LOS stabilization of optic-electro landing system

Abstract

To increase line-of-sight (LOS) tracking and pointing accuracy of an Optic-Electro (O-E) landing guidance system, this work explores how to isolate the LOS tracking and pointing of a O-E theodolite from the carrier motion disturbance. A carrier-based O-E theodolite model was established with various disturbance factors introduced. Three kinds of controllers, Lead-lag, LQG/LTR(Linear Quadratic Gaussian/Loop Transfer Recovery) and H∞ were designed to improve the stability and performance of the system. The Kalman filter and H∞ weighting matrix were investigated in detail. Then, the controllers were emulated in Matlab and verified on a swing bench. The compared experiments for the three kinds of controllers on time domain, frequency response and stability were performed. Obtained results show that both LQG/LTR and H∞ controllers can satisfy the design specifications, and their decoupling effects are as deep as 50 dB, which can ensure precise tracking and pointing performance of LOSs in O-E landing guidance systems.