GPS (Global Positioning System)
The United States' satellite-based navigation system providing global positioning, navigation, and timing services. Commonly used for outdoor asset tracking, fleet management, and construction equipment monitoring. Typical accuracy 5-10 meters with standard receivers. Limitations include no indoor coverage, limited accuracy without RTK, and susceptibility to interference.
US government satellite navigation system providing global positioning. GPS constellation consists of 30+ satellites in medium Earth orbit (20,000 km altitude), each broadcasting navigation signals enabling receivers to calculate position through triangulation.
Civilian GPS accuracy: 3-10 meters horizontal (95% confidence) under good conditions. Differential GPS (DGPS) using reference stations improves accuracy to 1-3 meters. Real-time Kinematic GPS (RTK) using carrier phase measurements achieves centimeter-level accuracy but requires base station within 10-20 km and unobstructed satellite view. In industrial RTLS, GPS use cases limited to: large outdoor facilities (shipping yards, ports, construction sites, mining operations), vehicle tracking in transport between facilities, and perimeter security for outdoor areas. GPS limitations for industrial RTLS: (1) No indoor operation - GPS signals cannot penetrate buildings. (2) Degraded performance in semi-enclosed areas - loading docks, covered storage areas, areas surrounded by tall structures. (3) Update rate - typically 1 Hz (vs. 1-10 Hz for indoor systems). (4) Power consumption - GPS receivers consume significant power (200-500 mW), limiting battery-powered operation to 6-18 months. GPS-enabled industrial RTLS typically hybrid systems: GPS for outdoor positioning, indoor technology (UWB/BLE/Wi-Fi) for indoor, with automatic switching at building boundaries. Pure-GPS tracking suitable only for assets remaining outdoors. GPS module costs ($15-40) and power requirements often make GPS impractical for applications where simpler outdoor zoning (geofencing building exterior) suffices. In the context of industrial RTLS portfolios combining multiple technologies, GPS/GNSS serves as the outdoor layer of a three-technology stack: GNSS for outdoor yards and inter-building transport, BLE for large indoor areas requiring meter-level accuracy, and UWB for precision production zones requiring centimeter-level accuracy. This triptych approach optimizes cost and performance across different facility zones.