基于CORS与UHF的农用GNSS差分信号中继方法

CORS and UHF Based GNSS Differential Signal Relay Method for Agricultural Application

为利用现有丰富的连续运行参考站(CORS)资源,给精准农业提供高精度、高可靠、高并发的差分信号,本文结合农业应用特点,利用GNSS误差的空间相关性,提出基于CORS和UHF电台的GNSS差分信号中继方案,解决测绘用CORS传输方式单一、并发性不足、使用成本较高以及单站RTK重复建设、频率干扰和基准不统一等问题。在北京市海淀区、顺义区和平谷区建立了3个基准站,组建了试验用CORS网,构建了基于PC、i80和智能手机(Phone)的3套中继试验系统,分别开展了定位性能综合验证、机组控制精度验证和应用推广原型验证。试验表明:在10 km范围内,中继定位的平面内、外符合精度分别优于0. 022 m和0. 033 m,基本满足农机作业定位要求;作业机组控制精度达到0. 066~0. 076 m,略高于0. 050 m的理论控制要求,由于机组为挂载农具空驶,该指标属可接受范围;智能手机中继传输的可靠性高、扩展性好。因此,利用智能手机和UHF电台,可快捷获取与转发CORS差分改正数,使10 km之内的流动站实现RTK级定位。该模式简单易用、成本低廉,有一定的应用推广价值。

How to use the existing and rich continuous operation reference stations(CORS) resources to provide high precision,high reliability, and high concurrency differential augmentation signals for precision agriculture is still an unsolved problem. Based on the characteristics of agricultural application,a CORS and UHF radio GNSS based differential signal relay scheme was proposed,which can solve the problems such as single transmission mode,lack of concurrency,high cost of using in CORS application,repeated construction,frequency interference and frequency interference existing in single RTK station application. An experimental CORS system with three stations was established. The stations were established in Haidian District,Shunyi District and Pinggu District of Beijing. Three sets of relay test systems based on PC,i80,and Phone were constructed. The positioning performance verification,operation unit control accuracy verification and application prototype verification were carried out respectively. The test result showed that within 10 km,the plane inside and outside accuracy values of relay positioning were better than 0. 022 m and 0. 033 m,which met the requirements of agricultural machinery operation(usually 0. 03 m). The control accuracy of the operation unit reached 0. 066 ~0. 076 m,slightly higher than 0. 050 m. The reliability of the phone based relay system was high,and the system had good expansion. Therefore,by using smart phone and UHF radio,the differential signal of CORS can be easily obtained and transmitted,which can realize RTK positioning by the rover within10 km. The mode was easy,low cost,and had certain feasibility and application value.