Bistatic ISAR image fusion with sub-aperture based parameter estimation

A bistatic inverse synthetic aperture radar (Bi-ISAR) system can receive echoes from different observation angles simultaneously, thus an image with higher signal-to-noise ratio (SNR) and more abundant information of a certain target can be obtained by fusing the two images attained by the two distributed receivers. However, the geometrically dependent image dissimilarity of the two target images induced by bistatic angle highly complicates the image fusion process. In this paper, a new approach is proposed to solve this problem. The algorithm firstly extracts the Doppler difference between two sub-apertures of the echo data from a prominent scatterer to estimate the rotation velocity and half bistatic angle, then maps the two data sets from different observation angles onto a global coordinate system to perform the coherent image fusion, resulting in an ISAR image of higher quality. Its performance is verified via simulations.