Two PhD CASE Studentships (funded from Pinpoint Faraday Partnership)
1. Tropospheric Water Vapour Effects on Nationwide RTK GNSS
The delay caused by tropospheric water vapour is the largest error source
in real-time kinematic (RTK) GPS. Variations between the delays
experienced by the user and the RTK reference receiver cause problems with
ambiguity resolution, and lead to degraded user positioning accuracy,
especially in the height component. Since this decorrelation increases
with the distance between the user and the reference station, this error
source imposes a practical limit of around 20 km on the use of the RTK
technique.
The tropospheric delay can be estimated from GPS measurements. This
approach enables the mitigation of the tropospheric delay bias in order to
obtain improved receiver coordinates.
Proposed Research
This CASE studentship aims to address several areas of research which
should enable the effects of tropospheric delay to be minimised for RTK
users. This should improve not only the accuracy, but also the
availability of that accuracy to a wider range of users.
The CASE funding is in collaboration with the Ordnance Survey of Great
Britain. The successful applicant will be based at the IESSG. Much of the
work will involve the analysis of data gathered in the field and for
periods of 4 to 6 weeks per year, the student will work with the Ordnance
Survey to organise and assist with specific field trials.
2. Next Generation Real-Time Kinematic GNSS Networks
Precise positioning with GPS carrier phase measurements relies on the
measurement of a three-dimensional vector (a baseline) between the user's
GPS receiver and a known reference receiver. To yield the highest
accuracy, the technique requires the accurate resolution of the so-
called 'carrier phase ambiguities'. For mobile users, the challenge is to
resolve the ambiguities independently at every measurement epoch, and in
real-time. This is the On-the-Fly (OTF) approach to Real-Time Kinematic
(RTK) positioning, which is currently used with the existing GPS signals,
but with certain limitations - it is not a robust system, and relies on a
number of conditions relating to receiver environment and the distance to
the reference receiver.
Proposed Research
This CASE studentship aims to address several areas of research which
should lead to improved availability and robustness of RTK systems, and
thus provide wider access to the highest level of accuracy that GNSS can
offer. The research will initially address current and imminent
implementations of RTK systems, focussing on performance testing and an
investigation of the modelling issues.
The CASE funding is in collaboration with Leica Geosystems. The successful
applicant will be based at the IESSG. A significant amount of fieldwork is
also expected. In addition, there is the possibility of spending up to a
month per year on study visits to Milton Keynes, Heerbrugg (Switzerland),
and Calgary.
Further Information and Admission
The studentship is open to UK and EU students. For home students it covers
tuition fees, and it provides a maintenance stipend of £9,000 for the 03/04
academic year, rising to £12,000 for the 05/06 academic year. For EU
students it covers tuition fees only. In addition, for both UK and EU
students, a stipend contribution of at least £3,000 per annum will be made
by the CASE sponsor.
Applications should be made through the Graduate School, using the online
application form, or on a form which can be downloaded. (Applications also
require two references)
http://www.nottingham.ac.uk/prospectuses/postgrad/introduction/applying/appl
y/form.phtml
For further information please contact: [log in to unmask]
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