Can we measure sea surface wind speed with a smartphone?

We aim to explore the feasibility of using a smartphone in-built GNSS sensor to measure sea surface wind speed. For this purpose, a proof-of-concept campaign is conducted. Two observables that may be sensitive to wind speed, namely, the reflected-to-direct ratio (RTR) and texture correlation time (TCT), are defined, and a smartphone and geodetic receiver are equipped in the experiment. The results show that the carrier-to-noise ratio (CNR) of the smartphone in-built GNSS sensor presents some sensitive to wind speed. As the elevation angle and wind speed increase, the RTR and TCT both gradually decrease. A rational function is used to develop the empirical geographic model functions (GMFs) between the defined observables and wind speed. The multipath signals from the surrounding buildings have an important influence on the measured wind speed. After a simple data quality control, the retrieved wind speed has an RMSE of 2.06 m/s.