Diving Forward-Looking Spaceborne-Missile BiSAR Imaging Method Based on Improved 2D Stolt Interpolation

The traditional monostatic missile-borne SAR cannot achieve forward-looking imaging during the missile's dive phase, whereas the spaceborne-missile bistatic SAR system model precisely compensates for this limitation. However, the bistatic SAR model also makes the slant range equation more complex, leading to increased coupling between range and azimuth in the echo signals, more severe range migration and space-variance. To tackle these issues, a frequency-domain imaging algorithm based on improved 2D Stolt interpolation is proposed. This algorithm transforms the signal into the 2 D frequency domain, decomposes the phase in the 2 D spectrum into three parts, and then applies 2D Stolt interpolation to the spatial-variant phase. The result is a focused signal. The algorithm effectively compensates for the space-variance in both range and azimuth, achieving high-resolution imaging of the missile's dive phase in the spaceborne-missile bistatic SAR system. The effectiveness of the proposed algorithm is validated through simulations.