The design method was discussed for merging multi-sensor information in the strap-down inertial navigation expert system.The hardware components of the system as well as the work modes of the sensors were analyzed

and an information fusion algorithm based on the space-time coordinate transformation was proposed.The algorithm achieved the match of time and space to obtain a better multi-sensor data fusion effect.Simulation results show that the accuracy can reach under 0.3 ° by the filtering of multi-sensor information fusion.So it can enhance the assessment precision of the whole expert system.