Carrier phase GPS navigation to the North Pole

Over the last few years on-the-fly integer ambiguity resolution for GPS has consistently proven to be successful over short baseline (< 20km). However, the remaining challenge has been to extend the length of the baseline between the reference station and the mobile receiver, whilst still maintaining the capability of on-the-fly resolution and true carrier based kinematic positioning. The goal has been to achieve centimetric level positioning at ranges of over 500 km. New techniques have been developed at the University of Nottingham to allow very long baseline integer ambiguity resolution, on-the-fly. The details of the novel technique are presented in this paper. A major limiting factor with the use of carrier phase data is that posed by cycle slips. A technique for detecting and correcting these has been developed at the University of Nottingham and is detailed in the paper.

The new technique has also been proven through a series of trials, one of which included two flights to the North Pole, performing centimetric level positioning all the way to the pole. Each year the GD AeroSystems Course of RAF College Cranwell execute a series of equipment flight trials to the North Pole, called the Aries Flights. In May 1996 the authors were fortunate to take part in both flights, via Iceland and Greenland, to the North Pole. Based on reference stations at Thule Air Base, integer ambiguity resolution was accomplished, on-the-fly, and centimetric level navigation maintained throughout the flights. Additional trials detailed in the paper demonstrate that the technique can resolve integer ambiguities on the fly within a few seconds over a baseline length of approximately 134 km, resulting in an accuracy of 12 cm. The majority of the error source for this being the ionosphere.