PilotAware
British Forum => General Discussion => Topic started by: SteveHutt on March 24, 2016, 12:21:27 pm
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FYI,
http://fasvig.org/new-easy-process-to-enable-electronic-identification-of-light-aircraft-announced (http://fasvig.org/new-easy-process-to-enable-electronic-identification-of-light-aircraft-announced)
Steve
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Hi
Having read through the document linked to above and then the further reading document that it links to and then ploughed my way through the CAP 1391 document i am not a lot wiser as to how this effects the PAW Project. My initial reaction is that the CAA are trying to encourage established manufactures to produce a device operating on the 1090 Mhz frequency for Tx/Rx for around a similar cost to PAW and that this would be the only system they would recognise or authorise.
I have to admit that most of the jargon and technical references in these documents are way over my head so if there is anyone out there who can translate it into "Dummies" speak for those of us without a degree in Avionics.
As far as I can deduce, PAW hit the target in that it can receive and alert us to other ADS-B and Mode S traffic in our vicinity but due to the proposed new RF Bridge being on *** Mhz it will only render us visible to other PAW equipped aircraft and not the ADS-B In equipped aircraft and therefore lacks the compatibility that they seem to be squawking about. (Pardon the Pun).
I look forward to others comments on this and hopefully to to be proved wrong that this is a deliberate attempt to thwart the initiative which has been demonstrated by this project.
Regards
Alan
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Hi Alan,
You say you are "not a lot wiser as to how this effects the PAW project?" Well in my mind it is pretty obvious. The CAA want to increase the number of GA a/c flying with ADS-B Out and if you have a PAW then that is a good thing for your flying safety as you would then be able to detect them.
The CAP 1391 document lays out a spec for anyone that wishes to develop a portable low power electronic conspicuity device that provides ADS-B Out (and In, if desired) on the 1090MHz frequency.
Another key thing is that they are proposing to reduce the regulatory burden for the manufacturer. They say:
"As part of the planned introduction of the proposal we are consulting with manufacturers on a new process that aims to remove regulatory barriers, making it easier for manufacturers to build a range of devices. Once the process is up and running manufacturers will be required to make a declaration to the CAA that their device complies with the relevant approval. This will ensure that all EC devices, that have an acknowledged declaration, meet the standard set out for it to be used legally on board an aircraft. The administration charge for declaration has been waived for the first year of the scheme."
So... The proposed process is along the lines of the CE verification that PilotAware have undertaken for the new Bridge.
This CAP 1391 proposal has been a long time in the making and follows on from work on electronic conspicuity dating back several years. 1090MHz ADS-B is the international standard for electronic conspicuity and the certified EC world by definition must support it so the CAA have to as well. I applaud the work the CAA have done. My only sadness is the time it has taken.
Talk of "thwarting" PAW is just plain silly. If PilotAware so chose they could set about adding 1090MHz ADS-B Out capability into PAW by taking advantage of the simpler regulations the CAA are proposing. Personally, I think it would be great if PilotAware were to do this and I would encourage them to do so. As a PAW user you would be safer if PAW output 1090MHz ADS-B Out as it would be helping to make you seeable by more aircraft that you are sharing airspace with.
Steve
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Talk of "thwarting" PAW is just plain silly. If PilotAware so chose they could set about adding 1090MHz ADS-B Out capability into PAW by taking advantage of the simpler regulations the CAA are proposing. Personally, I think it would be great if PilotAware were to do this and I would encourage them to do so. As a PAW user you would be safer if PAW output 1090MHz ADS-B Out as it would be helping to make you seeable by more aircraft that you are sharing airspace with.
Great idea Steve but we still seem to have the restriction that 2 devices cannot emit 1090Mhz from the same aircraft meaning PAW's ADS-B out would have to be switched off in a transponder equipped aircraft. Same issue with LPAT. No one want's pilots to turn off their transponders.
I had hoped the trials would have been testing this in the air to see if it actually mattered.
Allowing two devices (same hex code) would accelerate adoption not least amongst Garmin transponder owners. My guess is greater that 50% of the aircraft flying have Garmin transponders that will cost £1200 to upgrade or in the case of the GTX328 never be upgradable. That could be a huge jump in take up.
