Receiver Widelane Analysis and Its Effect on Precise Point Positioning
- Department of Hydrographic Surveying, Faculty of Maritime Studies, King Abdulaziz University P.O. Box 80401 Jeddah 21589, Saudi Arabia
Keywords: Precise Point Positioning, Widelane Bias, Hardware Delay, Ambiguity Resolution
Abstract. Typically, differential carrier-phase-based methods have been used in positioning applications that require high accuracy. The main advantage of differential methods is solving the carrier-phase ambiguities and obtain millimetre-level accuracy carrier-phase measurements. Recent studies showed that it is possible to fix the un-differenced carrier-phase ambiguities into integers which is well-known as un-differenced carrier-phase ambiguity resolution. Unfortunately, the IGS neglects satellite hardware delay during satellite clock corrections estimation process. In case of differential methods, however, this will not affect the user as all common errors between the reference and rover receivers will be cancelled out by. Point positioning, on the other hand, will be affected by neglecting satellite hardware delays as those hardware delays will be lumped into the carrier-phase ambiguities destroying its integer nature. To solve this problem, satellite clock corrections must be estimated based on clock correction for each observable bases. The user, on the other hand, can form the ionosphere-free linear combination and divide and fix its two components, namely widelane and narrowlane. If both ambiguities are successfully fixed, few millimetres level of accuracy measurements are then obtained. In this paper, one month (December, 2013) of GPS data is used to study the receiver widelane bias, its behaviour over time, and receiver dependency are provided. It is shown that the receiver widelane bias is receiver dependent, stable over time for high-grade geodetic receivers. These results are expected to have a great impact on precise point positioning (PPP) conversion time and PPP carrierphase ambiguity resolution.