The Algorithm Study On BDS/GPS Baseline Solution

Static baseline solution, with phase observations of two or more sites, is the solution procession of their relative vectors due to their relativity. As one of the most crucial parts of the precisely post-procession of data, phase relative positioning is wildly utilized in many fields and the algorithm of it is intensively studied.Recently, international GNSS includes Global Navigation System of America, the GLONASS of Russian and the BDS of China. Our Chinese BeiDou Navigation Satellite System has already the abilities of Navigation, Positioning and Timing. To enable the BDS to benefit fully, the combined baseline solution of BDS and GPS becomes one trend of multi-system data procession. Under this background, this thesis analyzes the theory of static relative positioning and general errors, discusses different methods for all kinds of errors combining the characters of baseline solution, studies the theories of cycle-slip and fixing ambiguity, lastly, combined the features of GPS and BDS satellites, develops the double system baseline solution software by the single baseline solution way.The main contents and achievements in the research:1. discuss the crucial questions in preliminary preparation of dataAnalyze the unification of GPS and BDS in the timing and space, the characters of general errors and the correct methods of them, detection ways of cycle-slip, theories of fixing ambiguity. While the ionosphere distribution is stable, this paper comes up a measure to repair cycle-slip based on polynomial fitting.2. linear combinations and their application in the baseline solutionPhase observations, due to it’s short wavelength, is wildly used in the precise positioning. To satisfy different demands, the observations need to be combined. This paper analyzes different methods in the baseline solutions with different distances and counts the wavelengths and error magnification.3. choose the baseline solution stochastic modelDouble difference method is general applied in function module of baseline solution, which is relative to the satellites’ elevations and the quality of observations. The weight distribution of satellite of different types, which belong to the same system and satellites or to different systems, and the consideration on the relativity of satellite observation equations, are included in the model.4. build normal equation and choose base satelliteThe paper discusses the process of building normal equations, especially when the reference satellite is changed and some satellites disappear and some arise. By arranging unknown parameters properly, the unknown ambiguities are correctly calculated.5. compare and analyze the solution characters of single baseline and baseline webSingle baseline method is relatively simple, while multi-baseline method needs to be taken account of the relativity and common sessions of baselines, the relationship between baseline is still crucial questions in building random model. This paper attempts to explore the features of two baseline solution methods.