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Aaron Fraser

BEng, BSc, GradDipRailSigTel, MIRSE

Tehnika

Ultra-Wideband (UWB) technology is a radio frequency technology that uses a very large bandwidth to transmit and receive small pulses that are used to calculate precise locations. UWB has been proven to provide industry-leading positioning within 2 centimetres from over 300 metres away. UWB is a next generation positioning technology that can be fully integrated with Communications Based Train Control (CBTC) to provide train localisation, speed, and positioning in tunnel environments or used to augment Global Positioning System (GPS) based signalling systems such as Positive Train Control (PTC) or European Train Control System (ETCS) Level 3 in the urban environment where GPS coverage may be limited.

UWB in tunnels operates similarly to GPS, but for the underground environment where satellites cannot see. For train positioning in tunnels, the system consists of UWB beacons onboard the train and at fixed wayside locations, for instance attached to the tunnel walls. The system provides precise location through always-on, real-time ranging between the beacons on the train and the wayside. UWB ranging uses a technique called Time of Flight (ToF) to precisely determine a train’s location within centimetres. UWB replaces typical CBTC odometry systems including transponders, onboard tachometers, and under-carriage antenna. It has been proven to enable quicker installation and reduced cost compared with traditional CBTC equipment, is more readily maintainable, and is immune to adverse environmental conditions such as snow and flooding. The ultra-precise positioning can also enable increased capacity by enabling trains to run closer together and more frequently.