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05 May 17. The Battle For Drone Tracking Technology. There has been a lot of discussion in the past couple of years about just what the right technology is for tracking the swarms of drones coming our way in the next decade. Because uAvionix is a communications, navigation, and surveillance (CNS) company focused almost solely in the drone industry – we are wrapped right up in the middle of the debate.
There are a lot of opinions on the subject, for sure – and like many debates in this day an age – you tend to hear a lot of negatives as to why this technology or that one won’t work:
“If ADS-B were on every drone the whole National Airspace System would crash…”
“Do you really want to trust your navigation to LTE? What would happen if the call gets dropped?”
But behind all of that naysaying is a common core concept that is agreed to almost so universally that it isn’t really debated at all – that drones DO need to be tracked and identified electronically.
There is a fundamental agreement that drones will need to be “cooperative” – to borrow a term from manned aviation. A cooperative aircraft has a transponder onboard (either Mode A/C/S or ADS-B) that allows the aircraft to be seen by other aircraft or Air Traffic Control (ATC).
In the drone industry – the debate is really on what that “transponder” should be. For the rest of this article, I’ll try to articulate the four primary options being discussed and the pros and cons of each. And here is a little foreshadowing – they serve different purposes and aren’t really in all-out competition at all. I’m going to rank-order these from highest to lowest Technology Readiness Level (TRL) for the specific application we’re discussing here.
ADS-B derives its strength from its inherent compatibility with a large and growing population of manned aircraft worldwide. ADS-B is an international standard and is being adopted across the globe for the specific purpose of surveillance and see and avoid functionality. For Detect and Avoid (DAA) applications, drones need to be able to detect nearby manned aircraft – and this is easily done if the manned aircraft have ADS-B on board. But almost more importantly, ADS-B has the ability to allow the manned aircraft to electronically “see” the drone – right in their cockpit – with equipment they already have. ADS-B’s TRL is highest among the choices because it was designed for aviation, is an existing standard, and is in widespread and ever increasing use, and through the efforts of uAvionix – is now an affordable and size appropriate solution for drones.
The arguments against ADS-B are focused on both spectral capacity and pilot or ATC “overload” associated with too much information on cockpit or ATC displays. We’ve addressed both of these arguments pretty specifically in a previous article – but to summarize – we envision a 3 step approach to prevent those concerns from happening:
1. Reduce the number of drones with ADS-B. It is unrealistic to consider a mandate for every drone to carry ADS-B. It is much more realistic however to consider a mandate for drones that are conducting risky operations – flights over people, BVLOS, or even near airports or in controlled airspace.
2. Reduce the transmit power. The biggest impact to solving the potential spectral problem is by drastically lowering the power output of the transceivers – which directly correlates to the range of how far the signal can be “heard.” The power standards that exist today were determined for manned aviation for the purpose of communicating with the ATC system over long distances (100-200 miles or more). If the primary focus for drones is to alert only nearby aircraft – this power can be significantly reduced. A recent study by MITRE’s Center for Advanced Aviation System Development (CAASD) conf