Navigation accuracy of integrated GPS and INS under flight conditions

GPS could provide a low cost means of accurately calibrating other navigation systems including radio beacons, Loran, VOR/DME-Tacan, etc. However several issues remain to be resolved concerning system availability, integrity and accuracy. The paper discusses the current status of GPS, illustrates the position and velocity accuracies achievable and identifies problematic areas that users of the system for calibration purposes should be aware. Ultimately GPS or derivatives such as Differential GPS (DGPS) may replace many of the present radio navigation system as present equipment becomes obsolescent and replacement costs increase. As the debate over MLS has demonstrated even systems currently being implemented are not immune from the suggestion their function could be satisfied by GPS