Abstract: In this paper, the error sources of strapdown inertial navigation system (SINS) are researched. The mechanism of noncommutativity error and quantization error is illustrated from the geometrical point of view, and the mutual influence between them is analyzed. Considering the sample quantizing condition of the output pulses of the ring laser gyroscope (RLG), the multi-sample attitude algorithm of SINS is discussed. The simulation is carried out using MATLAB/Simulink. It is concluded that the three-sample rotation vector algorithm with the proper quantization factor outperforms others when the impact of quantization errors is taken into account.

Key words: SINS, attitude algorithm, noncommutativity error, quantization error, multi-sample