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Hi Steve
Call me an old cynic but i was a little suspicious of your initial involvement in this forum but had come to accept that you had a genuine interest in the efforts of Lee and the team to succeed. Even making requests and suggestions to make the software useful for users to obtain the verification required to connect the non-certified GPS unit to their Xponders.
My comment of "not a lot wiser as to how this effects the PAW project?" was somewhat tongue in cheek as it is fairly obvious that as PAW is not using 1090 mhz it would not apparently be supported in the newly announced process. The dialog in all of the linked articles constantly refers to "manufactures" and is obviously prioritised toward them.
If you consider my "Talk of "thwarting" PAW is just plain silly" then why do you believe there is a sudden rush to take this forward after all of the dalliance of the intervening years since first mooted. I believe that the PAW project has given the "manufactures" & the CAA the boot up the proverbial that they required as they saw a potentially lucrative market being snatched from under their noses
Your suggestion that PAW should adopt the 1090 Mhz route is as far as I can establish going to fly in the face of producing a low cost, self build unit that uses off the shelf available parts as I'm not aware of any readily available 1090 Mhz transceivers in this category. I'm sure these will be far more available to the established manufactures & probably cheaper.
I now feel vindicated in my initial suspicion of your motives for being involved in this forum as I cannot believe that you did not know what was going to be contained in the CAA announcement.
That is not meant to be a condemnation or criticism of anything you have said or done by being involved in the forum but just my personal observation that it was less than honest.
Having reviewed some of your posts Steve, I see the following from a post in another thread which i suppose demonstrated your thinking and I think was what alerted me subliminally to the fact that you were not totally on board with PAW but maybe I have to consider that you were more honest than I've given you credit for.
"I am a supporter of PilotAware but I view ADS-B Out as a much more valuable thing to broadcast than P3i.
Everyone with ADS-B In (including PilotAware) will see ADS-B broadcasts.
Only PilotAware users will see P3i Broadcasts.
ADS-B Out (i.e. transponder) antennas will be fixed externally installed therefore offer more reliable transmissions that P3i
ADS-B Out transmissions are more powerful
As has been said, things are still developing. ADS-B is not going to go away but how it is going to be used may well adapt with time.
And the usage of ADS-B may well have an influence on other things, airspace being an obvious candidate.
Steve"
Regards
Alan
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Great idea Steve but we still seem to have the restriction that 2 devices cannot emit 1090Mhz from the same aircraft meaning PAW's ADS-B out would have to be switched off in a transponder equipped aircraft. Same issue with LPAT. No one want's pilots to turn off their transponders.
I had hoped the trials would have been testing this in the air to see if it actually mattered.
Allowing two devices (same hex code) would accelerate adoption not least amongst Garmin transponder owners. My guess is greater that 50% of the aircraft flying have Garmin transponders that will cost £1200 to upgrade or in the case of the GTX328 never be upgradable. That could be a huge jump in take up.
I very much agree with you Steve, and have been saying so for a very long time. If two devices in the same a/c both broadcast the same Hex code and one does the non-ES bits while the other does ONLY the ES bits then in theory I see no reason why this ought not work and is worthy of investigation.
I gather there is a flag in the broadcast data that indicates whether a device can respond to being interrogated by SSR. Mode S transponder set this flag to "yes". The problem would be if two devices sharing the workload on a single Hex code set this flag different to each other as it may confuse SSR ground stations. The simple idea that comes to my mind is that a portable ADS-B device operating on its own would have the respond to interrogations flag set to "no", but if paired with a device on the same Hex code that can respond then the portable ADS-B device would flag "yes" as its 'partner' device will do the responding. (There is no response mechanism in the pure ES part of the system). That is all a bit of a pfaff but it hangs together in my mind.
I have not given up hope that this two devices in one aircraft issue will be resolved. I guess that comes after giving a portable ADS-B Out option to those aircraft with no transponder.
There are other issues like currently 'UK only' that are unwelcome and efforts are underway to try to address that.
Regards,
Steve
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Hi Alan,
I very much put PilotAware in the category of 'manufacturers'. They have already announced they will be selling complete devices. See here: http://pilotawarehardware.com/product/pilotaware-complete/ (http://pilotawarehardware.com/product/pilotaware-complete/). And they can provide feedback to the CAA via the manufacturer survey if there are any aspects of the proposal that they feel need improving.
