eprintid: 1507935
rev_number: 25
eprint_status: archive
userid: 608
dir: disk0/01/50/79/35
datestamp: 2016-11-10 10:13:55
lastmod: 2020-02-12 16:15:31
status_changed: 2016-11-10 10:13:55
type: thesis
metadata_visibility: show
creators_name: Atkins, CLE
title: Observation-domain sidereal filtering for high-rate GPS precise point positioning
ispublished: unpub
divisions: UCL
divisions: A01
divisions: B04
divisions: C05
divisions: F44
keywords: sidereal filtering, precise point positioning, GPS, carrier phase, seismology, multipath
abstract: Accurate and timely determination of coseismic displacement (the quasi-permanent displacement of the ground caused by an earthquake) is crucial for tsunami warning and situational awareness systems. Seismometers measure acceleration or velocity very precisely. However, the process of integrating such data to yield displacement data is difficult and error-prone. In contrast, The Global Positioning System (GPS) can measure displacement directly, but is also subject to errors, one of which is multipath. Multipath errors can lead to errors in the measurement of small displacements or obscure the displacement entirely. Errors due to multipath are highly dependent on the geometry of GPS satellite orbits and surrounding reflectors relative to the receiving antenna itself. Each satellite has a ground track repeat period of approximately one sidereal day. Hence, this relative satellite-reflector geometry will repeat with the same period. Using this fact, it is possible to identify and remove the error signature induced by multipath by analysing data from adjacent days, yielding an improved time series of displacements and hence a more discernible coseismic offset. This process is commonly known as 'sidereal filtering'. This thesis describes a sidereal filter algorithm that attempts to remove the multipath error signature from the GPS measurements themselves before processing them rather than from the resulting position time-series. It is shown to generally produce a more stable position time series over periods from a few tens to a few hundred seconds, remove high-frequency multipath error more effectively, yield better stability during satellite outages and measure small centimetre-level displacements more accurately than a position-domain sidereal filter. However, results are inconclusive when applying the algorithm to the measurement of the coseismic displacements of a real earthquake, but it is demonstrated that an observation-domain sidereal filter is better at enabling one to distinguish certain types of seismic wave from a position time series.
date: 2016-08-28
date_type: published
oa_status: green
full_text_type: other
thesis_class: doctoral_open
language: eng
thesis_view: UCL_Thesis
primo: open
primo_central: open_green
verified: verified_manual
elements_id: 1146341
lyricists_name: Atkins, Christopher
lyricists_name: Ziebart, Marek
lyricists_id: CLEAT95
lyricists_id: MZIEB32
actors_name: Atkins, Christopher
actors_id: CLEAT95
actors_role: owner
full_text_status: public
pagerange: 1-363
pages: 363
event_title: UCL (University College London)
institution: UCL (University College London)
department: Civil, Environmental & Geomatic Engineering
thesis_type: Doctoral
editors_name: Ziebart, M
citation:        Atkins, CLE;      (2016)    Observation-domain sidereal filtering for high-rate GPS precise point positioning.                   Doctoral thesis , UCL (University College London).     Green open access   
 
document_url: https://discovery.ucl.ac.uk/id/eprint/1507935/1/Thesis_final.pdf