Optimizing and designing hybrid altimeter filtering system for small sea-skimming unmanned aerial vehicle (UAV)

To achieve the altitude control precision of a small sea-skimming UAV, we design a third-order hybrid altimeter filtering system that uses a radio altimeter and a vertical accelerometer. We analyze the flight data of the vertical accelerometer on the small UAV and the sea wave spectra and then establish the error model of the vertical accelerometer and the sea wave noise model of the radio altimeter. We minimize the mean square error of the output altitude signal of the hybrid altimeter filtering system and use the genetic algorithm to optimize its feedback gains. The simulation results, given in Figs. 2 through 6, and their analysis show preliminarily that: (1) our third-order hybrid altimeter filtering system can effectively filter sea wave noise; (2) the feedback gains optimized with the genetic algorithm has better filtering results than those obtained with the traditional equivalent root method.