Can ADS-B provide position information for Search and Rescue?

On Friday, February 17, 2017 at 8:41:59 AM UTC-8, wrote:
The Air Avionics TRX products look like they will be filling the gap to provide ADS-B in capability for traffic in a glider friendly way. They also have models with FLARM TX and RX so you can have both if you want. I agree with your premise entirely that a transponder with ADS-B out is the proper way to go. FLARM is just a stopgap, and not a particularly good one at that. We need to participate in the airspace system as peers with everyone else if we want to expect to be treated as peers.

The TRX product is essentially what is built into every PowerFLARM in the USA.

So can you explain what gap exists and how the TRX fills it?

"ADS-B out is the proper way to go." Proper for what? Proper for avoiding other gliders in busy glider locations, no, absolutely not. Proper in busy airspace with airliners, fast jets, GA traffic, sure. But the critical starting point there is *transponder*, especially vs. airliner and fast jet traffic. If that'a a concern get a transponder in the glider ASAP. ADS-B is secondary and can be worried about later.

On Friday, February 17, 2017 at 8:19:58 AM UTC-8, wrote:
I believe it's worthwhile for an experimental glider to transmit adsb-out, even if only using an uncertified gps, because it will make your glider show up more accurately on Flarm receivers even if you don't carry flarm yourself (adsb-out targets show up on flarm with exact location and altitude). You should also show up for equipped power aircraft even if out of ATC radar contact.

The main reason to pay for a certified gps to send adsb-out would be if you also plan to install adsb-in and a traffic display. I still don't see a low-cost low-power adsb-in system for a glider, although I'm sure they will come. The FlightBox adsb-in device appears to draw 1.3A at 5V, ie probably 0.7A at 12V, which would be too much for my glider battery. Also, I would want a sunlight-readable display (I don't find iphones etc to be sunlight readable).

I don't plan to install flarm in my glider, because I think transponder+adsb will soon be the better choice.

Better choice? For what? You not planning to fly much with other gliders?

---

One wrinkle to be aware of is certified ADS-B In systems will *not* see your traffic at all if it is using a non-certified/non-compliant ADS-B source. They are as anal-retentive as the FAA ADS-B ground infrastructure (or rather last year the FAA made the ground infrastructure deliberately as anal-retentive as the airborne certified ADS-B In systems to discourage use of non-compliant GPS sources partially to help force better compatibility with those certified airborne ADS-B In systems).

So folks who have an experimental glider sure they can hook up any old GPS source say to a Trig transponder, and it will show up on PowerFLARM and non-certified ADS-B In systems. But really not a good idea, probably not a good idea to talk about without being clear on the limitations, especially now there is a Trig TN72 GPS is suitable for use in experimental gliders and does not have those limitations (Lots of discussion on the TN72 on other threads on r.a.s.). But if folks have an experiential glider with a Trig transponder and want ADS-B Out the TN72 is really now likely the minimum they should be thinking of.

Trig says the TN72 ($359) and TA70 antenna ($345) will start shipping second quarter of this year. Because I usually fly in busy airspace near New York City, and I rarely fly competitions or with a dozen other gliders, I'm leaning toward this rather than Powerflarm.

My partners and I have just installed an ADS-B out system in our Grumman Cheetah -- a Garmin GTX 335 transponder with associated WAAS antenna. For ADS-B in we are experimenting with an SDR (software defined radio) USB dongle connected to an 8" android tablet running the free Avare app. Avare requires the addition of a second app, Avare ADS-B Pro, which tunes the SDR allowing you to toggle between 1090 and 978 and has a hefty $2.99 price tag. The SDR dongle with included antenna set us back $15. That's the total cost. It appears to work remarkably well.

It seems like this simple, ridiculously affordable system could work well in a glider using a smaller tablet or phone for a display. However, I don't relish the idea of another screen in the cockpit in addition to my Oudie. I wrote to Naviter to see if they would contemplate software for the Oudie that would allow it to display TIS-B and FIS-B, but haven't heard back....

Are there currently any glider flight computer programs that will display TIS-B?

One wrinkle to be aware of is certified ADS-B In systems will *not* see your traffic at all if it is using a non-certified/non-compliant ADS-B source. They are as anal-retentive as the FAA ADS-B ground infrastructure (or rather last year the FAA made the ground infrastructure deliberately as anal-retentive as the airborne certified ADS-B In systems to discourage use of non-compliant GPS sources partially to help force better compatibility with those certified airborne ADS-B In systems).

