positioning
of technical and design issues – like the proximity of the radiowave-absorbing human body – that must be taken into account if interference is to be eliminated, accuracy improved and the urban canyon issue resolved. In reality, there are currently only a handful of TETRA devices out there that are using GPS technology to full advantage.” Awareness of other vulnerabilities within GNSSs is leading,
however, to some interesting innovation. For a start, attention has turned once again to the potential of LORAN – a low- frequency terrestrial beacon system whose history stretches right back to the early days of World War II. Tough the US switched off its LORAN system last year as a budget-saving measure, an increased focus on public safety in that country and an awareness of the vulnerabilities of GPS – as well as further innovation in other parts of the world such as the UK – may bring Enhanced LORAN (eLORAN) increasingly into focus as a practical and complementary technology to GPS.
Modernizing LORAN Roke Manor Research in the UK, for example, has developed a miniature integrated eLORAN module called MILOR. It also includes GPS and GSM functionalities as well as MEMS- based sensors that provide inertial navigation backup. Simon Atkinson, business sector manager at Roke, takes
up the story. “While GPS has many benefits against the older LORAN-C navigation system, it is highly vulnerable to jamming and incidents of deliberate or inadvertent interference with GPS are on the increase”, he explains. “E-LORAN is very complementary to GPS as its high powered signals can penetrate areas and maintain contact even where GPS signals are blocked – such as in buildings, tunnels, areas of dense foliage or during severe weather. We’ve been able to combine multiple positioning technologies into a single package and, given that governments around the world are realizing that an ‘all your eggs in one basket’ approach to critical navigation systems wasn’t the most prudent move, it’s possible to see eLORAN and GPS as becoming complementary to one another.”
Under cover Switching now from the macro stage to the micro come parallel innovations being developed to provide positioning information actually within buildings – especially important in the ‘lone worker’ context of TETRA usage such as in prisons or large industrial sites. Once again, a range of technology options is on the table,
some mature and some still at the pilot stage. Positioning specialist Zonith, for example, offers a range of Bluetooth- based systems and software development kits that allow the development of a variety of indoor applications. Eoin Foy, Zonith’s international channel sales manager,
explains further: “Tere are many situations where some form of indoor positioning is required, such as with lone workers in hazardous environments. Bluetooth gives you a range of options for locating workers – from just knowing that they’re in a particular area or building to knowing that they’ve passed a specific point. “Te wider issue, though, concerns how this information
can be best used in different situations and integrated with other applications to really add value to the technology. One recent example of this was a project that we did for Dong Energy, Denmark’s largest power generator, who wanted to maximize the safety of their lone workers [picture overleaf].
Issue 3 May 2011 TE TRA TODAY “Not only did we implement standard lone worker
features such as the requirement for regular ten-minute terminal activations by the employee and automatic alerts in the event of no response, but we also added on a number of enhancements to improve both safety and performance. Tese included integrating technical alarms coming from SCADA systems to go directly to the right workers’ radios based on their position and status; alarms warning workers if they go outside the range of the network; the opening of the appropriate outer gates to allow emergency access; and finally, automatic switch-off of lone worker status when they come into areas defined as safe – such as control rooms.”
Tagged with RFID Tere are also obviously many situations where it is not necessary to know the exact location of every employee. In this context, RFID also has a role to play in terms of automatically checking people in and out of particular hazardous zones. Zonith, along with the Austrian wireless tracking specialist Identec Solutions, has implemented just such a system in a road tunnel construction project in Stockholm. With TETRA being used for on-site communications,
25
GPS can be pocket- sized – but so can eLORAN. Picture at top shows MILOR, a miniature integrated eLORAN position- finding module developed by Roke Manor Research. The smartphone is included for size comparison
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44