Inertial Navigation System Tests having Improved Observability of Error Sources
William S. Widnall, Peter A. Grundy, Walter G. Murch · Journal of Aircraft · 1976
Optimal filtering of simulated inertial navigation system (INS) test data is used to evaluate alternate laboratory and flight test echniques, which are intended to determine the value of each significant source of navigation error. Tests of both gimbaled and strapdown systems are evaluated. The major problem preventing more accurate determination of the dozens of sources of error in an INS is the high correlation between the contributions of many of the sources of error. Laboratory test sequences and flight test trajectories are presented that reduce these correlations and improve the observability of the individual sources of error. Parametric studies include the effects of flight duration and distance, multi directional flights versus straight out-and-out flights, frequency and direction of maneuvers, and supersonic flights vs subsonic flights. The effects of the range instrumentation (reference system) accuracy and measurement frequency are demonstrated.