Study On Time Transfer Technology Using GPS Precise Point Positioning Method

Time transfer is an important part of the time keeping between the time laboratories toestablish and maintain the standard time scale. The accuracy of time transfer is an importantindicator of the time synchronization performance which impacts the standard time scale. Thearticle focuses on the actual needs of the Time and Frequency Primary Standards Laboratory inthe National Time Service Center, the GPS Precise Point Positioning (GPS PPP) time transfertechnology is researched. Through understanding the principle of PPP and the algorithms, thesoftware is implemented. After the computation, a good time transfer results is got. The GPScommon-view and GPS all in view time transfer are analyzed and implemented to comparedwith; At the end of this paper, several different time transfer methods are compared. The resultsshow that a variety of different time transfer method accuracy is different. The different timetransfer accuracy meets the time user synchronization needs.(1) The basic principles and features of the GPS CV, the GPS AV are analyzed. The specificimplementation of a variety of time-transfer method is described and GPS AV time transfersoftware is developed.(2) The paper giving an-depth understanding of GPS precise point positioning principle fortime transfer. The PPP mathematical model, the data pre-processing methods, and the errorcorrection strategies in satellite navigation system is analyzed. Combination the Turbo-Edit andionospheric residual technology the cycle slip is detected, using the forward and reversecombined phase smoothing pseudo-range method to reduce the code noise of initial epoch thepseudo-range error.(3) GPS PPP time transfer software is developed, the forward and reverse combined methodis adopted to use phase smoothing pseudo-range in data preprocess. The data of key timelaboratory in and abroad such as USNO, KRIS and NICT is used to compute by the software wedeveloped. The result using PPP time transfer software computed is satisfied the time transferneeds. The results between two time laboratory using GPS common-view, all in view and PPPmethod are compared. From the time compared result, GPS PPP time transfer method can get abetter stability than GPS common-view and all-in-view method with its frequency is1E-14for960second.