ADS-B for GA in Europe?

[betterfromabove]

Hi,

Can anyone enlighten me on whether we shall see ADS-B being taken up by GA, especially the light end, in Europe in the forseeable future?

In the US, it seems to be being touted as the solution to a series of potential ills for GA pilots (navigation, collision avoidance, comms in remote areas, distress calls, infringement avoidance) with wonderful portable tablet or fixed unit displays.

Is it really such a silver bullet?

In the US, there appears to be an infrastructure already being built for all to use. Any sign of this on the cards for Europe?

And devices for the US seem to be retailing in the high single digit $1000's, so does this mean substantially more in Europe? And hence likely out of reach for many GA's?

What are the technical considerations and the likely evolution? Are the devices going to be feasible to install in light GA (SEP's or lighter)?

Appreciate any info.

All the best,
BFA

[peterh337]

Very unlikely to be mandated for GA here.

Even Mode S is not mandatory for VFR for many/most areas.

You can already achieve much the same thing by enabling what is in effect partially Enhanced Mode S, by allowing your transponder to radiate your GPS position. AIUI, ADS-B gives you just that, except it radiates your position continuously even if you are not interrogated by SSR.

Yet, any form of Enhanced Mode S is explicitly banned by EASA, on aircraft on which it is not mandatory

I recall going to a Eurocontrol presentation in 2008 where they said they want to dismantle primary radars to save costs and replace them with ADS-B. These people live in their own world...

[Rod1]

You will find ADSB will be in the news a lot over the coming months.

Rod1

[mm_flynn]

In the US they have decided two key principles

1 - To move to an ADS-B infrastructure for the primary source of ATC data (I believe with a 2020 change over) so everyone who participates in the ATC environment will need a GPS as a source of position coupled to an ADS-B transmitter. This will cost some good chunk of money for GA to comply with and GA has negotiated getting extra data broadcast. Also, to provide ATC with data across the country they need remote receivers and these receivers are configured as repeaters (so they re transmit the ATC image of targets so that ADS-B in people can see the two different flavours of ADS-B plus Mode-A/C traffic)

2 - The US has also decided to have a two tier ADS-B infrastructure. One using the Mode-S frequency/protocol and one using a different frequency. The Mode-S one has the advantage of being consistent with world wide CAT equipment, but has the disadvantage of very limited bandwidth (i.e. no uplinked weather). The other system (UAT) has much higher bandwidth and the ability to provide all of the sexy features described in the OP.


It will come as no surprise that the European implementation is scheduled further into the future and is only based on the Mode-S datalink with none of the extra features (beyond being able to see all the other ADS-B traffic - but not I believe a retransmission of legacy Mode-C targets).

[Denti]

Yet, any form of Enhanced Mode S is explicitly banned by EASA, on aircraft on which it is not mandatory

No, it is not banned. However the technical and therefore financial barrier is high enough to make it impracticable. However, Enhanced Surveillance delivers more information than needed for simple ADS-B out (except the position of course). ADS-B out can be achieved pretty cheap currently. As can be a simple ADS-B in traffic display. For example powerflam is available for less than 1k€ and displays flarm data as well which is used in over 18.000 glider and GA airplanes worldwide, most of them in europe.

Isn't the Mode S extended squitter (1090MHz) required above FL240 in the USA for ADS-B? Which really does not matter for most GA airplanes of course.

[mm_flynn]

Originally Posted by Denti

No, it is not banned. However the technical and therefore financial barrier is high enough to make it impracticable. However, Enhanced Surveillance delivers more information than needed for simple ADS-B out (except the position of course). ADS-B out can be achieved pretty cheap currently. As can be a simple ADS-B in traffic display. For example powerflam is available for less than 1k€ and displays flarm data as well which is used in over 18.000 glider and GA airplanes worldwide, most of them in europe.

Isn't the Mode S extended squitter (1090MHz) required above FL240 in the USA for ADS-B? Which really does not matter for most GA airplanes of course.

A more precise version of Peter's statement could be

Under the existing EASA approvals for installing a Mode-S transponder providing elementary surveillance data, it is not permitted to radiate additional data elements such as position. Not withstanding that is what the Garmin 330 does if coupled to a GPS (for example to provide the ground air switching) and which is standard configuration in FAA aircraft.

