Ai Xiaofeng

Repeating Decoys Discrimination Based on Range Glint

Repeating decoys (based on DRFM), through the main lobe into the radar receiver, realistically simulate real targets echo in both time and frequency domain, and cause serious threat to radars search, identification and tracking. At the near distance, angular error caused by targets angular glint is an important noise source and it can be utilized to the discrimination of repeating decoys. At the remote and ultra long distance, angular glint is not applicable for the discrimination of repeating decoys. Compared with the angular glint error, the range glint error is completely independent of the targets absolute distance. Therefore, the targets range glint provides a basis to the discrimination between the repeating decoy and the actual target. This paper, based on the premise that the actual target is multi-feed radiation and the repeating decoy is single feed radiation, analyzes the range glint of extended targets by sampling ratio ranging model and explains its physical essence from the perspective of echo spectrum distortion. On the basis, by analyzing the range measuring variance of both actual targets and repeating decoys, the Neyman-Pearson theorem and GLRT are utilized to make correct discrimination. Finally, the performance of the discrimination algorithm is illustrated by Monte Carlo simulations.

Repeating decoy discrimination based on angular glint

Repeating decoys (based on DRFM), through main lobe into the radar receiver, realistically simulate real targets echo in both time and frequency domain, and greatly affect radar regular operation of radar. This paper, based on the premise that the actual target is multi-feed radiation and the repeating decoy is single feed radiation, analyzes in theory and explains its physical essence from the perspective of echo spectrum distortion. On the basis, it utilizes the monopulse amplitude comparison angle estimation method to establish angular glint statistics model and analyzes the differences between actual target and repeating decoys in angle measuring variance. Then, the Neyman-Pearson theorem and GLRT are utilized to make correct discrimination. Finally, the performance of the discrimination algorithms are illustrated through Monte Carlo simulations.

A study on effectiveness modeling of multi-false-target jamming

Multi-false-target jamming, a typical active deception jamming mode, will have different effects on the radar with different-signal parameters. Based on the principle of constant false alarm (CFAR) detection, the principle and process of multi-false-target jamming to radar are discussed in this paper. Then the relationship between the detection performance and two parameters, the jamming to signal ratio (JSR) and the distance of false targets, is deduced. Moreover, the critical values of the two parameters above corresponding to different effects are obtained, as well as a simulation model of the multi false target jamming effect on radar. Finally, some simulations are conducted to verify the correction of the proposed model.

Bistatic Micro-Doppler Characteristics of Precession Targets

Micro-motion is one of the most important features for radar target recognition. Firstly, the bistatic micro- Doppler models corresponding to the bistatic scattering centers of the precession targets are derived. Then, The dynamic simulation method of the bistatic echo of the precession target is presented using the bistatic scattering coefficients obtained via electromagnetic calculations, and the bistatic scattering coefficients of the blunt-nosed biconical model are calculated using the multilevel fast multipole method. Finally, the theoretic analysis is verified by comparing the time- frequency distribution of the bistatic echo sequences with the theoretical bistatic micro-Doppler. This research is helpful for utilizing the bistatic micro- Doppler for feature extraction and recognition of spatial micro-motion targets.

Experimental Study on Full-Polarization Micro-Doppler of Space Precession Target in Microwave Anechoic Chamber

Based on the background of radar target detection and recognition of space precession targets, an experimental study on full-polarization micro-Doppler of those targets is introduced. The wide-band scattering properties of space precession targets are analyzed, and then the theoretical full-polarization micro-Doppler models are proposed. The scenario of the experiment is introduced, and the measured data are analyzed, and then the differences of full-polarization micro-Doppler of different scattering structures can be observed during precession.

Feature extraction of wobbling rotational symmetry targets

Feature extraction and recognition of wobbling targets are very important in spatial target surveillance. It has been shown that the scattering centers are slipping on the edge of the rotational symmetry target with the target micro-motion according to the electromagnetic scattering theory and electromagnetic computation analysis. Based on the slippery scattering center model, the micro-motion model and high-range resolution profile (HRRP) model of a wobbling rotational symmetry cone-shaped target are introduced, and the observed HRRP sequence is used to construct a time-range distribution matrix, then a estimation method of the wobbling period is proposed based on time-range distribution matrix correlation, which is validated by electromagnetic computation data and dynamic simulation.