The wavelet domain hidden markov model analysis of ship attitude based on dual star sensors

With the development of large field-of-view and high precision star sensor technology, ship attitude can be measured using star sensor, and then the measurement accuracy of measuring equipments in the Spacecraft Tracking, Telemetry and Command (TT&C) ship can be improved greatly. According to the non-Gaussian and nonlinear characteristics of the ship attitude data, a filtering algorithm based on wavelet domain Hidden Markov Model(HMM) model is proposed in this paper. The algorithm establishes models between the wavelet coefficients of ship data using HMM model, which parameters are estimated using expectation maximization method. Experiments show that the model proposed has a smallest variance comparing with the maximum likelihood method and time series method, and also has the best consistency with the estimation of random error.