There has not been a sudden rush to produce the CAP 1391 proposal. It has been under development for a significant time and the related Project EVA work has been ongoing for a long time now. Just google LPAT and Project EVA. You can even read about them on this very forum. Nothing has been hidden.
I do take exception to you questioning my honesty. I have never sought to undermine PilotAware. You are free to search my posts here and on the Flyer Forum. I was asked by Lee if I would join the PAW Technical Committee and I politely declined on the basis that I supported a standards-based approach to electronic conspicuity so I have been very straight. I have focussed my involvement in PilotAware on the parts of PAW that support the ADS-B standard. And On that score I am pleased that PilotAware have been able to provide benefit to the GA community.
EDIT
I see you have amended your post Alan, but saying "more honest" is still not saying "honest" so I still take exception I am afraid. I have never acted other than what I see is in the best interests of the GA community.
Regards,
Steve
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Hi guys,
As a moderator, I'm a little uncomfortable with the way this thread is heading. So far this forum has avoided the bad feeling that so many others have, and that is due to the underlying sense that we are all on the same side here with a ground breaking project that has come from the grass roots and put the authorities to shame.
Personal attacks will not be tolerated, attack the idea, not the person.
Thanks.
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Hi
No need to worry, there was no personal attack intended, just the thoughts rolling round my head at what seems to me a crucial point in the development of this great project,
As i said, I am now more interested in other contributors thoughts on where this goes in the future, especially those of the team who have committed so much time and effort for, so far, so little reward.
I am still 100% behind Lee and the team as even with two or more systems we are still much safer if we in the GA sector can see and be seen by each other. Much of the research quoted states that the most likely event of a mid air is with like for like type of aircraft so the more PAW units that are out there the safer we will be.
The gliding fraternity have gone their own way with a system incompatible with any other as far as I am aware which I suspect was in response to the same problem.
Following the trials, we are now able to fit non-certified GPS to our transponders that will allow SSR & PAW equipped aircraft to see them but ACAS/TCAS still can't see them. ???????
Yes, It's always preferable if everyone sings from the same hymn-sheet but that would require legislation and at what cost?
Alan
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Thank you Moderator for stepping in as you have. I too felt that sentiments were edging towards personal.
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I think we can all agree that PAW is an Electronic Conspicuity (EC) device. However, it is not an ADS-B transmitting device and does not seem to fall within the definition of CAP1391 which only deals with the specification of an EC transmitting ADS-B ES on 1090 MHz.
Although PAW can serve as an uncertified GPS source for a Mode S transponder, as such, it appears to fall within the definition of a Full Category Device (para2.2) and therefore outside the scope of Chapter 6 of CAP1391. It is the Mode S transponder itself that carries the appropriate approvals. Furthermore, while PAW is able to receive ADS-B and ADS-B ES, there is no requirement for approval for receiving on 1090, only recommendations, that are sensible to comply with as far as they impact on PAW as a device. Colour coding of alerts for example will not be a PAW issue but instead fall under the remit of the navigation software provider, such as SD or PocketFMS/Easy VFR.
Whilst I broadly agree that for the future EC might be better served if all systems standardised on 1090 ES, the fact is that the RF output powers quoted, are much, much higher than likely to be utilised by the new PAW Bridge, and the power drain of a CAP 1391 EC device will hence be more difficult to accommodate in many of the airframes which PAW is aimed at. There is also the considerable disadvantage that a CAP 1391 EC has to be inhibited from transmitting if the airframe is already equipped with a transponder.
PilotAware as a completed product, WILL be a manufactured item and it may be sensible to apply for approval by submitting a Declaration of Conformance, especially as it is likely that fees are to be waived initially, according to Steve Hutt (though I cannot find reference to this in CAP 1391). I feel that it may be important for the future of this project that PilotAware attempts to follow the "spirit" of CAP 1391 with regard, to sections concerned with Testing , Manuals, Receiver characteristics etc. in so far as they apply.
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There are a lot of ideas being expressed in this thread and a few misconceptions. As someone who has been involved in ADS-B (on 1090MHz and other frequencies) for a long time, and who also participated in the Electronic Conspicuity Working Group, I have tried to set out the main principles of Electronic Conspicuity, Airborne Collision Avoidance for GA and their relationship to ADS-B, together with a short summary on current activities.
I must also correct the initial statement of the post dated 26.03.16 08.01.21pm, which states "PAW ... is not an ADS-B transmitting device". It most definitely is an ADS-B transmitting device!!
