International Global Navigation Satellite Systems Association
IGNSS Conference 2016
Colombo Theatres, Kensington Campus, UNSW Australia
6 – 8 December 2016
Coarse-time Positioning without
Continuous GPS Signal Tracking
Wonjae Yoo (1)
School of Electronics and Information Engineering/Korea Aerospace University/Republic of Korea
+82-2-300-0131, wjyoo@kau.kr
Kwang Ho Choi (2)
School of Electronics and Information Engineering/Korea Aerospace University/Republic of Korea
+82-2-300-0131, sahnhara@kau.ac.kr
Joonhoo Lim (3)
School of Electronics and Information Engineering/Korea Aerospace University/Republic of Korea
+82-2-300-0131, limjh@kau.ac.kr
Lawoo Kim (4)
School of Electronics and Information Engineering/Korea Aerospace University/Republic of Korea
+82-2-300-0131, lakeone@naver.com
Hyoungmin So (5)
Agency for Defense Development/Republic of Korea
+82-42-821-4463, hmso@add.re.kr
Hyung Keun Lee (6)
School of Electronics and Information Engineering/Korea Aerospace University/Republic of Korea
+82-2-300-0131, hyknlee@kau.kr
ABSTRACT
This paper proposes an efficient coarse-time positioning method that can be
applied to the environments where continuous GPS signal tracking is not
guaranteed due to frequent signal blockages, attenuation, interference or
jamming.
If a GPS receiver operates in a normal mode with continuous GPS signal
tracking, navigation message acquisition and user position/clock bias
estimation, its coarse-time can be aligned with the GPS time accurately.
Between the time alignments, the coarse-time usually drifts from the last
synchronized GPS time based on the receiver’s internal low-cost crystal
oscillator.
If GPS signal tracking cannot be performed, the coarse-time largely deviates
from the GPS time and varies from a few milliseconds to several tens of
seconds since the GPS time information contained in the navigation message
cannot be acquired from the signal tracking process. The proposed coarse-
time positioning method is purposed to enable positioning in these cases. By
an experiment with a software GPS receiver, performance of the proposed
method is evaluated.
KEYWORDS: GNSS, GPS, Code Phase, Coarse-time, Coarse-time
positioning
