Integrated navigation approaches of vehicle aided by the strapdown celestial angles

Abstract

The integrated navigation method based on star sensor celestial angle (altitude angle and azimuth angle) is proposed to serve the need of rapidly responsive, reliable and precise of hypersonic vehicle under complex environment. An integrated navigation algorithm suitable for large azimuth misalignment is established under launching point inertial coordinate and local geographical coordinate system based on altitude angle and azimuth angles. A nonlinear filter is applied to implement the simulation on account of the nonlinear feature of the state and measurement equations. The simulation results showed that integrated navigation of hypersonic vehicle could be accomplished by altitude angle and azimuth angle aiding in both launching point inertial coordinates and local geographical coordinate system, which were convergence to 1’ in 10 seconds. The designed method indicated that the major errors derived from initial localization and orientation initial attitude alignment in launch-point inertial coordinate system could be modified by SINS aided by star sensor’s celestial angle in local geographical coordinate system before launching, then during the flight, the feasibility and validity of integrated navigation were guaranteed aided by celestial angles in launching point inertial coordinate system.