基于图像质量评估的MIMO-SAR等效相位中心误差界

Equivalent phase center error bound in MIMO-SAR based on image quality evaluation

受等效相位中心误差的影响,新体制的多输入多输出合成孔径雷达(MIMO-SAR)方位成像结果存在"假峰"而导致成像质量下降。该文提出基于虚假旁瓣比、积分旁瓣比及峰值能量损失等图像质量指标联合评价"假峰"对SAR成像质量的影响,进而确定MIMO-SAR等效相位中心误差界,为系统设计和信号处理提供了依据。结果表明:当等效相位中心误差超过0.2rad时,一般需要对其进行补偿以满足常规指标要求;星载系统较机载系统更适合等效相位中心处理,通常可忽略等效相位中心误差的补偿环节。

The image quality of novel multi-input multi-output synthetic aperture radar （MIMO-SAR） may be degraded with a series of ＂spurious peaks＂ in the cross-range direction due to equivalent phase center error. The influence of ＂spurious peaks＂ on image quality was analyzed by evaluating SAR image quality using the guidelines of spurious side lobe ratio,integral side lobe ratio and peak power loss. The equivalent phase center error bound in MIMO-SAR was then determined,which benefits MIMO-SAR system design and signal processing. The results show that the equivalent phase center error should be compensated to meet conventional guideline requirements when the error is more than 0.2 rad. Compared with an airborne system,a spaceborne system is more favorable to equivalent phase center processing,usually with the error compensation neglected.