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Communication and Tracking Technologies. MSHA Communication and Tracking Workshop March 17, 2010. Definitions. Wireless System A system where the link between the user and the system is wireless. A system that operates locally without wires. Mesh Network
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Communication and Tracking Technologies MSHA Communication and Tracking Workshop March 17, 2010
Definitions • Wireless System • A system where the link between the user and the system is wireless. A system that operates locally without wires. • Mesh Network • A communications system where every node is connected to every other node and consequently has built in redundancy. In underground mines, this connectivity may be limited by the mine’s geometry. • Leaky Feeder • A communications device also known as “leaky coax,” which assists wireless transmission. A coaxial cable that has been modified to allow signals traveling within it to leak out over its entire length
Definitions • RFID • A system that uses radio waves to communicate identification information between a tag and a reader. In currently MSHA approved coal mine tracking systems, the tag is worn by the miner and readers are placed throughout the mine. • Through-the-earth (TTE) • A low frequency communications system that does not rely on any devices, wires, or structures between the transmitter and receiver. Because of the low frequency it can transmit signals through solid matter like rock.
Definitions • Medium Frequency • Communications systems that operate in the range of 300-3000 KHz. MF systems have been shown to work well in tunnels where there are metallic structures such as power lines and pipes. The signals can couple onto conductors and travel long distances. • Redundancy • Redundancy involves the duplication of system functions to ensure that those functions willsurvive some level of damage to the system; in the context of communications systems; it is used to describe a system that can maintain communications with the surface when a single communication path is disrupted.
Approved Product Listing Review • http://www.msha.gov/techsupp/PEDLocating/CommoandTrackingMINERActCompliant.pdf • Peripherals • Leaky Feeder Communication Systems • Tracking Systems • Fixed Node Based Communications and Tracking • Wireless Mesh Communications and Tracking • Medium Frequency Communications
Approved TechnologiesLeaky Feeder Communications • High percentage of mines specified in ERPs • VHF vs UHF • Trade-off of high cost cable vs. optimized coverage • MINER Act compliance requires redundant entry coverage.
Approved TechnologiesRFID Tracking • Radio Frequency Identification • Common technology used in many other industrial applications. • Majority of mines specified this tracking method • Zone based tracking • Accuracy is dependent on spacing of readers.
Approved TechnologiesWired Mesh Communications and/or Tracking • Mesh based systems relying on wires for signal propagation • Fiber optic, coaxial, etc. • Some use standard protocols, e.g., 802.11; others don’t
Approved TechnologiesWireless Mesh Communications and Tracking • Mesh system that use wireless signal propagation • Some use standard protocols; others don’t • Most rely on external antennas for optimal signal propagation • Can use relative signal strength for tracking
Approved TechnologiesMedium Frequency Repeater • Allows interconnection of medium frequency communications with leaky feeder • Use existing metal infrastructure for signal propagation • Medium frequency radio not yet MSHA approved
Developing Technologies • Fully Wireless • No antenna wires • No mine power cables • Normally battery powered • Through-the-earth • Several NIOSH contracts • one under evaluation for MSHA approval • Would be limited application solution • Point to point communications • Secondary communication system • Does not provide tracking.
Developing Technologies • Medium Frequency Radios • Good secondary communication system • Could be viable mine emergency solution • Does not provide tracking. • Inertial navigation tracking • Potential to provide precision tracking • + 10 feet • Reverse RFID tracking • Person worn readers • Tags would be mine infrastructure • Potential to provide greater degree of accuracy
Thanks for your attention! Juliette Hill Phone: (304) 547-2063 Email: hill.juliette@dol.gov