Will the SV-GPS-250 demostrate ADSB performance?

[Carl_Froehlich]

I spent a couple of hours this week listening to the FAA ADSB program manager go over where we are on the road to 2020 compliance. Filtering though all the regulatory double speak one aspect jumped way up above the noise level - the recent ADSB compliance technical revision. Specifically that the FAA now says the ADSB out source need not meet TSO requirements, just demonstrate performance.

I'm looking for an update from Dynon - are you all on the road to demonstrate the SV-GPS-250 receiver meets ADSB out performance requirements?

While I'm currently using the GTN-650 for ADSB out, I like the next project to be ADSB compliant without the need for this $10,000 overpriced box.

Carl

 

[dynonsupport]

Discussed here when the rule "change" came out:

http://dynonavionics.com/cgi-bin/yabb2/YaBB.pl?num=1423512001

and here:

http://www.vansairforce.com/community/showthread.php?t=122582

 

[Carl_Froehlich]

Thanks - but I've read those threads before and they do not answer my question.

Yes or no, is Dynon working toward demonstrating the SV-GPS-250 meets the ADSB performance requirements?

If Dynon wishes to explore options and be non-committal, just say so. It seems to me however that having a soup to nuts SkyView ADSB offering would fill a huge market hole.

The 2020 ADSB compliance date will be a train wreck. I also hear rumor that next year the FAA will turn off ADSB traffic feeds to anyone not fully compliant (as in a non-compliant GPS source). This adds urgency to creating solutions other than grossly overpriced Garmin GPS boxes.

Carl

 

[dynonsupport]

Carl,
Realize the FAR says "Must meet the performance requirements of the TSO." So it does, in fact need to meet the TSO in some ways.

We are non-committal on what our solution will be. The FAA is currently in the process of issuing guidance on exactly what the performance requirements of the TSO are (there's no section titled "performance requirements") and until that's cleared up, there's no way for us to be sure of what the most affordable solution will be.

 

[dorante]

I was at the same ADS-B presentation by the FAA Rep. What worries me most is that he stated there is a pending rule/implementation that will prevent ATC from report my ADS-B OUT aircraft as traffic to other aircraft since it has non-compliant Dynon GPS source. I will be able to see other compliant aircraft, but they won't see me. He stated that he expect this to be implemented next year. This is a great decrease in safety.

 

[KRviator]

I was at the same ADS-B presentation by the FAA Rep.  What worries me most is that he stated there is a pending rule/implementation that will prevent ATC from report my ADS-B OUT aircraft as traffic to other aircraft since it has non-compliant Dynon GPS source.  I will be able to see other compliant aircraft, but they won't see me.  He stated that he expect this to be implemented next year.  This is a great decrease in safety. 

I disagree. What assurance do you have that your transmitted position is accurate? That US flyers can output an unproven GPS position for ADS-B doesn't sit well with me, and obviously the FAA feels the same way now. If you are wanting to use ADS-B for separation, you should be using a certified - or otherwise proven accurate - position source.

 

[swatson999]

I was at the same ADS-B presentation by the FAA Rep.  What worries me most is that he stated there is a pending rule/implementation that will prevent ATC from report my ADS-B OUT aircraft as traffic to other aircraft since it has non-compliant Dynon GPS source.  I will be able to see other compliant aircraft, but they won't see me.  He stated that he expect this to be implemented next year.  This is a great decrease in safety. 

I disagree. What assurance do you have that your transmitted position is accurate? That US flyers can output an unproven GPS position for ADS-B doesn't sit well with me, and obviously the FAA feels the same way now. If you are wanting to use ADS-B for separation, you should be using a certified - or otherwise proven accurate - position source.

Are aircraft flying IFR being given separation by ATC based on ADS-B at this time?

 

[KRviator]

I'm pretty sure Australian ADS-B equipped aircraft are using it for separation, and, like it or not, if ATC calls traffic based on an ADS-B report, then yes, it is a defacto form of separation and you have a right to expect it to be demonstrably accurate no matter where you are.

 

[jakej]

As I understand it ATC here will not & are not able to give separation (via ADSB) unless the ADSB OUT is done with a Tso 145/146 'box', any other Gps is useless in that case.  ALL IFR aircraft here will have to be compliant in Feb 2017 with the Tso 145/146 system.

The AOPA (Australia) homepage has a link to ADSB info.

