Primarily for general aviation discussion, but other aviation topics are also welcome.
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User avatar
By PaulSS
#1654884
If PAW did a unit which had ADSB-out with SIL=1 there would be a lot of interested folks who would buy it.

There is no technical reason they can't.

I suspect the price difference between PAW and SkyEcho is about the cost of an ADSB transmitter and certified GPS Chipset allowing SIL=1.


Whereas the PAW people are very clever and I'm absolutely positive they could incorporate ADSB Out, it is incredibly naive to think the difference in price is just an ADSB and GPS dongle. UAvionix have been in the ADSB game for a long time and have a large market where there is a large market i.e. the USA. To suggest that PAW would be able to produce a similar box of tricks, on top of what they already do, when they do not have the economies of scale, nor the market to sell enough of the units to get the price down, is wishful but flawed thinking.
#1654886
Buzz53 wrote:
Maxthelion wrote:This may be a stupid question, but will Uavionix products be able to pick up PAW?


It seems clear that the secondary radio in the SkyEcho2 could be programmed to received PAW. In which case you'd also get the OGN rebroadcast of Flarm traffic (which I suspect will work a lot better the direct airborne reception most of the time anyway) and also the multilaterated Mode S traffic which PAW seem to be about to launch. No fees to pay either! Can't see it happening though.
Alan


Not quite. In order to receive OGN/R messages (FLARM and Mode 3D/S) you need to be transmitting P3I (otherwise it won't know which aircraft data to send). You may get some traffic on the back of someone else’s transmission. But it will be the traffic around them, not you. Receive only PAW would be a big mistake unless you do not want the data transmitted by OGN/R stations.
User avatar
By gaznav
#1654915
@G-BLEW

Pilot Aware, thanks to the OGN re-transmission, is doing a good job of being able to see a significant amount of traffic, but to answer your question, its P3i that cannot be seen by SkyEcho (or any ADS-B 'in' kit), nor can it be seen by FLARM, a TAS systems, TCAS or SSR.

The CAA has put its weight behind ADS-B, but neither it nor EASA is currently talking about mandatory equipage. On the other hand, the growth of airline traffic and the predicted (huge) growth in the number of unmanned aircraft systems will, I believe, make airspace access reliant on being able to participate in an EC solution. In my opinion that's likely to be ADS-B (or a development of it) rather than FLARM or P3i.


Ian

You Sir, have hit the nail on the head in my humble opinion with my bold added. Firstly, there are so many EC solutions out there that cannot see P3i, which is the biggest reason why I never ‘took the plunge’ for one. The PAW is a great receiver for small amounts of cash (although you get what you pay for in terms of finish quality) but if you want to be seen by anyone else who hasn’t got a PAW then there is no other unit that can do that right now (which to me was the biggest turn off as I don’t have a transponder). Secondly, that briefing by the Principal Lead for Electronic Conspicuity from the CAA revealed what I suspected all along - there will be Surveillance Mandatory Zones (SMZ) in the near future that will require you to have Mode S, Mode S ES or ADS-B. Without it, these SMZs (which I suspect will be quite large - but that’s my hunch) will be off limits to those without those capabilities - so whilst not mandatory for the whole of the UK FIR, there will be areas where flight without will not be possible.

Best, Gaz
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By patowalker
#1654916
there will be Surveillance Mandatory Zones (SMZ) in the near future that will require you to have Mode S, Mode S ES or ADS-B. Without it, these SMZs (which I suspect will be quite large - but that’s my hunch) will be off limits to those without those capabilities -


That will be less restrictive than a TMZ today, so will make no difference to those who have PAW. What evidence is there that SMZs will be larger than the present TMZs?
User avatar
By gaznav
#1654947
patowalker wrote:
there will be Surveillance Mandatory Zones (SMZ) in the near future that will require you to have Mode S, Mode S ES or ADS-B. Without it, these SMZs (which I suspect will be quite large - but that’s my hunch) will be off limits to those without those capabilities -


That will be less restrictive than a TMZ today, so will make no difference to those who have PAW. What evidence is there that SMZs will be larger than the present TMZs?


Have a read of CAP1690 - https://consultations.caa.co.uk/policy-development/draft-airspace-modernisation-strategy/supporting_documents/CAP1690%20FINAL%20Draft%20Airspace%20Modernisation%201807182.pdf
There is a lot of information in there but to me it all points to providing all air-users with a system that makes them visible to all. Further, EASA are supposed to be looking hard at the safety cases for having instrument approaches in VFR Class G airspace - the favvourite at the moment is introduction of Class E like the Germans have:

Image

I also believe if we want to minimise the restriction of GA then a voluntary fitment of either Mode S, Mode S ES and ADS-B is likely to be the future. The added benefit of ADS-B is that receivers are cheap for small airfields and we can all see each other. :thumright:
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User avatar
By Dave W
#1654957
Electronic Conspicuity - General Aviation Airfields'​ view of the world

An interesting article by Steve Cooper, FISO at Barton where (in conjunction with Airspace4All) they have a trials installation of an ADS-B groundstation and display based around a uAvionix pingStation.
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#1654985
gaznav wrote:I also believe if we want to minimise the restriction of GA then a voluntary fitment of either Mode S, Mode S ES and ADS-B is likely to be the future. The added benefit of ADS-B is that receivers are cheap for small airfields and we can all see each other. :thumright:


Yes, I agree with all that. I thought you made the replacement of TMZs by SMZs sound like an added restriction, when the opposite is true, thanks to those cheap ADS-B thingies. :)
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#1655069
Pilot Aware, thanks to the OGN re-transmission, is doing a good job of being able to see a significant amount of traffic, but to answer your question, its P3i that cannot be seen by SkyEcho (or any ADS-B 'in' kit), nor can it be seen by FLARM, a TAS systems, TCAS or SSR.

