Abstract: A sliding mode observer is designed to estimate the angle of attack and flight path angle for a hypersonic vehicle. By solving an eigenvalue assignment problem in real time, the switching gains of the observer on the sliding surface are determined according to observer states and desired dynamic performance. Hence uniform dynamic performance of observer can be guaranteed in the full flight envelope. The design procedures for both single-output and multi-output nonlinear systems are presented. Application of the observer to a benchmark hypersonic vehicle to demonstrate its construction and performance is also presented.

Key words: hypersonic vehicle, observer, sliding mode, pole assignment, nonlinear system