Xiaobin Liu

An Equivalent Simulation Method for Pulse Radar Measurement in Anechoic Chamber

When a pulse radar signal is implemented in a range-limited anechoic chamber for radar measurement, the transmitted and reflected signal will be coupled at the receiver. To solve this problem and equivalently simulate the whole process of pulse radar measurement in an anechoic chamber, the interrupted transmitting and receiving method is proposed in this letter based on interrupted sampling. The constraints of the transmitting and receiving parameters are deduced with the sizes of the anechoic chamber and target. The pulse compression of the proposed method is performed. Then, the window function is applied to extract the main peaks after pulse compression. Both the simulation and experimental results are provided to demonstrate the effectiveness of the proposed method in overcoming the coupling between the transmitted and reflected pulse signals.

High resolution range profile reconstruction for rotating targets based on random stepped frequency signal

To extract the micro-motion parameters of the rotating targets, SFS (Stepped Frequency Signal) is usually adopted to obtain the HRRP (High Resolution Range Profile). To reduce the sub-frequency counts SFS needs to synthesize the wideband, RSFS (Random Stepped Frequency Signal) is raised. By randomly transmitting the sub-frequencies of SFS, the frequency counts are obviously reduced. Then HRRP reconstruction algorithms based on compressed sensing theory are proposed for the received sparse echo. Both math simulations and field experiments are conducted to prove the effectiveness of the proposed algorithm. The experiment results indicate that when the selected sub-frequency count of the RSFS is no less than some lower bounds, the recovered HRRP is qualified for the micro-motion parameter extraction of the rotating targets.

Extended target detection of MIMO radar based on GLRT in compound-Gaussian clutter

Multiple-input multiple-output (MIMO) radars with wideband signals are useful to discriminate target in clutter. With wideband MIMO radar, the problem of extended target detection in compound-Gaussian clutter is considered in this paper. By obtaining target echoes from each antenna, the detector based on generalized likelihood ratio test (GLRT) is developed. It shows that the shape parameter of clutter, Doppler mismatches and antenna configurations of MIMO radar heavily affect the performance of GLRT detector. Therefore, the detection performance is respectively analysed with different shape parameters and Doppler mismatches. By using maximum likelihood estimation (MLE), the detection curves with typical parameters are presented to illustrate that the proposed detector outperforms that obtained in Gaussian clutter. Then, the detection performance is discussed with different antenna configurations. Mathematical analysis and simulation results show that the detection performance reaches the best when the numbers of transmitters and receivers are equal, which provides reference for the antenna configuration of MIMO radar.

Equivalent simulation method for pulse radar countermeasure in RFS

Vulse radar signal is widely used in radar countermeasure and detection. When pulse radar signal is adopted in radio frequency simulation (RFS) for radar countermeasure, the target echo will return before the pulse signal is totally transmitted because the size of anechoic chamber is small. The reflected signal and transmitted signal will be coupling and the radar countermeasure cannot be implemented. In this paper, the interrupted transmitting and receiving (ITR) method is adopted to solve the coupling between transmitted and reflected signal. The equivalent simulation method for radar countermeasure and detection is proposed. Then, the processing and detection results of ITR echo and complete pulse radar echo with typical convolution noise jamming are both compared and analyzed. Simulations are conducted to indicate that the detection results of ITR echo are identical with those obtained by the complete pulse echo in the same jammer to signal ratio (JSR). Therefore, the proposed simulation method is effective and applicable.

Performance analysis of Sidelobe Canceller under the influence of ground clutter

By adopting Sidelobe Canceller (SLC) technology to realize spatial adaptive filtering in radar, it can eliminate the jamming from the antenna sidelobe. However, radar suffers serious ground clutter when detecting the target in low-altitude. The spatial complexity of ground clutter reduces the performance of SLC and even makes it invalid. Due to the influence of ground clutter, the optimum weighs calculated by SLC cannot be applied and the disagreement of main and auxiliary channel responses increases, which is certified by numerous simulation results in the case of standoff jamming and ground clutter. Therefore the estimate for the angle of arrival (AOA) of the jamming deviates from the real value. Besides, the bias of the AOA of the jamming increases against the jamming to clutter ratio (JCR) and the performance of SLC decreases consequently.