基于子空间投影的双基地地波超视距雷达直达波抑制方法

Subspace-Projection Based Direct-Path-Interference Suppression in Bistatic GWOTHR

双基地地波超视距雷达采用岸基阵列发射正交频率编码信号,舰载单根全向天线接收回波信号。由于发射站全方位辐射能量以及接收平台运动,不能直接采用已有的如发射置零、旁瓣对消等技术来抑制直达波。该文结合该雷达特点以及自适应置零技术,提出基于子空间投影的直达波抑制方法并对其性能进行分析。该方法利用接收端等效信号构造直达波子空间的正交投影矩阵,对接收信号进行投影,从而抑制直达波干扰。仿真和实测数据结果表明,该方法能对直达波干扰进行有效抑制。

Bistatic Ground-Wave Over-The-Horizon Radar （GWOTHR） uses an array located on a coast to transmit orthogonal frequency coded signals, and a single antenna to receive the returns. The direct-path-interference suppression methods such as transmit nulling and sidelobe cancellation are inapplicable because the energy is radiated isotropiclly and the receive platform is moving. The method of subspace-projection based direct-path-interference suppression is presented in this paper with the characters of this radar and the interference nulling technique considered, followed by the anlysis of the technqiue＇s performance. The orthogonal projection matrix to the direct-path subspace is formulated using the received signals which are then projected to the null space and the direct-path interference are suppressed. Both the simulated and the real data prove the validity of the method.