So folks who have an experimental glider sure they can hook up any old GPS source say to a Trig transponder, and it will show up on PowerFLARM and non-certified ADS-B In systems. But really not a good idea, probably not a good idea to talk about without being clear on the limitations, especially now there is a Trig TN72 GPS is suitable for use in experimental gliders and does not have those limitations (Lots of discussion on the TN72 on other threads on r.a.s.). But if folks have an experiential glider with a Trig transponder and want ADS-B Out the TN72 is really now likely the minimum they should be thinking of.


Daryl, maybe I misunderstood....I had read that an adsb target using an uncertified gps would not be considered a 'client' by ATC, but I assumed the location of an uncertified-adsb target would still be included in data broadcast by ATC to client aircraft. I would have thought the transponder alone would have justified inclusion.

Also, would an uncertified-adsb target be detected by a certified-adsb receiver via direct (air-to-air) transmission, and at what approximate range?

Thanks for any help.

Any further information on using "not certified, but meets the
standards" so that I can install a TN72 and TA70 in my Stemme?

On 2/17/2017 9:44 PM, Paul Villinski wrote:
Trig says the TN72 ($359) and TA70 antenna ($345) will start shipping second quarter of this year. Because I usually fly in busy airspace near New York City, and I rarely fly competitions or with a dozen other gliders, I'm leaning toward this rather than Powerflarm.

My partners and I have just installed an ADS-B out system in our Grumman Cheetah -- a Garmin GTX 335 transponder with associated WAAS antenna. For ADS-B in we are experimenting with an SDR (software defined radio) USB dongle connected to an 8" android tablet running the free Avare app. Avare requires the addition of a second app, Avare ADS-B Pro, which tunes the SDR allowing you to toggle between 1090 and 978 and has a hefty $2.99 price tag. The SDR dongle with included antenna set us back $15. That's the total cost. It appears to work remarkably well.

It seems like this simple, ridiculously affordable system could work well in a glider using a smaller tablet or phone for a display. However, I don't relish the idea of another screen in the cockpit in addition to my Oudie. I wrote to Naviter to see if they would contemplate software for the Oudie that would allow it to display TIS-B and FIS-B, but haven't heard back....

Are there currently any glider flight computer programs that will display TIS-B?

--
Dan, 5J

Are there currently any glider flight computer programs that will display TIS-B?

Assuming you are a fully participating ADSB-out client, TIS-B would be 978Mhz AND 1090es relayed for you. (I think so anyway, in terminal radar environments.)

In that case, either Powerflarm or something like the cheaper $300 TRX-1000 would be able to receive 1090es and feed a common FLARM compatible glider display. Beware though - you would not receive air-air UAT data directly.

If you really need to receive UAT or TIS-B on 978Mhz, you'd need a different receiver. I have read posts on the Stratux ADSB receiver github page about a sw version that emits FLARM formatted strings. This could be connected to LXnav or Oudie, etc. through a USB-to-serial adapter. A bit too experimental for me quite yet.

--Sarah


On Friday, February 17, 2017 at 10:44:40 PM UTC-6, Paul Villinski wrote:
Trig says the TN72 ($359) and TA70 antenna ($345) will start shipping second quarter of this year. Because I usually fly in busy airspace near New York City, and I rarely fly competitions or with a dozen other gliders, I'm leaning toward this rather than Powerflarm.

My partners and I have just installed an ADS-B out system in our Grumman Cheetah -- a Garmin GTX 335 transponder with associated WAAS antenna. For ADS-B in we are experimenting with an SDR (software defined radio) USB dongle connected to an 8" android tablet running the free Avare app. Avare requires the addition of a second app, Avare ADS-B Pro, which tunes the SDR allowing you to toggle between 1090 and 978 and has a hefty $2.99 price tag. The SDR dongle with included antenna set us back $15. That's the total cost. It appears to work remarkably well.

It seems like this simple, ridiculously affordable system could work well in a glider using a smaller tablet or phone for a display. However, I don't relish the idea of another screen in the cockpit in addition to my Oudie. I wrote to Naviter to see if they would contemplate software for the Oudie that would allow it to display TIS-B and FIS-B, but haven't heard back....

Are there currently any glider flight computer programs that will display TIS-B?

On Tuesday, February 14, 2017 at 10:30:57 PM UTC-5, Paul Villinski wrote:
Wondering if ADS-B equipped aircraft have any advantage should they
need search and rescue, given that they broadcast their ID and coordinates.