Jake J

 

[gtae07]

I'm pretty sure Australian ADS-B equipped aircraft are using it for separation, and, like it or not, if ATC calls traffic based on an ADS-B report, then yes, it is a defacto form of separation and you have a right to expect it to be demonstrably accurate no matter where you are.

Yes, if ATC is providing separation based on ADS-B, then you want the data to be "accurate"... but do we really need to go through an entire certification process (which the TSO effectively is) to demonstrate that this GPS source is more reliable than perhaps every other system on the entire airplane, in order to provide separation to/from aircraft operating VFR? Pretty much any GPS, certified or not, will give better and more reliable information than the current radar/transponder system. Shouldn't that be good enough for VFR traffic? Why do I need a position source reliable enough to guide airliners to 200ft in IMC, just to be able to fly under Atlanta's class B in a VFR-only RV?

That's my beef with this, more so than certified vs. experimental aircraft... why do VFR aircraft need to meet IFR standards?

For IFR I understand wanting/needing an even more more reliable position source, but those aircraft are increasingly likely to be fitted with some form of approach-capable GPS that the ADS-B could piggyback off of.

 

[jakej]

Agree completely however there is a solution for VFR which has been on the go for a while & will apply here in OZ as well     http://www.icao.int/APAC/Meetings/2015%20ADSBSITF14/SP08b_FAA%20TABS%20briefing.pdf   or google TSO-C199 


Jake J

 

[dynonsupport]

In the USA, C199 does not let you into rule airspace, so no Class B, C, or above 10K feet. It just wakes up ground stations so you can get traffic info when you are outside of rule airspace. Because of this, it's hard to justify an investment in developing a product like that for the US market.

 

[KRviator]

I'm pretty sure Australian ADS-B equipped aircraft are using it for separation, and, like it or not, if ATC calls traffic based on an ADS-B report, then yes, it is a defacto form of separation and you have a right to expect it to be demonstrably accurate no matter where you are.

Yes, if ATC is providing separation based on ADS-B, then you want the data to be "accurate"... but do we really need to go through an entire certification process (which the TSO effectively is) to demonstrate that this GPS source is more reliable than perhaps every other system on the entire airplane, in order to provide separation to/from aircraft operating VFR?  Pretty much any GPS, certified or not, will give better and more reliable information than the current radar/transponder system.  Shouldn't that be good enough for VFR traffic?  Why do I need a position source reliable enough to guide airliners to 200ft in IMC, just to be able to fly under Atlanta's class B in a VFR-only RV?

That's my beef with this, more so than certified vs. experimental aircraft... why do VFR aircraft need to meet IFR standards?

For IFR I understand wanting/needing an even more more reliable position source, but those aircraft are increasingly likely to be fitted with some form of approach-capable GPS that the ADS-B could piggyback off of.

The question then becomes, why did you equip your VFR-only aircraft with ADS-B?

If you want to use ADS-B's capabilities, not just the TIS-B component, then you need to provide accurate position info, so others who do need to use it, can.

Just because the GPS is usually pretty good, does not mean a VFR GPS, or even a C129 GPS is good enough for ADS-B, hence the requirement to use a TSO'd C145/6 GPS, that has FD&E capabilities, to make sure you cannot output an incorrect position. Bad data is worse than no data at all, and that is why the authorities are taking this line, and I for one fully agree with it.

 

[dynonsupport]

Kevin,
In the USA, all aircraft that want to operate in, under, or above Class B/C or above 10K feet have to have ADS-B. Doesn't matter if they are VFR or IFR. If you're IFR outside of those areas you don't need ADS-B either.

Dynon does believe the rule is a bit too aggressive. The GPS performance required (in both reliability and accuracy) is about 10X more accurate than radar currently gives ATC which is used for separation. Requiring this for aircraft which are VFR, and by definition rely on visual separation, seems like an unneeded burden. Given the ADS-B system allows multiple levels of integrity to be transmitted, it would be possible for the FAA to allow a lower integrity level for VFR aircraft, while still maintaining an equivalent level of safety to today's radar based systems, and then require the higher integrity for aircraft that are using ADS-B for separation.

Additionally, radar is not going away in Class B/C areas, so there is a backup, and in fact the FAA is using Radar to help identify ADS-B systems that are not performing properly.

In reality, the IFR aircraft don't have an issue- you can use your IFR GPS navigator for the ADS-B position at no additional cost, so everyone uses that. It's the VFR aircraft that are experiencing a cost burden from ADS-B, yet they are the ones that need it the least and also benefit other aircraft the least.

