Department of Geomatics

1
Land Vehicle Navigation in the Urban Canyon A
Kalman Filter Solution using Integrated GPS,
GLONASS and Dead Reckoning
Allison Kealy The University of Melbourne
Maria Tsakiri, Mike Stewart Curtin University of
Technology
2
Positioning Technologies
Beacons
WAAS
EGNOS
GPS
LORAN C
Land Vehicle Navigation
GLONASS
GNSS-1
GNSS-2
DR
INS
3
(No Transcript)
4
Land Vehicle Navigation

• IVHS, ITS, AVL
• Problem of Urban Canyon
• First generation solutions
• integrated GPS/DR
• Kalman filter solution
• stochastic models
• performance over time
• Second generation solution
• integrated GPS/GLONASS/DR
• smart stochastic modelling

5
Land Vehicle Navigation -Transperth Western
Australia
6
DGPS
DGPS/DGLONASS
7
Integrated Navigation System

• KVHTM gyro stabilised digital compass
• NitestarTM digital odometer
• Ashtech GG24TM GPS/GLONASS receiver
• timing algorithm

8
START
Initialise
Devices
Create thread for each device
Wait for timing strobe (GPS)
Send trigger strings to other devices
NO
YES
GPS data available?
Take data from devices
Write to Output File
NO
End of Observations ?
YES
STOP
9
Offset between DR distances and derived
distances from the DGPS
Offset between DR headings and derived headings
from the DGPS
10
The Accumulation of Errors on DR Sensors
11
First Generation System - Integrated GPS and DR

• 9 state Kalman filter
• stochastic modelling
• over filtering
• under filtering
• smart stochastic modelling
• outlier rejection

12
(No Transcript)
13
(No Transcript)
14
Second Generation System - Integrated GPS/GLONASS
and DR
15
Odometer Scale Factor .998
Gyro Offset 1o
Gyro Drift Rate .2o/sec
16
(No Transcript)
17
Summary

• For the duration of the test, GPS-only
  positioning is unavailable approximately 30 of
  the time
• When GLONASS is available only 10 of the time
  there are no position solution
• When satellite positions are available the
  additional GLONASS satellites do not improve
  positional accuracy
• Combined GPS/GLONASS provides more fixes for the
  calibration of the DR component of the system
• When GPS/GLONASS fixes are unavailable, the DR
  operates without excessive degradation as the
  primary system

18
Thank you Allison Kealy Department of
Geomatics The University of Melbourne a.kealy_at_eng
.unimelb.edu.au