Roke Manor Ltd

GPS is easy to jam with off-the-shelf technology. An alternative, called MILOR, promises to succeed where GPS fails, and it could launch commercially as soon as next year.

It's hard to discuss GPS these days without using the word "ubiquitous". Satellite navigation directs supertankers, airliners and minicabs. It takes hikers to the most distant peaks, and the rest of us to the nearest pizza. It tracks valuable cargoes and stolen cars, and guides emergency services to accident scenes. But GPS can fail; it stops working in some places, and it's vulnerable to interference. Now a British company has come up with the solution: a navigation system that works where GPS fails. It's a case of back to the future using a technology dating back to WWII.

GPS does not extend everywhere. There are dead zones where it's blocked by tall buildings, and it won't work indoors, in tunnels or in underground car parks. But the biggest threat to GPS is interference. For example, it recently emerged that the 40,000 transmitters of LightSquared's new satellite broadband in the US may interfere with GPS reception. Solar activity can also affect GPS. And deliberate jamming is also a growing problem, with the ready availability of GPS jammers for as little as £20 on the internet. White Van Man uses them to stop the boss from tracing his movements; thieves use them to foil anti-theft GPS tracking devices.

"We believe there are an increasing a number of cases where jammers have been used by thieves to prevent stolen vehicles being tracked," says Simon Atkinson, Business Sector Manager at Roke Manor Ltd.
The GPS signal is very weak, the equivalent of a car headlight over ten thousand miles away. A portable half-watt jammer is powerful enough to overwhelm the GPS signal to every device within its line of sight. This is why New Jersey airport's approach system kept going down last year. The GPS-based system was being knocked out by a trucker who regularly used the New Jersey Turnpike, because he had a jammer to fool the GPS road toll. It took months to catch him.
This vulnerability is causing concern in the navigation community. GPS jamming, accidental or deliberate, could cause all sorts of problems. As well as the obvious applications, it is increasingly used in agriculture, and the construction and manufacturing industries for automatically routing deliveries and controlling stock. GPS tags are used to warn if Alzheimer's patients wander out of designated areas, and to keep tabs on offenders.

There is an alternative to GPS, known as LORAN, which was first set up by the military to guide ships and aircraft during WWII. It has been widely used by merchant shipping for decades, and was the standard for navigation before GPS. LORAN uses ground-based radio beacons that are far more powerful than GPS satellite transmitters, and broadcast on a much longer wavelength. This makes LORAN virtually impossible to jam. Performance is similar to GPS, with an accuracy of about 20 metres. The big issue is that the LORAN receivers used on ships are bulky and expensive.
"A traditional LORAN receiver is usually about the size of a cycle helmet," says Atkinson. "The cost can run to thousands of pounds."

The answer is Roke Manor's miniature LORAN receiver, called MILOR. This is tiny by comparison, barely larger than a matchbox. Atkinson says that when it is produced in bulk the pricing will be suitable for consumer applications.

Roke Manor will not reveal how they have achieved this feat of miniaturisation. However, they do have a long track record in advanced communications and radar systems, and clearly their expertise is applicable to LORAN receivers.
MILOR also includes an integrated GPS receiver, and switches seamlessly between GPS and LORAN depending on availability, without the user having to touch it.
"GPS is great when you can get it," says Atkinson. "When you can't, for example inside buildings or car parks, you can always use LORAN."


  1. This really sounds very interesting. It is true that there are lots of dead zones for GPS and if this story about MILOR becomes true - I`m in line! :-)Carla  

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