When willl the PAW be ready?

[Ian Melville]

Hi Peter,
I am not sure how you post was aimed at?
We know the license will not be transferable to the Pi2B. The question was what will it cost is we upgrade the Pi Free, £12 or £15?
Who is Vince? The rest of the sentence supports my query.
I don't have a Pi2 or any sort yet, but want to be clear about what functions I will lose if I do not upgrade.

[exfirepro]

Hi Ian,

As you will have seen, I have been chatting to Bill M out in Oz over the past few days about developments and my post was specifically in reply to his, though I thought Gareth (and presumably others including yourself) might benefit from what I suggested as a possible temporary workaround to get Pi2 units online. I'm afraid I can't answer definitively re licensing costs as that is not within my remit (principally beta testing of the mode 'S' functionality). I would, however, think that if you are building what is in effect a 'new' unit it would require a 'new' licence, obtainable through the purchase of a full kit or bridge as has been reported many times before. If I'm wrong, I'm sure Lee will correct me.

For 'Vince' please read Keithvinning - mental block, sorry Keith - I have corrected my earlier post.

In effect ADSB is also Mode-S...

Yes, in a way as it is derived from the same transmitter, but mode 'S' is not ADSB and is not displayed on beta or current B+ units.

In short, what you will 'lose' if you don't upgrade is the mode 'S' detection and the audio alerts, which you don't currently have on the B+ anyway, so not sure 'lose' is the right term. Perhaps better to look on any additional licence cost as a very worthwhile (and remarkably cheap) upgrade expense.

Hope this helps clarify the situation

Best regards

Peter

[Ian Melville]

Hi Peter,
So are you saying that the traffic that I can see on my Beta PiB+ is not mode S, but just ADSB?

My understanding was that ADSB Required mode-S to function. ADSB being the method of how Secondary Survailance Radar see a mode-S transponder. Extender squitter adds more data to ADSB. Need to have a read up on this tonight.

[exfirepro]

Hi again Ian,
That's right. The Beta Pi B+ (without the original ARF board or Pilotaware P3i bridge) receives ADSB only.
Without getting too technical, an ADSB transmission is generated by the transmitter of a suitably set up Mode -S transponder independently of its Mode-S operation by adding position data from a suitable gps.
The ADSB data, which includes the aircraft identity, altitude and position is transmitted regularly and automatically by the aircraft independently of any Mode-S transmission.
Mode-S on the other hand is only transmitted when triggered by an external interrogation such as a ground based radar unit. When this happens, the Mode-S transponder 'replies' with a preset 'squawk' code, plus the aircraft's ID and altitude. Unlike ADSB, transponders do not transmit their location. Instead, this is worked out by the radar unit from the time ot takes to get an answer from the transponder plus the angle the radar head is pointing. Hence in a nutshell why receiving, decoding and providing meaningful warnings for Mode-S is more complicated.
Hope this helps
Regards
Peter

[SteveHutt]

Ian,
Extended Squitter (ES) is the function of transmitting ADS-B data from a Mode S transponder. Not all Mode S transponders are ES-capable. And ES-capable Mode S transponders need to have the ES function switched on plus be in receipt of valid position data from a connected GPS device.

It is also possible to have devices that only do ES, i.e. ADS-B Out, without the rest of the non-ES Mode S conventional transponder functionality. That is what the demo NATS LPAT (Low Power ADS-B Transceiver) does, as per CAP1391 (plus ADS-B In and very basic Mode C&S range detection).

Steve

[Ian Melville]

I'm a techy type, but just want to know why my beta PiB+ will no longer be able to see the ADSB broadcasts it currently can, once we move to the latest software. As per Keith's news.

 
 
I will have to bow to the greater knowledge of you guys as you work with this stuff.

[Deker]

So will the Pi 2 become the new hardware standard and the B+ use phased out?

The new Pi2 has a much gruntier processor than the original B+, so I guess the additional processor overhead of decoding Mode S and extended squitter transmission and other new features needs the newer Pi version.
If so, my B+ will have to be evicted from its case to the shelf and a new Pi2 installed in place?
ATB
Deker

[AlanG]

Ian

You will still see the ADSB contacts that you have always seen.  the Mode S referred to in this case are the non-directional or bearingless contacts that the engineering group were testing to assess the usefulness or otherwise of including these in the final product.  As these are derived from the signal strength being received from the various transponders it required more calculations and therefore increased processor demand which Lee has decided requires the better RPi2B.  As someone has already stated you will lose none of your existing functionality, still be able to fit the new bridge and use that but you will not receive bearingless warnings or voice alerts which are the added extras.  You will have everything you originally expected to have from your PAW but if you want to benefit of the extra functionality you will have to upgrade.  I'm in the same boat and I have been doing a lot of the testing on an RPiB+ and have experienced some of the dropouts referred to so I will have to invest in an RPi2B.
Hope that's clear to you and anyone else who is worried about this.

