SURVEYING TOOLS AND DATA PROCESSING FOR ROAD INFORMATION SYSTEMS
G. Manzoni **, G. Caroti ", S. Martinolli *, R. Pagurut *, C. Palermo *, A. Purga *, T. Sluga^*
* Università degli Studi di Trieste-Facoltà di Ingegneria-Dipartimento di Ingegneria Civile e Centro di Eccellenza per la Ricerca in
TELEGEOMATICA, GEONETLAB
manzoni(@univ.trieste.it - (martinolli, pagurut, purgaa, sluga)@dic.univ.trieste.it - ciro.palermo@iuav.it
^ Università di Pisa- Dipartimento di Ingegneria Civile - g.caroti@ing.unipi.it
Commission VI, Working Group 3
KEY WORDS: Cartography, GIS, GPS/INS, Laser scanning, Mapping, Multisensor, Real-time, Surveying
ABSTRACT:
A group of Italian Universities have collaborated in setting up a road survey system. Actually two small vans are in operation: one
(University of Trieste as the leader) is equipped with high accuracy GPS/triaxial INS positioning system and two digital cameras as
well as a monoaxial laser scanner; an other one (University of Pisa) is equipped with a GPS/monoaxial INS positioner and a small
digital camera. The former has the task of the road survey for a Road Information System, RIS; the latter has the task of updating the
RIS for maintenance and emergencies.
Cooperation with some Universities of the Central Europe Initiative Countries, CEI, are in progress and a project to use these tools
for a RIS of some of these countries has been already submitted to the Italian Authorities as well as presented to the CEI Economic
Forums. The paper will show the results of an pilot experience for the Province of Teramo RIS. This experience has shown that the
RIS is useful also for developing local Small and Medium Enterprises.
1. THE SURVEYING APPROACH
The adopted surveying technology is based on a “Mobile
Mapping System”. A MMS is a van mounted high performance
surveying system, both made up by positioning and survey
sensors, which solutions are synchronised to each other.
The choice of such a surveying technology is justified by its
high productivity and its completeness level. All the relevant
mapping data for the Road Cadastre are obtained from the
camera images by photogrammetric processing. Each camera
image is georeferenced in the global frame from the positional
data obtained by the trajectographic subsystem.
2. THE LEADER VAN
The system we are going to describe has been thought, and set
up, in order to satisfy the Italian law requirements, that previews
the institution of a Road Cadastre:
e Road axis plane coordinates must have 1-metre accuracy in
the global frame, after data smoothing.
e Accuracy is defined for the segmented attributes with
metric values (road widths): each measured attribute must
have 1-decimetre accuracy.
e — Accuracies are defined also for the road slopes: the slope
data, longitudinal and transversal, must have 1% accuracy.
e QGeoidical height must have 5-metre accuracy, in
longitudinal profile, after data smoothing.
To date there exists a complete Road Cadastre implementation
for an experimental road network of about 90 Km in the
Province of Teramo.
2.1 Van Equipment
The MMS equipped at the University of Trieste, a Piaggio
Porter, mounts high accuracy instrumentation.
Positioning and Attitude solutions are supplied by the means of
Applanix POS/LV (Position and Orientation System for Land
Vehicles); this is a GPS/INS integrated system, able to supply
high accuracy real time navigation data, thanks to the aid from
DGPS, from a second GPS antenna for high precision Azimuth
detection, and from a 1024 pulses per revolution Distance
Measuring Indicator (DMI).
Real time navigation data can be improved by post-processing
sensors’ raw data.
The POS/LV has the capability of monitoring sensor health,
isolating sensors that show degraded performance and
reconfiguring itself to maintain optimal performance. Sensor
errors are estimated on an ongoing basis using a Kalman
filtering technique (Applanix Corporation, 2000).
Figure 1. The vehicle equipped at the University of Trieste
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