Carrier phase GPS navigation to the North Pole

Over the last few years, on-the-fly integer ambiguity resolution for GPS ha s proven to be successful over short baselines (< 20 km). However, the rema ining challenge has been to extend the length of the baseline between the r eference station and the mobile receiver, whilst still maintaining the capa bility of on-the-fly resolution and true carrier-based kinematic positionin g. The goal has been to achieve centimetric level positioning at ranges of over 500 km. New techniques have been developed at the University of Nottin gham to allow very long baseline integer ambiguity resolution, on-the-fly. A major problem with the use of carrier phase data is that posed by cycle s lips. A technique for detecting and correcting cycle slips has been develop ed, and its use is discussed in this paper. The new technique has been prov en through a series of trials, one of which included two flights to the Nor th Pole, performing centimetric level positioning all the way to the pole. For many years, the GD Aero-Systems Course of the Air Warfare Centre based at RAF Cranwell executed a series of equipment flight trials to the North P ole, called the ARIES Flights. In May 1996, the authors were fortunate to t ake part in both flights, via Iceland and Greenland, to the North Pole. Bas ed on reference stations at Thule Air Base, integer ambiguity resolution wa s accomplished, on-the-fly, and centimetric level navigation maintained thr oughout the flights. Earlier trials detailed in the paper demonstrate that the technique can resolve integer ambiguities on-the-fly within a few secon ds over a baseline length of approximately 134 km, resulting in an accuracy of 12 cm. The majority of the residual error source for this being the ion osphere.