Terrain-Referenced Navigation using an Interferometric Radar Altimeter

Abstract

This paper addresses measurement models in a particle filter for application in terrain-referenced navigation using an interferometric radar altimeter (IRA). We propose a novel method for utilizing an IRA in a terrain-referenced navigation system based on the fact that an IRA provides accurate three-dimensional measurement of the closest target point on the ground. The proposed measurement model searches for the closest point on an on-board digital elevation model and constructs an estimated measurement to calculate the measurement residual. Comparative simulation analysis with an existing method shows the proposed method provides outstanding navigation performance in terms of root mean square position error. The proposed method yields positioning solutions with an average root mean square error less than 3m whereas that of the existing method is more than 11m using a virtual digital elevation model fulfilling the HRTI-3 specification. Simulation results on the effects of terrain roughness, cruising altitude, sampling frequency, and magnitudes of inertial navigation system/barometer biases are also presented. (C) 2018 Institute of Navigation