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Universal Positioning Theory Based on Global Positioning System UPGRADE Details for the RnS approach. Julien CARATORI Marc FRANCOIS Nel SAMAMA Institut National des Télécommunications, Evry, FRANCE. Contents. Introduction The GPS Repeater The R1S approach The RnS solution
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Universal Positioning Theory Based on Global Positioning System UPGRADE Details for the RnS approach Julien CARATORI Marc FRANCOIS Nel SAMAMA Institut National des Télécommunications, Evry, FRANCE
Contents • Introduction • The GPS Repeater • The R1S approach • The RnS solution • Comparison RnS/R1S • Conclusion
Contents • Introduction • The GPS Repeater • The R1S approach • The RnS solution • Comparison RnS/R1S • Conclusion
Navigation Group of INT: objectives • Developement of new approaches in navigation • Small scale validation approaches • Modelisation • Simulations • Experiments • Simplicity of implementation
Indoor navigation: introduction MULTIPLE SOLUTIONS Badges Ultrasound RF GSM/UMTS Bluetooth … OUR APPROACH GPS Universal Positioning System
Indoor Navigation with GPS: the real difficulty Weakness of signals
Indoor Navigation with GPS: current efforts • Receiver Sensitivity Improvement • (TRIMBLE, THALES Navigation,etc.) • « Terrestrial Constellation » approaches (pseudolites) • (Northrop Grumman, DLB Ltd, • Seoul National University , etc.)
Indoor Navigation with GPS: Nav Group approach • Transmission from outdoor to indoor environment with « GPS repeaters » • Navigation equation resolution and raw data exploitation • Definition of indoor navigation system architectures
Contents • Introduction • The GPS Repeater • The R1S approach • The RnS solution • Comparison RnS/R1S • Conclusion
Sk Sk Sj Sj Si Si Sm Sm RnS R1S Si .. Sm Sk The GPS Repeater n Satellites (RnS) 1 Satellite (R1S)
Actual receiver induced problem Since , the current receiver resolution method is no longer valid. t1 t3 t2 Need for new receiver algorithms to solve the navigation equations.
Contents • Introduction • The GPS Repeater • The R1S approach • The RnS solution • Comparison RnS/R1S • Conclusion
R1S j R1S i dj di dk dm R1S k R1S m The R1S inddor positioning system architecture Spatial diversity Position calculated by receiver obviously wrong
The R1S indoor positioning possible methods • Find correlations between the calculated location and the true receiver position. • Solve, from raw data, the new navigation problem, given the repeater positions. • Solve, from raw data, the new navigation problem, not knowing the repeater positions.
dri R1S i di The R1S indoor positioning resolution, knowing about the repeater positions (1) Measured by the GPS receiver
d’ri d’’ri dri R1S i di The R1S indoor positioning resolution, without knowing the repeater positions (1) Triple measurements from fixed point lead to repeater position We compute (XR1Si, YR1Si, ZR1Si) using a 3-sphere expansion method with sphere centers at satellite positions
Contents • Introduction • The GPS Repeater • The R1S approach • The RnS solution • Comparison RnS/R1S • Conclusion
The navigation equations: an interesting feature with RnS RnS d
RnS j RnS i dj di dm dk The RnS indoor positioning solution
Details for the RnS approach: Oscillator offset Typical Oscillator Offset versus Time
Details for the RnS approach: Resulting Dt Comparison of Methods of Calculating Dt
Details for the RnS approach: Positioning error Histogram of Induced Localisation error Dx (cm) 0 20 40 60 80 100 120 140 160 180 200
Contents • Introduction • The GPS Repeater • The R1S approach • The RnS solution • Comparison RnS/R1S • Conclusion
Comparison of RnS and R1S solutions RnS Repeater electronic architecture Ease of installation cDtu stability Sequential approach (receiver modifications) R1S No modification of receiver hardware architecture Data transmission required to decrease processing complexity Repeater complexity Advantages Neither Disadvantages
Contents • Introduction • The GPS Repeater • The R1S approach • The RnS solution • Comparison RnS/R1S • Conclusion
Universal positioning: remaining questions ... • How does the navigation receiver know that one is indoors? • … and certainly a few others. • What happens in the region where direct satellite signals are of a similar strength to signals from repeaters?