Analysis Of L5/E5 Acquisition, Tracking And Data Demodulation Thresholds
Proc. of the ION GPS Conf., (September 2002)Abstract
The combined use of proposed GALILEO signals and current and also
future GPS signals will help users to greatly improve positioning
accuracy, continuity of service, availability and integrity. The
performance brought by all these signals is degraded by the same
perturbations such as multipath, effects of ionosphere or jamming.
However, differences in signal designs and environments imply differences
in protection against these perturbations. One type of critical criterion
is the set of the key operations thresholds in receivers such as
acquisition, tracking and data demodulation. The aim of the submitted
paper is to propose required signal power to noise spectral density
ratio to perform acquisition, tracking and data demodulation given
a desired performances. Some of the considered performance are acquisition
false alarm, detection probabilities, mean acquisition time and bit
error rate. These thresholds are computed for GPS L5 and Galileo
E5a/E5b signals. The paper starts with a brief review of studied
signal relevant characteristics such as central frequency, code frequency
and period, data rate and used coding and minimum received C/N0.
After this, the second part is dedicated to the presentation of the
different methods that can be used for acquisition, tracking and
data demodulation thresholds computation. These thresholds take into
account some degradations originating from the front end bandwidth,
the tracking errors, and acquisition time. Benefits from pilot channels
and data encoding are also highlighted. Obtained results enable to
estimate C/N0 margins with respect to minimal available C/N0 for
different GNSS signals.