The GNSS Practice in Intelligent
Transportation System and
Traffic Management
Jaching Chou
Institute of Transportation
Chinese Taipei
APEC GNSS Summit and 12th GIT Meeting
Bangkok, Thailand
26-30 May, 2008
Agenda
• What is ITS (Intelligent Transportation System)?
– ITS applications overview (US)
– Eight sub-services of ITS (Chinese Taipei)
– Nine areas of ITS (Japan)
• GNSS and NEMA 0183
• GNSS in ITS
– Advanced traffic management services (ATMS)
– Vehicle tracking and management
• For the applications in commercial vehicle, public transit,
emergency vehicle, container,….
– Advanced public transportation services (APTS)
– Commercial vehicle operation services (CVOS)
– Advanced traveler information services (ATIS)
• Car navigation with real time traffic information.
• Conclusions
What is ITS?
• ITS improves transportation safety and mobility
and enhances productivity through the use of
advanced information and communications
technologies.
– ITS encompass a broad range of wireless and wire
line communications-based information and
electronics technologies. When integrated into the
transportation system's infrastructure, and in vehicles
themselves, these technologies relieve congestion,
improve safety and enhance American productivity.
– ITS is made up of 16 types of technology based
systems. These systems are divided into intelligent
infrastructure systems and intelligent vehicle systems.
Research and Innovative Technology Administration (RITA), U.S. Department of Transportation
(http://www.its.dot.gov/its_overview.htm)
ITS Applications Overview
Research and Innovative Technology Administration (RITA), U.S. Department of Transportation
(http://www.its.dot.gov/its_overview.htm)
GNSS
•
GPS (US)
– Positioning, location and orientation (WGS84).
– Navigation, the ability to determine current and desired position
(relative or absolute) and apply corrections to course, orientation, and
speed to attain a desired position anywhere around the world, from subsurface to surface and from surface to space;
– Timing, the ability to acquire and maintain accurate and precise time
from a standard (UTC).
(http://pnt.gov)
•
GALILEO (European Satellite Navigation System)
– A permanent reference in time and space.
(http://ec.europa.eu/dgs/energy_transport/galileo/index_en.htm)
•
Time and location data from commercially available GNSS(GPS)
receivers
– Data format is NEMA-0183 which is a standard sentence (NEMA:
National Marine Electronics Association).
– Reference coordinate system is WGS84 (World Geodetic System).
NEMA 0183 Sentence
(commonly used in ITS)
•
$GPGGA (Global Positioning System Fix Data)
– $GPGGA,123519,4807.038,N,01131.000,E,1,08,0.9,545.4,M,46.9,M,,*47
•
$GPRMC (recommended minimum sentence C)
– $GPRMC,123519,A,4807.038,N,01131.000,E,022.4,084.4,230394,003.1,
W*6A
•
$GPGSA (overall satellite data)
– $GPGSA,A,3,04,05,,09,12,,,24,,,,,2.5,1.3,2.1*39
•
Definitions
–
–
–
–
–
–
–
–
–
–
123519: 12:35:19 UTC.
230394: Date (23 rd of March 1994).
4807.038,N: Latitude 48 deg 07.038' N.
01131.000,E: Longitude 11 deg 31.000' E.
545.4,M: Altitude, Meters, above mean sea level.
022.4: Speed (knots, 1 nautical mph = 1.852 kph = 1.151 mph).
084.4: Track angle.
2.5: PDOP (dilution of precision).
1.3: Horizontal dilution of precision (HDOP).
2.1: Vertical dilution of precision (VDOP).
http://www/gpsinformation.org/dale/nema.htm for details.
GNSS in Intelligent
Transportation Systems
• Advanced traffic management services (ATMS)
– Retrieve essential traffic characters
– Synchronize traffic signal
– Traffic signal preemption for transit and emergency vehicles,
combined with automatic vehicle location (AVL)
• Vehicle tracking and management
– For commercial vehicle, public transit, emergency vehicle,
container,….
– Application domains
• Advanced public transportation services (APTS)
• Commercial vehicle operation services (CVOS)
• Advanced traveler information services (ATIS)
– Car navigation with real time traffic information.
Advanced Traffic Management
Services (ATMS)
• Essential traffic characters of urban and
freeway traffic management
– Traffic volume
– Vehicle speed
– Travel time
–…
Traffic Characters
Using GNSS to
Retrieve Link Travel Speed
• GPS’s information from probing vehicles
(such as buses).
– “$GPRMC,123519,A,4807.038,N,01131.000,
E,022.4,084.4,230394,003.1,W*6A”
• Steps to retrieve link travel speed.
– Geo-coding vehicle’s location
807.038,01131.000.
– Matching this location to the closest link.
– Determining vehicle’s orientation based on
track angle (up-stream or down-stream).
– Assign speed to that particular link.
Using GNSS to
Retrieve Travel Time
• GPS’s information from probing vehicles
(such as buses).
– “$GPRMC,123519,A,4807.038,N,01131.000,
E,022.4,084.4,230394,003.1,W*6A”
• Steps to retrieve link travel time.
