Just to avoid any confusion, I want to make it clear that this blog ('Police drone') has nothing to do with the forthcoming world tour by the rock band The Police (Wikipedia), but rather the forthcoming trial of an unmanned air vehicle (UAV) by the Merseyside Police force in the UK for "tackling anti-social behaviour and public disorder" ( 'Pilotless police drone takes off', BBC News).
The BBC News story, and a related article 'Police spy in the sky fuels 'Big Brother' fears' (The Telegraph) focus on the use of the technology in reducing crime, and also the increasing use of surveillance in society, which is a somewhat controversial issue in the UK at the moment as it has the most CCTV cameras of any European country.
However, my primary interest was in the technical aspects of the microdrones UAV and its operational parameters – it weighs less than 1 kilogram, uses carbon fibre rotor blades and can fly at altitudes of up to 500m (1640ft). It can carry CCTV or night vision cameras a which can stream images to a police ground vehicle, and it can be fitted with on-board GPS navigation systems.
This is an impressive technical achievement, but I have a number of safety concerns about the use of these small UAVs operating in a densely populated urban environment, specifically:
- Can we be sure the ground pilot will always have line of sight visibility to the UAV? In an urban environment, the ground-based pilot's
field of view could be obscured by tall buildings, which could have consequences in terms of an aerial collision or a ground collision, possibly involving people.
- When flying by pre-programmed GPS navigation, how will the UAV perform 'see and avoid' of other aerial vehicles, and also terrain collision avoidance? Are the control systems safety certified? How can we be sure that it won't wander into the flight path of other aircraft operating in the vicinity (e.g police helicopters), or with civil aircraft taking
off from on on landing approach to Liverpool airport.
Although the UAV does
not weigh much, a collision with helicopter rotors or an aircraft jet
engine could cause considerable damage – even a Canada goose colliding with a passenger jet can cause cabin depressurisation: Photo 1, Photo 2 (Aviation Safety).
The UK distributor is reported in the Telegraph article as saying the microdrones UAV is not subject to UK CAA regulations because it is "a toy". I am not reassured by this rather sweeping statement, especially in the light of the SkySeer UAV crash (IET) last year, which was operated by the Los Angeles
Police Department Sheriff's Department (LASD) without FAA approval.
I'm aware that the situation was quite complex as there is a diverse range of air vehicles
from model aircraft, through UAVs to manned aircraft, and there are also
the different types of airspace to consider. So, I thought I'd do a bit of research, and fortunately, there is plenty of relevant information on policy and guidelines on the CAA website. In particular, 'CAP 658 – Model Aircraft: A Guide to Safe Flying', 'CAP 722 – Unmanned Aerial Vehicles Operation in UK Airspace' and 'UK CAA Policy for Light UAV Systems' (PDF).
On reading CAP 658, I noticed that the definition of model aircraft only applies to those used "for sporting and recreational purposes…", so the use of a UAV for law enforcement activities doesn't appear to fit this definition.
However, the Light UAV System definition seems more appropriate in this case, and here the CAA guidelines clearly state: "Operational constraints include line-of-sight operation at a range not exceeding 500 metres from the UAV-pilot, and at a height not exceeding 400ft above ground level".
So this would seem to place at least some constraints on the operation of the drone, but are they sufficient alone?
Well, now having droned on (if you'll excuse the pun) about safety, I don't have any space left in this blog to discuss security issues (control link security/interference, data link encryption, etc.), so maybe I'll just mention that the control frequencies are published on the microdrone website? Discuss.