On Friday, January 30, 2015 at 8:00:10 PM UTC-8, George Haeh wrote:
In Europe, Garrecht sells an ADS-B receiver that can also provide Classic
Flarm GPS data to a Mode S transponder for 680 Euros.

http://www.butterfly-store.de/en/TRX...eceiver,i4.htm

PowerFlarm already receives ADS-B and Mode C/S; so all that's needed is
filtering out the non-GPS data from the PF or other GPS feeds such as
advanced varios: Air Glide, CNV, LX.

The Europeans are waaaaay ahead on this.

If you peruse the Trig TT-2x Transponder Installation manual, you will
find configuration parameters for stuff such as wingspan, fuselage length,
location on airframe etc.

It's all great for ensuring wingtips don't snag some other airframe on
adjacent taxiways and aprons at major airports. 3m accuracy or better gets
critical in this case.

Once airborne 50m accuracy from the little guys would be just fine for the
heavy stuff that doesn't want to come within half a mile of any of us.

It's a real surprise to see the FAA's head firmly stuck in the sand while
the Europeans are producing solutions that will work for GA.

I think I've got pretty good grasp on the technology here and I'm having trouble following what you are talking about.

The exact same capability as in the TRX 1090 is already included in the PowerFLARM (with 1090ES receiver).

PowerFlarm already receives ADS-B and Mode C/S; so all that's needed is
filtering out the non-GPS data from the PF or other GPS feeds such as
advanced varios: Air Glide, CNV, LX.

This sentence makes no technical sense, maybe you mistyped something. Filtering out non-GPS data from the PowerFLARM? For what? If all you want is a GPS output as good as PowerFLARM or simmilar devices you can do that for a pretty low component cost. Getting that COTS GPS signal is not the issue, the issue is whether you can use that signal to transmit a ADS-B signal. You cannot do so in the USA in a certified aircraft. And any aircraft you did it in would not meet the 2020 ADS-B Out carriage mandate.

Europe is ahead of the USA? I'd rather look at it as so far Europe has not done some of the particularly stupid things the FAA has done like making ADS-B dual-link, but in other ways Europe is further behind the USA, e.g. there is no European mandate for ADS-B adoption in light/GA aircraft and I hope when it eventually happens it is a lot more sensible than the roll out in the USA.

I'm not sure where 50m accuracy number comes from, but the FAA would tell you their concerns about positional accuracy of a non TSO GPS has worse case concerns greater than this. Its a much more complex discussion, but yes there is a place in this space for a non TSO/IFR GPS receiver, and that is directly acknowledged by TSO-C199, so I'd say the FAA's head is not entirely stuck in the ground, they've looked at this exactly, worked with vendors experienced with COTS GPS technology and this new TSO is the result.

All this ADS-B stuff is largely futureware, not something most pilots should get over-excited about, if you fly gliders in the USA and are worried about fast jets and airliners (and GA aircraft) install a transponder, worried about gliders install a PowerFLARM.