Research On Ranging Error Of Micron Level Based On Gravity Field Estimation

The inversion accuracy of the Earth gravity is of great importance to the Earth Science research. At present, there are a variety of measurement systems among which the two satallites ranging has higher accuracy. In order to get high enough accuracy, the satellite ranging precision must reach micron level. Many factors can influence the whole system ranging accuracy in dual-satellite-ranging, such as frequency source, time synchronization, the attitude and perturbation of the satellite, ionosphere, etc.This article focuses on the measurement system of the gravity field dual-satellite-ranging, dual-one-way-ranging, and the error factors of this measurement system and promote a method of reducing or even eliminating the error in data processing on the ground. Based on all those research above, this paper finally gave the modeling and simulate result of the whole system, the error factors and the effects of some important error factors.Firstly, this thesis introduces the basic principles of dual-one-way-ranging, analysis the source of error by divided them into two groups--system noise and random noise, and after that promote simulate method for each error.Secondly, this thesis give the data processing on the ground according to the error factors introduced in the first part. In the post data processing part, this thesis use the GNSS time data to correct the error caused by time non-synchronization, dual frequency ionosphere correction to eliminate ionosphere delay, and get the flight time correction(LTC) and the geometric distance correction value by theoretical derivation, and finally get the range, range rate and acceleration by applying down sample filters to the system.Then, verifying the correctness of the post-data processing on the ground. In this part, the thesis give the whole system simulate results and the ranging result with each error factor and the ranging result with the corresponding error reduced.Finally, giving the effects of phase noise, time synchronization and distance to the range accuracy. In this part, the thesis mainly introduce the IIR method to generate phase noise. After all the data tests, this thesis reach the conclusion that in order to control the whole system within micron accuracy, the error sources should reach what level.Previous research in this area are all about the whole system, not the particular error factors effects on the range system. In addition, all the study focused on the algorithm on the satellite, that is to say, the dual-one-way-ranging algorithm, not the post-data processing on the ground. Therefore, this paper’s results has a very important role and value of specific engineering practices.