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DOE OSTI · 2585103

Analysis of the Trusted Inertial Terrain-Aided Navigation Measurement Function

Haydon, Tucker Caelan Ellis [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Univ. of Texas, Austin, TX (United States)]·Huang, Andy [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)]·Humphreys, Todd E. [Univ. of Texas, Austin, TX (United States)]
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Abstract

The trusted inertial terrain-aided navigation (TITAN) algorithm leverages an airborne vertical synthetic aperture radar to measure the range to the closest ground points along several prescribed iso-Doppler contours. These TITAN minimum-range, prescribed-Doppler measurements are the result of a constrained nonlinear optimization problem whose optimization function and constraints both depend on the radar position and velocity. Owing to the complexity of this measurement definition, analysis of the TITAN algorithm is lacking in prior work. This publication offers such an analysis, making the following three contributions: (1) an analytical solution to the TITAN constrained optimization measurement problem, (2) a derivation of the TITAN measurement function Jacobian, and (3) a derivation of the Cramér-Rao lower bound on the estimated position and velocity error covariance. These three contributions are verified via Monte Carlo simulations over synthetic terrain, which further reveal two remarkable properties of the TITAN algorithm: (1) the along-track positioning errors tend to be smaller than the cross-track positioning errors, and (2) the cross-track positioning errors are independent of the terrain roughness.

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BibTeXRIS

Haydon, Tucker Caelan Ellis [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Univ. of Texas, Austin, TX (United States)], Huang, Andy [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)], Humphreys, Todd E. [Univ. of Texas, Austin, TX (United States)]. 2025-07-22. Analysis of the Trusted Inertial Terrain-Aided Navigation Measurement Function. https://doi.org/10.33012/navi.707

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