A carrier-phase Global Positioning System (GPS) is an accurate type of differential GPS (DGPS). Its measurements are based on radio-frequency (RF) technology for precise phase locking and tracking of carrier waves emitted by GPS satellites. So the measured carrier phases are interpreted as the distance from the GPS satellites to the position of a GPS receiver. The carrier waves have wavelengths of 0.190 m at the L1 frequency and 0.244 m at the L2 frequency, and their measurements of phases have precisions of a few hundredths of a cycle. Consequently, the measurements should achieve centimeter-level precision of location positionings. However, the measured phase can suffer an unknown term of integer ambiguity in the phase cycles. Moreover, discontinuities caused by the loss of phase tracking (known as cycle slips) are very frequent in urban environments. These discontinuities are also unknown integers. In this work, the author achieved restorations of determination and continuation for these unknown integers. The used method consists of measurements of the simultaneous multiple carrier phase observables and an estimative continuation based on the linear combinations and differences of these observables.
Abstract