基于低采样率CORS的GNSS高频率高精度实时动态定位技术

Traditional synchronous RTK positioning technology needs the synchronization of observation data between stations, which limits the improvement of real-time performance, and thus it is difficult to meet the requirements in the field of high-speed kinematic precision intelligent navigation applications. This project intends to study GNSS high-rate, high-precision and real-time kinematic positioning technology based on low sampling rate CORS. We first break through the synchronization differential positioning constraints and solve the CORS observation data link transmission time delays problem by establishing a rove station asynchronous differential positioning model and a reference station network asynchronous differential error correction generation model. Then, we present the online compensation algorithm for the data link transmission time delays and further improve the asynchronous differential positioning accuracy. Finally, we establish the theory and methods of GNSS asynchronous differential kinematic precise relative positioning. GNSS high-rate, high-precision and real-time kinematic positioning technology based on low sampling rate CORS can not only save the cost of self-built reference stations and data links, but also can effectively improve the real-time capability of RTK positioning and improve the stability and accuracy of RTK positioning when the data link transmission is blocked or interrupted. It probably provides technical and theoretical foundation for the application of precise navigation to the aircraft automatic landing, intelligent transportation control and plant protection drone automatic operation and other high-speed fields.

传统同步RTK定位技术由于需要站间观测数据同步而限制了实时性的提高，难以满足高速动态精密智能导航领域的应用需求。基于此，课题拟研究基于低采样率CORS的GNSS高频率高精度实时动态定位技术：通过建立移动站异步差分定位模型和基准站网异步差分误差改正数生成模型，突破同步差分定位思想约束，解决CORS观测数据通信链路传播时延问题；在此基础上，研究通信链路传播时延在线补偿算法，进一步提高异步差分定位精度，最终形成GNSS异步差分动态精密相对定位理论与方法。基于低采样率CORS的GNSS高频率、高精度、实时动态定位技术，不仅无需自建基准站和数据通信链路，而且还能有效提高RTK定位的实时性，同时能改善通信链路传播阻塞时RTK定位的稳定性和精度，有望为精密导航应用于飞机全自动着陆、智能交通控制和植保无人机自动作业等领域奠定技术和理论基础。

课题以高速动态精密智能导航应用领域的低时延、高更新率和高精度需求为背景，开展基于低采样率CORS的GNSS高精度高频率实时动态定位技术研究，主要从模型上解决RTK定位技术中基准站观测数据传播时延问题。建立了移动站异步差分定位模型与方法，分析了异步差分定位误差传播机理，推导了异步双差整周模糊度解算和异步双差载波相位周跳探测修复算法。实测GNSS观测数据处理结果表明，在基准站观测数据传播时延15s内，异步差分载波相位实时定位精度为厘米量级，并且优于已有的基于历元差分的“移动站外推法”和基于多项式的“基准站预报法”。建立了观测值域传播时延在线补偿模型和方法，顾及异步双差载波相位误差不同频点间的强相关性，估计异步双差载波相位误差变化率，对异步双差载波相位的系统性偏差进行校正。实测GNSS数据处理结果表明，在基准站观测数据通信链路模拟中断60s条件下，三维实时定位精度为厘米量级；在基准站观测数据通信链路模拟中断120s条件下，平面实时定位精度为厘米量级，高程定位精度为亚分米级；在基准站观测数据通信链路模拟中断300s条件下，平面实时定位精度为亚分米级。建立了CORS非差载波相位改正数及其变化率在线估计模型，基于多历元多频点非差载波相位改正数滑动窗口序列，顾及非差载波相位改正数不同频点间的强相关性，联合精确估计非差载波相位改正数变化率。实测GNSS观测数据处理结果表明，在较短基站观测数据传播时延内，实时定位精度与滞后的同步RTK定位精度一致；在较长传播时延内，实时定位精度为厘米量级。. 课题建立的移动站异步差分定位模型、基准站网异步非差载波相位误差改正数及其变化率计算模型和传播时延在线补偿模型，初步形成了动态异步差分实时高精度定位理论与方法，可实现基于低采样率CORS的GNSS高频率、高精度实时动态定位技术。实测GNSS数据处理结果表明，GNSS异步差分定位理论和方法能够在基站观测数据传播中断60s、120s条件下仍能实现高精度实时定位。