Brief Survey on ADS-B and Small Drones


I've got a brief 10-question survey which seeks to get your opinions about ADS-B solutions for small drones.

The technology for tracking small unmanned aircraft systems (UAS) has advanced rapidly in the past few years.  New and disparate solutions all claim great promise.  Many of these solutions are based on automatic dependent surveillance-broadcast (ADS–B), a cooperative surveillance technology in which an aircraft determines its position via satellite navigation and periodically broadcasts it, enabling it to be tracked by ground control station. ADS-B signals can also be received by other aircraft to provide situational awareness and allow self-separation.

But is it the right solution for small UAS (under 55 lbs.) operating in low-altitude class G airspace?

When its done I'll post the results back here in a new post.  Thanks much! - Colin

Take survey here:

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  • Thanks everyone for your comments and discussion.  It's been very helpful.  

    The full report is still WIP, but I've published preliminary results in this SlideShare presentation:

  • Exactly. A quite effective setup could look like this:

    • Onboard device: a smartphone.
    • The smartphone has a permanent connection with a relay server on the ground which could "capture and aggregate" drone traffic not only for a single drone but for many of them.
    • Theoreticaly there could be one global provider in the cloud, which collects any ongoing drone movement in realtime. This provider then could maintain a network of local ADS-B transmitters, which feed the information back into the air (like e.g. Flightradar24 maintains a global network of ADS-B receivers).
    • If enough pilots join, rather moderate fees might be enough to keep the stuff running.

    Before my inner eye I could see a system architecture which at least in part already exists in my project FlightZoomer. See my post on the diydrons main page or under this link:

  • The solutions should be found in smart phone technology, which technology is refreshed every six months and cost a fraction due to high volumes of sales. ADS-B is expensive, bulky and not really suitable for a fast evolving technology market like sUAS
  • Moderator

    P.S. - At the altitude he flies at, I have about 20-40 seconds from when I hear him until he is right on top of me. Now, I text my friend anytime I want to fly in one of their service areas, and he lets me know if they are flying that day. 

  • Moderator

    Just a quick first-hand experience: 

    I started looking into keeping an aircraft radio and setting up ADS-B after a rotarwing crop duster flew between myself and an RC airplane. He was flying around 150ft AGL and heading back to a field after refueling, I found out later.

    I called a guy I know that works for the company and told him that I was flying at 350ft, telem log shows 622ft from home and it was high visibility in all directions. I said "I didn't even hear him until he came over the top of some trees. What do I need to get to avoid that situation? An aircraft radio and ADS-B?" He told me that the pilot has nothing with him when he flies, cell phone included, because he thinks all of it is a distraction. 

    Pilot didn't even see the plane, and my friend said there is literally no way to communicate with him in-flight. 

  • Gary, The regulation for US registered aircraft to be ADS-B equipped by 2020 ONLY applies to airspace that already requires a mode C transponder.  This is only classes A, B, and C airspace (we should not be operating UAVs in B or C surface areas anyway).  Aircraft operating in other airspace, D, E or G have no such requirement.  The traffic that can be seen via ADS-B IN is severely limited unless the aircraft is registered for and broadcasting ADS-B OUT signals.  Depending on a $20 dongle for ADS-B IN information can be very misleading unless we are confident of seeing 100% of potential conflicts.


    Open Glider Network - Open Glider Network Project
  • Hi,

    There is a study by ONERA to integrate FLARM on UAVs. It is a low cost solution, mandatory on all gliders in France and widely used in Europe.


  • Lol Gary.

    I'm sure we all have some stories to share over a drink! ;-)

    I agree on the problem with trying to integrate legacy systems.

    I've proposed this elsewhere here on the forum as well, and that is the other "contentious" issue with airspace is the "airwaves" that is locked up in "analog mentality" and regulation that is outdated in the digital age of data packets n Co. This would remove the "clutter" as you say from a lot more industries that exhibit monopoly traits and stifle development.

    I think a much better solution would be to have a non-centralized mesh network to relay relevant information between users that are in proximity. That way all participants also help maintain coverage and infrastructure, with mesh routing this also increases system capacity as more users come in range, which in turn reduces cost, provides resilience to outages and disruptions, security against localized and systemic manipulation, and allows for both incremental and substantial improvements to be made over time without significant hardware updates etc. With packet routing done this way there's even the possibly to expand ADS-B with telemetry, comms channels, data relay and even aircraft inter-net-connectivity with the ground. A type of swarming hive of inter-dependent nodes. For lack of a better term: A "smart sky".

    But maybe I've just been watching too many Star Trek episodes about the Borg? ;-)



    I think that the ADS-B system will need to be implemented on the UAV itself so that it can operate even on loss of comms with the ground station. The ADS-B "out" system could be potentially integrated on the base station (e.g. via 3G), but I can see issues arising through the mis-use of low cot ADS-B transponders to disrupt traffic without some sort or verification.

    I'd also expect that an air based system won't experience as much signal loss through ground proximity and obstacles, and having the transmitter in the air at altitude would more than compensate for the reduction in signal strength due to the UAV size, weight and power constraints. The objective of ADS-B out is to inform other airspace users, preferably at range, which typically means line of sight to the receiver from the transmitter (at around 1GHz), so I'd imagine an airborne solution will always be favorable to a ground one. ADS-B output ranges from 7-40W, but have fairly short transmission cycles around 0.03%, so power use isn't that bad anyway and can be achieved on the UAV, provided the TX equipment is compact. I'd say about 1Wh of battery per 30 minutes of flight should cover it.

    The other thing is that UAV ADS-B out would only be required to manage airspace safety, so even a few kilometers of range should suffice for avoidance. The UAV is both low speed and low altitude and therefore out of "range" of manned airspace users that also use the ADS-B for inflight course corrections, should other aircraft, that could be approaching at super sonic speeds not adhere to their flight plan or airspace control. For example: two commercial aircraft flying head on is an approach at 500m/s(!) So you'd want at least 30sec or 15km RF range up there with the big boys! Airline with UAV interaction on approach or departure at low altitude will be nearly one order of magnitude slower by comparison, so the range can safely be less to maintain enough reaction time, which means a low powered UAV mounted system will suffice.

  • Moderator

    I did'nt know that particular chap, just some of the shift workers at Heathrow that dealt with it. I do know some other stories that may or may not have involved me and as such best heard over a beer ;-) Perhaps going out of fashion, primary radio contacts as well. When I worked in North Devon we had a spot in the hills where vans would appear painted on the radar, that is to say the radar picked up vehicles driving on high ground. RAF Lyneham had the railway line between Bristol and London marked as east west primary traffic would pop up on that. So having ADSB could well help remove the clutter. I see no sense in rushing to integrate last years tech with old fashioned transponders. All the N numbers being generated in the USA have suitable ICAO identifiers.

    With the 333 system the FAA now have more than 1000 operators they can turn to for trials.

    @Andrew, something like that is already in hand.

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