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Old 7th Jan 2019, 08:18
  #1142 (permalink)  
Join Date: Aug 2007
Location: Devon
Age: 61
Posts: 6
Originally Posted by alexgreyhead View Post
So, has anybody given an indication of how these systems work? Their level of reliability in doing so? And are they effective against drones which are operating on a pre-programmed GPS-based route?

To the latter point, the limited discussion from other internet commentators* is that it's neither likely nor wise to try and interfere with GPS signals to jam drones in the vicinity of airports for the entirely reasonable reason that there would be unintended consequences for legitimate traffic.

* Naturally I have no idea how qualified they are to comment...

I'm concerned that the public proclamations of having drone defenses at airports is at least partly using the same psychology that TV license detector vans employ - i.e. a significant amount of bluff and bluster...

From my perspective - GNSS Security Technologist these days, ex aircraft dispatcher once upon a time, you raise some good points. I worry about the idea of pointing a GPS jammer towards a moving drone with no real idea of how jamming GPS is likely to affect the drone (if at all), no idea of whether GPS jamming will affect others nearby, (directing RF isn't as easy as pointing a [email protected] beam, the cone of RF energy is likely to be much larger), or how those nearby users are using GPS - any other safety critical systems being used for precise time or positioning applications?
In a webinar on GPS jamming I participated in 3 years ago, I shared the platform with a US Sheriff who used drones - we were asked about deploying GPS jammers to incapacitate drones - the Sheriff said " why would I tackle one risk by adding several others?" - he meant the collateral caused by interfering with GPS signals and agreed with me that it was a plain bad idea. Of course the other idea that goes around is the idea of spoofing GPS signals - this is what some people think happened to the US drone brought down in Iran - and the University of Texas have also demonstrated how to "take over" a GPS equipped drone using spoofing. But you really need the drone to be hovering in a stationary position for this to work, again, you are going to affect other nearby systems (probably) and there is absolutely no guarantee that the drone will be affected at all.

For me personally, the idea of someone using a powerful GNSS jammer or spoofer gun, moving it around erratically to try and bring down a moving drone in the vicinity of other legitimate systems that depend critically on GPS position or timing data just doesn't sound like a sensible idea unless the potential consequences are known - I spend a lot of my time helping people test systems and devices in order to make them more robust against real-world jamming and spoofing events - we really don't want to be deploying jammers or spoofers deliberately without a full risk assessment being carried out (perhaps this could be part of obtaining an exemption to use one of these devices near an airport?)
Using Geo-fencing is also often talked about as being a potential solution, this means that whilst GPS is being used by a drone, it is prohibited in flying in restricted areas. Another nice idea except for - what are the defined restricted areas, can they be updated - and there are also devices for some of the drones with these geo-fenced systems that can be programmed to apply a set of co-ordinate offsets - this is very easy to do - and the devices are cleverly marketed as being for users who need to film or carry out ostensible activities in a geo-fenced area...

I can't post a link yet but for those of you interested in a good assessment of drone defences there was an excellent presentation at DEFCON 25 which is well worth watching - if you google "DEFCON 25 game of drones" you'll find it. If anyone finds it useful, please feel free to add the link
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