I. Introduction
With the rapid development of mobile internet and IoT technologies, precise positioning technology has become a core foundation for modern smart applications. Global Navigation Satellite System (GNSS) and WiFi technology, as two mainstream positioning methods, each have unique advantages and limitations. Organically combining these two technologies to form a complementary hybrid positioning solution has become an important direction in the development of positioning technology.
GNSS (Global Navigation Satellite System) is a general term for global navigation systems that use satellite signals for positioning, including GPS (USA), BeiDou (China), GLONASS (Russia), and Galileo (EU). GNSS positioning has advantages such as wide coverage and high positioning accuracy, but its performance drops significantly in environments with severe satellite signal obstruction, such as indoors and urban canyons.
Combining WiFi and GNSS technologies can fully leverage their respective advantages to achieve seamless indoor and outdoor positioning, providing more reliable technical support for various location services. This combined positioning method has been widely used in many fields such as smartphone navigation, logistics tracking, emergency rescue, and intelligent transportation.
II. Working Principles
WiFi Positioning Methods
Fingerprint Positioning: A database is built by pre-collecting signal strength characteristics of various locations in the environment. During actual positioning, real-time measurements are matched with the database to determine the location.
Triangulation Positioning: Based on a signal attenuation model, distances are calculated using the signal strength of multiple access points (APs), and then the location is determined through triangulation.
GNSS Positioning Principles
Based on satellite ranging principles, the receiver measures the propagation time of signals from at least four satellites, calculates the distance to each satellite, and combines this with the precise position information of the satellites. Spatial resection is then used to determine the receiver's position (longitude, latitude, altitude) and time.
Technology Integration
Location results from WiFi and GNSS are fused using filtering algorithms (such as Kalman filtering) to improve positioning accuracy and reliability:
When GNSS signal is strong: GNSS is the primary signal source.
When GNSS signal is weak: Switch to WiFi positioning or use WiFi-assisted GNSS positioning.
III. Application Scenarios
1. Smartphone Navigation and Location Services
Modern smartphones generally integrate both WiFi and GNSS chips. The combined positioning provides a seamless experience for various navigation applications. Typical applications include continuous positioning and navigation in large shopping malls, airports, and subway stations.
2. Logistics and Supply Chain Management
Full-process location monitoring from warehouses to transport vehicles to delivery points enables end-to-end cargo tracking.
3. Intelligent Transportation Systems
High-precision vehicle positioning, combined with roadside WiFi infrastructure, improves positioning accuracy in urban canyon areas.
Guiding vehicles to quickly find parking spaces, especially inside multi-story parking garages, enables parking management applications.
IV. Conclusion
The combined WiFi and GNSS positioning technology, through complementary advantages, effectively solves the coverage and accuracy limitations faced by single technologies and has become the mainstream solution for modern positioning systems. From smartphone navigation to the Industrial Internet of Things (IIoT), this combined technology underpins a wide range of location-based service applications.
As technology continues to advance, WiFi+GNSS combined positioning will further improve accuracy, reliability, and availability. Simultaneously, its integration with other emerging positioning technologies (such as 5G and UWB) will drive location services to even greater heights.
In the future, we can expect to enjoy seamless and accurate positioning experiences anytime, anywhere, providing a solid foundation for digital transformation and innovative applications across various industries.