低成本实时动态载波相位差分GPS的定位精度研究

Research on positioning accuracy of low cost real time kinematic-global positioning system(RTK-GPS)

以农田导航的实际应用为目的,以美国Swift公司的Piksi定位模块为基础,构建实时动态载波相位差分(real time kinematic,RTK)系统进行定位精度研究。结果显示:Piksi单个模块静态单点的定位精度(2倍均方根误差,置信度为95%)约为8 m,RTK的静态精度(2倍均方根误差,置信度为95%)约为1.5 cm。设计的动态双轨试验验证了用直线拟合评估动态直线精度的可行性,当流动站在0.4～2.3 m/s的平均速度范围内进行直线运动时,通过拟合得到的定位精度约为1.5 cm。采用测量点到拟合圆心距离与拟合半径的差值评估圆周运动的定位精度,发现在0.4～1.6 m/s的平均线速度范围内运动时,流动站的精度约为1.5 cm;考虑到实际应用过程中点对点的问题,拟合分析得到的测量误差整体偏小,初步判定Piksi RTK的真实动态精度为3～5 cm,可以满足农业实际需求。

For the purpose of practical application of farmland navigation,we constructed a system of real time kinematic(RTK)to study its positioning accuracy mainly based on Piksi positioning module of Swift Company in the United States.The results showed that single Piksi module point positioning accuracy[root mean square error by two folds(2DRMSE),with 95%degree of confidence]was about 8 m,and the RTK static accuracy(2DRMSE,95%)was about 1.5 cm.The design of dynamic dual-track experiment verified the feasibility of using line fitting method for dynamic linear accuracy:When the flow station was linearly moving at an average speed of 0.4 m/s to 2.3 m/s,the positioning accuracy obtained by fitting was about 1.5 cm.According to the difference between the distance of measured point to the fitting center and the fitting radius,we evaluated the positioning accuracy of the circular motion,and found the accuracy of linear motion at 0.4-1.6 m/s was also about 1.5 cm.Considering the point-to-point problem in the actual application process,the measurement error obtained by the fitting analysis was small and the true dynamic accuracy of Piksi RTK was about 3-5 cm after a preliminary judgment.It is suggested that the low cost RTK-GPS can meet the actual needs of agriculture.