Robust time synchronization method based on step frequency signal for wideband distributed coherent aperture radar

The distributed coherent aperture radar consists of several cooperating small aperture radars and a control center, which is proposed as a new technology to replace traditional large aperture radars for the next generation radar. The coherent performance of distributed coherent aperture radar is mainly affected by time synchronization. However, current time synchronization technology could not meet the requirement of high accuracy of time synchronization for wideband distributed coherent aperture radar. In this paper, a robust time synchronization method is proposed based on step frequency signal, which can reduce significantly the requirement of time synchronization accuracy into a realizable level. In this paper, after the mathematical model of time synchronization is described, the estimation methods of time difference by using orthogonal signals and coherent signals are proposed, respectively. In the following, the impact of time synchronization error on coherent performance is investigated. And then, a robust time synchronization method based on step frequency signal is proposed. At last, the effectiveness of proposed method is verified by simulations. The proposed method is very helpful for the practical application of wideband distributed coherent aperture radar technology in engineering.