The design, simulation and implementation of an accurate positioning system for automatic flight inspection

The design and simulation of the integrated navigation algorithms of the C-29A automatic flight inspection system (AFIS) are presented. The automatic flight inspection design problem is one of determining the inspecting aircraft´s position with respect to the threshold of the runway independently of the ILS (instrument landing system) beam being inspected. The C-29A design is a unique application of the integrated navigation concept, in which the aircraft position is computed by an aided inertial navigation solution where the primary aiding measurements are the aircraft position at the runway threshold and end, each occurring once per inspection pass. A UD-factorized Kalman filter estimates the navigation errors, and a modified Bryson-Frazier smoother improves these estimates to provide the best estimate of aircraft position for calibration of the ILS beam. Results indicate that the errors occurring in the runway referenced position estimates can be controlled quite well. Moreover, the limited measurements available are sufficient to calibrate some sensor errors. The key component to achieving a specified Accuracy is the PPS (precision position subsystem)