Research On Eliciting CGCS2000Coordinate Using Continus Observse Stations

This paper involes8stations of International GNSS Serverice (IGS) which areCHAN,BJFS,XIAN,URUM,LHAZ,SHAO,TWTF,DAEJ as foundational data that received in1th day of2011. uses the function of GAMIT in long baseline and combinates the adjustmentof COSAGPS for discussing how to use the continuously operating stations to get thecoordinate of CGCS20000independently. The main conclusions are as followed:Caculates the data observed from surveying area with IGS stations’ data, one can getthe CGCS2000coordinate of the surveying area. Under the15degree cutoff angle of thesatelite elevatation condition, observation time shows same trend with Positioning accuracy.With the observation time increases continually, the Positioning accuracy is improvedproportionately. When the observation time is not longer than12hours, the Positioningaccuracy will not be improved evidently. And when the observation time is longer than14hours or more, the Positioning accuracy wil be improved evidently. The Logistic Model canreveal the relationship between the observation time and Positioning accuracy appropriately.According to Logistic Model, to get CGCS2000coordinate of surveying area which meet theprecise demand of national standards,18hours continual obervation or more is need.satellite elevation angle can effect Positioning accuracy indirectly.According to tests,15degree is the most conductive satelite elevation cutoff angle for observation. When sateliteelevation cutoff is15degree, it can not only reduce the impact of multipath disturbance andautomphere delay but also ensure enough redundant observation to improve Positioningaccuracy.When random error exists in control survey, expanding the inter-distance of the controlpoints can improve the relative accuracy of the survey net. Length accuracy has closedrelationship with azimuth accuracy. Keeping the accuracy of length can control the relativeazimuth accuracy indirectly. When0.03m point error allowed in national GPS control surveynet, the inter distance of the points in the control survey net should not be shorter than4200m.Provided the inter distance mentioned above, the accuracy of the survey net can meet the requirement of regular engineering.