Wei Yinsheng

New anti-jamming waveform designing and processing for HF radar

In this paper several typical HF radar waveforms are synthetically analyzed and compared. To improve the low system resolution and weak anti-jamming ability that the conventional HF radar meets with, a new waveform with interrupted spectra is presented. By cutting off the interference band based on the results of the spectrum surveying system before transmitting, the HF radar could make use of some fractional silent spectra. Processing such a waveform using the method of FFT would result in a very high sidelobe and thus may greatly degrade the HF radars performance. We introduce a new signal processing method based on the least square technique to lower the sidelobe. It is easy for processing and application. Simulation results show that this method could successfully suppress the sidelobe with high resolution in the congested electromagnetic environments.

A novel array calibration method based on spatial correlation matrix for HFSWR

This paper addresses a new method based on spatial correlation matrix to calibrate uniform linear array for HF Surface Wave Radar (HFSWR). Strong point echoes, such as target, clutter, transponder and so on, which are highly spatial correlated, can be used to structure spatial correlation matrix. And the matrix contains angles of echoes and phase errors information. In this paper, we use two-dimension FFT to estimate angle of strong point echo, and then obtain the corrections. Computer simulations and experimental results are conducted to show the validity of the new method.

A novel adaptive learning method for low-sidelobe step frequency waveform designing

For a step frequency waveform, high range resolution can be achieved by inter-pulse sysnthesis processing and its sidelobe level can be controled by weighting in frequency domain. Howerver, high range sidelobe arise when the frequeuy steps is sparsely spaced. For this, low sidelobe can be obtained in two ways. One is by signal processing after receiving. And the other is to design the waveform with low sidelobe. In order to avoid the SNR loss, The latter is more effective. In this paper, a novel adatpive learning method is given. The method can adaptively adjust the frequencys by max sidelobe discrepancy between the matched filtering out of present and the ideal one. The result of simulation shows that it can approach the optimal frequencys for which the max sidelobe is lowest.