Precise Point Positioning Integer Ambiguity Resolution with Decoupled Clocks
Date
2012-12-18
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Abstract
Precise Point Positioning (PPP) integer ambiguity resolution has been a challenging topic during
the past five years. So far, three PPP integer ambiguity resolution methods – the singledifference
between satellites method, the decoupled clock model and the integer phase clock
model – have been developed. By using integer ambiguity resolution in PPP, cm-level
ambiguity-resolved positioning accuracy can be obtained with hourly observations. However,
some limitations still exist. First, no comprehensive comparison is provided to derive the
equivalence of three existing PPP integer ambiguity resolution methods. Second, no user
confirmation is made to assess the PPP integer ambiguity resolution method and corresponding
products. Third, specific integer ambiguity searching and validation methods in PPP have not yet
been developed. Fourth, although the ambiguity-resolved horizontal positioning accuracy has
been found significantly improved, the height coordinate improvement is always less significant
than its horizontal counterparts. How the ambiguity-resolved height solution can be improved
requires further investigation. Fifth, no efforts have been made to assess the ambiguity-resolved
troposphere solution, which could potentially benefit some meteorological applications.
This thesis has derived the equivalence of three PPP integer ambiguity resolution methods. A
comprehensive comparison among the three has been provided with a focus on the nature of the
clock, the bias and the ambiguity terms in each method. The method equivalence is demonstrated
in three aspects: the integer property recovery, the system redundancy and the correction
broadcasting burden.
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The user implementation procedure of the PPP integer ambiguity resolution method with
decoupled clocks has been derived. Following the assessment of satellite decoupled clock
products from NRCan, some user implementation details not clarified in existing publications,
such as the clock/ambiguity datum, the unknown parameters and the system redundancy, are
discussed. Furthermore, a set of partial ambiguity resolution and validation methods have been
developed for PPP.
The first user confirmation of the PPP integer ambiguity resolution method and corresponding
products have been conducted with the decoupled clock model and satellite decoupled clock
products provided by NRCan. First, the performance evaluation of ambiguity fixing time and
positioning accuracy has been conducted. Second, the limiting factor to the insignificant height
improvement is identified and a troposphere constraint method has been proposed. Third, the
ambiguity-resolved troposphere solution has also been evaluated for its potential benefits to
meteorological applications.
Some future works are provided in the end to consider the user confirmation using nonpermanent
stations under various observation environments, the user performance maximization
and the extension of PPP integer ambiguity resolution with decoupled clocks into real-time
applications.
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Citation
Shi, J. (2012). Precise Point Positioning Integer Ambiguity Resolution with Decoupled Clocks (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/27397