非正交发射的宽域高分辨MIMO InSAR成像模式研究

MIMO InSAR具有比多基线InSAR更稳健和精确的地形高程重建能力，但其关键技术之一是在各阵元接收端分离出源自不同阵元发射信号的回波。现有正交信号正交性不足，依赖它们实现回波分离会产生严重回波间相互干扰。为此，该文提出了一种非正交发射的MIMO InSAR成像模式，该模式首先通过控制各阵元交替发射信号，使其主瓣回波交替出现在各脉冲重复周期，此时只需压低各阵元天线俯仰维旁瓣即可大幅降低回波间的相互干扰，从而避免回波分离对发射信号正交性的依赖。在此模式基础上，该文又引入基于方位向多通道处理的波束扫描技术以缓解交替发射时方位不模糊与距离不模糊之间矛盾，从而实现宽域、高分辨观测。仿真结果证明了该文MIMO InSAR成像模式的有效性。

A Wide-swath High-resolution Imaging Mode for MIMO InSAR without Transmitting Orthogonal Signals

The ability to reconstructing the terrain height profile of MIMO InSAR outperforms the ordinary multibaseline InSAR. One key technology of MIMO InSAR is the echo separation on the receiver. The available orthogonal signals introduce great cross-interferences between different MIMO Channels due to their inadequate orthogonality. An equivalent MIMO InSAR imaging mode without transmitting orthogonal signals is presented in this paper, whose echo separation do not depend on the orthogonality of transmitting signals. Instead, the elements of this MIMO InSAR system transmit alternately in different pulse duration under this mode, hence the mainlobe echoes of different transmitting signals appear in different pulse duration coordinately. The cross-interferences are suppressed sufficiently with low sidelobe transmitting pattern in elevation. Furthermore, the multichannel azimuth processing based ScanSAR technique is employed in this MIMO InSAR imaging mode to improve its swath width and azimuth resolution. The numerical simulations prove the validation of the proposed mode.