduce the risk of collision.

scholarly journals MI-Based Robust Waveform Design in Radar and Jammer Games

Complexity ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-14 ◽  
Author(s):  
Bin Wang ◽  
Xu Chen ◽  
Fengming Xin ◽  
Xin Song
Keyword(s):  
Parameter Estimation ◽  
Prior Information ◽  
Design Method ◽  
Waveform Design ◽  
Game Model ◽  
Radar Target ◽  
The Real ◽  
Target Spectrum ◽  
Transmitted Waveform ◽  
Real Target

Due to the uncertainties of the radar target prior information in the actual scene, the waveform designed based on the radar target prior information cannot meet the needs of parameter estimation. To improve the performance of parameter estimation, a novel transmitted waveform design method under the hierarchical game model of radar and jammer, which maximizes the mutual information (MI) between the radar target echo and the random target spectrum response, is proposed. In the hierarchical game model of radar and jammer, the radar is in a leading position while the jammer is in a following position. The strategy of the jammer is optimized based on the radar transmitted waveform of previous moment, then the radar selects its own strategy based on the strategy of the jammer. It is generally assumed that the radar and the jammer have intercepted the real target spectrum and then the optimal jamming and the optimal transmitted waveform spectrum are obtained. However, the exact characteristic of the real target spectrum is hard to capture accurately in actual scenes. To simulate this, the real target spectrum is considered to be within an uncertainty range which is confined by known upper and lower bounds. Then, the minimax robust jamming and the maximin robust transmitted waveform are designed successively based on the MI criteria, which optimizes the performance under the most unfavorable condition of the radar and the jammer, respectively. Simulation results demonstrate that the robust transmitted waveform design method guarantees the parameter estimation performance effectively and provides useful guidance for waveform energy allocation.

scholarly journals A Deception Jamming Method Countering Bi- and Multistatic ISAR Based on Micro-Doppler Effect

2018 ◽  
Vol 2018 ◽  
pp. 1-6
Author(s):  
Zheng-Zhao Tang ◽  
Yang-Yang Dong ◽  
Chun-Xi Dong ◽  
Xin Chang ◽  
Guo-Qing Zhao
Keyword(s):  
Theoretical Analysis ◽  
Synthetic Aperture Radar ◽  
Real Time ◽  
Doppler Effect ◽  
Synthetic Aperture ◽  
Equivalent Number ◽  
False Target ◽  
Simulation Results ◽  
Time Movement ◽  
Real Target

Bi- and multistatic inverse synthetic aperture radar (ISAR) operate with spatially separated transmitting and receiving antennas. A deception jamming method countering bi- and multistatic ISAR is proposed in this paper based on the study of micro-Doppler effect. The jammer modulates the intercepted ISAR signals with added micro-Doppler information and retransmits them to the real target, which scatters the jamming signals to the radar receivers. Deceptive false-target images with interference bands in the cross-range direction will be induced by the jamming signals through the imaging process of radar receivers. Additionally, real-time movement features of the false-targets can be flexibly adjusted by changing the modulation parameters, which improves the fidelity of the false-targets. The equivalent number of looks (ENL) index is used to evaluate the jamming effects. Simulation results validate our theoretical analysis and show the effectiveness and practicability of our method.

scholarly journals Radar Target Simulation for Vehicle-in-the-Loop Testing

Vehicles ◽  
2021 ◽  
Vol 3 (2) ◽  
pp. 257-271
Author(s):  
Axel Diewald ◽  
Clemens Kurz ◽  
Prasanna Venkatesan Kannan ◽  
Martin Gießler ◽  
Mario Pauli ◽  
...  
Keyword(s):  
Autonomous Vehicles ◽  
Autonomous Driving ◽  
Development Stage ◽  
Test System ◽  
Radar Signal ◽  
Radar Target ◽  
Current Development ◽  
Automotive Radar ◽  
Radar Echoes ◽  
Test Beds

Automotive radar sensors play a vital role in the current development of autonomous driving. Their ability to detect objects even under adverse conditions makes them indispensable for environment-sensing tasks in autonomous vehicles. As their functional operation must be validated in-place, a fully integrated test system is required. Radar Target Simulators (RTS) are capable of executing end-of-line, over-the-air validation tests by looping back a received and afterward modified radar signal and have been incorporated into existing Vehicle-in-the-Loop (ViL) test beds before. However, the currently available ViL test beds and the RTS systems that they consist of lack the ability to generate authentic radar echoes with respect to their complexity. The paper at hand reviews the current development stage of the research as well as commercial ViL and RTS systems. Furthermore, the concept and implementation of a new test setup for the rapid prototyping and validation of ADAS functions is presented. This represents the first-ever integrated radar validation test system to comprise multiple angle-resolved radar target channels, each capable of generating multiple radar echoes. A measurement campaign that supports this claim has been conducted.

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