Multi-modal Trip Planning for the San Francisco Bay Area - Mentz ...

8 mdv news I/2011
AVM Light – Dynamic Timetables in the Vogtland Region
The title of this article may pose a series of
questions, even to the experienced mdv news
reader. What is AVM Light? What do AVM and
mdv have to do with one another? And what is
the Vogtland Region doing with this innovative
technology?
The idea to build AVM Light came about with
the advent of powerful easy-to-use smart
phones like the iPhone and Android phones.
They provide enough processing power for the
functions of an AVM driver data terminal, can
be easily installed in a vehicle, and are afforded
enough screen readability for use while driving.
Newer phones would even provide an integrated
GPS antenna for vehicle tracking. Yet real
world use has shown that GPS antennas inside
vehicles are much less reliable than an externally
mounted device. Now there are even
off-the-shelf products of this kind as well.
Behind the concept of AVM Light is the idea of
having an AVM system without the hardware
and vehicle installation. So the word 'light'
mainly refers to the lack of hardware and its
associated investment and maintenance costs,
and not to its functionality.
System Concept
Regarding the vehicles, a distinction is made
between those to be equipped with new data
terminals and those that already have an
onboard computer which only needs to be
upgraded (see Figure 1).
Vehicles without on-board computers will be
equipped with two components, a GPS tracker
and a PDA.
The GPS Tracker is a GPS receiver with an
antenna and integrated GPRS modem, which
has been mounted on the roof of the vehicle
and merely has to be connected to the vehicle’s
electrical system. The GPS Tracker has its own
SIM card and sends messages to the AVM system
over the mobile network in customizable
time intervals as soon as the vehicle is turned
on. These messages indicate the GPS position,
speed and direction of the vehicle as well as a
vehicle-specific ID.
In the vehicle, a PDA is installed on which the
application runs. Using this application, the
driver can log on at the beginning of their shift.
AVM Light can work with or without block information.
The assignment of a vehicle to a trip or
a block occurs when a driver logs on to a
respective route/block.
In addition to driver log on/off, vehicle and
route registration, communication with the
center of operations occurs over the PDA. This
is either done via text messages or over the
telephone features of the PDA.
Rather than having a GPS module in the PDA,
using an external GPS track provides a number
of advantages. Due to the high-quality antenna,
receiver and installation on the vehicle roof, significantly
more stable and reliable GPS reception
can be achieved. Moreover, position and
vehicle ID are sent whenever the vehicle is in
operation, regardless of whether a route and
driver are logged onto the system.
In vehicles with on-board computers, position
indication and log on/off communication for
routes have to be performed by the on-board
computer. Communication with the AVM system
occurs over an interface that has been
agreed upon by the manufacturer of the
computer.
Control center
Figure 2 shows the control center in correspondence
with the DIVA / EFA system. It is from the
DIVA system that the AVM system is supplied
with scheduled data via a VDV 452 interface.
Based on the scheduled data and the current
vehicle position, timetable forecasts are calculated
by the AVM system. The forecasts are then
sent either directly to EFA real-time or first to
the DDIP via interfaces VDV 454 AUS and AUS-
REF for use in the EFA journey planner. The vehicle
positions are transmitted via the VDV 453
VIS interface to EFA and to third parties over the
DDIP. The AVM system is also able to receive
third party VDV 453 VIS to display their vehicles
on the control center display.
Both the application of the control center and
the application for the vehicle data terminals
run on the application server. Both applications
are fully web-based. The control center application
can be accessed in a browser on user workstations.
The same applies to the use of vehicle
data terminals, which also only require a
browser on a PDA.
Installation of AVM-specific software to user
workstations or PDAs is not necessary.
The applications on the application server communicate
with the AVM system over a WCF
interface. It is also possible to open this interface
for communication between the AVM system
and the on-board computers.
Figure 1 Vehicle system Figure 2 Control center and data management system DIVA/EFA