The CAA has put its weight behind ADS-B, but neither it nor EASA is currently talking about mandatory equipage. On the other hand, the growth of airline traffic and the predicted (huge) growth in the number of unmanned aircraft systems will, I believe, make airspace access reliant on being able to participate in an EC solution. In my opinion that's likely to be ADS-B (or a development of it) rather than FLARM or P3i.


Thanks Ian. Also the trials are going very well for the rebroadcast of Mode S (Mode-S/3D) transmissions augmented using MLAT from 360 RADAR. This will really light up the Flight bag screens as another possible 8000 targets can be shown. We now have exceeded our 2018 target and have 102 OGN-R stations installed. The new target is 200 sites by 2020. So in this respect we (the flying community) has gathered together to prove the art of the possible and increase the coverage. Thanks to all.

As I and other parts of the industry see it, the big technical limitation when using ADSB at 1090MHz is the very inefficient 70+ years old modulation technique used. When constrained to using Pulse Position Modulation there isn't the bandwidth available if all present and future flying machines are mandated to use it. The CAA and EASA know that this must be addressed before any mandate can sensibly be contemplated.

The early FAA studies showed that the bandwidth using PPM was insufficient. This is one of the reasons why they have a dual solution in the states with the second frequency using a more modern efficient modulation technique.

The South East of the UK is possibly the most congested airspace in the world and mandating EC at 1090MHz is probably, for the reason above, not technically achievable in its current form.

At the various CAA and EASA EC forums and committees there has been several calls from industry for a peer reviewed study to prove if this is or not the case. Until this is done it is less than sensible to mandate something that has not been modelled to work at the volumes anticipated.

Please let's have a peer reviewed study to prove that there is sufficient capacity one way or the other then we will be more confident that it will or will not be as you suggest ADS-B at 1090MHz using PPM (or a development of it).
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User avatar
By gaznav
#1655479
1090 congestion shouldn’t need to be an issue if you use low power for GA purposes. The 20W used by SkyEcho is perfectly sufficient and with even lower power outputs then there is plenty of capacity on 1090 unless we all fly about in close formation! :lol:

The biggest problem for 1090 is the continued insistence on using transponders that output at 500W, 250W and even the lower power 125W Class 2 transponders. It’s crazy using ADS-B Out with those sorts of power levels for GA as who wants to track my aircraft flying over Newcastle with a receiver based in London!

That is why CAP1391 is a great initiative and the whole idea of a Low Power ADS-B Transceiver (LPAT). In fact in 2014 the UK’s QinetiQ did such a peer reviewed study called “Low Power ADS-B Transceiver (LPAT) RF Environment Modelling Study”. The conclusions of which mean that low powered units would not need to suffer the spectrum congestion problem that others talk about.

The biggest problem for 1090 congestion is the ‘willy nilly’ interrogation on 1030 by TCAS, SSR and Military Interrogators producing lots of replies on 1090 - many of these being 250W or more from multiple sources. Removal of the older Mode 3/A transponders and using ADS-B for collision avoidance rather than a 1030/1090 set up for TCAS would really help. The US’s insistence on keeping Mode 3/A means that they had to open up 978 for their GA ADS-B solution, but the use of LPATs as per CAP1391 expects that this would not be necessary. TCAS/ACAS is a big offender as well to adding to frequency congestion - Hybrid Surveillance using ADS-B has already demonstrated that it produces much less spectral congestion.

I often liken the 1090 debate in my thoughts to that of ‘Project Fear’ in that it is often quoted to be an issue to those that really do not understand what is the root cause of the problem - that frightens them unnecessarily in my humble opinion.

Yes, independent studies and trials are good. It would be great to hear from the scientific community on the effectiveness of the various EC devices rather than from their various sales teams!
#1655502
gaznav wrote:1090 congestion shouldn’t need to be an issue if you use low power for GA purposes. The 20W used by SkyEcho is perfectly sufficient and with even lower power outputs then there is plenty of capacity on 1090 unless we all fly about in close formation! :lol:


<my bold>
Is that just a Gaz opinion or based on some technical (inverse square law and all that) fact? :roll:
User avatar
By Ian Melville
#1655548
Er Gaz, your theory only stands if every single transponder has it's power reduced. Something I don't think is going to happen overnight, if ever. The FAA have the same concerns and you have posted links to FAA reports that state this.

In conversational terms we cannot have a conversation if mega mouth across the room keeps shouting.
User avatar
By gaznav
#1655567
Ian, if that were correct then 1090 would not work now. The problem is if you introduce lots more “mega mouths” then it gets congested - hence the time is right to consider the power outputs being used on 1090. The phase out of Mode 3/A which is effectively answering everyone in the room when someone asks a question is a good example!

The FAA are still allowing the sale and use of Mode 3/A which meant that they had to open 978...
User avatar
By PaulSS
#1655575
The phase out of Mode 3/A which is effectively answering everyone in the room when someone asks a question is a good example!


It doesn't, though. It only answers the person who asks a question. The answer can be seen by some others in the room but not everybody hears the answer.

Of course, from you there's mute response as you didn't hear the question and can't answer :wink:
Ian Melville liked this
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