For the purpose of improving the precision of SAR interferometric measurement, the registration of InSAR complex images

is one of the key technologies involved in SAR interferometry. For the airborne dual-antenna InSAR system, the accurate terrain

elevation measurement needs to be ensured by the accurate interferometric phase; therefore, the registration of sub-pixel complex

images is very important. In order to improve the registration precision and computational speed of airborne dual-antenna

interferometric SAR complex images, the authors employed the methods of complex correlation fine registration based FFT and over

-sampling image fine registration in this study. Chinese airborne dual-antenna InSAR complex images were chosen to perform the

above-mentioned algorithms; meanwhile, interferogram was generated and the coherence of registered images was analyzed．The

results show that both algorithms are feasible and robust．However, through analyzing registration precision and computational

speed of the two algorithms, the authors have reached the conclusion that the complex correlation fine registration  based FFT

method is more accurate, and its computation efficiency is higher. The practical application also proves that the complex

correlation fine registration based FFT method is applicable and effective.