REVISTA ROMÂNĂ DE AUTOMATICĂ - IPA SA

REVISTA ROMÂNĂ DE AUTOMATICĂ
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Software components of the passenger
information system:
• software applications made in
assembler and in VB.NET language:
embedded application for local
data acquisition and display;
desktop application for central
communications with the bus
stations;
desktop application for prediction
of the bus station arrival.
• Microsoft SQL Server 2005
SMARTBUS central database.
The prediction application for bus station
arrivals
The prediction application for the bus station
arrivals of the VTP (Public Transport
Vehicles) has the role to treat in real time the
received position data from the buses and to
provide estimated values for the bus station
arrivals.
The SMARTBUS software applications from
the central level communicate with each other
through common SMARTBUS SQLServer
database tables.
The updates interval for the bus station signs
is 1 minute, and during this time the
prediction application makes at least two
estimations to calculate the prediction value.
The application has been made to monitor the
bus line 5 from Suceava city.
The prediction algorithm is based on periodic
readings of the bus coordinates and their
comparison with the N points vectorized bus
route. Thus the current positions are
estimated and the delay values for each bus
station are chosen relative to the current bus
position (the calculated values are
summarized to obtain the delay of the bus
from the current position to the monitored
station). The calculations are repeated for all
buses on the route. The minimum value of
these values for each bus station represents
the estimated arrival time of the first bus.
This value and the command buffer for the
bus station sign are written in a database
table, used by the local control application for
the station signs.
The delay values estimated and stored are
obtained taking into account a value of 36
km/h as a medium speed planned to cover
the current line route. These values can be
dinamicaly modified, applying a correction
factor according to a particular case.
In order to perform bus monitoring it was
also implemented an algorithm which has as
inputs the bus planned schedule taken from a
database table and as output the analysis data
regarding the realized bus schedule,
depending on the information collected in
real time. The status of the on-route vehicles
can take 4 values: in time, in delay, in
advance (headway), stopped because of
technical problems.
The informational panel
The information panel is an alphanumeric
display, AlphaEclipse type, used for public
information. This is composed of a display
panel made up by LED display modules, in a
metal enclosure with the command and power
elements.
The displayed information is: the hour, date
and temperature, the buses that are nearby the
station; a summary description of the current
routes (most significant points), text
messages or graphic images.
The main units that compose the electronic
sign are: a) the controller board; b) the
display module; c) the comon supply source;
d) the thermostat.
The text messages are sent from the software
dispatcher described below.
The software dispatcher for data
communications with the bus stations
The application for communication with the
bus stations has the considerable role to
render valuable the informations obtained
from the equipments aboard the vehicles,
transmitting the prediction data obtained at
the central level to the local equipments in the
bus stations, to display useful passenger
information.