TITLE:
GPS Receiver Tracking Performance under Ionospheric Scintillation
Conditions

AUTHOR:
Dr. Susan Skone
Department of Geomatics Engineering
University of Calgary
2500 University Dr. NW
Calgary, AB
Canada T2N 1N4

ph: 403-220-7589
fax: 403-284-1980
email: sskone@ensu.ucalgary.ca

ABSTRACT:
GPS receiver tracking performance can be degraded during periods of
enhanced ionospheric activity, such as magnetic storm events. Such
storms are associated with small-scale scintillation effects (phase and
amplitude variations) which are most commonly observed in the high
latitude auroral region and the low latitude equatorial anomaly region.
During periods of intense scintillation, the availability of carrier
phase observations may be limited through loss of signal lock, with a
significant impact on precise positioning applications. Such effects
have a larger impact on the L2 tracking performance, where codeless and
semicodeless technologies are employed to extract the encrypted L2
signal.

The tracking performance of a given receiver depends not only on the
magnitude of scintillation activity observed, but also on the receiver
tracking capabilities. Recent research has shown that tracking
performance can vary significantly between receivers, under identical
scintillation conditions. In this paper, the impact of scintillation
effects on various receiver tracking capabilities is presented. A
comparison of receiver technologies is conducted, using both codeless
and semicodeless GPS receivers (Trimble 4000SSi, NovAtel MiLLennium,
Ashtech Z-12, TurboRogue). Performance comparisons are established and
interpreted with respect to GPS network applications and GPS
availability at solar maximum. The frequency and magnitude of receiver
tracking errors is also examined on a regional basis, with a discussion
of the global distribution of such effects.