Over the last few years, on-the-fly integer ambiguity resolution
for GPS has proven to be
successful over short baselines (<20 km). 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. A major problem
with the use of
carrier phase data is that posed by cycle slips. A technique for detecting
and correcting cycle
slips has been developed, and its use is discussed in this paper. The new
technique has 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. 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 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.
Earlier 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 residual error source
for this being the
ionosphere.
Ionospheric Delay Handling for Relative Navigation by Carrier-Phase Differential GPS