[peterh337]

I think Denti you need to become aware of the issues surrounding the GTX330 and connecting NMEA data to it

Posts crossed with mm_flynn

There is new firmware for a GTX330 which solves that "European issue" but of course all "foreigners" are unaware of it to start with and it doesn't do any harm whatever.

[Daysleeper]

Did I not read something in a magazine recently that NATS had taken up the challenge of electronic conspicuity for light aircraft? Following the success of their other projects they were looking at a light weight low power/cost ADS-B based product.

Ah ha! found some of it in December 2011's iAOPA

In the UK, NATS is attempting to drive R&D on the issue. But the level of European or government funding is almost non-existent, again in stark contrast to the USA. In some cases, we need to actually disable the function in our US-specified box when flying in Europe!

[Denti]

Interesting issue then. We got a Becker transponder installed and certified by the local authority (LBA) in 2006 which includes a connection to the GPS and position report available via the extended squitter. Might be that that was a grandfathered installation, but it is still flying today and allows ADS-B out.

Interesting that EASA made that into a major issue now, but the reason might be the issues around position data integrity which most if not all GA installation do not provide which means that ADS-B reports have to be discarded by ADS-B in systems anyway.

Interesting though that ADS-B out will be mandatory in less than three years for certain aircraft (more than 5,7t or 250kts cruise speed) within europe but the certification standards are not yet published.

[peterh337]

the reason might be the issues around position data integrity which most if not all GA installation do not provide which means that ADS-B reports have to be discarded by ADS-B in systems anyway.

Can you elaborate on why the data integrity is a problem?

Interesting though that ADS-B out will be mandatory in less than three years for certain aircraft (more than 5,7t or 250kts cruise speed) within europe but the certification standards are not yet published.

Those have mandatory Enhanced Mode S so radiating the stuff the whole time is a small step.

[Rod1]

“the reason might be the issues around position data integrity which most if not all GA installation do not provide which means that ADS-B reports have to be discarded by ADS-B in systems anyway.”

All ADSB out via certified mode s transponders will have SIL enabled which will handle this.

Rod1

[peterh337]

The data integrity issue is nonsense. In all cases of Enhanced Mode S, the data comes from a collection of avionics boxes, including an airdata computer, and it is concentrated at the transponder. It either works or it doesn't.

Quite what ATC use it for in the GA case (say TBM850 / light jets) would be a good question.

[ATCast]

There is some debate going on about how to handle GA and ADS-B in Europe.

ADS-B is a distributed cooperative type of surveillance. This has its advantages and its risk. One of the risks is that (uncertified) installations transmit misleading data, which could lead to misidentification, loss of separation or worse. Therefor it is undesirable that GA is equipped with uncertified ADS-B transponders. At this moment there is a lack of certification standards for GA type aircraft. Also the technical standards are aimed at transport aircraft. Low power transponders or pure ADS-B transmitters are not yet standardised.

I don't expect Europe to go down the US route and have 2 separate and incompatible ADS-B systems. If GA in Europe is going to be ADS-B equipped, it will be on 1090ES so that everybody is visible to everybody.

To experience full benefits of ADS-B, everyone it the airspace must be equipped with ADS-B so everyone can see each other on a traffic display.
What to do? Mandate everybody to have ADS-B out including GA. Close down parts of the airspace for non-ADS-B aircraft?

In short, it's not very straight forward, and there are many decisions to be made. I don't see ADS-B mandated in Europe for GA very soon.


Although the rest of this post is a bit beside the OP's original question, I'll reply to some of the ADS-B related comments made here.

peterh337: I recall going to a Eurocontrol presentation in 2008 where they said they want to dismantle primary radars to save costs and replace them with ADS-B. These people live in their own world...

Primary radars are not likely to be replaced by ADS-B, they serve a different purpose (security). A number of Secondary and Mode S radars is likely to be replaced.

Denti: Interesting though that ADS-B out will be mandatory in less than three years for certain aircraft (more than 5,7t or 250kts cruise speed) within europe but the certification standards are not yet published.

