Phase Wrap Error Correction by Random Sample Consensus With Application to Synthetic Aperture Sonar Micronavigation

Accurate time delay estimation between signals is crucial for coherent imaging systems such as synthetic aperture sonar (SAS) and radar (SAR). In systems, estimates resulting from the cross-correlation of complex are commonly used to generate navigation scene height measurements. presence noise, can be ambiguous, containing errors corresponding an integer number phase wraps. These ambiguities cause bathymetry reduce quality imagery. this article, algorithm introduced detection correction wrap errors. The random sample consensus (RANSAC) fit 1-D 2-D models ambiguous made in step redundant center (RPC) micronavigation. Phase then corrected by recalculating using best-fitting model. approach demonstrated data collected 270-330 kHz SAS NATO Centre Maritime Research Experimentation Minehunting unmanned underwater vehicle Shallow water Covert Littoral Expeditions. Systems with lower fractional bandwidth were emulated windowing increase occurrence refined both RANSAC algorithms branch-cuts method. Following qualitative assessment smoothness full-bandwidth after application these three methods, results method chosen reference estimates. Comparison shows that methods outperform method, improvements 29%-125% 30%-150%, respectively, compared 16%-134% set.