> The transportation system is a person, the
vehicle, the road and its the environment combined action complex and
the huge system, therefore, only separately from the person, the
vehicle, the road aspect considered by the time thorough settlement
traffic congestion question is impractical. Now, the people
start from the system viewpoint to embark, factor synthesis
consideration and so on the person, vehicle, road, modern synthesis
and so on communication technology, control technology utilizes to the
transportation system management: On the one hand enable
transportation system and so on in the person, vehicle "the pitch
point" to have the full understanding to the system condition, thus
makes the nimble reflection; On the other hand enables the
transportation superintendent the tendency, the real-time
understanding and the monitoring transportation system, causes the
system display peak efficiency, causes "the pitch point" and the
system can the intelligence interactive, the realization overall
system intellectualization, this is the intelligence transportation
system (ITS, Intelligent Transportation System) [ 1>.
The vehicles position is the ITS important information.
The global positioning system (GPS) and the geography
information (GPS) unifies may real-time, accurately provide the
positional information, obviously GPS realizes the transportation
intellectualization essential technology. Along with information
advancement speeding up, the intelligence transportation system will
play the more and more vital role in the modernization traffic
engineering.
First, GPS technology outline
The global positioning system (GPS, Global Poitioning
System) was has established a satellite navigation positioning system
by US, generally by the spatial part, the ground monitoring part as
well as the user receiver three major part was composed, (21 hosts
used including 24 satellites, 3 spare), used this system, the user may
realize all in the global scope to wait, continual, the real-time
three dimensional navigation localization and to measure fast.
Receiver through GPS satellite transmission data computation
two-dimensional (after, latitude) or three dimensional (after,
latitude, highly) position [ 2>.
The GPS localization technology has the precision high, the
speed quick, the cost low remarkable merit, becomes in the present
world the application scope to be most widespread, the usable
strongest whole world precise time service, the range finder, the
navigation, the positioning system. Our country GPS technology
also in the survey, the sea and air navigation, the vehicles directs
aspect and so on line, missile guidance, precise localization, dynamic
observation, time transmission, velocity measurement to perform to
apply.
Second, GPS in ITS application
At present, along with the GPS satellite navigation
localization technology and the radio traffic network development, GPS
mainly divides into two big kinds in the ITS application.
1st, based on GPS technology realization guidance system
Like chart 1 shows, based on the GPS realization
vehicles guidance system by the GPS receiver, the microprocessor,
navigation software, the monitor, the geographic information system is
composed.
The GPS receiver may the simultaneous reception four above
satellites signals, the determination three dimensional coordinates,
with the definite vehicles position. Navigation software uses in
the overall system data processing and the management. The
monitor may use in the entity movement situation real time display.
The geographic information system uses in to deposit the map and
the related navigation information. The main model application
includes:
(1) vehicles navigation
The GPS vehicles monitoring center for real-time
provides the navigation and other increment services for it, for
example: "Front the street intersection right extension", "you
already the sheer", "front lkm 堵车, please chose other routes" and
so on the information prompt. Vehicles guidance system principle
like chart 1 shows.
(2) pedestrian navigation
GPS can realize the real-time satellite positioning in
individual traveling, helps 旅游?to obtain the correct
geographical position and the route, the position error may control in
10m, guarantees does not lose the direction, safeguards 旅游?to
play joyfully also is safe.
2nd, based on GPS technology realization vehicle operation
management system management system
The vehicle operation management system management
system is by GPS, GIS, the radio traffic network, multimedia, the
telemetering remote control integration is a body one kind of new
vehicle operation management system management system, like chart 2
shows, it mainly is for cause the vehicle operation control section,
the safety and security department promptly to grasp the vehicles the
movement condition, is advantageous for carries on the direction
dispatch to the vehicles, simultaneously provides the transportation,
the public security and the service information for the pilot.
According to the different request, this system administration
vehicles may install the vehicles guidance system, also may only
install the GPS receiver, provides the vehicles positional
information.
The vehicles monitoring center has many microcomputers, a
workstation and the large screen monitor. In order to carries on
the monitor and the management to the vehicles, has the urban road
database, vehicles running status monitor software, the important
vehicles movement route in the computer internal installation
optimizes design software, vehicle operation dispatch management
system management system software, the vehicles reports to the police
urgent processing software and so on.
The main model application includes:
(1) administers first aid the labor to hand over the vehicle
monitoring and the dispatch system [ 3>
The first aid department, the labor will hand over the
vehicle and the taxi may use the GPS mobile target supervisory system
to send the mouth to various vehicles the information to carry on the
generalized analysis, again will dispatch the order transmission for
the driver, promptly will adjust the vehicles movement situation, the
realization effective management. At the same time, but also may
promote the use electron station sign, the electronic station sign
soon arrives the position and the speed information through the
wireless data link receive which the station vehicles sends out,
demonstrated the vehicles movement information, and forecast the
station time, is the passenger provides the convenience.
(2) the gentleman hires a vehicle the service system
The gentleman hires a vehicle the service system and the
GPS supervisory system interconnection exchanges, it when customer
with telephone request service, fast found through the GPS
localization to the passenger recent idling vehicle, answered
immediately the customer carries passengers gentleman's vehicle
trademark and the arrival time, and simultaneously inform this vehicle
to go sends and picks up the visitor, thus realizes the fast response
high quality to hire a vehicle the service.
(3) long-distance transport freight transportation system
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