Efficient, Automated Cycle-Slip Correction Of Dual-Frequency Kinematic GPS Data

摘要

In order to attain high precision positioning andrnnavigation results with GPS, cycle slips must be correctlyrnrepaired at the data preprocessing stage. A slip of only arnfew cycles can bias measurements enough to makerncentimetre-level positioning or navigation difficult. Overrnthe past decade a number of methods have beenrndeveloped to detect and repair cycle slips. The majorityrnof approaches involve forming cycle-slip-sensitive linearrncombinations of the available observables. Algorithmsrnhave been designed to detect, determine, and repair theserncycle slips by fitting functions to the linear combinationsrnand observing differences between the functions and therndata combinations. These methods invariably require userrnintervention for problematic cycle slips in portions ofrndata, tuning of input parameters to data, or introduction ofrnadditional carrier-phase ambiguity-resolution parametersrnin the main data processing where pre-processing cyclesliprndetermination has failed.rnA method has been developed from various existingrntechniques, that provides fully automatic cycle-sliprncorrection at the data preprocessing stage. The algorithmsrnutilise two dual frequency, double-difference carrierrnphase and pseudorange geometry-free linearrncombinations. These combinations are filtered to allowrnfor high-resolution cycle-slip detection, and are thenrncompared with least-squares-fitted Chebyshevrnpolynomials for cycle-slip determination. Resultsrnindicate that single-cycle slips can be reliably detected forrnreceivers in varied environments, and that these slips canrnbe repaired correctly.