My main concern is safety and to get the greatest benefit for the widest possible range of GA pilots by promoting mutual interoperability - which leads to the mantra of SEE, BE SEEN, AND AVOID.
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I must also correct the initial statement of the post dated 26.03.16 08.01.21pm, which states "PAW ... is not an ADS-B transmitting device". It most definitely is an ADS-B transmitting device!!
Hi Bob,
I was initially confused when I read the above, but having read your summary and given this more thought, you are of course correct that PAW, with its RF Bridge fitted, can be classed as an 'ADS-B' transmitting device as in poor man's speak it is... 'Broadcasting positional information to make the plane more visible,' just not on the normally accepted ADS-B frequency of 1090MHz, ...though I suppose if used as the GPS source for a Mode 'S' transponder, PAW would certainly form a significant component of a 1090MHz ADS-B Out Transmitter.
From personal experience, I am well aware of the effectiveness of such a system as I currently use my PAW to provide the 1090 MHz ADS-B in component of a full 1090MHz ADS-B system and have significant experience of and great confidence in its performance in this area.
I await with interest commercial LPAT developments, though have some concerns that any significant cost (over that of systems like PAW) will inevitably lead to resistance to its broad take-up. I also have concerns that the cost of LPAT may be prohibitive to those like myself, who have already invested in 1090MHz ADS-B out capability via a Transponder, who would be buying yet another transmitter which we would (at least under current rules) be obliged to disable.
Another serious concern is the current position whereby ADS-B generated on 1090MHz through the use of 'non-certified' GPS must transmit an SDA/SIL '0', which I understand makes it effectively invisible to ATC / TCAS - making me suddenly invisible again to everyone except PAW, FLARM and presumably LPAT (oh and of course - very important - FR24). I hope this situation can be improved otherwise why would we bother?
Please don't think I'm being negative - far from it - I have taken on considerable expense (almost £5,000 in the past year) to make my aircraft more conspicuous and will be delighted when everyone else is finally able to see ME (other than via FR24).
Regards
Peter
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Hi all after reading through the latest developments I want to ask - What is the point of the conspicuity trial of LPAT, PilotAware and FLARM, as it looks as though there is already a decision made on LPAT and 1090 EC equivalent units?
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I must also correct the initial statement of the post dated 26.03.16 08.01.21pm, which states "PAW ... is not an ADS-B transmitting device". It most definitely is an ADS-B transmitting device!!
How can it be a ADS-B transmitting device when it does not transmit ADS-B messages (PAW=P3i) and it uses a frequency in the public band?
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How can it be a ADS-B transmitting device when it does not transmit ADS-B messages (PAW=P3i) and it uses a frequency in the public band?
Hi StevN,
My reading of it is that Bob is saying that ANY system which deliberately transmits positional information with the intention that this will be received and decoded by another device to tell that system it is 'here', technically fits the definition of 'Automatic Dependent Surveillance (by) Broadcast (of that positional information). We just normally presume the term to be exclusive to specific transmissions on 1090MHz. That being the case, I guess FLARM would also fall into Bob's definition too!
To pick up bryannortje's point,
I would guess that what the NATS Project Eva Team are interested in is to investigate compatibility of LPAT by testing how well (or otherwise) it is received and actionned by other ADS-B in systems such as PAW and FLARM (a positive marketing point), by average pilots in a variety of aircraft and where a transmitter IS present that there are no interference problems, though I may of course be far off the mark. I was thinking of registering to get involved but reading the bit in their script about '...pilots having to talk live to HD video cameras as alerts are received...' and the fact they presumably need to attend your airfield to fit the video cameras and oversee the trials, I have my doubts as to the level of interest a couple of flex wings up in Scotland would provide. I may still make them the offer though just to see what is going on. Certainly TRIG, which is a major part of all this are only a couple of miles from where I live and it's their transponder gear I use, so you never know.
Best regards all
Peter
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Having reminded myself what the initials ADS-B actually mean, via Wikipedia I have to conclude that Bob D is correct in his assertion that PAW is indeed an ADS-B device. I had always associated the term with 1090 ES, in my own thoughts. (Incidentally, Bob, I congratulate you on your informative paper; there is a dearth of info regarding ADS-B that is readily available or understandable and I'm surprised that I had not seen it previously, it's like the subject is top-secret. Where is the repository of all info on this subject held?).
