Android智能手机GNSS高精度实时动态定位

Android smartphone GNSS high-precision real-time dynamic positioning

本文基于智能手机GNSS观测值的质量和性质,利用手机载波相位观测值不确定度进行粗差处理,使用星间单差法消除智能手机伪距和载波相位观测值之间差值不固定特性的影响,针对手机观测值修改滤波过程中的观测值噪声方差数值,采用不固定载波相位整周模糊度的常加速度动态单频Kalman滤波模型实现实时PPP和RTK两种定位方法,提高手机实时GNSS定位精度。使用某智能手机进行验证,单频实时动态PPP定位在99s内达到稳定状态,平面定位精度为1.51 m,高程精度为2.79 m;RTK定位在27 s内达到稳定状态,平面定位精度为0.73 m,高程精度为0.78 m。测试结果表明目前智能手机的GNSS定位模块具有提供更加精准的位置服务能力,甚至在某些特定场景下具有实施测绘作业的潜能。

Based on the quality and peculiarity of smartphone GNSS measurements,the existing methods of real-time dynamic PPP and RTK positioning are improved,and better smartphone GNSS positioning results obtained.Both positioning methods use a constant-acceleration dynamic single-frequency Kalman filter model with unfixed carrier phase integer ambiguity.Improvements include using smartphone carrier phase observation uncertainty for gross error processing,adopting the strategy of between-satellite single-difference to eliminate the influence of that the differences between smartphone pseudorange and carrier phase observations are not fixed,and modifying the value of smartphone measurements noise variance in the Kalman filtering process.Using one selected smartphone for experimental verification,the results show that its real-time dynamic PPP can reach a stable positioning state within 99 s,the horizontal and vertical RMS positioning error after stabilization are 1.21 and 2.79 m,respectively.RTK positioning can reach a stable state in 29 s,the horizontal and vertical RMS positioning error after stabilization are 0.73 and 0.78 m respectively.The experimental test results show that the current GNSS positioning module of smartphones could provide more accurate location services,and even has the potential for mapping operations in certain specific scenarios.