ADS-B will be mandatory in European airspace for aircraft over 5.7t MTOM or 250 kts max cruise speed build after January 8th 2015. After December 7th 2017 all aircraft above 5.7t MTOM / 250Kts must be equipped. EASA is taking a long time getting the CS published indeed, but manufacturers seem to be aware of what will be required and are developing their systems.

Denti: the reason might be the issues around position data integrity which most if not all GA installation do not provide which means that ADS-B reports have to be discarded by ADS-B in systems anyway.

peterh337: Can you elaborate on why the data integrity is a problem?

Data integrity is one of the concerns for GA installations. GPS position can be calculated when a signal is received from 4 GPS satellites. If one of these signals is faulty (e.g. due to satellite orbit deviation, satellite failure, spoofing etc) the measured position will be off without the user knowing it. Therefor aviation receivers have RAIM, (Receiver Autonomous Integrity Monitoring) which requires at least 5 satellite signals. If all five (or more) signal are consistent with the same measured position, all is ok. If the signals are inconsistent a flag is raised and the position data is not to be trusted. The maximum horizontal position error that could go undetected by RAIM is the called the Horizontal Integrity Limit or containment radius. This is send out in the form of a quality indicator by ADS-B. If there is no integrity information available from GPS, the quality will be 0 and the position data is not trusted. The NMEA data format for example does not contain Horizontal Integrity Limit and therefor NMEA based GPS units are not suitable for certified ADS-B.

Rod1: All ADSB out via certified mode s transponders will have SIL enabled which will handle this.

SIL is Source Integrity Level (in 1090ES version 2) and indicates the robustness (probability of exceeding the containment radius without raising an alert) of the RAIM checks . It is one of the quality indicators that is transmitted, others being NIC (position integrity), NACp (position accuracy), SDA (system design assurance)

peterh337: The data integrity issue is nonsense. In all cases of Enhanced Mode S, the data comes from a collection of avionics boxes, including an airdata computer, and it is concentrated at the transponder. It either works or it doesn't.

There is a difference between data integrity and system integrity. Data integrity refers to undetected corruption in the original measurement (e.g. GPS position or pressure altitude). System integrity refers to corruption during the transport and processing of the data. You seem to be talking system integrity issues. Unfortunately it is not a case of "it either works or it doesn't", I have seen cases where misleading data was sent during a particular flight phase, which looked credible on first sight but was faulty on closer inspection.

mm_flynn: It will come as no surprise that the European implementation is scheduled further into the future

For aircraft above 5.7t MTOM / 250 KTAS Europe is ahead of the US. As said before, there is no schedule for GA.

[peterh337]

One of the risks is that (uncertified) installations transmit misleading data

Why would a certified installation be accurate? The difference is almost wholly just paperwork (and price ).

If one of these signals is faulty (e.g. due to satellite orbit deviation, satellite failure, spoofing etc) the measured position will be off without the user knowing it.

How will he be navigating then?

[ATCast]

Why would a certified installation be accurate? The difference is almost wholly just paperwork (and price ).

Certainly it is not holy writ that certified installations are perfect. However, many installations could be thought off (and some are flying right now) that send out ADS-B data that is misleading. Certification is one method of ruling out installations that just don't work.

How will he be navigating then?

What happened to VORs/ NDBs / DME's/ dead reckoning / eyeball & the good old map? Are you implying that GPS without RAIM should be used as sole means of navigation?

[mm_flynn]

Originally Posted by ATCast

For aircraft above 5.7t MTOM / 250 KTAS Europe is ahead of the US. As said before, there is no schedule for GA.

While I appreciate everyone with Mode S Enhanced be transmitting an accurate position by 2015, I am not sure this is a material step in the movement from SSR to ADS-B as the primary means of providing location data to ATC for separation of aircraft.

It is difficult for me to see the advantage of moving to ADS-B for separation of aircraft over 5.7 tonnes and staying with SSR for less than 5.7 tonnes. As I understand the US position is that in 2020 ATC will use ADS-B instead of SSR and everyone with a transponder will need to be ADS-B out equipped. There will clearly remain a need for primary radar for security and maybe for providing basic lateral tracks for non-transpoinding aircraft. The European 2015 data seems an isolated requirement on an undefined (and probably distant) implementation plan.

