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.

I have no problem with the small fee (a few tows) to compensate for the trouble and expense to deliver this US-only functionality. It's a significantly complex task to integrate these new target types - at less than a 10% upcharge on the core unit. Keep in mind that they had to do this from a country that doesn't have these services so all the testing and refinement of the code had to be done based on a remote unit installed at my house overlooking SFO followed by flight testing 7 time zones away with emailed flight logs and pilot reports - no direct hands-on. They didn't have to do it at all - the US is a small segment of the total global soaring market for Flarm. I'm glad they did. It works well.

If you get a Fusion it's all included. That might be the preferred choice if you don't like the feature unbundling.

Andy Blackburn
9B


On Wednesday, January 13, 2021 at 3:26:55 PM UTC-8, Moshe Braner wrote:
On 1/13/2021 3:53 PM, MNLou wrote:
I can't say that I'm happy that they choose to charge for this pretty important upgrade.

Lou

Right. It's just a software change, like other firmware updates. And
it enhances safety. Charging (149 euros) for activating the feature
means a lot of people will skip it, and ADS-R "targets" will remain
invisible. And those UAT "targets" are generally small airplanes who
share our altitudes. It's one thing to charge extra for non-safety
bonus features (such as IGC approved logging) and another to cut into
the basic collision avoidance purpose of the device.

Question: the lack of collision warnings due to low accuracy fix, does
that apply to ADS-R or only to TIS-B? You'd think the position of
airplanes transmitting GPS coordinates on UAT is precisely known, just
like those transmitting on 1090? Only airplanes whose position is only
derived from ground RADAR would be imprecise.