非差非组合PPP-RTK:模型算法、终端样机与实测结果

Undifferenced and uncombined PPP-RTK:algorithmic models,prototype terminals and field-test results

智能驾驶、精密农业和无人机等新兴行业要求全球导航卫星系统(GNSS)提供更加快速、准确的导航定位服务。非差非组合PPP-RTK融合了精密单点定位(PPP)和实时动态定位(RTK)两者的优势,能灵活处理多频多模数据并实现区域广覆盖的快速高精度定位。然而,PPP-RTK仍处于技术研发阶段,产业化应用尚未完全成型。本文从理论到实践,构建了码分多址和频分多址非差非组合PPP-RTK模型,开发了相应的实时解算软件,并研制了一款终端样机。基于平均站间距为154 km的京津冀参考网估计的精密改正产品,将终端样机分别搭载在无人机、农机和跑车上,开展了实时动态定位试验。试验结果表明,PPP-RTK终端样机在3个场景下的模糊度首次固定时间分别为5、2和7 s,模糊度固定成功率分别为99.79%、99.14%和98.96%,水平和高程定位精度分别在1 cm和4 cm左右。试验结果证明了自研PPP-RTK终端样机能提供连续、可靠、高精度的定位服务。

The emerging industries like intelligent driving,precision agriculture and the drones require the global navigation satellite system(GNSS)to provide faster and more accurate positioning services.The undifferenced and uncombined PPP-RTK combines the advantages of precise point positioning(PPP)and those of real-time kinematic(RTK)technique,enabling one to process flexibly the multi-frequency and multi-GNSS data,and achieve rapidly the high-precision positioning with wide-area coverage.However,PPP-RTK is still in the stage of technology research and development;its industrial application has not yet completely formed.From theory to practice,this study formulates the code and frequency division multiple access undifferenced and uncombined PPP-RTK models,develops the corresponding real-time processing software,and designs a set of prototype terminals.Based on the precise corrections estimated by the Beijing-Tianjin-Hebei reference network with the inter-station distance of 154 km,we mount these terminals on a drone,an agricultural tractor and a car to carry out real-time positioning experiments.The results show that the times to first fix for three scenarios are 5 s,2 s and 7 s,the success rates of ambiguity resolution are 99.79%,99.14%,and 98.96%,respectively.The horizontal and vertical positioning accuracy are about 1 cm and 4 cm for all three scenarios.The results demonstrate that our PPP-RTK implementations can provide continuous,reliable and accurate positioning services.