– Geo-coding location P1 at t1.
– Geo-coding location P2 at t2.
– Travel time between Point 1 and 2 is t2 - t1.
Advanced Traffic Management
Services (ATMS)-Synchronization
• Synchronize traffic signal
– To “synchronize” the timing of a series of adjacent signals to
optimize the movement of traffic “platoons or groups of vehicle”.
– Signal coordination provides a mean where the sequence of
green lights is established along a series of traffic signals to
allow for the uninterrupted flow of traffic between these traffic
signals.
• Urban traffic control system (UTCS)
– Time-based coordination (TBC) systems.
– Time base sources: AC power source, Crystal Oscillator, FM
radio broadcasting, Traffic Control Center (Network Time, NTP).
• GPS’s RMC Sentence
– “$GPRMC,123519,A,4807.038,N,01131.000,E,022.4,084.4,2303
94,003.1,W*6A”
– 23 rd of March 1994 and 12:35:19 UTC as traffic signal time
base.
Traffic Signal Preemption for
Transit and Emergency Vehicles
• Combine
– Real-time transit/emergency vehicles location via
GNSS.
– Urban traffic operation to provide signal preemption.
• Bus rapid transit (BRT) and transit signal priority
(TSP).
• Steps
– Vehicle location (Pv) at tv with speed Vv
• “$GPRMC,123519,A,4807.038,N,01131.000,E,022.4,084.4,2
30394,003.1,W*6A”
– Intersection location (Pi) - given
– Time for vehicle reach the intersection
tr = (Distance between Pv and Pi) / Vv
– Based on tr, traffic signal controller can decide
whether priority should be granted.
Vehicle Tracking and Management
• Basic concepts
– Using the $GPRMC sentence to acquire the location,
speed, orientation, and time of vehicle.
– Then integrate these under GIS environment for
management issues, such as fleet management
(scheduling, dispatching,…),….
• Applied Domains
– Advanced public transportation services (APTS)
– Commercial vehicle operation services (CVOS)
Advanced Public Transportation
Services (APTS)
Fleet management
- Scheduling/dispatching
Route tracing
•Pre-trip and en-route transit information
•In-terminal/wayside information systems
Quantified Measurement of Using
GNSS in APTS
• Average passenger waiting time
– Reduce by 5 minutes (experience from nearly 40% passengers).
– Reduce by 10 minutes (experience from 10% passengers).
• Ridership
– In 2005, 233,000 riders increase monthly in Kaohsiang city.
– In 2006, 36% increase annually in Tainan city.
• Fuel consumption and CO2 emission (case study in
Kaohsiang city )
– 1,051,000 litres (277,000 US gallons) gasoline reduce annually.
– 2,360 tons CO2 reduce annually (equivalent to 520,000 trees in
terms of environmental concern).
• Operational efficiency
– Scheduling process from 2 hours (manually) to 10 minutes.
Commercial vehicle operation
services (CVOS)
• Security and trade facilitation issues
– ICAO’s “Regulated Agent (RA)”
• “a cargo agent, freight forwarder or any other entity that
conducts business with an airline and provides cargo security
controls acceptable to the Aviation Security Authority.”
– World custom organization's authorized economic
operator (AEO)
• “all the parties in the supply chain industry increase security
to improve the efficiency and ultimately reduce costs and
improve partner relationships.”
– US C-TPAT program
• “To build cooperative relationships that strengthen and
improve overall international supply chain and U.S. border
security.”
GPS ETC
車 機OBU
ETC
RSU
監 理 單 位
E T C C en ter
監 控 中 心
相 關 單 位
事 故 救 援 單 位
緊 急 事 件 通 報
緊 急 救 援 體 系
貨 運 業 者
行 政 作 業 系 統
定點查核子系統
全程監控子系統
基 地 台
Advanced Traveler Information
Services (ATIS)
• Car navigation with real time traffic
information.
– Using GPS’s RMC and GGA sentences to
acquire time, location, attitude, speed,
orientation of car.
– Using GPS’s GSA sentence to evaluate the
data quality of GPS by using DOP value
(dilution of precision).
– Using RDS-TMC (radio data system, traffic
message channel) to deliver traffic information
in real time.
Photo: from Wikipedia Web site
Car Navigation
Conclusion
• GNSS has
demonstrated it capability and
Reduce
effectiveness in ITS applications, which might be
fuel consumption
expensive
or hard to approach previously.
– ToCO
combine
existing
probing
vehicles
and then
2 emission
“
Small
”
device,
integrated with traffic management systems to
Magnificence outcome!!
• Provide signal priority operation.
• Increase traffic detecting coverage for better traffic operation.
– To increase or improve ridership or operational
- “operational
efficiency.
– To preventand
unnecessary
travel delay
and stop by”
financial
benefits
using navigation devices and receiving real time
traffic information to discover better route choice.
Source:http://www.navcen.uscg.gov/ftp/gps/ggeninfo/gps-iif.tif