Aperture coherent processing in distributed SAR

In synthetic aperture radar (SAR), the azimuth resolution is limited by synthetic aperture length and it is difficult to be improved. A novel solution is to construct a bigger aperture by using several apertures in distributed SAR. But the precondition is to obtain the coherent information, that is, the time delay between these apertures. In this paper, the problem of abstracting coherent information between apertures is researched, and the algorithm of aperture coherent processing is provided. Firstly the signal models are built by modern spectral estimation techniques, and then by the model the original signals received by distributed SAR are extrapolated. Finally, the time delay between apertures is estimated by cross correlation. The algorithm is proved to be valid by simulation.