Fast Convergence Real-Time Precise Point Positioning with Android Smartphone GNSS Data

Abstract

Precise smartphone positioning using GNSS (Global Navigation Satellite System) would benefit massive mobile phone users since higher positioning accuracy will improve the user experience of location-based-related services and generate potential innovative applications. However, due to the linear polarized antenna in the limited space, shared antenna module with other hardware types, and electromagnetic radiation of other electronics, there remain various challenges in processing GNSS observations with a lower and more unstable carrier-to-noise ratio than other types of GNSS receivers. In recent years, precise smartphone positioning has attracted increasing academic and industrial attention, and various techniques have been developed to improve smartphone positioning accuracy. The existing work to date, however, has been largely conducted in ideal observing environments or not designed for real-time implementation. Given the strong demand for real-time precise smartphone positioning in operational environments, this work presents IP3-Mobile, a fast convergence real-time PPP (Precise Point Positioning) system developed by Profound Positioning Inc. to support real-time use and the development of new smartphone-based applications. An Android-based APK has been developed to test IP3-Mobile on several smartphone models, such as Xiaomi 8 (MI8). The system development involves several technological innovations. For instance, the system facilitates fast convergence to achieve sub-meter level accuracy (CEP50) in sub-urban environments within a few seconds, which satisfies the accuracy requirement for many location-based applications. Robust methods and algorithms are developed to process smartphone GNSS observations in different environments, including intelligent detection of non- line-of-sight GNSS signals and outliers. Advances have also been made to apply more effective statistical testing algorithms to improve the robustness of the developed system.