Navigation data prediction for GPS and GLONASS weak signal tracking

摘要

Prediction methods for navigation message symbols of satellite systems, such as GPS (Global Positioning System) and GLONASS (Global Orbiting Navigation System), that use information repetition in navigation data messages are disclosed. The methods enable one to eliminate the impact of symbol modulation for a received signal on the threshold performance of any navigation receiver, thereby permitting its operation in severe environments when the carrier-to-noise ratio C/N₀ of “weak” satellite signals falls to levels below C/N₀=20 dB*Hz.