Department of Computer Science and Electrical Engineering
Modelling of an Autonomous Doppler Navigation System Sensor Input Processing
Unit
Paul V. Petraitis
Abstract:
Modern carn navigation systems use signals from GPS satellites to determine
their position. If contact with the satellite signal is lost, an
autonomous system that does not rely on external signals must assume navigation
responsibilities. Current autonomous systems use expensive gyroscopes.
A doppler radar implementation, with sensors pointing at the road at each
corner of the car, would be much cheaper. However, signals received
by the doppler sensor experience signal spreading, asymmetry and ray scattering
by the road surface. This makes it difficult to determine the exact
doppler frequency, and hence speed, of the vehicle. This model, presented
in Matlab, proposes a novel method for extracting speed information using
cross correlation of the detected power spectral density with an ideal
distribution. With the speed of each sensor known, the veolcity of
the vehicle can be determined by geometry. Limiting analysis to circular
trajectories, the model obtains low average errors in position but at relatively
high computation times. The computation time can be reduced but at
the cost of increased error. The implementation of this model on
a dedicated DSP would reduce computation time and is proposed for future
investigation.
Complete thesis:
thesis.pdf
conference_paper.pdf
Additional material:
Matlab code
About the Author
Dept of Computer Science and Electrical
Engineering / Paul Petraitis / pvpx@yahoo.com
last mod 03/09/98