Detection Technique Of Low-level Moving Targets And Parameter Estimation Based On DS-CDMA

With the quick development of the technology of flying objections hidden ,more and more attentions are paid to the research of coherent passive detection for thereasons of its potential concealment and anti-hidden abilities.This thesis considers the detection of low-level moving targets using thereflected signals from the targets and the objects around , of which the source isDS-CDMA base stations(BS) . In the comparison of the methods by televisionsignals or that of radio , the technique in this paper has advantages of abroad basestations and the known PN sequence . On a detailed analysis of the forward channel inDS-CDMA system , on one hand , a novel method is proposed in Chapter Fourunder the circumstance of a single BS . It mainly discusses the solution to the adaptivereduction of the direct echo and multipath clutters and the research of the coherentaccumulation of target echoes .The robustness of the method proposed iscomputationally efficient and is comfirmed by computer simulations .On the otherhand, it is taken into account that DOAs and time delays of multipath signals areestimated jointly for passive coherent detection .The echo signals are receivedcoherently with Walsh0 code , then MUSIC and LCMV are applied to estimate theparameters. The computer simulations testify that DOAs closed in space anddifferent time delay can be estimated . Additionally , the two obtained parameters arematched automatically.