Nonetheless, I stand by my comments that CAP 1391 contains little that is relevant to PAW. How should Lee and the Team respond to it, if at all? PAW doesn't directly transmit on 1090 ES. Without a Mode S ES associated with the PAW there is NO 1090 output; with a transponder, it's the transponder that's handling the ES broadcast, presumably using something other than DF 18 because it's a real transponder with current approvals rather than a "pseudo transponder" specified by CAP 1391. ( PAW solely outputs NMEA as RS232 to provide the necessary GPS source).
Like FLARM/ POWERFLARM, PAW transmits and receives on a different frequency using a different protocol to that described in the CAP. FLARM has already received some kind of approval from EASA, and as Lee has pointed out, there could be mutual interoperability with FLARM if they deemed to publish their protocol in the interests of safety.
I too am very interested in safety. Our group invested in a Becker Mode S transponder in 2010 which I think?? /hope may have ES capability, though it's not easy to be sure from its documentation or design iterations. I am desperate to be able to connect it to an uncertified GPS source to more readily "Be Seen" but the firmware does not currently allow SDA to be set to zero so this is a non-starter. Becker say they will address the problem but to be honest, I'm not holding my breath!
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Hi Bob D,
Are you trying to steal my identity ? :) :)
Seriously, I wonder if it is possible for the Administrator to change one of our User Names, without losing the posts, to avoid confusion ?
As a longer standing member, I claim squatters rights :) ;)
BobD (no space)
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Hi Bob D,
Are you trying to steal my identity ? :) :)
Seriously, I wonder if it is possible for the Administrator to change one of our User Names, without losing the posts, to avoid confusion ?
As a longer standing member, I claim squatters rights :) ;)
BobD (no space)
Appeal upheld, "Bob D", I have altered your screen name. Please modify if new name is not suitable
Admin
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I have read on several posts that it is not permitted to have two devices that transmit on 1090Mhz in one aircraft installation. May I ask where this rule is written please.
I don't understand the technical reason either.
The Mode S transponder is an interogation led device, i.e it gets interogated on 1030mhz and replies on 1090Mhz.
The ES transmission occurs pseudo randomly on 1090 with the ADSB data.
Where is the conflict ? Can they not co -exist. Is it a worry that the two transmissions ( on some occasions) may overlap?
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I have read on several posts that it is not permitted to have two devices that transmit on 1090Mhz in one aircraft installation. May I ask where this rule is written please.
I don't understand the technical reason either.
The Mode S transponder is an interogation led device, i.e it gets interogated on 1030mhz and replies on 1090Mhz.
The ES transmission occurs pseudo randomly on 1090 with the ADSB data.
Where is the conflict ? Can they not co -exist. Is it a worry that the two transmissions ( on some occasions) may overlap?
Reading the now published CAA document I believe the following applies
There shall be only one device using the ICAO aircraft address therefore;
If you have an A/C transponder with a low powered ADS-B device then only the ADS-B device will be broadcasting the ICAO aircraft address. In my interpretation that means I could have both devices operating.
If you have a Modes-S transponder with no ES output the Mode-S device will also be transmitting the ICAO airactft address and therefore only one device can be used.
If you have a Mode-S transponder with ES and a GPS connected then you would not need a separate transmitter as you would already be broadcasting your position as an ADS-B output via the transponder.
That is my interpretation of the published documentation and effectively I am interpreting the published information that the ban is effective on using a 1090 ADS-B out device in conjunction with a conventional Mode-S transponder with no ES and a Mode-S ES transponder you would not need a separate ADS-B out device anyway.
I was assisting NATS and AOPA during the trails of the LPAT and we asked all volunteers to switch off their transponders at the request of the CAA and NATS to ensure no cross interference during the trial.
This is my interpretation and I have already raised this with the CAA conspicuity working group as a Member of the FASVIG Conspicuity working group for a clear understanding as it is creating a good deal of conversation and needs to be closed down.
As a former radar engineer I have a clear understanding of the issues and why it's essential that the data to ATC systems is not compromised especially where maintaining separation of traffic is required. However I also believe the issue can be addressed and a better picture provided.
You have to appreciate that these devices and the rules around their use are in their infancy hence questions like this will arise and therefore good positive feedback is necessary to clear these issues. I hope you will also response to the CAA consultation on the low powered ADS-B specification so they are recorded through that mechanism.
