Research On Identification And Parameter Estimation Of Teh Radar Signals

The identification and parameter estimation of the radar signals (NS、LFM、DLFM、MLFM、PPS、BPSK、QPSK、Frank、P1、P2、P3、P4、FSK、COSTAS、SFM、DSFM、LFM-BPSKand SFMLFM) based on the phase unwrapping is discussed in this dissertation. Thus the methodof filtering the signals in the process of Hilbert transformation if the instantaneous bandwidth’snumber meets the conditions is put forward. It can be used to estimate the phase under theconditions of low SNR. Consequently, the new phase unwrapping algorithm is applied to thefrequency estimation of a sinusoid. Use the instantaneous phase signal curve characteristic and theinstantaneous frequency signal curve characteristic of all radar signals, we can identify themodulation. After this, the parameters of all kinds of signals can be estimated.In this paper, the decode and parameter estimate algorithm based on LFM-BPSK is proposed.The square of the right recognition signal is made to eliminate the PN code, the fast de-chirpalgorithm is used to obtain the initial frequency and modulation factor with which the LFM signalis reconstructed. The base-band PN code signal is to get with the multiplication of the conjugatedreconstructed signal and received signal. Finally the symbol rate of PN is extracted by the wavelettransform approach. Based on the LFM-BPSK carrier frequency estimation、modulation slopeestimation and code rate estimation, considering the phase is constant in every code period, thechanging of code can be estimated by analyzing the phase difference of adjacent code.Simulation shows that the proposed method can identify signal modulation method in lowSNR, and the parameter estimation algorithen has low computing complexity and high accuracy.