DEVINE - 
GPS Tools
GPS and Risk Management
Two important components of risk management are
1) locating the risk and
2) directing resources to this region for managing the risk.
The project DEVINE will contribute to the first aspect, by providing
geographic information concerning seismic and landslide risk.
Another objective of the project DEVINE is to contribute to the second
aspect of risk management through the development of GPS Tools for accurate
cartography, positioning and navigation.
What is GPS?
The Global Positioning System is a constellation of 24 satellites
broadcasting radio signals that allow individuals equipped with a receiver
to determine their position, speed, and direction at any moment at any
place on the earth.
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For a more detailed description of GPS (en français) see:
Extraits d'un article de vulgarisation publié dans la revue
Technologies Internationales, intitulé "GPS : un positionnement
précis à la portée de tous" par Dr. Eric Calais
du laboratoire CNRS Géoscience-Azur :
100 meter accuracy
In its basic configuration, a receiver can calculate its position from
4 overhead satellites with an accuracy better than 100 meters. These antennas
are frequently installed on boats for marine navigation.
1 meter accuracy
Simple differential corrections broadcast by a base station give meter-level
precision for short baselines and can be used in real time for mapping,
vehicle tracking, and fleet management.
Active Meter-Level Positioning Service
The DEVINE objective of dissemination of geo-information derived in research
laboratories extends to the exploitation of the existing REGAL
regional permanent Global Positioning System (GPS) Network for the benefit
of a wider user community.
Development Plans
An example of a possible implementation of a broadcast system for 1 meter
differential positioning corrections (DGPS) shows its use for managing
a Fire Department fleet.
System Features
-
Each vehicle equipped with low-cost GPS receiver and DGPS radio receiver
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DGPS corrections broadcast over FM band radio to wide user area
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Precise vehicle position transmitted to client control center
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Link to client control center shares client managed voice communication
line
A second example implementation demonstrates the concept of Inverse
Differential Corrections, where the corrected position is known only at
the control center, where it is most crucial for fleet management.
System Features
-
Each vehicle is equipped with low-cost GPS receiver
-
Client dedicated DGPS corrections are transmitted to client control center
-
Uncorrected vehicle position is transmitted to client control center
-
Link to client control center shares client managed voice communication
link
-
Corrected vehicle position is available at client control center
The most expensive components of the system - the reference GPS base
stations - are already available. Within the context of the DEVINE project,
a prototype system will be developed and tested in late spring 1999.
Operational Centimeter-Level Positioning Support
Service
An increased level of precision is often necessary for surveying,
cartography, and resource management applications without the demand
for real-time. The most basic example is for entering data reliably into
a GIS database.
Centrimetric level precision positioning is possible using the GPS when
the raw phase data is post-processed simultaneously with data from a reference
station with known coordinates.
The data from the REGAL network, managed by the CNRS-Geoscience Azur,
are already available for a subset of sites. Two additional sites within
PACA, financed through the DEVINE project will be installed in the next
several months. The data
files may be downloaded by internet connection for post-processing
by the user.
Map of currently operating permanent
GPS stations in south-eastern France.
Last modified 2-Feb-1999
Email: jh@acri.fr
Planned
Active Real-Time Meter-Level Positioning Service