Secondary Navigation



The Differential Global Positioning System (DGPS) is an augmentation of the Global Positioning System (GPS) that provides improved location accuracy. It consists of a network of fixed, ground-based reference stations that broadcast the difference between the positions indicated by GPS satellites and its known fixed position. These signal corrections are broadcast using short-range, ground-based transmitters that are typically co-located with the differential Reference Station and Integrity Monitoring (RSIM) equipment. The transmissions operate in and around the 300 KHz band, and are usable out to about 200 miles. If the GPS constellation is unusable, then DGPS (because it is an augmentation) is also unusable. The US DGPS service currently consists of Maritime, Nationwide, and High-Accuracy sites. It is expected that only the Maritime sites will remain in operation after 2016. The Differential Global Positioning System usage has been on a constant decline since the Wide Area Augmentation System (WAAS), a Space-Based Augmentation System (SBAS) developed by the FAA, was declared operational.

How Does UrsaNav Use DGPS?

In certain instances, and for certain customers, UrsaNav resells and installs Nautel’s Differential Global Positioning System transmitter technology, typically along with Trimble’s RSIM technology. UrsaNav has most recently installed high-accuracy DGPS equipment at the U.S. Pueblo, CO site, and standard DGPS technology at two sites in the Kingdom of Saudi Arabia.