Analysis of IMU and GNSS Data Provided by Xiaomi 8 Smartphone

The quality of positioning information given by smartphones is not always fully evident and might be inaccurate. With the possibility to access the Inertial Measurement Unit (IMU) data of the smartphone using the Android application program interface (API) functions and the Global Navigation Satellite System (GNSS) signals using the GNSS analysis App from Google, more or less unprocessed data is made available to developers and users. This enables the assessment of the quality of the smartphone chipsets and final positioning information. In this paper, we investigate the quality of available GNSS and IMU measurements and final track estimates of the smartphone. The analysis includes both static and dynamic measurements. A platform is developed to carry both, the smartphone and high accurate reference sensors for a fair comparison in the dynamic tests. The data of the different sensors are synchronized and the lever arm is removed. Open-sky and urban environments are considered for the GNSS analyses. Depending on the environment and on the dynamics, we show the different quality impairments of the data in this paper. Moreover, the Google Android indicators are investigated and their consistency and context with the data are provided.