Exploring the New GNSS Capability in Smartphones with Android N for Satellite Geolocation Validation, TPW, and Radio Occultation

The rapid development of the Global Navigation Satellite System (GNSS) including GPS, GLONASS, Galileo, and Baidou, has profound impacts on science and technology as well as our daily lives, with expanding benefits and capabilities. Unlike previous GPS receivers, the latest GNSS receivers in Smartphones with Android N emerged since mid 2016 are now making the raw GNSS measurements available to developers and scientists to explore new applications. This is significant because it enables sub-meter level geolocation accuracy using pseudorange, Doppler and carrier-phase measurements, which will facilitate geolocation validation for satellite observations especially for point source targets such as lights observed by the VIIRS Day/Night Band. More importantly, this new capability potentially can enable GNSS integrated total precipitable water (IPW) measurements by anyone who owns such a Smartphone, thus may produce massively amount of data for realtime weather applications. This will also facilitate the experimentation with GPS Radio Occultation (RO) from ground based and other platforms since inexpensive GNSS raw measurements are available for RO retrievals, thus potentially enable new weather applications. The current study explores the Android N raw GNSS measurement data for both geolocation accuracy improvements, IPW, and RO. The methodologies are discussed, and examples of sample measurements, algorithms, and results are presented. The enabling capabilities of this new observing capability related to bigdata, internet of things, distributed computing, will also be explored.