Influence analysis of GPT3 model on medium and long-distance RTK with large height difference
Tropospheric delay is the main error source of real-time kinematic (RTK) in large elevation environment,which seriously affects the positioning accuracy of RTK. In order to suppress the influence of tropospheric delay on RTK positioning in the environment of large elevation difference,it is necessary to analyze the influence of tropospheric model and different prior variance on RTK positioning results,so as to propose a reasonable scheme to improve RTK positioning performance. Taking Hong Kong continuous operational reference system (CORS) as an example,this paper evaluated the accuracy of the tropospheric model of the global pressure and temperature model 3 (GPT3) with four different elevation baselines in different seasons,and compared and analyzed the positioning performance of the medium and long-range RTK before and after the introduction of the GPT3 model constraints. The results showed that the total relative tropospheric delay of the 19～34 km medium-long baseline in Hong Kong was in the centimeter to decimeter range,which seriously affected the RTK positioning results. The error of the GPT3 model in Hong Kong was between±1cm,which could be constrained as a priori tropospheric information. After adding the constraints of the GPT3 model,the accuracy of the RTK positioning U component of the BDS and BDS/GPS combinations of the four baselines was significantly improved,with BDS increasing by 35.1％,32.7％,32.3％ and 56.9％,BDS/GPS increasing by 29.1％,26.1％,31.2％ and 63.3％,respectively,and the fixed rate of single BDS ambiguity of the four baselines increasing by 5.7％,2.6％,6.4％ and 4.5％,respectively,while the BDS/GPS combination had little effect. In addition,the value of the prior variance had a certain influence on the baseline of the large elevation difference,and the prior variance should be updated in time according to the statistical atmospheric modeling error in the tropospheric active months.
large elevation differencereal-time kinematic (RTK)tropospheric delayglobal pressure and temperature model 3 (GPT3)
NETL
NSTL
万方数据
