On Tuesday, January 19, 2021 at 10:53:27 PM UTC-8, Ramy wrote:
I assume TIS-B is not available in Europe otherwise wouldn’t it be beneficial also in Europe to rebroadcast non ADS-B transponder equipped aircraft like gliders? Or in Europe there are no exceptions so all gliders have ADS-B? Otherwise there is an advantage to the US TIS-B as we can now see most gliders which are only equipped with transponders.

Yo Ramy

(I know I'm not going to do this justice in one paragraph, but here goes). A glider type exemption for ADS-B does not really apply. European mandatory ADS-B Out carriage mandates have been more focused on IFR traffic and larger aircraft. Europe has had a different approach than the USA. It's favored what I'd see as a more structured methodical move to Mode-S and ADS-B/1090ES Out. If everybody, or at least folks in busy airspace eventually end up with ADS-B Out you maybe don't need TIS-B. But Europe has also dragged their feet in some areas. All that complex infrastructure to rebroadcast SSR as TIS-B is a significant undertaking and extra complex when you have multiple nations involved. And EUROCONTROL and SESAR and all the collaborating nations have had other priorities. TIS-B for example does not directly help increase controlled airspace utilization/density of airline flights, and wether right or wrong the airline requirements drive much of the planning in Europe, as they also did in the USA. But in the USA TIS-B (and FIS-B and continuation of Mode-C transponder use) was sold by the FAA in part to appease the GA political lobby and seen as an inducement to get folks to folks to adopt ADS-B Out... which will then enable it's use in NEXTGEN to help the airlines. I'm not sure all that political appeasement actually resulted in the best overall system. EUROCONTROL member nations prioritized adoption of Mode-S and Mode-S enhanced surveleice (Google it) to help increase airline safety and density while the USA went with "Mode-S lite" and skipped to a dual link ADS-B system.

TIS-B has been played with by European researchers so folks there sure understand the technology. Some of the Thales (currently 1090ES) ADS-B ground stations deployed in Europe should be very UAT Out/FIS-B compatible. Currently it looks like SESAR (kind of the European version of Mitre Corp.) is looking at a FIS-B like system maybe combined with some TIS-B like capability (I've not kept up) using entirely different (cellular?) frequency bands and aimed at portable devices in GA aircraft. There is a long running differences between the USA and Europe around other data uplink approaches/standards so don't expect everybody to agree on this stuff :-) (but I'd hope Europe looks hard at FIS-B over UAT).

If the future includes a lot of drones/UAVs then surveillance and traffic awareness for them may cause challenges here, all these existing systems were just not designed for that and it's going to need to affect what happens in future.

Ramy
On Thursday, January 14, 2021 at 6:12:27 AM UTC-8, Urban Mäder wrote:
On Thursday, January 14, 2021 at 8:23:00 AM UTC+1, wrote:
Moshe,

Only TIS-B has position uncertainty from the imprecision of SSR, which varies with the distance from the radar station. Both ADS-R and TIS-B have some position error from delay introduced by the reception-processing-rebroadcast sequence. ADS-B is not designed for close proximity collision warning - it's more a traffic separation tool - 5 miles and 1000 feet. I believe you can get ADS-R/TIS-B traffic alerts at, say, 1 mile, depending on on your display.
Yes. We will try enabling traffic alerts for ADS-R, but I'm a bit reluctant since correctly detecting tow trains may be hard, given the (uncertain) time delay.

Honestly, the dual-ADS-B setup in the US - of which ADS-R/TIS-B is the consequence - is a surprisingly complex beast. We're thus happy to hear your feedback, preferably with IGC log files sent along to .

Thanks
- Urban