Estimation And Application Of Real Time Satellite Clock Bias Based On Regional CORS Network

In recent ten years, Precise Point Positioning (PPP) as a GPS positioning technology, has a greatprospect in many fields, such as low earth orbit satellite precise orbit determination,regional or globalscientific investigation and air dynamic survey, which has become a hot spot in GPS navigation andpositioning research.After nearly ten years of domestic and foreign scholars’ research, PPP post-processing algorithmsand applications have been already quite mature. There is a wide range of needs on the GPS dynamicreal-time positioning, However, real-time PPP is limited by real-time clock offsets precision and timedelay. Therefore, it is important to base on regional GPS continuously operating reference stations(CORS) data, carry out a systematic research on the precise satellite clock offsets resolving methodand improve the precision and timeliness for PPP real-time applications. Meantime, the sampling rateof GPS observation continues to increase, such as a few seconds, one second, or even less than1second, in order to obtain high-precision PPP results, which has higher requirements for satellite clock.The solving method for high sampling rate satellite clock offsets research, has become a cutting-edgedevelopment trends of today’s GPS data processing. Nowadays, many countries and regions haveestablished real-time global or local reference station networks, it is necessary to develop a set ofprocedures for daily data processing, so that they will be able to carry out high-precision, automatedsolution when the user receives GPS data.In this paper, real time satellite clock is estimated basing on regional GPS continuously operatingreference stations (CORS) data and IGU predicted orbit, using the un-differenced ionosphere-freemodel. Then separately comparing the real-time clock with IGS final product and applying to thereal-time PPP. Experiments results show that the precision between the estimate clock bias and IGSfinal product is better than±0.2ns, the kinematical precision of PPP is better than±1cm in horizontal,±2cm in vertical. Meantime, a set of real-time GPS data automation processing program is developed,which can automatically download other required data, and extract solution required files, thenautomatically work according to the selected mode solver, making the tedious manual processingconverted to automated unmanned operation treatment. Finally, an improved mix model highsampling rate satellite clock offsets solving method is proposed, you can get a better clock offsetsprecision, so verified the effectiveness and feasibility of the method, which has a certain practicalvalue and significance.