Analysis of a cascaded INS calibration filter

The authors address some critical issues associated with improving the system performance of integrated GPS (global positioning system) sand inertial systems. Emphasis is placed on the correlated data coming from a primary filter into a cascaded or secondary filter. A sophisticated Monte Carlo simulator was used to simulate the primary GPS system and a cascaded INS (inertial navigation system) calibration filter. The primary system is either an 11-state unaided or a 12-state inertially aided system. The cascaded filter is coupled with a gimbaled inertial system and is simulated in a 15-state configuration (position, velocity, tilts, gyro drifts, and accelerometer biases)