Regards
Alan

[exfirepro]

Ian,

I think you're getting confused. As Alan has just posted, the PiB+ will still receive the ADSB contacts as it does at present, plus if/when you fit a PAW Bridge it will also transmit and receive 'similar' but specific P3i signals between your aircraft and any other aircraft within range similarly equipped. What Keith is saying is that by upgrading to a Pi 2, you would also be able to receive 'Mode-S' signals and the associated audio alerts - though you don't of course have to upgrade unless you want to. (But having tested the new system, I would seriously recommend doing so).

Hope this helps make things clearer

Best regards

Peter

[Keithvinning]

For 'Vince' please read Keithvinning - mental block, sorry Keith - I have corrected my earlier post.

Not to worry. As a PilotAware minion I am used to being called all things. My wife has been known to call me me Steve. Should I worry?

Keith (Vince, Steve or whatever) Vinning

[Bill Maxwell]

I think the air would be better cleared by a definitive statement by Lee (for example), on behalf of the team, rather than by individual members, on the RPiB to RPi2B licence upgrade requirements. While at it, include a definitive statement on just who will be entitled to participate in the "trade-in" offer on the old Wireless things RF deck. Keith's recent message about PAWs licenced before the October SOU announcement is at odds with the statements by Dave Styles on 1 December, when he said that the transceivers bought before the SOU would be eligible. I have just again come across Dave's advice in the Known Good Hardware thread.

To round all that off, I think a formal announcement should also include a definitive statement on the sales priority issue that Peter raised a few days back.

We all appreciate that changes in priorities, policies or strategies can be driven by economic, supply or other considerations but I for one would far preferred that such changes be announced publicly  as soon as determined, such as was done in the SOU announcement back in October, rather than being left to dribble out in as they now appear to be. Of course, all that assumes that the marketing strategy has actually been determined

[Bill Maxwell]

Damn, this creaky old laptop is prone to enter its own return if pressure is applied to certain areas of the case. It posted my latest suggestion before I had finished editing it. Still, I think the message is there.

I'm not meaning to appear critical but only to aid common understanding on these points and certainly to clarify my own.

Cheers
Bill

[Ian Melville]

Peter, Alan and Steve,
I now understand what Keith and you have been trying to put across. However still confused by the terminology you are using.
For many months non-directional bearingless transponders have been referred to as mode A/C in all posts and it was the aim of PAW to try and provide some warning of these. Keith's news post is the first time I have seen these being called bearingless mode S.

Correct me if I am wrong
When mode A/C transponders are interrogated, they respond with the Squawk code and if mode C the pressure altitude encode by Gillham code.
When a Mode S transponder is Interrogated its response depends on the format of the interrogation. The response may be just the 24bit aircraft code, but can contain additional data.

Mode S transponders have co-located ADSB transmitter, which periodically transmits ADSB packets which contain data of interest to PAW such as Aircraft code, height and position.
ADSB packets can also be transmitted without a Mode S transponder.

Hence a PiB+ will be able to see a Mode-S transponder units ADSB packets as well as P3i packets. It will not have sufficient power to compute the distance of Mode A/C transponders (or voice alerts)

Why would PAW need to try and figure the threat distance from a Mode S transponders Bearingless transmission when it can also see it's ADSB packet? Which is why I am puzzled by Keith referring to them in his news update.

[AlanG]

Hi Ian

The confusion arises from the fact that all the latest generation of Xponders are Mode S Which broadcasts only "Altitude" info as well as the ident. info and most of them, if not all, are capable of producing ADSB-out when attached to a certified GPS and will then give positional info too. (Lat/Lon).  Unfortunately a certified GPS is very expensive and so it is usually only the larger airliners that are so equipped.  This was the reason for the trials we have been reading about recently which have now resulted in some GA aircraft being allowed to fit un-certified GPS to their Xponders to enable this extra positional info to be broadcast.
Ground stations, air traffic etc, obtain positional info from mode S only aircraft via the primary radar.
It's the ADSB-out that allows any suitably equipped (PilotAware, other adsb receivers are available)  aircraft  to receive all of this info and display it.
Lee and the team have been putting in a lot of effort to try to enable bearingless alerts for Mode A/C/S but this has been reduced to only Mode S now as the A/C proved not to be that useful and were even more processor hungry than the system could support.
I think that's more or less how it all works and if I've missed anything or got any of it wrong I'm sure someone will correct me.   Hope I've not confused you even more.

Regads
Alan

[Moffrestorer]

Hi Ian,

Some Mode S transponders have Extended Squitter (ES, the co-located ADS-B transmitter to which you refer). The earlier units do not have this and the transponder is similar to a Mode C but with the addition of transmitting the aircraft's ID code and flight code.

The later transponders with ES will not use the ES facility unless a GPS source is connected to the transponder and the ES is enabled. This is what the NATS trial and agreement to connect uncertified GPS has been all about. Until this is done, the Mode S transponder is effectively like the mode C type and will not transmit position data (via ES), so that's why PAW needs to work out where it is as its "bearingless". At present I imagine very small percentage of GA Mode S transponders are yet fed with a GPS source! If it's in a certified aircraft its likely to be way more complicated to impliment than for LAA and BMAA aircraft.