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Relative Positioning in Remote Areas Using a GNSS Dual Frequency Smartphone
Américo Magalhães1, Luísa Bastos2, Dalmiro Maia1
1Astronomical Observatory, Faculty of Sciences, University of Porto, 4430-146 Vila Nova de Gaia, Portugal.
Sensors (Basel, Switzerland)
|December 28, 2021
Summary
Recent smartphones achieve centimeter-level precision using Global Navigation Satellite Systems (GNSS). This study demonstrates that even with long baselines over 100 km, smartphones like the Xiaomi Mi8 provide accurate positioning for mapping applications.
Area of Science:
- Geomatics and Geodesy
- Mobile Computing and Sensor Technology
Background:
- Mobile phone Global Positioning System (GPS) capabilities have been common for over a decade.
- Recent advancements in Global Navigation Satellite Systems (GNSS), particularly the European Galileo system, enable centimeter-level precision.
- New hardware and software in mass-market smartphones, including Android 7's access to GNSS raw code and phase measurements and Broadcom's dual-frequency chip (BCM47755), have revolutionized positioning performance.
Purpose of the Study:
- To confirm centimeter accuracy in relative static positioning with short baselines.
- To investigate the feasibility of achieving accurate positioning using long baselines (>100 km) with recent smartphones.
- To demonstrate the utility of smartphones as low-cost tools for precise georeferencing and mapping, especially in areas with sparse or absent Continuously Operating Reference Station (CORS) networks.
Main Methods:
- Utilized the Xiaomi Mi8 smartphone, which integrates dual-frequency GNSS capabilities and access to raw measurements.
- Performed relative static positioning in post-processing mode.
- Employed wide baselines exceeding 100 km, leveraging dual-frequency code and phase measurements from both GPS and Galileo systems.
Main Results:
- Confirmed centimeter-level accuracy in relative static positioning for distances up to tens of kilometers.
- Achieved Root Mean Square Error (RMSE) below 30 cm for precise surveys using baselines over 100 km.
- Demonstrated that smartphones can yield accurate positioning results even with significant baseline lengths.
Conclusions:
- Smartphones equipped with advanced GNSS capabilities can achieve high-precision positioning over long baselines.
- These devices offer a viable low-cost alternative for georeferencing and mapping applications.
- The technology is particularly beneficial for applications in remote regions lacking extensive CORS infrastructure.
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