Road Transport
Based on the number of GPS receivers sold globally, road transport applications are the majority users of GPS positioning – for commercial fleet management and freight tracking, taxi services, public transport monitoring and passenger information, and emergency vehicle location, dispatch and navigation. Private car owners have also widely adopted in‑car GPS navigation systems and most automobile manufacturers now release new vehicles with optional factory-fitted GPS.
Shipping & Rail Transport
Maritime applications include ocean and inshore navigation, dredging, port approaches, harbour entrance and docking, Vessel Traffic Services (VTS), Automatic Identification System (AIS),hydrography, and cargo handling. Railway applications include the management of rolling stock, passenger information, preventing doors opening until the carriage is alongside the platform, cargo tracking signalling, train integrity and level crossing approach.
Heavy Vehicle Guidance
GPS is being used increasingly to guide and track heavy vehicles in engineering applications such as mining and construction. For example, in
highway construction, surveyors and marker pegs have been replaced with in-cabin vehicle guidance and control systems for excavators, graders,
bulldozers and road paving machines that allow drivers to follow a surveyor’s pre-programmed site plans and achieve close tolerances for
position, level and gradient.
GPS is being used increasingly to guide and track heavy vehicles in engineering applications such as mining and construction. For example, in
highway construction, surveyors and marker pegs have been replaced with in-cabin vehicle guidance and control systems for excavators, graders,
bulldozers and road paving machines that allow drivers to follow a surveyor’s pre-programmed site plans and achieve close tolerances for
position, level and gradient.
Surveying, Mapping and Geophysics
Professional, survey-grade GPS receivers, capable of utilising signals from both L1 and L2 GPS frequencies, can be used to position survey markers, buildings, bridges and other large infrastructure. GPS is widely used in mapping, including aerial mapping, and other Geographical Information System (GIS) applications. In geophysics, GPS is used to time stamp seismic activity and to monitor position changes in sensitive physical formations such as volcanoes and earthquake fault lines.
Telecommunications
GPS timing is important for telecommunications applications, particularly for mobile telephone networks. Synchronous technologies are much more efficient than asynchronous technologies but require a time source with appropriate accuracy, stability and reliability to operate effectively or at all, and GPS satellites can provide this. While ground‑based clocks are accurate enough for this purpose (especially with the availability of chip scale atomic clocks (CSAC)), the synchronisation of many such clocks is problematic. GPS allows the derivation of synchronised UTC time through resolving the signals from a number of atomic clock.