Search

In order to detect targets accurately in electromagnetic environment, a decomposition of time reversal operator method for detecting targets with uniform circular array (UCA) is proposed in this paper. In this method, the time reversal operator in UCA is obtained by the transmission functions of targets and antenna array. And then, the eigenvector decomposition of time reversal operator is performed. According to the eigenvectors and the transmission functions of targets and scanning points in the given targets area, the focusing values of all scanning points are calculated, and the direction of scanning points whose focusing values are far greater than others are the direction of targets. Finally, the simulations verify the effectiveness of the proposed method.

In this paper, the performance of a new secured coded DS/FFH/TH hybrid spread spectrum system is evaluated. The evaluation is performed using four different spreading codes, which are long sequence, PN sequence, gold sequence, and chaotic sequence. The evaluation is performed under the effect of AWGN, Rayleigh fading, and frequency selective fading channels. The results show that the system presents a superior improvement in the performance especially in the severe fading conditions.