The invention belongs to the technical field of airship SAR fine motion compensation. The invention provides an airship SAR fine motion compensation method based on a DSP. According to the embodiment of the invention, the PGA and MD algorithms are fused, low / high order errors are compensated through the PGA, the
azimuth modulation frequency is accurately estimated through the MD, and the second-order phase residual error is corrected; and a high-frequency vibration space-variant model is constructed, and a time-varying
phase error estimation module is introduced, so that the improvement of
azimuth and distance resolution is ensured. A self-adaptive sub-block division strategy is designed, sub-apertures are overlapped by half length, and
phase error continuity is guaranteed; a parameter self-optimization mechanism is introduced, and the PGA / MD sub-aperture length, the number of samples and the number of iterations are optimized in real time in combination with scene features. A PGA + MD refined model is constructed, the long aperture characteristic is adapted, and the DSP load is reduced; a real-time priority
resource scheduling strategy is designed, high-frequency access data is stored by adopting an L2 cache to reduce
delay, and
power consumption is controlled while
high resolution is guaranteed in combination with dynamic task allocation.