WiFi and GNSS: Complementary Advantages for Seamless Indoor and Outdoor Precise Positioning
- 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 the US GPS, China’s BeiDou, Russia’s GLONASS, and the EU’s Galileo system. 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.
- Working Principle
WiFi Positioning Methods
Fingerprint Positioning: A database is established 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 Principle
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 Fusion
The positioning results of WiFi and GNSS are fused using filtering algorithms (such as Kalman filtering) to improve positioning accuracy and reliability:
* When GNSS signal is good: GNSS is the primary signal.
* When GNSS signal is weak: Switch to WiFi positioning or use WiFi to assist GNSS positioning.
III. Application Scenarios
- Smartphone Navigation and Location Services
Modern smartphones generally integrate both WiFi and GNSS chips. This 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.
- Logistics and Supply Chain Management
End-to-end location monitoring from warehouses to transport vehicles to delivery points enables full cargo tracking.
- 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 in multi-story parking garages, enabling parking management applications.
- Conclusion
The combined WiFi and GNSS positioning technology, through its 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, this combined technology supports a wide range of location service applications.
To achieve seamless and accurate indoor and outdoor positioning by leveraging the complementary advantages of WiFi and GNSS, EBYTE offers a variety of modules to choose from. Below is an introduction to some modules that meet the requirements:
E103-W07: This is a serial-to-WiFi module with self-organizing and self-healing features. It uses the ESPMESH network protocol, allowing a large number of devices distributed over a wide area (indoors and outdoors) to connect to each other in the same WLAN. Its operating frequency is 24122484MHz, with a transmit power of 20dBm. The WiFi version is IEEE 802.11b/g/n, meeting the WiFi coverage and device connectivity needs within a certain range both indoors and outdoors, and providing support for indoor positioning.
The E103-W11 is a dual-mode WiFi module supporting Bluetooth Low Energy (BLE) 5.1 and WiFi 6 (IEEE 802.11 b/g/n/ax). It operates in the 2.42-4835 GHz band, with a transmit power of 20 dBm, a communication range of 300 m, and an air speed of 150 Mbps. This module can transmit and receive data via serial port, supports both AP and STA roles, and simultaneously supports BLE Low Energy Bluetooth connectivity. It can communicate and exchange data effectively with other devices, making it suitable for various indoor and outdoor scenarios and providing stable WiFi communication support for seamless indoor and outdoor positioning systems.
E108-GN02 Series: This is a highly integrated, low-power, and low-cost GNSS multi-mode satellite positioning and navigation module. It supports multi-system joint positioning (BDS, GPS, GLONASS, GALILEO, QZSS, SBAS) and single-system independent positioning. The horizontal positioning accuracy can reach 2.5m. It can be used in GNSS positioning applications such as vehicle navigation, smart wearables, and drones, providing basic support for outdoor positioning.
The EWM108-GN05 series is a high-performance dual-frequency GNSS satellite positioning module equipped with Huada Beidou’s HD8040D chip solution. It supports the new generation Beidou-3 signal system and all global civilian navigation satellite systems, including BDS, GPS, GLONASS, Galileo, SBAS, and QZSS. The satellite positioning accuracy can reach sub-meter level. Its excellent anti-multipath interference function improves positioning performance in urban and canyon scenarios, making it suitable for outdoor scenarios with high positioning accuracy requirements.
E108-GN07IS: This module features both inertial navigation and dual-frequency (L1/L5 or L1/L2) capabilities, meeting the needs of low-power and high-performance industry applications. It also supports the next-generation BeiDou-3 signal system and other global civilian navigation satellite systems including BDS, GPS, GLONASS, Galileo, SBAS, QZSS, and IRNSS. Its positioning accuracy reaches centimeter level, providing high-precision positioning information in complex environments, and is particularly suitable for high-dynamic scenarios and special environments such as tunnels. Combined with a WiFi module, it can better achieve seamless and accurate indoor and outdoor positioning.
The EWM108-GN06B series is based on the AT9880B, a new generation of single-BeiDou multi-frequency SOC chip from Zhongke Microelectronics. It supports B1I, B1C, B2I, B3I, B2a, and B2b frequency signals of BeiDou-2 and BeiDou-3, which can significantly improve positioning performance in complex environments such as urban canyons. The timing accuracy is better than 10 nanoseconds. It features low power consumption, small size, and easy integration. It can be used in intelligent transportation, precision agriculture, power systems, and IoT devices, providing high-precision support for outdoor positioning.
With continuous technological advancements, 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 a higher level.
In the future, we can expect to enjoy seamless and accurate positioning experiences anytime, anywhere, providing a solid foundation for the digital transformation and innovative applications across various industries.
