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1 INTRODUCTION
The economic development of a country depends to a high degree
on the state of its network of lines of transportation. Therefore,
highways, railroads and shipping routes have to be extended,
improved and maintained permanently. Prerequisite to an efficient
management of these public responsibilities is an up-to-date
information system founded on a current database.
This information system contains the geometry and the topology of
the transportation network, usually georeferenced, and attribute
data, describing the condition, the capacity and the furnishings of
the trade routes. It is usually designed as a special purpose geo
information-system (GIS).
The data acquisition for the databases is extremely costly since
existing maps are usually outdated, incomplete and inaccurate, so
that additional field survey is required to meet even moderate
quality requirements and the data base must be updated with high
frequency. A yearly revision rate of up to ten per cent has to be
envisaged. The effort to keep up with these changes is often
underestimated since the unavoidable field work is slow and
expensive. An attempt to automate the field survey and thus to
speed up and economize the data acquisition for building and
updating databases is the development of the Kinematic Survey
System (KiSS) at the Institute of Geodesy of the University of the
Federal Armed Forces Munich.
2 REAL TIME DATA ACQUISITION WITH KiSS
The mobile measuring unit of the KiSS consists of two subsystems
serving different purposes. The trajectory subsystem contains an
inertial navigation system (INS) in strap-down mechanisation,
featuring two two-axes mechanical, dry-tuned gyros and three
accelerometers. This main sensor package provides autonomously
position and attitude of the van at a high frequency.
Figure (1) shows an overview of all sensors of the KiSS. The
sensors for the determination of the trajectory are placed in the left
side of the scheme. Since the signals of inertial sensors are
contaminated by progressive systematic deviations, aiding
observations are required to obtain steady accuracy. These are zero
velocities (ZUPT), when the van stands still, velocities from an
odometer, heights from a barometer and DGPS-positions whenever
four or more satellites are in view. The satellite fixes using pseudo
ranges have an accuracy of about 0.5 m and are provided with 5 Hz.
The availability of DGPS is close to 80 percent, while the coverage
of OTF-positions using phase measurements is below 20 per cent.
Figure 2: The mobile measuring system on the roof rack of the van
The second subsystem is composed of a pair of monochrome CCD-
cameras which take simultaneously images of the situation in
driving direction. Fig (2) shows the mobile measuring system with
the GPS antenna and the CCD Cameras mounted on a roof rack of
the van 1,80 m apart. They cover an area from 10 to 50 m in front
of the van and 20 to 30 m to the right. So, driving both directions,
all objects in a corridor of about 50 m are captured by the system.
Additional information on objects along the route and on the
condition of the roadway is provided by a color VHS video system
and a voice recording unit. The sensor readings are synchronised
with the PPS-signal of the Global Positioning System.
Figure 1 : Overview of the Kinematic Survey System (KiSS)