1) ADS-B ground stations logging data would need to receive ADS-B down
to near ground level to get close to the crash site. A glider can travel
a long distance from the altitudes mentioned as ground-station receive
floor in this thread.

2) FLARM can assist in SAR (and has done a number of times). This requires
other gliders flying in FLARM-range of the crash, otherwise the search
area will not be narrowed to a helpful size. And the FLARM log files need
to be promptly recovered from gliders in the area and forwarded to FLARM
for analysis.

On Saturday, February 18, 2017 at 2:15:12 AM UTC-8, wrote:

One wrinkle to be aware of is certified ADS-B In systems will *not* see your traffic at all if it is using a non-certified/non-compliant ADS-B source. They are as anal-retentive as the FAA ADS-B ground infrastructure (or rather last year the FAA made the ground infrastructure deliberately as anal-retentive as the airborne certified ADS-B In systems to discourage use of non-compliant GPS sources partially to help force better compatibility with those certified airborne ADS-B In systems).

So folks who have an experimental glider sure they can hook up any old GPS source say to a Trig transponder, and it will show up on PowerFLARM and non-certified ADS-B In systems. But really not a good idea, probably not a good idea to talk about without being clear on the limitations, especially now there is a Trig TN72 GPS is suitable for use in experimental gliders and does not have those limitations (Lots of discussion on the TN72 on other threads on r.a.s.). But if folks have an experiential glider with a Trig transponder and want ADS-B Out the TN72 is really now likely the minimum they should be thinking of.


Daryl, maybe I misunderstood....I had read that an adsb target using an uncertified gps would not be considered a 'client' by ATC, but I assumed the location of an uncertified-adsb target would still be included in data broadcast by ATC to client aircraft. I would have thought the transponder alone would have justified inclusion.


A transponder alone will make you a TIS-B target for client aircraft. As long as you are within both SSR and ADS-B ground system coverage. The SSR coverage there is the gotcha, e.g. no coverage at many gliderports and airport pattern areas or say down low on ridges where there might be lots of glider traffic. And TIS-B is so imprecise and has other issues it's of little use compared to Flarm for glider-glider traffic avoidance.

I believe non-compliant GPS (e.g. TSO-C145c or meets performance requirements of, or TSO-C199) will *not* make you a ADS-R target, and even TSO-C199 may not get you on ATC traffic displays (but again if within SSR coverage ATC will see you via that).

Also, would an uncertified-adsb target be detected by a certified-adsb receiver via direct (air-to-air) transmission, and at what approximate range?

Absolutely not. A *certified* ADS-B In receiver will not display non-complaint ADS-B Out equipped aircraft via ADS-B direct. It will run right into that target with no warning at all. If the aircraft is also equipped with TCAD/PCAS and the target aircraft has a transponder then that system would provide traffic display and TA and (for TCAS-II) RA alerts.

The bottom line is probably just don't mess with non-compliant GPS sources, they will not provide the results that most glider pilots will just expect.. The TN72 (esp. with a Trig transponder) should be the minimum goal to use in experimental gliders today if you want to do ADS-B Out. As folks actually get those systems installed it would be great to hear their experiences and costs. Unfortunately certified gliders currently require installation of a full TSO-C145c certified GPS source, with costs that are non-starters for most owners. I would be nice to see TSO-C199/TABS installation and use regulations that allowed for installation of a TN72 type ADS-B Out GPS sources in certified gliders.

All this mess is part of why PowerFLARM for glider-glider traffic awareness is a popular choice. And its PCAS and 1090ES In helps provide some inbound traffic coverage.

For awareness to other traffic and ATC, especially airliners and fast jets, the humble transponder (Mode-C or Mode-S) is very very effective. In busy traffic areas get a transponder like a Trig TT-22 that you will be able to upgrade to ADS-B Out in future, hopefully as costs fall and regulations improve. In really busy traffic areas please don't put off installing and using a transponder while waiting for ADS-B future toys.

Thanks for any help.

No problem.

As folks get ADS-B Out stuff installed and working, please share your experiences with others.

On Saturday, February 18, 2017 at 9:26:19 AM UTC-8, Sarah wrote:
Are there currently any glider flight computer programs that will display TIS-B?

Assuming you are a fully participating ADSB-out client, TIS-B would be 978Mhz AND 1090es relayed for you. (I think so anyway, in terminal radar environments.)

