The use of sliding time window in the real-time solution of ground-based GPS data

With the uses sliding time window to define the starting time and ending time of GPS data involved in the solution, the sliding time window makes the latest observed data added to the real-time data solution and raises efficiently the real-time property of the results of data analysis. Using time windows with fixed width, the ambiguity resolution accuracy can be guaranteed with the least occupation of computer resource. This paper, using the sliding time window and taking the example of data from 6 IGS stations in China, calculates parameters of troposphere of all these stations. Using the daily ZTD of the stations mentioned above that posted on the website of CODE as normal value, this paper calculates the standard deviation respectively and analyzes the influence exerted to the accuracy and real-time property of ZTD solution by time windows with different width. The operational system of “Ground Based GPS Real Time Water Vapor Retrieval” with the use of sliding time window can gain parameters of troposphere with high-accuracy and meanwhile meet the real-time demands of the operation. The best time window width is 6-8 hours.