What is NDGPS?

The Nationwide Differential Global Positioning System (NDGPS) is hoped to make traveling safer and to reduce the problem of road congestion. NDGPS is a radio navigation system implemented by the US Department of Transport. It is used in conjunction with global positioning systems (GPS) already in use to provide a more accurate picture of travel conditions.

Recent reports have shown that almost 40,000 Americans die in auto crashes every year. Eighteen thousand of these deaths are due to single vehicle crashes. It is hoped that the use of NDGPS can greatly reduce these fatalities. NDGPS can tell drivers when they are leaving the roadway and exactly where they are in terms of the highway infrastructure.

By using this system, drivers can be informed in advance of congestion hotspots and potential and actual crash sites. Consequently, drivers will be able to navigate their journey with greater accuracy and safety. Drivers will also be able to save time by avoiding congested areas.

GPS will be far more accurate when combined with NDGPS than when used alone. A GPS system only has a range accuracy of 4 to 20 meters (about 13 to 66 feet). When combined with NDGPS, the accuracy is improved to 1 to 3 meters (3.3 to 9.8 feet). NDGPS improves on the accuracy factor by using fixed reference stations that can broadcast any inaccuracy given by the GPS satellite signal. NDGPS can compare the data and return the correct information to the driver.

NDGPS uses a low frequency radio broadcast process. This type of broadcasting has been used for many years in both maritime and flight applications. Low frequency broadcast is the most accurate type of signal over large areas and over areas where obstructions can occur.

NDGPS is already used in a broad range of applications. Transportation departments in many states use this system to map out their highway and road infrastructures. An inventory of a road grid using traditional methods can take days. By using NDGPS, the inventory can take only a few hours.

Police departments use NDGPS to identify road accident locations. The system is also used by environmentalists to collect data on endangered species and to record different types of locations, such as wetlands. The accuracy of the system is extremely useful in rough terrain such as forests and other hazardous environments. NDGPS is a free service that will not only save time, but could also save lives.