That's not guaranteed. What ADS-B link layer TIS-B is broadcast for a client aircraft on depends on the capability code (CC) data transmitted by the target aircraft. All aircraft with ADS-B Out need to have those CC bits set correctly to match their ADS-B In capabilities.

In that case, either Powerflarm or something like the cheaper $300 TRX-1000 would be able to receive 1090es and feed a common FLARM compatible glider display. Beware though - you would not receive air-air UAT data directly.

No. Unfortunately this is not correct.

The PowerFLARM does not understand how to process a TIS-B (or ADS-R) message. The European unregulated ADS-B environment that PowerFLARM were developed for is the cause of this limitation. I suspect the TRX-1000 has the same limitation. This is an important limitation that pilots need to be aware of, and why I and others have mentioned in on r.a.s. so many times.

If you really need to receive UAT or TIS-B on 978Mhz, you'd need a different receiver. I have read posts on the Stratux ADSB receiver github page about a sw version that emits FLARM formatted strings. This could be connected to LXnav or Oudie, etc. through a USB-to-serial adapter. A bit too experimental for me quite yet.

The most flexible/effective ADS-B In traffic system especially for gliders would use dual-link ADS-B In. Much better than relying on ADS-R and all it's limitations. Unfortunately there is no system that does this today and is compatible with typical glider cockpit systems (e.g. supports Flarm serial dataport protocol to transmit traffic data to a display device)

The Stratux for FLARM protocol stuff was really people tinkering with ideas and I don't think it went anywhere.

--Sarah

In that case, either Powerflarm or something like the cheaper $300 TRX-1000 would be able to receive 1090es and feed a common FLARM compatible glider display. Beware though - you would not receive air-air UAT data directly.

No. Unfortunately this is not correct.

The PowerFLARM does not understand how to process a TIS-B (or ADS-R) message.

Ah, too bad. I did not know TIS-B messages are not properly decoded by Powerflarm. PF must then only correctly parse air-air 1090es squawks. Thanks for the clarification.

On a related question, if someone were to connect an uncertified GPS source to a 1090es transponder, with the intention of appearing on others PF displays.... how often would the transponder send this data? Only when interrogated (ie never, out of Radar coverage/TCAS ping range) or often, for each GPS position string? If the latter, this may have power consumption implications.

The Stratux for FLARM protocol stuff was really people tinkering with ideas and I don't think it went anywhere.

Well it appeared to 'work for them', but I agree... it's too experimental for me yet.


On Saturday, February 18, 2017 at 12:56:10 PM UTC-6, Darryl Ramm wrote:
On Saturday, February 18, 2017 at 9:26:19 AM UTC-8, Sarah wrote:
Are there currently any glider flight computer programs that will display TIS-B?

Assuming you are a fully participating ADSB-out client, TIS-B would be 978Mhz AND 1090es relayed for you. (I think so anyway, in terminal radar environments.)

That's not guaranteed. What ADS-B link layer TIS-B is broadcast for a client aircraft on depends on the capability code (CC) data transmitted by the target aircraft. All aircraft with ADS-B Out need to have those CC bits set correctly to match their ADS-B In capabilities.

In that case, either Powerflarm or something like the cheaper $300 TRX-1000 would be able to receive 1090es and feed a common FLARM compatible glider display. Beware though - you would not receive air-air UAT data directly.

No. Unfortunately this is not correct.

The PowerFLARM does not understand how to process a TIS-B (or ADS-R) message. The European unregulated ADS-B environment that PowerFLARM were developed for is the cause of this limitation. I suspect the TRX-1000 has the same limitation. This is an important limitation that pilots need to be aware of, and why I and others have mentioned in on r.a.s. so many times.

If you really need to receive UAT or TIS-B on 978Mhz, you'd need a different receiver. I have read posts on the Stratux ADSB receiver github page about a sw version that emits FLARM formatted strings. This could be connected to LXnav or Oudie, etc. through a USB-to-serial adapter. A bit too experimental for me quite yet.

The most flexible/effective ADS-B In traffic system especially for gliders would use dual-link ADS-B In. Much better than relying on ADS-R and all it's limitations. Unfortunately there is no system that does this today and is compatible with typical glider cockpit systems (e.g. supports Flarm serial dataport protocol to transmit traffic data to a display device)

The Stratux for FLARM protocol stuff was really people tinkering with ideas and I don't think it went anywhere.

--Sarah