Zusammenfassung
This paper presents a methodology to evaluate the position availability
of automotive grade global positioning system (GPS) receivers intended
for Telematics applications utilizing a multichannel GPS satellite
signal simulator in a controlled laboratory environment. Initially,
field testing of two distinct GPS receivers was conducted in an urban
canyon environment and a foliage environment to assess each receiver�s
position availability performance. Test scenarios were then developed
on a multichannel GPS satellite signal simulator in order to create
controlled and repeatable stimuli to the GPS receivers. The scenarios
take into account the actual satellite constellations at the same
day, time, and locations of the field data collections. Furthermore,
the number of visible satellites and power levels was adjusted in
order to stimulate the hardware tracking sensitivity, hardware acquisition
sensitivity, dynamic range, and navigation filter design, all of
which impact position availability for GPS receivers. Quantitative
results demonstrated good correlation between the results obtained
using the developed test scenarios and the results from the field
testing. The proposed methodology will result in reducing validation
cost and time to market for automotive Telematics products.
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