A software GPS receiver is a functional GPS receiver in software. It has
several advantages compared to its hardware counterparts. For instance,
improvements in receiver architecture as well as GPS system structure can be
easily adapted to it. Furthermore, interaction between nearby sensors can be
coordinated easily. In this thesis, a SGR (software GPS receiver) is presented
from a practical point of view. Major components of the SGR are implemented
in Matlab environment. Furthermore, some alternative algorithms are
implemented. SGR implementation is considered in two main sections namely a
signal processing section and a navigation section. Signal processing section is
driven by the raw GPS signal samples obtained from a GPS front-end of
NordNavTM R-25 instrument. The conventional and the block adjustment of
synchronizing signal (BAAS) processing methods are implemented and their
performances are compared in terms of their speed and outputs. Signal
processing section outputs raw GPS measurements and navigation data bits.
Since the output data length is insufficient in our case, navigation section input
is fed from AshtechTM GPS receiver for a moving platform and TrimbleTM GPS
Receiver for a stationary platform. Satellite position computation, pseudorange
corrections, Kalman filter and LSE (least squares estimation) are implemented
in the navigation section. Kalman filter and LSE methods are compared in
terms of positioning accuracy for a moving as well as a stationary platform.
Results are compared with the commercial GPS outputs. This comparison
shows that the software navigation section is equivalent to the commercial GPS
in terms of positioning accuracy.
| Identifer | oai:union.ndltd.org:METU/oai:etd.lib.metu.edu.tr:http://etd.lib.metu.edu.tr/upload/2/12606305/index.pdf |
| Date | 01 July 2005 |
| Creators | Gunaydin, Ezgi |
| Contributors | Tuncer, Temel Engin |
| Publisher | METU |
| Source Sets | Middle East Technical Univ. |
| Language | English |
| Detected Language | English |
| Type | M.S. Thesis |
| Format | text/pdf |
| Rights | To liberate the content for METU campus |
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