机载双站SAR频率同步与误差补偿

The Frequency Synchronization and Synchronization Error Compensation of Airborne Bistatic SAR

机载双站SAR系统中,收发平台是分置的,收发载机本振频率源的不同步,将会引起回波信号相位误差的积累,其积累时间长度为整个合成孔径时间.本文给出了"GPS+独立高稳定频率源"实现双站SAR收发频率同步的方法,并对该同步方法引起的同步相位误差进行了分析,提出了一种基于收发平台视距通信的频率同步误差补偿方法.最后给出了对几种典型频率同步误差的补偿仿真,仿真结果表明,该频率同步误差补偿方法能够有效地补偿由收发不同步引起的误差项.

For airborne bistatic SAR system, bistatic SAR uses separated transmitter and receiver flying on different platforms, the difference between the oscillator clock of receiver and transmitter will result in phase drifts error, which will accumulate during the whole imaging time. The paper will concentrate on the problem of frequency synchronization between a bistatic transmitter and receiver pair, firstly a possible solutions（GPS ＋ high stable local oscillators） for synchronization error compensation is given, and the corresponding phase error aroused by the above frequency synchronization method is analyzed, then a synchronization error compensation method based on the direct commtmications between the transmitter and receiver pair is studied in detail. At last, this paper shows the simulation of frequency synchronization error compensation of several representative frequency synchronization error models, which shows the validity of the compensation method in the paper.