Hope this helps.
Alan
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Just a thought then....
My Mode S transponder has a switch that allows me to have Mode A-S, Mode A-C and Mode S. If I select Mode C (Actually Mode A and C) then I will no longer be sending my Hex and A/C I.D. Then I could switch on my LPAT and would also be sending my Mode S E.S data allowing much more information to be sent than with the Mode S on my Txpdr. I was wrong
Also - if the spec says "only one device using" then isnt that still the case when the Mode S transponder is sending its burst of data, it is "using" the i.d and then when the Lpat sends its millisecond(s) burst - it is then "Using". Ok, occasionally they may both transmit simultaneously and produce fruit but it wont be decypherable.
John
Reading the now published CAA document I believe the following applies
Have you a link or CAP number for this please.
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John,
See very first post on this thread.
Steve
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Just a thought then....
My Mode S transponder has a switch that allows me to have Mode A, Mode C and Mode S. If I select Mode C (Actually Mode A and C) then I will no longer be sending my Hex and A/C I.D. Then I could switch on my LPAT and would also be sending my Mode S E.S data allowing much more information to be sent than with the Mode S on my Txpdr.
Also - if the spec says "only one device using" then isnt that still the case when the Mode S transponder is sending its burst of data, it is "using" the i.d and then when the Lpat sends its millisecond(s) burst - it is then "Using". Ok, occasionally they may both transmit simultaneously and produce fruit but it wont be decypherable.
John
Reading the now published CAA document I believe the following applies
Have you a link or CAP number for this please.
As Steve has pointed out the first post in this thread points to the CAP document and the opportunity to comment.
My own transponder is either on or alt with no option to disable the Mode-S features. I would also suggest that disabling a perfectly good Mode-S transponder would remove the advantage of providing ATC with your aircraft Callsign which aids them contacting you either on receiving a service or using a listening squawk.
The Hex code in the Mode-S response aids correlation in the plot extractors and display software and having multiple transmissions from the same target must all be processed, see the CAP document explanation, increasing the amount of fruit and time to determine the correct target and position.
Mode-S is a means of reducing fruit on the frequency by allowing selective interrogation in high density target areas using the ICAO Hex code. Deselecting that feature means that only an All Call from the ground interrogator will get a response form an A/C transponder. That together with MonoPulse all provides a greater integrity of target reasonsolution and verification allowing the reduction of separation criteria in areas where Mode-S predominates. So there are many factors to consider in this debate - but it is a debate and currently only my opinion based on my knowledge and experience.
In my view if you have a Mode-S transponder then having the ES option enabled with a GPS output would be my preferred option as then I would only be concerned about having a device that is listening for other targets.
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This thread is seeming like a moot point to me.
PilotAware is most definitely not 1090 ADSB out.
All this talk of one device etc etc may be pertinent to whether LPAT is compatible with a transponder, but I fail to see how it is pertinent to PilotAware.
With PilotAware you can SEE any of these other ADSB devices, you can BE SEEN if you have a mode S transponder and you connect PilotAware to it to give ADSB out (or indeed any GPS, but what's the point in doing only that, you can't "SEE" if you just connect GPS to your transponder) and you can even BE SEEN and SEE other PilotAware users.
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This thread is seeming like a moot point to me.
PilotAware is most definitely not 1090 ADSB out.
All this talk of one device etc etc may be pertinent to whether LPAT is compatible with a transponder, but I fail to see how it is pertinent to PilotAware.
With PilotAware you can SEE any of these other ADSB devices, you can BE SEEN if you have a mode S transponder and you connect PilotAware to it to give ADSB out (or indeed any GPS, but what's the point in doing only that, you can't "SEE" if you just connect GPS to your transponder) and you can even BE SEEN and SEE other PilotAware users.
Nothing wrong with what you state.
As I have posted earlier the use of electronic conspicuity devices is going beyond the old PCAS and FLARM units and equivalent and is in its early stages.
There is a lot going on in the development of he standards headed by the CAA and sponsored by Europe through Project EVA and the start of this thread highlighted the CAA CAP Document for those wishing to read, and comment as they desire.
I suggest that as operators of small light aircraft we only have room and money for one device and therefore we want value for money in a device that provides maximum visibility of others in the airspace and provides the maximum visibility of us to others.
