Anonymous Feature-Based Terrain Relative Navigation

Terrain relative navigation is a technique that uses observations of the terrain surrounding a vehicle to provide useful updates within a navigation filter. Standard approaches to these filtering problems require explicit specification of the measurement generation process in order to reliably produce updated state estimates. However, nonstandard measurement types, such as those provided by terrain cameras, contain measurement errors that cannot be formally accounted for in the standard approaches, such as missed detections, misidentification of features, and spurious returns. This Paper derives a new measurement likelihood and corresponding update that formally account for these nonstandard error sources, and Monte Carlo analysis indicates that the new update produces a significantly more reliable estimator in the presence of inevitable flaws in the collected data.