But- The rule is the rule and we're doing our best at Dynon to come out with an affordable, industry leading solution that is fully compliant with the USA rules.

 

[lolachampcar]

Thanks - but I've read those threads before and they do not answer my question.

Yes or no, is Dynon working toward demonstrating the SV-GPS-250 meets the ADSB performance requirements?

If Dynon wishes to explore options and be non-committal, just say so.  It seems to me however that having a soup to nuts SkyView ADSB offering would fill a huge market hole.

The 2020 ADSB compliance date will be a train wreck.  I also hear rumor that next year the FAA will turn off ADSB traffic feeds to anyone not fully compliant (as in a non-compliant GPS source).  This adds urgency to creating solutions other than grossly overpriced Garmin GPS boxes.

Carl

Carl,
I appreciate your desire for clean crisp clear information on this subject but I think you need to keep in mind that we are dealing with the FAA.  Decisions are not made on the logic/science involved but more on the politics of who is involved.  Most of the entities driving the process to this point have had mostly financial motivations.  It is only when we start to creep up on the mandate date that we, the people, are getting involved.

As it has been explained to me, proving that you meet the TSO standard is complying with the standard (the way the FAA is doing this).  There are full nav. packages already in existence in larger aircraft that "meet the spec." by complying with a more stringent specification.  I think it is these sources that were meant to be wrapped into the ADSB-Out mandate, not Dynon puck type products.

To meet the spec., apparently the GPS code base must be TSO compliant.  I've been told that no masked die GPS engines (the silicon based DSP that does the calculations) have TSO'd code but it would be logical to think that they will if there is sufficient demand.  The mandate should provide that demand.  A second problem will be getting TSO compliance with electronics that exist encapsulated with the antenna as is currently the case with the puck.  It may be that we will be stuck with a separate GPS receiver and TSO'd antenna for some time which keeps costs high.

Lastly, there is what I call the antenna to antenna requirement.  Basically, the FAA learned that not all 100% TSO'd hardware solutions provide mandate compliant installations.  Work must be done to prove that the compilation of hardware meets the performance requirements.  Dynon is working on that as last I heard.  Hopefully their efforts will yield a "use one of these GPS units hooked up this way and installed in this manner and you have a mandate compliant system" result.  This is really what we need at this point while we wait for more cost effective GPS sources.

I do not blame Dynon for not getting into the TSO'd GPS market.  There are too many other companies out there who have sunk costs in TSO'd firmware.  Dynon would need to re-create that wheel which is not much of a value add for the effort it would take. I would prefer to see them direct their efforts on more "Dynon" like products where they tend to knock it out of the park.

Bill

 

[gtae07]

The question then becomes, why did you equip your VFR-only aircraft with ADS-B? 

just to be able to fly under Atlanta's class B in a VFR-only RV?

"Just don't fly there" isn't an option for everyone at airports within a Mode-C veil.  After 2020, the moment the airplane leaves the ground, they will be in ADSB-Out compliant airspace.  That includes the airplane in question--Dad's VFR-only RV-6--which is based at one such airport.  My RV will be a frequent visitor there once completed, and will therefore also require a TSO'ed installation (or equivalent).

I'd wager that a significant fraction (if not the majority) of light airplanes in the US are based at airports within Mode C veils.  Most of them are probably never operated IFR, and a fair number probably never talk to ATC at all.  But all of them will be affected by the 2020 mandate. 

If you want to use ADS-B's capabilities, not just the TIS-B component, then you need to provide accurate position info, so others who do need to use it, can.

Just because the GPS is usually pretty good, does not mean a VFR GPS, or even a C129 GPS is good enough for ADS-B, hence the requirement to use a TSO'd C145/6 GPS, that has FD&E capabilities, to make sure you cannot output an incorrect position. Bad data is worse than no data at all, and that is why the authorities are taking this line, and I for one fully agree with it.

If I'm mixing it up with airliners (say, passing through Class B on my way somewhere else), I can kind of see that.  It certainly makes sense for IFR.  But when I'm not--when I'm outside the Class B, operating VFR, I don't understand why I still need to be reporting my position to within a wingspan, with a reliability that exceeds anything else on that airplane, especially when the the current half-mile (or more!) inaccuracy of current terminal radars is considered good enough today.  Are there really that many near-misses between airliners in Class B and light airplanes outside it to justify this increase in accuracy?  Or is it just a solution in search of a problem?  <tinfoil hat>Or is it a way to automate enforcement action and bring the hammer down on the tiniest infractions?  And you thought red light and speed cameras were bad...</tinfoil hat>

The problem is that, in typical government/FAA fashion, the system and mandate have been developed behind closed doors, by people to whom a "small airplane" is a King Air or Pilatus, with the needs of the highest-end users as the goal, and without consideration to the "small end" of the market regarding cost, required capability, or effects on the system as a whole (will the ADS-B system be able to cope with all the little airplanes?). 