Users have a choice of devices and I have no allegiance to any.
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John,
See very first post on this thread.
Steve
My Mistake - I thought there was another document. I had read this and could not find the reference to not having two devices in the same aircraft with the same hex code programmed in.
It does say that:-
6.14 EC devices offer no interoperability with interrogative collision alerting systems since DF=18 squitters from non-transponder EC devices will not be monitored by such systems.
This equipment offers interoperability at varying levels across functional capabilities and ranges from Airborne Collision Avoidance System (ACAS) II and Mode S transponders, required for most commercial air transport aircraft operated in controlled airspace, to ACAS I, Traffic Advisory Systems (TAS) and Mode S transponders for aircraft that are not required to be equipped to the same level, but that are voluntarily equipped to improve surveillance capability and situational awareness.
I read that as the EC is operable at the same time as the Mode S transponder.
This thread is seeming like a moot point to me.
PilotAware is most definitely not 1090 ADSB out.
Maybe not but does concern PAW owners who have bought early Mode S with no ES - (I believe Garmin Owners).
Deselecting that feature means that only an All Call from the ground interrogator will get a response form an A/C transponder. -
But they will have ES so will already be broadcasting their position, Altitude, possible speed, Velocity and so on - so they would not require interogating.
The Hex code in the Mode-S response aids correlation in the plot extractors and display software and having multiple transmissions from the same target must all be processed, see the CAP document explanation, increasing the amount of fruit and time to determine the correct target and position.
But in the report it says its not a factor and would only have to process the initial part of the data stream to decide its not relevant.
I would also suggest that disabling a perfectly good Mode-S transponder would remove the advantage of providing ATC with your aircraft Callsign which aids them contacting you either on receiving a service or using a listening squawk.
But you are sending it in your E.S transmission.
But for those that already have a Mode S that cannot send E.S, but want LPAT, If you do not program a 24-bit address /hex or set it as “000000“ the Mode S transponder operates as a Mode A/C transponder only, but you would have your LPAT and ES, to send your Callsign/Hex + Altitude etc.
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I would also suggest that disabling a perfectly good Mode-S transponder would remove the advantage of providing ATC with your aircraft Callsign which aids them contacting you either on receiving a service or using a listening squawk.
I totally agree Alan.
But you are sending it in your E.S transmission.
That's correct John, but as NATS/ATC apparently can't receive ADS-B outside the south east of England, being able to get your call sign from your Mode 'S' transmission is essential for the listening squawk system to work properly throughout the rest of the U.K.! I had personal experience of this recently when passing below the TMA under Edinburgh's Base Leg and squawking the listening squawk, (while carrying out some PAW Mode 'S' tests). Edinburgh called me to confirm my max altitude and intended route when two ADS-B equipped airliners requested immediate descent above me due to severe icing on approach. Fortunately, thanks to PAW / SD I could see them coming so was already aware of the possible conflict as soon as I heard their request on the radio and was able to advise that I would stay below 2,000ft allowing Edinburgh to descend both airliners immediately to 3,000ft, both passing close above me on their approach. Unfortunately LPAT wouldn't have been much help here as presumably neither ATC or the CAT traffic would pick it up (assuming it runs SDA/SIL '0' as we have been told ADS-B with non-cert GPS has to).
Regards
Peter
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But you are sending it in your E.S transmission.
That's correct John, but as NATS/ATC apparently can't receive ADS-B outside the south east of England, being able to get your call sign from your Mode 'S' transmission is essential for the listening squawk system to work properly throughout the rest of the U.K.
Regards
Peter
Currently the ES element of the Mode-S transmission is not used by NATS in an Operation capacity in any location.
The Mode-S element sent in response to a ground interrogator contains two elements. The conventional A/C response with additional data fields on the end containing the Hex Code, Aircraft Id etc
The ES element of a Mode-S transponder is broadcast from the transponder and is a data message. The timing is set to ensure that the transponder response to a ground interrogator is not overlapped with an ES broadcast response.
If I may go back to the original issue regarding the use of two devices simultaneous transmitting the same aircraft id. We are both making individual interpretations of what we have heard and what is written. The ultimate deciding factors is the response from the CAA and if what has been published so far, or is in the public domain, is being interpreted differently then it needs clarification and I suggest that feed back to the CAA is necessary to sort this issue.