GPS is the modern answer to the ancient question about one’s place in the world yet it has its limitations. It depends on the time of flight of radio signals emitted by satellites twenty ...

Also called a "differential GPS" (DGPS), an augmentation system compensates for those discrepancies by transmitting corrections to the GPS receivers either via satellite or terrestrial radio.

the U.S. Coast Guard (USCG) to provide 326 NT200CG GPS receivers for use in the USCG's Aids to Navigation (ATON) vessels. Differential GPS positioning information from Trimble's NT200CG will be ...