Antti Lehtinen Doppler Positioning with GPS - Matematiikan laitos

Abstract
TAMPERE UNIVERSITY OF TECHNOLOGY
Department of Electrical Engineering
Institute of Mathematics
Lehtinen, Antti: Doppler Positioningwith GPS
Master of Science thesis, 58 pages
Examiners: Prof. Keijo Ruohonen and M.Sc. Paula Syrjärinne
Funding: Nokia Mobile Phones
March 2002
Satellite positioningis expected to have hundreds of millions of users in the near
future. There is a huge commercial potential in personal positioning. The standard
positioningsystem nowadays is the Global PositioningSystem (GPS). The
GPS is very accurate in good conditions. In indoors and urban areas, however,
the standard GPS positioningusually fails. This decreases suitability of the GPS
for personal positioning.
The objective of this thesis was to examine a new GPS positioningmethod based
on Doppler measurements. Doppler positioningwith the GPS has generally been
overlooked because it provides worse accuracy than the standard method. However,
the Doppler measurements can be obtained even in very bad conditions.
Thus, when combined with cellular network assistance, the method may prove
valuable.
In this thesis, a new positioning algorithm is developed. The algorithm needs only
the Doppler measurements from at least four GPS satellites, the GPS satellite
orbital parameters and the current time. A general theory for estimating errors
in GPS Doppler positioningis also developed. Numerical results are compared
with the measurements and the accuracy of the algorithm is assessed.
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