通道失配对多通道子带合成SAR性能的影响分析与补偿

摘要

The channel imbalances will reduce the performances of the multi-channel synthetic-bandwidth SAR system, so measures should be taken to correct them. In this paper, a correction method based on the raw data is presented. Before acquiring the synthetic-bandwidth signals, the system is switched to emit and receive single sub-band signals, and then the channel imbalances are extracted from the Doppler spectra between different channels. In the method, the additional inner calibration circuits can be left out, which will simplify the system design. Finally, the practicability of this method is confirmed by the processing of the real data which obtained by the displaced phase center multiple-beam SAR system.%通道间的不一致性会降低多通道子带合成SAR的成像性能,必须设法补偿.该文提出了一种基于原始数据的通道间幅相误差的补偿方法.在采集子带合成数据前,先发射和接收一段单一子带信号,并利用各通道信号间的多普勒谱关系来提取通道误差.它不需要借助额外的内定标通路,从而大大简化了系统设计.实测偏置相位中心方位向多波束数据处理结果表明,这种方法对于子带合成通道间的幅相补偿具有较高的实用性.