Low-Cost Laser Range-Measurement-Based Terrain-Following Concept and Error Analysis

The feasibility of a new, low-cost, low-signature, all-weather, terrain-following concept is presented and evaluated. The terrain altitude is assumed to be modeled as a discrete-Markov process with respect to the longitudinal coordinate x. In addition to the two-dimensional (planar) scenario assumption, a point-mass model is chosen to express the aircraft planar dynamics. Consequently, the aircraft motion is represented by a three-degree-of-freedom model. For trajectory-tracking purposes, as an inner loop for the guidance algorithm, the aircraft is also assumed to be equipped with normal acceleration command autopilot, which, for the assumed negligible angles of attack, is equivalent to a flight-path angle rate autopilot. The suggested system that is based on a few simple laser range sensors was shown to be feasible for terrain-following applications. An error analysis of the suggested system was performed and validated against Monte Carlo simulation results. Finally, the proposed analysis model was then used to obtain optimal configuration parameters, in particular optimal pointing angles of the laser range sensor, and its sensitivity to system variations.