Spotlight SAR Data Processing Hyperbolic Orbit Correction

The patent applies preliminary action by pre-calculating and applying orbit curvature corrections and tropospheric delay corrections before the main matched filter processing. The distance history is adapted to a hyperbolic course with azimuth-dependent phase corrections applied in advance, so that when the conventional matched filter processes the data, the corrections are already incorporated, maintaining simplicity while improving accuracy.

The patent changes key parameters in the phase history model by adapting the distance history to a hyperbolic course instead of a simple linear approximation. It introduces azimuth-dependent phase corrections based on actual measured orbit courses and tropospheric delay models, modifying the phase parameters to account for orbit curvature and atmospheric effects, thereby eliminating defocusing while preserving processing efficiency.

The patent segments the correction process into distinct modular components: orbit curvature correction, tropospheric delay correction, and the main matched filter processing. Each correction is applied as a separate phase multiplication step in the azimuth direction, allowing the complex corrections to be broken down into manageable segments that can be processed independently and combined systematically.

The patent uses an intermediary approach by introducing a hyperbolic distance history model as a mediator between the raw radar data and the final image formation. This hyperbolic model serves as an intermediate representation that incorporates orbit curvature and tropospheric effects, allowing conventional processing algorithms to operate on this pre-corrected representation rather than directly handling the complex physical effects.