Development of an electronic chart display system (ECD) with global positioning satellite (GPS) data

To aid aircrews in maintaining geographical orientation and to reduce navigation workload, an electronic chart display (ECD) system coupled with a Global Positioning System (GPS) was developed and ground-tested in the local area with both 1:500,000 and 1:100,000 scale digitized maps. System accuracy was not limited by GPS accuracy (±100 ft), but rather by the area represented by each map pixel. A calibration technique, which correlated reported GPS position with a known map location, made it possible to take full advantage of the increased system accuracy. This system was flight-tested during a NASA C-130 Ice and Snow Reflectance Study over Glacier National Park. The ECD system was compared to the paper map/inertial navigation system currently used for geographical orientation and navigation. Initial results show that GPS data were more accurate, but less reliable due to satellite constellation gaps. The navigator/ photographer assessed the ECD, even with its current limitations, to be as useful as the system with which he is highly experienced, but much more flexible