Robustelli Umberto, Paziewski Jacek, Pugliano Giovanni
Department of Engineering, Parthenope University of Naples, 80133 Naples, Italy.
Department of Geodesy, Faculty of Geoengineering, University of Warmia and Mazury in Olsztyn, Oczapowskiego 1, 10-719 Olsztyn, Poland.
Sensors (Basel). 2021 Mar 18;21(6):2125. doi: 10.3390/s21062125.
The new generation of Android smartphones is equipped with GNSS chips capable of tracking multi-frequency and multi-constellation data. In this work, we evaluate the positioning performance and analyze the quality of observations collected by three recent smartphones, namely Xiaomi Mi 8, Xiaomi Mi 9, and Huawei P30 pro that take advantage of such chips. The analysis of the GNSS observation quality implies that the commonly employed elevation-dependent function is not optimal for smartphone GNSS observation weighting and suggests an application of the C/N0-dependent one. Regarding smartphone code signals on L5 and E5a frequency bands, we found that they are characterized with noticeably lower noise as compared to E1 and L1 ones. The single point positioning results confirm an improvement in the performance when the weights are a function of the C/N0-rather than those dependent on the satellite elevation and that a smartphone positioning with E5a code observations significantly outperforms that with E1 signals. The latter is expressed by a drop of the horizontal RMS from 8.44 m to 3.17 m for Galileo E1 and E5a solutions of Xiaomi Mi 9 P30, respectively. The best positioning accuracy of multi-GNSS single-frequency (L1/E1/B1/G1) solution was obtained by Huawei P30 with a horizontal RMS of 3.24 m. Xiaomi Mi 8 and Xiaomi Mi 9 show a horizontal RMS error of 4.14 m and 4.90 m, respectively.
新一代安卓智能手机配备了能够跟踪多频和多星座数据的全球导航卫星系统（GNSS）芯片。在这项工作中，我们评估了三款近期智能手机（即小米8、小米9和华为P30 Pro，它们都利用了此类芯片）的定位性能，并分析了所收集观测数据的质量。对GNSS观测质量的分析表明，常用的与仰角相关的函数对于智能手机GNSS观测加权并非最优，并建议应用与载噪比（C/N0）相关的函数。关于智能手机在L5和E5a频段上的码信号，我们发现与E1和L1频段的信号相比，它们的噪声明显更低。单点定位结果证实，当权重是C/N0的函数而非依赖于卫星仰角时，性能有所提升，并且使用E5a码观测的智能手机定位明显优于使用E1信号的定位。对于小米9和华为P30，这表现为小米9的伽利略E1和E5a解决方案的水平均方根误差（RMS）分别从8.44米降至3.17米。华为P30的多GNSS单频（L1/E1/B1/G1）解决方案获得了最佳定位精度，水平RMS为3.24米。小米8和小米9的水平RMS误差分别为4.14米和4.90米。
