With concern to military applications, GPS allows accurate targeting of various military weapons including ICBMs, cruise missiles, and precision-guided munitions.  It is used to navigate and coordinate the movement of troops and supplies.  The GPS satellites also carry nuclear detonation detectors which form a major portion of the United States Nuclear Detonation Detection System.
Accurate and [...]

Electronics errors are one of several accuracy-degrading effects.  They include ionospheric effects, ephemeris errors, satellite clock errors, multipath distortion, tropospheric effects, and numerical errors.
Inconsistencies of atmospheric conditions affect the speed of the GPS signals as they pass through the Earth’s atmosphere and ionosphere.  Correcting these errors is a significant challenge to improving GPS position accuracy.
These [...]