Research on GNSS RTK positioning performance of smart phone based on extended antenna
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摘要: 本文对外接低成本螺旋天线的Mi8智能手机观测数据质量进行了研究,从载噪比(CNR)、伪距残差、相位残差等方面进行了分析和评估. 结果显示:外接天线的Mi8手机原始全球卫星导航系统(GNSS)观测值的CNR比内置天线手机高约10 dB-Hz,和测量型接收机CNR水平几乎相当;伪距残差在5 m以内;与内置天线手机不同,外接天线手机伪距残差与高度角、CNR的相关性都较强. 在此基础上给出了基于高度角和CNR的两种定权模型,并基于扩展天线的Mi8手机开展了静态和动态环境下的实时动态(RTK)精密定位性能测试实验. 实验结果表明:在静态环境和动态环境下外接天线的Mi8手机RTK定位精度均可达到厘米级;使用基于CNR定权的随机模型相较于高度角定权的随机模型,在动态场景下具有更高的定位精度,具体表现为在水平和高程方向上分别有约16%和50%的精度提升.Abstract: The observation data quality of Mi8 smartphone with external low cost spiral antenna is studied, and the analysis and evaluation are carried out from the aspects of carrier to noise ratio (SNR), pseudo-distance residual, phase residual, etc. The results show that the carrier to noise ratio of original Global Navigation System (GNSS) observation value of Mi8 smartphone with external antenna is about 10 dB-Hz higher than that of mobile phone with internal antenna. And the carrier to noise ratio level is almost the same as that of the measured receiver. Pseudo range residual within 5 m, phase accuracy within 3 m. Different from the mobile phone with internal antenna, the pseudo distance residual of the mobile phone with external antenna has strong correlation with height angle and carrier to noise ratio. On this basis, two kinds of weighting models based on height angle and carrier to noise ratio are given, and real-time dynamic (RTK) positioning performance tests are carried out in static and dynamic environments based on the extended antenna of Mi8 mobile phone. The experimental results show that the RTK positioning accuracy of Mi8 mobile phone with external antenna can reach centimeter level in both static and dynamic environments. Moreover, using a random model based on carrier to noise ratio weighting has higher positioning accuracy in dynamic scenarios compared to a random model with height angle weighting. Specifically, it has an accuracy improvement of about 16% and 50% in the horizontal and vertical directions, respectively.
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表 1 外接天线Mi8手机静态RTK定位精度
m 方向 高度角定权 CNR定权 均值 RMS 均值 RMS E 0.011 0.068 0.009 0.048 N 0.021 0.081 0.016 0.038 U 0.013 0.058 0.012 0.028 表 2 外接天线Mi8手机动态RTK定位精度
m 方向 高度角定权 CNR定权 均值 RMS 均值 RMS E 0.015 0.115 0.020 0.098 N 0.014 0.079 0.016 0.064 U 0.015 0.101 0.010 0.050 -
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