Sense and Avoid Explained

With the recent addition of ADSB support in Mission Planner and the discussion about feeding data from a drone into a 'national feed' there has been much excitement about the possibilities in the future.

This video is a great explanation about the challenges we face with sense and avoid using existing technology and then also goes into some exciting research that the author Bruce Simpson is working on involving passive radar technology.

Bruce has been in the UAV game for a long time and while I am not affiliated with him in any way, his material and youtube reviews are very interesting.

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  • I dunno whether his difficulties with the authorities are anything to do with what he is working on or the way he deals with things.
    By all accounts Bruce has a good heart and the right intentions but is a fairly polarising person. People either love him or he rubs them up the wrong way and that can make life very difficult.
  • I am no technician but his passive spherical radar that uses the electrosmog for tracking objects seems to be a task for the sensors and the mainframe of the ncc 1701 enterprise. Since he is in constant fight with some authorities to let him fly at "his" airfield again it seems to be reasonable to suspect that his "secret invention" has a more political than technical background.

  • While ADS-B will be mandated in the US for many aircraft in 2020, this does not mean all aircraft in US airspace will be equipped.  It will only required for aircraft certified with electrical systems flying in Class A, B, C airspace and Class E airspace above 10,000 ft within the continental US.  Gliders, balloons, paragliders, ultralights (US equivalent of microlights), other aircraft without electrical systems (Piper Cubs and the like), agricultural aircraft, etc., will be flying under various exemptions from the requirement for the foreseeable future.  

    Very few aircraft that are exempt will be equipped, due to cost and installation issues.  The FAA is now requiring that all ADS-B installations in certified aircraft be done under a Supplemental Type Certificate, a requirement that imposes additional costs.  In reality, an operational ADS-B installation currently costs $10000 to $20000, if you can get it installed at all (as there are many aircraft that don't have, and never will have, the necessary STC).

    In other words, at least in the US, ADS-B is not considered a "collision avoidance system" for regulatory purposes, and can't be a solution to the "sense and avoid" problem, now, or in the near future.  The sad part is that the FAA could have taken a number of steps to make it possible to equip all US aircraft with ADS-B out at significantly lower cost (meaning ~$2000/aircraft or less), but by applying the same requirements to VFR-only aircraft as those that are IFR-capable, they essentially killed any chance of that ever happening.

  • I've been told (industry hear-say and rumours) that the future of collision avoidance is ADS-B for all aircraft. That's why TCAS has been stopped at version 7.1. But I really do think it's still a long way off.

  • Moderator

    Well it really depends where you are, I have flown hot air balloons, helicopters and gliders in the UK below 1000' with a mode S transponder. Its coming. Back when this site started flying straight and level with rudder guided turns was the order of the day. Commercial APs that could do that started at $5k if you wanted a GPS don't ask below $10k

    You can do all that and more for less than $200 now.

    I can foresee a time where hobby full sized pilots have to justify their reason for flight amongst unmanned platforms doing work for cash money. As 100LL disappears many of those 50s airframes just won't justify the cost of many mods required. Taking out dated electronics out of the picture.

    If enough money comes into play we will see who ends up getting easier airspace access.

    For sure if you are a full sized pilot the maps on mission pilot are more than crude and the ADSB does not show every aircraft but the process has started. To paraphrase Pulp lets all meet up in the year 2019 (five years was the gap between their song and 2000) and see where we are then. One thing is almost certain there will be no commercial sUAS ops in the USA.

    Frightening thought of the day we have members that were born when this came out and they will soon be twenty. That can't be right. 

    Aviation Gasoline – About Aviation Gasoline
  • The problem with using ADS-B on MAVs is that most aircraft with ADS-B equipped transponders fly well above 10000ft, and most MAVs fly well below that. I think until ADS-B is mandatory for all aircraft, it's really nothing more than a gimmick.

  • I always enjoy Bruce's videos, and he is working on a solution to a very real problem, even if it is not open source.

  • Moderator

    There are fantastic very small very light vision based systems out there. In many ways this is a little cart before the horse as in many places you are still gong to need at least an ATPL to fly BLOS for many years to come.

  • An entertaining video with an amusing presenter who gets a few things wrong (transponders don't use GPS, unless they are ADS-B out enabled).  After 30 minutes, he finally gets around to his solution, which involves a secret sauce he won't reveal.  A waste of time, if you have spent any time looking into this subject...

  • There's certainly a lot of hope that every RC pilot is going to wait the 45 seconds required for their uBlox to get a lock before flying & their uBlox is going to be fully functional.  Depending on the stock market, hope can be good enough. 

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