To borrow a title from a former chancellor of our alma mater; in this post we'll provide a paraphrased history of the project from inception to the present day.
Intro and early days
Getting straight into it - the idea for the project came from a conversation between Tom M & Tom A at a friends' wedding in 2014 - thanks Andy and Michelle!
During the project we've been very fortunate to be invited to the Natural History Museum to give a talk and have a stand at a couple of events. One of the questions that comes up most often is "what company or university are you at?" We're not. The project is simply a very enjoyable hobby. We want to help further bat conservation it's a great way that we can assist with this using our respective skills. Tom A is our bat expert (and is now a qualified and competent drone pilot) and Tom M is our drone designer, builder and operator.
We think this goes to show that if people are willing, you don't need the support of a big research grant or institution to push boundaries. Our advice is to "give it a go and see where it takes you".
We knew that quadcopters produced a lot of sound but didn't know how much of this was ultrasound. Our first tests showed us that it was a considerable amount. This ultrasonic interference has been a running theme through the project. The problem lies in the signal to noise ratio of the bat call. If there is too much noise from the drone we won't be able to 'hear' the bat call.
This meant that we had to separate the drone and the detector recording the bat calls by about five meters. The highly technical application of a piece of string was employed though this wasn't without it's problems as you can see in the video below.
The problem of the oscillation arose due to the high weight of the detector. We were glad we used a water bottle of the same weight as the detector in testing! The detector and recorder weighed about a third of the quadcopter mass. This led to loss of control and meant and it wasn't an option in this configuration.
In going back to the drawing board we wanted something that produced less noise and could comfortably fly with the payload of the detector. The obvious choice for us was to move to a plane; it had the added bonus of being able to fly for longer too (about 8 mins for the quad and 25 for the plane).
Way back when (in September 2014) during the initial phases of our project we were aware that flying a drone might have some legal implications so we took some care to search through the specific legislation (from the CAA, mostly Air Navigation Orders) and find out what we needed to do to stay within the law. You can check out the post here.
I (Tom A) recently gained my Permission for Aerial Work, this is the qualification you need to undertake commercial drone work in the UK. So we wanted to document the steps someone would need to take to use our bat-drone commercially in the UK, should we create a working platform.
Please note that 'commercially' in this case also refers to research undertaken by universities. The following also only applies in the United Kingdom.
Civil Aviation Publication (CAP) 393 is the legislation that covers drones and it stipulates that:
"The person in charge of a small unmanned aircraft must not fly the aircraft for the purposes of aerial work except in accordance with a permission granted by the CAA"
'Aerial work' here means commercial work in the broad sense, including exchange of services or a crate of beer for example!
The 'permission' that is mentioned is granted by the CAA after an individual has undergone training and in this way is similar to a license.
To get this we must:
This is a fairly significant investment, totaling approximately £1500 but would be required before you could do any commercial activities or get insurance.
A 'Permission for Aerial Work' is not required if the activity is not commercial. For example if you were just flying a bat drone around for fun you would be allowed to do so as long as you kept within the law:
The CAA have actually released a number of simple steps called the 'Dronecode' which give you a handy reference for what you should and shouldn't be doing with your drone. You can check it out here:
If you did want to use a bat drone commercially and did not want to get the qualification yourself then the alternative is to hire someone else to do it for you.
The legalities around flying UAVs in the UK seem to be pretty complex but Tom M did a good job of finding out the important points for our project:
Its a bit of a shame we can't fly the UAV out of sight as using autopilot we could have done some nice long transects. That said I can understand why this is the law.