Positioning for High-Speed Maneuverable Platform Based on Wrapped InSAR Interferogram.

The interferometric synthetic aperture radar (InSAR)-aided inertial navigation system (INS) is developed to introduce terrain elevation into registration, which gives out the accumulated error of INS. Unwrapped InSAR interferogram plays a key role in previous InSAR/INS frameworks, while airborne and side-looking assumptions are usually made. However, phase unwrapping is time-consuming, and high squint geometry with nonlinear trajectory is common for applications with InSAR/INS. In this article, a novel wrapped InSAR interferogram-based positioning method for the high-speed maneuverable platform is proposed. A novel back-projection-based InSAR (BP-InSAR) signal model for a slightly curved diving trajectory with a high squint angle is first presented. Then, the process that generates a phase gradient template from a given DEM is presented, considering both the estimated and measured trajectories. Error analysis is also made to discuss the performance of the proposed method in single dual-channel observation. Finally, a sequential maximum likelihood estimator based on error analysis is implemented to deal with the remained uncertainty in a single observation. Numerical experiments verify the proposed method and fully demonstrate its performance with curved trajectory and random errors in both position and attitude.