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51 ter manage both drivers' working behaviors and their orga- Tracks the position of the tractor with the time and date of nization's use of vehicles. the transmitted message, Tracks tethered trailers, and Provides for panic/emergency alerts. 3.2.2 Satellite-Based Fleet Management: Expanded Satellite-Based Mobile The technology components of the tested satellite-based Communications Tracking System communication system include satellites, in-vehicle commu- One of the communication methods implemented in nication units, antennae installed on trucks, tethered trailer an FMS is a satellite-based communications network. The tracking units installed on trailers, two panic buttons (one satellite-based mobile communications system has been installed in the truck and another remote button), a network deployed to monitor and track hazmat, high-value cargo, and management center, and customer application software. Spe- freight transportation. The system is effective in the areas not cific features of each technology component are as follows: covered by cellular towers. It is particularly valuable for locat- ing vehicles. The system also provides two-way communica- Satellite selected: A geosynchronous earth orbit (GEO) tions between truck drivers and communication centers at satellite, Galaxy 10R, located at 123W with Ku-band, was regular time intervals. This information can be shared with selected for the test. The satellite was served by Pan carrier-authorized third parties such as public agencies. AmSat. [The costs for lower earth orbit (LEO) satellites As an example, this section presents an expanded satellite- were prohibitively high because of low traffic demand in based mobile communications tracking system tested by the tests.] the U.S. DOT in Alaska and Hawaii (U.S. DOT, 2006, 2007). In-vehicle communication unit and antenna: A satellite- Because of special geographic characteristics in those two based mobile communications terminal (SMCT) installed states, especially Alaska, communication equipment, such as in a truck cab and a dome-shaped antenna GPS receiver antennae, has to be specially adjusted to ensure coverage and mounted on the roof of a tractor (see Figure 26). Messages quality of signals. and position information, including latitude, longitude, and time, are transmitted through the over the air (OTA) Capabilities and Technology Components messaging protocols. of the Satellite-Based System Tethered trailer tracking unit: To track trailers and to The wireless satellite-based mobile communications track- record time and location of trailer/tractor connections/ ing system tested by the U.S. DOT in Alaska and Hawaii has disconnections (see Figure 27). the following capabilities: Panic buttons: One installed in the cab and another wire- less unit (See Figure 28). Directs two-way data communication between the driver Network management center (NMC): NMCs may be located and the carrier with a driver interface unit for two-way text in different parts of the country. For instance, an NMC was communications, located in San Diego, California, and a back-up NMC was Source: U.S. DOT, 2007 Figure 26. In-vehicle communication unit and antenna for satellite-based systems.

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52 Drivers can request assistance, convey information, and report delivery status and Dispatchers can respond to drivers' requests, manage fleet movements, assign routes, and provide informa- tion back to customers. The panic button improved emergency responses between drivers and dispatchers. Tethered trailer tracking provided trailer status, con- nected or disconnected, to a trailer. Recording time: Trucks' locations were recorded every 15 min. The system would wake up, record its position, and take a reading to determine whether PamAmSat satel- lite coverage was available at that location. At hourly inter- vals, the first three position reports were archived and then sent with the fourth report at the end of the hour, along with other messages. Source: U.S. DOT, 2007 Information recorded: In addition to the location of trucks, Figure 27. Trailer tracking unit. the status of satellite communication was also recorded to indicate whether the truck was in or out of coverage. Storage of records: All data went through the NMC in San located in Las Vegas, Nevada, for the U.S. DOT's tests in Diego, CA. Alaska and Hawaii. The NMC is responsible for receiving Out-of-coverage (OOC): For Alaska, 16% of the responses and sending messages to drivers relayed through satellites were outside of the coverage area, and the total miles on a 24-hour-a-day, 7-day-a-week basis. recorded were 2,219. For Hawaii, OOC responses were Internet communication: The communication between 1% of the total responses, and the total number of miles the customer fleet management center and the NMC is recorded was 493. conducted using the Internet. Special Technical Requirements of the System Tested Functionalities of the System Optimizing the mobile unit antenna for coverage in Alaska Three technologies were tested: satellite-based mobile com- to maximize the signal strength throughout Alaska and to munications, panic buttons, and tethered trailer tracking. prevent signal drop-outs if vehicles were in mountain Test results indicated that areas. Satellite-based mobile communications improved two- Using a higher-powered 2W transceiver: A higher-powered way communication 2W transceiver was used to ensure more reliable communi- Panic Button mounted on tractor's dashboard Source: U.S. DOT, 2007 Figure 28. Panic buttons.