Feature Extraction For Communication Emitters

In order to accommodate the increasingly complicated electromagneticenvironment, to ensure the correct transmission of information, and to utilize the limitedfrequency resource reasonably, communication modulation technique and spreadspectrum technique have been dramatically developed. Therefore, the parameterestimation of communication signals and the blind detection for the DSSS signals innon-cooperative communication have become hot and key points in electronicreconnaissance.Based on the previous works, associating actual applications of communicationreconnaissance and jamming, this thesis mainly includes three parts:⑴For the difference reflected on signals by the difference of hardware undernon-steady state, the transient signal acquisition is a vital step before its analysis. Thisthesis realizes two methods of starting time detection.⑵Since the extraction of signal parameters is important in non-cooperativecommunication system, the delay-and-multiply(DM) algorithm is proposed for symbolrate estimation. After theoretical analysis and simulation verification is performed, theresult shows that this algorithm can be effectively used to extract symbol rate of FSKand PSK signals.⑶Aiming at the blind detection and parameter estimation for the DS/SS signals,the repetition period of the PN code can be obtained by adopting the cepstrum analysisand the secondary spectrum treatment. And via the signal subspace decomposition, thePN code can be determined and reconstructed combing the principle that theautocorrelation function of the PN code has lower side-lobe energy.