Abstract: The GNSS raw data observations are open for the Android system, and developers can directly obtain the GNSS raw observations through the API. In this paper, Xiaomi Mi 8 and Huawei P30 mobile phones are selected as the research objects. The original GNSS observation data output by the mobile phone is studied, and the data quality is analyzed from the aspects of multipath effects, data carrier-to-noise ratio. The experimental results show that compared with the measurement receiver, the original observation value of the Android smartphone is relatively low, and has serious multipath effect.