Feasibility Study of GPS-Inertial Navigation for Helicopters and Study of Advanced GPS Signal Processing Techniques. Volume III.

摘要

This report is presented in two parts. Part 1 presents the results of a feasibility study of a low-cost integrated GPS-inertial (strapdown) navigation system for Army attack helicopters. The conclusion is reached that a GPS-Doppler navigation system can more easily attain the cost and performance goals. It was also concluded that an integrated GPS-Doppler-inertial system might be very attractive if it could be used for providing attitude and heading reference data as well as navigation data. There would be a cost savings association with avoiding the need for the usual attitude and heading reference systems. Moreover, the integrated GPS-Doppler-inertial system would have excellent performance in the presence of aircraft dynamics and jamming. Part 2 presents the results of a study of advanced GPS signal processing techniques. Covered in the study are data aiding, comparison of phase-locked loops with Costas loops, variable predetection bandwidths in code-tracking loops, code loop dithering, aided tracking, variable tracking bandwidths, and effective gains of detectors in the presence of noise. The results are from computer simulation and theoretical analysis. (Author)