Wide Area Differential GPS (WADGPS) is an enhancement of the standard Global Positioning System (GPS) that provides improved location accuracy over large areas, typically continental scales. Here’s an overview of WADGPS:

Multiple Reference Stations: Unlike Local Area DGPS (LADGPS) which relies on a single reference station, WADGPS utilizes a network of reference stations distributed over wide areas to monitor GPS satellite signals.

Centralized Processing Centers: The corrections determined by these reference stations are sent to centralized processing centers. These centers compute corrected signals and, in some systems, these corrections are then broadcast via geostationary satellites to the DGPS receivers.

Coverage Area: WADGPS covers much larger areas than LADGPS. It can encompass entire continents or even global coverage.

Accuracy: WADGPS provides positioning accuracy typically within 1 to 2 meters, but this can vary depending on the specific system and conditions.

Applications:

  • Aviation: WADGPS is commonly used in aviation to aid in navigation and enable precise landing approaches.
  • Maritime Navigation: Ships traveling over vast oceanic areas benefit from the wide coverage of WADGPS.
  • Transportation: For fleet management across large areas, WADGPS provides enhanced tracking accuracy.

Satellite-Based Augmentation Systems (SBAS): WADGPS is often associated with SBAS, which are systems that support wide-area or regional augmentation through the use of additional satellite-broadcast messages. Examples include:

  • WAAS (Wide Area Augmentation System) in North America
  • EGNOS (European Geostationary Navigation Overlay Service) in Europe
  • MSAS (MTSAT Satellite Augmentation System) in Japan
  • GAGAN (GPS Aided Geo Augmented Navigation) in India

Benefits:

  • Wider Coverage: WADGPS offers corrections over vast areas, making it suitable for applications that require consistent accuracy across large regions.
  • Flexibility: Works in environments where LADGPS might not be feasible due to the requirement of having a nearby reference station.

Limitations:

  • Infrastructure Dependency: WADGPS relies on a robust infrastructure of multiple reference stations, centralized processing centers, and often geostationary satellites. Any disruption in this chain can impact its performance.

In summary, WADGPS is a system designed to improve GPS accuracy over vast regions, making it invaluable for applications that require consistent, precise location data across large geographical areas.