[peterh337]

Certification is one method of ruling out installations that just don't work.

How does it that work?

What happened to VORs/ NDBs / DME's/ dead reckoning / eyeball & the good old map? Are you implying that GPS without RAIM should be used as sole means of navigation?

For a brief moment I thought you worked for Eurocontrol because you write in the "right kind of language" but obviously I was wrong, because you are unaware that for IFR in CAS in Europe one needs BRNAV capability, for which the only means of compliance is INS or GPS.

Also it's obvious you are not an IFR pilot, because GPS (with or without RAIM) is used as the sole means of navigation routinely (and 100% legally).

It now sounds like you are an instructor, or an FTO ground school teacher, perhaps?

The European 2015 data seems an isolated requirement on an undefined (and probably distant) implementation plan.

I think so, but you could say that for a lot of stuff coming out of Eurocontrol.

They are still on 10,000 VLJs flying out of Luton Mind you, so is most of Swanwick, I believe

Primary radar will never go away for national security reasons alone, and then the extra cost of the SSR bit bolted on the top is.... not a lot. Actually the bulk of radar data collected around say Europe is not shared with civilian ATC, so if one was looking for savings...

[ATCast]

My comments were made with

GA, especially the light end

in mind.
We're now drifting towards the high end.

for IFR in CAS in Europe one needs BRNAV capability, for which the only means of compliance is INS or GPS.

Navigation is not my speciallity but IIRC B-RNAV requires 5 NM track keeping accuracy and compliance can be achieved by DME/DME and probably by VOR/DME as well. Do you know which AMC covers B-RNAV, I did only find the RNP-AR one.
Anyway that is not sole means GPS, but primary means. When GPS fails you can fall back on alternative systems that don't meet the requirements but at least give you a good sense of where you are.

GPS (with or without RAIM) is used as the sole means of navigation routinely (and 100% legally).

I doubt that, but again navigation is not my speciallity. GPS as primary means seems reasonable provided that you have RAIM (and you usually have it). But I don't believe that you don't have a clue where you are if GPS fails, at least I hope so.

ATCast

[peterh337]

Navigation is not my speciallity but IIRC B-RNAV requires 5 NM track keeping accuracy and compliance can be achieved by DME/DME and probably by VOR/DME as well.

That is incorrect, both legally and practically.

Legally, you need a BRNAV compliant nav means which in the GA context can be met only with an IFR approved GPS, or with a BRNAV approved (ancient) KNS80 installation with antenna filters for FM immunity.

Practically, ATC treat all that airspace as RNAV i.e. most of the waypoints you will be given will be either virtual waypoints (not navaid based or navaid-relative referenced) or they will be navaid names but the navaid itself is way out of DOC (e.g. a VOR 200nm away).

There is also no way to navigate using DME/DME - except using an FMS with an INS with DME/DME corrections, which is not GA. Only high-end bizjets and above will have that. Unless you fancy flying your entire route as a series of DME arcs

Anyway that is not sole means GPS, but primary means.

That is complete bollocks. There is no concept of "primary". The regs (for non AOC ops) dictate equipment carried, not equipment used. You must be a PPL instructor

When GPS fails you can fall back on alternative systems that don't meet the requirements but at least give you a good sense of where you are.

Actually, in BRNAV-mandatory airspace, you pull out your backup GPS and use that as a DCT box If you have lost all GPS reception, you advise ATC that you have lost RNAV capability and need VOR-VOR routes, or vectors. This is very rare (GPS is extremely reliable) but it happened to me once in Italy and I got assigned a different route with a higher MEA (FL160 instead of 140, IIRC).

[Rod1]

“Therefor it is undesirable that GA is equipped with uncertified ADS-B transponders.”

I am confused by that! In Europe we are using Mode S transponders with extended squitter to emit ADS-B out. I think all the transponders available are certified?

I would have thought that uncertified installations set with SIL=1 would have made the sky much safer than no ADS-B out at all? This appears to work in the US. In the UK I was under the impression that ADS-B was not in use by ATC apart from North Sea helicopters?

Rod1