How to down a drone…
February 11, 2010
“If you’ve done nothing wrong… you have nothing to fear.”
This year a UK Home Office backed coalition of regional Police Authorities will embark on a project to extend their national surveillance network by deploying unmanned airborne surveillance drones across the country. It’s planned that in the build up to 2012 the drones will be used to foil potential terrorist attacks, detect illegal immigration planning to cross the channel (by flying over France?), monitor anti-social behaviour and public order situations (demonstrations) and of course to gather intelligence on subversive activities.
The introduction of these drones represents a significant expansion of the surveillance state, planned and delivered by un-democratic consortium of police authorities and loosely regulated by vague and rarely tested laws. With this expansion of the surveillance state should come an equal counter-response probing the legal and practical boundaries of surveillance:
What methods can be used to disrupt or destroy drone technology?
The drones come in a number of flavours; the ‘military derived’ Afghanistan tested fixed wing HERTI drone from BAE Systems, the much smaller and less serious looking rotor driven Hicam Microdrone and the rumoured Lindstrand Technologies GA22 airship unmanned inflatable drone. the drones are usually equipped with remote cameras but have already been tested to carry loudspeakers, LRAD audio technology and weaponry such as Tasers and Flash-ball guns (as demonstrated by Tecknisolar Seni in France).
BAE HERTI Specification
- Payload: 150 kg
- Length: 5m
- Wingspan: 12 m
- Loaded weight: 750 kg
- Powerplant: Rotax propeller,
- Cruise speed: 125 knots
- Service ceiling: 20,000 ft
The first of the drones to be tested this year (in Liverpool – a strange choice considering the local’s aversion to aerial surveillance) is the ‘Hicam Microdrone MD4-1000‘ essentially an expensive (£30,000) rotor powered radio controlled helicopter equipped with night vision surveillance cameras and loudspeakers. The microdrone can take video images from a 500m distance and can track and follow human movement using movement capture technology. The drone is small; less than 1m diameter and 2lbs in weight, they can fly along a pre-programmed GPS route or be controlled ‘live’ by an individual (mobile) police controller viewing the camera’s output through head mounted lcd goggles.
Hicam Microdrone MD4-1000 technical Specification:
- Rotor blades: Four 37cm (15ins) carbon fibre blades mounted on ends of lightweight arms
- Antenna: Picks up signal from remote control handset and transmits images to controller
- Camera: Operates at up to 500m (1,640ft), with option for infra red images
- Central drum: Houses GPS system, which can be used to fly drone, a rechargable battery and other key electronics
- Remote control: Used to fly the drone and operate the camera
- Video glasses: Allow ‘pilot’ to see what is being filmed and to operate the drone when out of direct sight
- Weight: Under 900g (2lbs)
- Size: 70cm (28ins) across
- Flying time: Over 20 minutes
- Noise: Less than 65 decibels at 3m
- Take off: Vertical
Microdrone base station
- 2.4 GHz 4-fold antenna diversity receiver,
- Internal power supply, Inputs: 230/115VAC, 12/14.8VDC, LiPo Charger and true single cell balancer,
- USB video grabber, Video splitter 3x out, Downlink decoder for receiving the complete machine state (Battery, Receiver quality, RC-signals, Attitude, Altitude, GPS-position, Flight time etc.).
- Base station software “mdCockpit”,
- 1.4 Megapixel video eyeglasses, LIPO batteries 4s, 14.8V, 2300mAh included (same as flightpacks for md4-200) Peli case (fits into system case), Dimensions 486 x 392 x 192mm
Anti Drone Tactics:
The ‘insurgents’ in Iraq and Afghanistan have had some success in shooting down large fast flying US military drones – similar to the BAU Herti – using small arms fire; AK47s etc (currently unavailable at Maplins), so the slower moving Microdrones should be easy prey to automatic weapons fire – the obvious problem is that such weapons are illegal (in the UK) and not exactly subtle when used in a ‘public order’ environment.
For taking out Microdrones a (slightly) more legal option might be a paint ball gun which fires large calibre low velocity paint capsules that will blind as well as damage the target. Paint ball guns have the advantage of being legal and commonly available but again, probably not the best choice for riots and demonstrations. For these occasions, the simple hand held catapult firing a range of improvised ammunition should do the job though surreptitiously hitting a moving 1m sized target at a range of, say, 100 metres may require a little target practise…and may take a few shots as the drone can still fly with only two of its four rotors functioning.
Jamming the control and navigation signals should be an effective way of disabling the drones – jammers work within a fixed range radius rather than having to be targeted and have the added benefit of being non-destructive – allowing the capture and re-use of the confused drone…
Radio Control Frequency
The Microdrone uses the same radio control method as model RC aircraft to direct it’s flighpath. The exact frequency used by the police probably falls within the UK frequency regulations for RC aircraft otherwise RC frequencies can easily be scanned and jammed using RF jammers for selected frequencies or more crudely saturate the whole spectrum.
Build your own RF Jammer:
“If you want to saturate the bandwidth, you use an analog device with simple FM modulation. Eight 2.4Ghz wireless video transmitters of sufficient power would do it.”
The Hicam Microdrones navigate using standard GPS, which is particularly sensitive to jamming. There are a number of portable GPS jammers on the market or for a few quid you can build your own…
US authorities were alarmed when they discovered that the Taliban have been using Russian authored Sky Grabber software to intercept drone video signals:
“SkyGrabber is a hobby for person who accepting free to air satellite data by digital satellite TV tuner card from satellite provider. SkyGrabber is for fun.”
An important aspect of intercepting drone signals will be to use the footage against the police or is support of legal defence.
Other Anti-Drone ideas – please add your own!:
Focussed microwave beam
A standard domestic microwave could be focussed using a parabolic dish to direct the beam on a single source capable of destroying and disrupting circuity in cameras and motors. Downside is, mistakes could be dangerous or fatal…
Equip a common-or-garden toy RC helicopter with an attachable line that locks to a target drone. Once attached, pull the police drone down by hand…
Sources and Links:
RF Jammer instructions: http://www.instructables.com/id/RF-Jammer/
RF Jammer devices : http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXHKB1&P=0
‘Idrone’ a French UAV http://www.idrone.fr/
‘Technisolar’ French solar powered drone technology: http://www.tecknisolar.com/2/7/military-and-civil-security/drone-research-and-development.html
hacking via Sky grabber http://blog.taragana.com/index.php/archive/us-drones-hacked-via-skygrabber/