Or, more likely, it just went like this: "We need ATC to be able to separate airliners in low IMC flying parallel approaches into Atlanta." "Hey, an IFR WAAS GPS can do that for us. And it's already an existing standard." "Great! We'll just use that. Now, on to the next item..." At least, that's how things seem to work lately when it comes to aircraft certification...

 

[Carl_Froehlich]

Good discussion - but the underlining issues remain unresolved.

Here is part of a note I sent to the FAA ADS-B program office framing my thoughts toward a more practical approach to bring more people into the ADS-B world - and hopefully enhance safety for all.

"The underlining issues behind my interest are:
• While ADS-B requirement for experimental aircraft has been better defined of late, the TSO aspect of the GPS position is a major issue for most of the experimental, and for that matter certified light aircraft groups. While those choosing to pay the $10K+ for a Garmin like GPS box for IFR have a means to meet the ADS-B out rules, many in this group who are VFR only or LSA most likely will not see the value in such a major investment. This leaves them out in the cold for 2020.
• Flying with full ADS-B in/out I clearly understand the safety enhancement offered by the system. I want all aircraft flying anywhere near me to be in the system as a safety factor for me and them, regardless if ADS-B is required or not for that airspace.
• What I know about the Dynon WAAS GPS receiver (SV-GPS-250) and similar leads me to think it would be a boat load better to have a plane providing ADS-B position with it as compared with not being in the system at all.

Is it possible to approach this issue of GPS requirements working backwards? In other words, is there option for the FAA to look at the performance of the existing SV-GPS-250 receiver (or other brands) and evaluate if they meet most the practical aspects of the FAA’s requirement? If so is there opportunity to have an interim step toward ADS-B out compliance that promotes aircraft owners to jump into the ADSB system using such offerings so that overall safety is enhanced? My thought is having an off the shelf system like this that meets the majority of the requirements is better than people deciding ADS-B is just too expensive.

Perhaps your Risk Management folks can do some analysis to see if there is a safety gain to be made? Considering the rapidly approaching 2020 compliance date and the small ADS-B adoption rate, I believe there is need for a third compliance option."

 

[swatson999]

Are there really that many near-misses between airliners in Class B and light airplanes outside it to justify this increase in accuracy? Or is it just a solution in search of a problem? <tinfoil hat>Or is it a way to automate enforcement action and bring the hammer down on the tiniest infractions? And you thought red light and speed cameras were bad...</tinfoil hat>

It's not about airliners...it's about *drones*...everybody wants to be able to fly drones around in virtually any kind of airspace, IFR or VFR, but "seeing" and avoiding other aircraft (seeing via ADS-B traffic info).

 

[lolachampcar]

Carl,

The problem I see with the "not exactly TSO'd GPS sensors being used for mandate compliant systems" is that a new spec would have to be generated to define what is and is not allowable when it comes to non-TSO'd sensors like the Dynon Puck. I'm not sure the FAA has any energy to put into defining such a device. I am reasonably sure it is not in any major equipment manufacturer's interest to allow the FAA to do that. I suspect the Garmins of this world were instrumental in "helping" the FAA to write the mandate and you can bet they do not want any non-TSO'd camels getting their heads in the ADSB aircraft tent.

 

[Carl_Froehlich]

I believe my point is still valid. If we stay on this path we'll have few participating in ADS-B and miss what we could gain in safety. If we have a new requirement that products like the Dynon WAAS receiver can meet we'll have more planes in the system. I offer the later provides significant safety gains over non-participation.
I note with interest a recent FAA track of a non ADS-B GPS compliant aircraft. The track was exceptionally accurate. So my question to the FAA stands - is 99% accuracy better than 0%?
From what I piece together I also suspect the FAA is capable of knowing who in the ADS-B system is GPS position source compliant and who is not. This would lead to my suggestion of an interim step to final ADS-B compliance that would provide incentive for more people to jump into the ADS-B pool.