Drone journalists beware wreckers abound, GPS Jamming
I rather like the idea of Cornishmen waiting on misty cliffs for drones to land at their feet.
The implications for disrupted GPS signal’s to small drones might be a little more serious if the craft are being operated in built up areas. GPS jamming
equipment might become standard issue for local Police forces for use during demonstrations or to befuddle any location based action. They are not hard to find, 30 seconds of GoogleFu and you will discover them. Search a little longer and all manner of devices capable of jamming video downlinks and even command and control frequencies are available.
Its for these reasons that the World Radio Council is working on frequency standards for unmanned aviation systems. Until they are all in place and everyone is using them civil use sUAS in town might be put on hold.
Paul Marks from The New Scientist
GPS jamming: a clear and present reality
A secret network of 20 roadside listening stations across the UK has confirmed that criminals are attempting to jam GPS signals on a regular basis, a conference at the National Physical Laboratory, in London, will hear later today. Set up by the government’s Technology Strategy Board (TSB) and run by Chronos Technology of the Forest of Dean, UK, the Sentinel network has sensed an average of ten jamming incidents per month since September 2011, according to Chronos chief Charles Curry.
One way around this issue is to listen out for all three satellite guidance systems currently circling the earth.
The American GPS, Russian GLONASS and shortly European Galileo.
A solution already exhists Septentrio released in 2010 a receiver capable of hearing all three. 
Providing simultaneous access to legacy and modernized GPS, GLONASS, and Galileo signals on L1, L2, L5, E5a, E5b, and E5 AltBOC, AsteRx3 is a compact and future-proof original equipment manufacture (OEM) receiver on the market, the company said. The receiver has a range of features, collectively known as GNSS+ . ATrack+, Septentrio’s patented Galileo AltBOC tracking, provides low noise tracking and multipath resistance for Galileo’s most advanced signal. LOCK+ tracking guarantees tracking stability under high vibration conditions.
Beyond that though slowly gaining ground in small unmanned systems is vision based navigation.
Multicopters are successfully mapping and navigating their environments indoors and a few are even venturing into the great outdoors. Some flying wings are avoiding objects in their path unknown to them before they take off. That would allow very low level ingress without the need the for detailed flight planning.
Hovering platforms can ignore GPS all together if a camera is pointed down from the craft and its position kept relative to the bit of ground it sees. This is how the Parrot AR.drone keeps station without a GPS.
Further to that postion realtive to a know start point, much like INS where you punched your location into a flight computer that simply then counted how along up and across you moved from that position is also happening.
The evidence that active GPS jamming is happening in Englandshire will no doubt push developers of systems for civil use to create more robust navigation solutions.
Drones with decent eyesight will be the talk of 2014.
