Observability analysis of rotation of strapdown inertial navigation system

The observability of the combined state of the strapdown inertial navigation system(SINS) was inferred on the stationary base only by using velocity errors as the observable parameter,which is equal to evaluation of the SINS states by using the velocity errors and position errors as the observable parameters.Furthermore,the observability of continuous rotation of SINS was studied by means of the observability analysis theory of piece-wise constant system(PWCS).Results show that the continuous rotation improves the observability of SINS,the equivalent accelerometer biases both in the east and north are observable and can be compensated in the alignment,the accuracy and speed of alignment is improved obviously.