Dissertation/Thesis Abstract

A Nanosecond-level Time Accuracy Method Using Assisted-GPS Techniques with Variable Time Ambiguity Analysis
by Blay, R. C., M.E., University of Colorado at Boulder, 2019, 60; 13864516
Abstract (Summary)

In this thesis, a brief overview of the GPS L1 signal structure and GPS position and time estimation is given. Then, van Diggelen's A-GPS method is discussed with his millisecond ambiguity approach. Next, a way to accurately use any ambiguity time to reach nanosecond-level accuracy is developed. Experiments are then run to quantify the sensitivity of A-GPS to a priori errors in position and time, as well as the performance of the first sample time error as a function of ambiguity time. It is found that the safe zone for A-GPS is less than 35 km initial position error and less than 30 seconds initial time error. It is also found that an ambiguity time of 200 ms converges to nanosecond-level accuracy 99% of the time. Most first sample time errors are within one nanosecond while none exceed two nanoseconds as compared to a traditional GPS L1 SDR.

Indexing (document details)
Advisor: Akos, Dennis M.
Commitee: Morton, Jade, Shivaramaiah, Nagaraj C.
School: University of Colorado at Boulder
Department: Aerospace Engineering
School Location: United States -- Colorado
Source: MAI 58/06M(E), Masters Abstracts International
Subjects: Aerospace engineering
Keywords: Assisted-GPS, Coarse time, Timing errors
Publication Number: 13864516
ISBN: 978-1-392-25106-5
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