ADS-B for tracking antenna?

[Photons]

As a hobby UAS/UAV pilot who sees the incredible commercial potential for our flying robots, I think it is important for our community to work to create regulations rather than hide from them.

Keeping a safe airspace is in all of our interests, and to that end, ADS-B (http://www.faa.gov/about/office_org/headquarters_offices/ato/service_units/enroute/surveillance_broadcast/) seems like a perfect solution to me. Properly implemented, a system like this should allow us to coexist in the airspace without the burden of flight plans. We would also benefit from the increased situational awareness afforded by this system, as many ground based hazards such as bridges, antenna, buildings, etc. will broadcast their position to this system as well.

I think that all good aircraft engineers try to make every component on the craft do more than one thing if possible. With that in mind, we can use the ADS-B for purposes other than just boring old safety. Ground station antenna tracking and lost craft location are two important secondary uses that come to mind. I know that incorporating another Tx on our vehicles seems like a pain in the *ss, but we can figure this out.

I have had some very positive discussions with the staff of my Congressman (John Salazar) and the Sheriff's Department in my county. Everyone sees the incredible applications for flying robots and remote sensing, and they WILL become a normal part of our world. We just need to remember that bureaucrats are not innovators, we are the innovators and it is up to us to find the solutions.

Does anyone have an opinion on the ADS-B system, or the idea of using it to drive a ground station tracking antenna?

[Disciple4123]

Educate us, does it transmit it's GPS position and altitude for other aircraft to map out? I think it is practical to do that, sure, then comes cost, weight, and RF interference to other systems on the UAV. Being ignorant of ADS-B function, I cannot speculate all the ramifications.

[carguy84]

Some info:
http://en.wikipedia.org/wiki/ADS-B

[Photons]

Educate us, does it transmit it's GPS position and altitude for other aircraft to map out? I think it is practical to do that, sure, then comes cost, weight, and RF interference to other systems on the UAV. Being ignorant of ADS-B function, I cannot speculate all the ramifications.

Yes, it broadcasts position(lat,lon,alt), vector(speed,direction), and Identification, plus other info if needed. Check out the link to the FAA page for all the details. All of these broadcasts are put into a real time database that provides an image of the airspace.

[Gary Mortimer]

I don't know much about ADS-B but would'nt a mode S transponder be the international solution?? Or is it one in the same??

[Photons]

I don't know much about ADS-B but would'nt a mode S transponder be the international solution?? Or is it one in the same??

Yes and yes, basically. My understanding is that Europe (http://www.eurocontrol.int/cascade/public/subsite_homepage/homepage.html) is committed to this system.

The end goal with this is to reduce the demand on air traffic control and have a "free flight" system that gives every craft in the air the ability to see what is in the air with them.

The high cost and power needs of the transponders used in full scale craft can be avoided in my opinion. This could be dependent on the weight and performance envelope of the UAV. If we are operating a couple of kilogram craft a few hundred meters AGL, then a very low power transmit only (1090mhz) unit would be fine. Enough power to get back to our ground station. The ground station can relay the broadcast at a higher level if needed, and Rx info from the other craft in the area. The only other component needed on the craft is a GPS Rx, and that is something we all want anyway.

Just to clarify, a transponder usually receives an interrogation and then responds to it. The Automatic Dependent Surveillance- Broadcast is automatic in that it sends out a broadcast without being interrogated, and is dependent on each craft to know it's position and show itself.

[patrickegan]

ADS-B would be great for sUAS, but the cost for a certified system is deemed expensive by the manned community.

[Photons]

ADS-B would be great for sUAS, but the cost for a certified system is deemed expensive by the manned community.

This technology is really simple, I'm confident that the costs will fall to meet our demand. Check out the pdf here (http://www.mitre.org/work/tech_papers/tech_papers_08/07_0634/) .

[Photons]

For many UAS missions it might not even be necessary to broadcast from the craft at all. If one were doing commercial photography or photojournalism within a small radius of the ground station, then it should be adequate to broadcast ADS-B from the ground station only. In addition, the exact position of the craft might not need to be broadcast, instead, a max radius and altitude of operation would be broadcast. Everyone else on the system would know that an UAS is operating in that cylinder of air space and could act accordingly.

I've read about people being surprised by military aircraft flying low and fast, this system would allow military and air ambulance craft the ability to broadcast an electronic "siren" ahead of them to us at our ground stations. This would give us enough of a heads up to get our craft out of their way with no drama.