Calibrating accelerometers for space-stable inertial navigation systems at system level

A space-stable inertial navigation system is characterized by long-term high accuracy and a complex error model. It is now in pressing need to calibrate the accelerometer at system level to guarantee high precision. The main challenge is how to simultaneously calibrate the overall 9 accelerometer errors in mooring state. We propose a new calibration method at system level by arousing different gravity cones of the platform to excite all the accelerometer errors. Firstly, observability of accelerometer errors are surveyed by grids means. We find that at least 3 orientations of the platform are required to calibrate all the accelerometer errors. Secondly, we determine the optimal combination of platform orientations by minimizing the condition number of observation matrix. Simulation results confirm a calibration accuracy at 1 × 10−6 g. In addition, our method is easy to implement and can be applied in a relatively low cost.