Digital Map Technology for GPS-Based Navigation and Terrain Avoidance System

摘要

The U.S. Military has a need for a covert (non-emitting) system that will assist the pilot to navigate using terrain following techniques while maintaining maximum safety against terrain impact. This project addresses the software development and system integration of a GPS-Based terrain avoidance system. The system extrapolates the region immediately ahead of the aircraft and alerts the pilot when the current flight vector intercepts the safety margins surrounding upcoming terrain obstacles. The system performs its task using & a set of proprietary 'Adaptive Real time Altitude Detection' (ARAD) algorithms. These compare the present GPS-derived aircraft latitude longitude, and elevation above sea level, with the NIMA DTED data for the same location. The ARAD algorithms extrapolate ahead of the current position, giving the pilot adequate time to take evasive action in avoiding upcoming terrain. The pilot can view his current location on a laptop computer that displays topographical and military aeronautical charts, as well as photo-imagery and shaded relief depictions. The final product is called 'TerrAvoid' and runs on a COTS laptop computer using the Microsoft Windows NT operating system. A multi-window moving map application is also integrated.