PilotAware
British Forum => General Discussion => Topic started by: Ian Melville on July 10, 2016, 12:23:38 pm
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I have updated my two PAW without any issues using the LAN.
I thought the volume save was to be fixed in this version? It's a pain in the butt to crank it up to full volume every time it's powered up.
I keep seeing an option to set the QNH, but it later disappears. Is this only while the Baro sorts itself out?
Also what is Mode-S Select and how do we use it?
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Hi Ian,
I have updated my two PAW without any issues using the LAN.
great!
I thought the volume save was to be fixed in this version? It's a pain in the butt to crank it up to full volume every time it's powered up.
didn't quite get it working correctly :-\
I will revisit and try to get into next release
I keep seeing an option to set the QNH, but it later disappears. Is this only while the Baro sorts itself out?
absolutely, once it has connected to the bridge it removes the option
Also what is Mode-S Select and how do we use it?
If you search the forum for exfirepro postings, you will see lots of info on this.
yet to be fully documented
Thx
Lee
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Thanks Lee,
I have been unable to find anything on Mode-S Select using the search. I suspect it is linked to suppressing Mode-S alerts, but the last comments I can see, was that the method has yet to be decided.
In this case the options are not intuitive.
I'll also ask again if we can have the alerts in Nautical Miles, using the unit of distance that the majority of us use.
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Thanks Lee,
I have been unable to find anything on Mode-S Select using the search. I suspect it is linked to suppressing Mode-S alerts, but the last comments I can see, was that the method has yet to be decided.
In this case the options are not intuitive.
I'll also ask again if we can have the alerts in Nautical Miles, using the unit of distance that the majority of us use.
Hi Ian,
I now realise the confusion.
The Mode-S select at the moment is either None, or Mode-S, ie enabled/disabled.
In the internal Engineering build this is capable of
- None
- Mode-S
- Mode-S+C
- Mode-S+C+Filter
Basically adding in the capability of Mode-C detection and the ability to filter the strongest (ie locally equipped)
transponder.
This is still under development, and if successful, will be in a future release.
Thx
Lee
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Lee,
Can you just check that when in the web interface the link button from out of the traffic Page back to home page is working. I could not go to the home page from here. It did work ok from the other pages. I could be wrong and be suffering from fat fingers....
The colour rings is much better for mode S ..... Brilliant.... Thank you
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Lee, Thanks for the explanation. I have just done a bit of testing. By default the Mode-S Select is set to 'none'. Users need to be advised that this will turn off the Mode-S detection. So to get back to what they had before they need to set it to 'Mode-S' until the additional functions are available.
Richard, the link works for me on the latest version.
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Lee,
Can you just check that when in the web interface the link button from out of the traffic Page back to home page is working. I could not go to the home page from here. It did work ok from the other pages. I could be wrong and be suffering from fat fingers....
The colour rings is much better for mode S ..... Brilliant.... Thank you
Hi Richard,
This is possibly due to the refresh rate of th traffic screen, I think it is set to refresh either 1 or 2 seconds.
and in safari, if you hit the link - just as the refresh is started, it is sometimes ignored, very annoyingly.
I could slow the refresh, but I dont particularly like that idea
Thx
Lee
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Lee, Thanks for the explanation. I have just done a bit of testing. By default the Mode-S Select is set to 'none'. Users need to be advised that this will turn off the Mode-S detection. So to get back to what they had before they need to set it to 'Mode-S' until the additional functions are available.
Richard, the link works for me on the latest version.
Hi Ian
What has happened is that some of the menus have been shuffled so the previous settings for this
would have been discarded during the upgrade
Thx
Lee
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Lee, Thanks for the explanation. I have just done a bit of testing. By default the Mode-S Select is set to 'none'. Users need to be advised that this will turn off the Mode-S detection. So to get back to what they had before they need to set it to 'Mode-S' until the additional functions are available.
Richard, the link works for me on the latest version.
Hi Ian,
Due to the fact that detection and display of 'bearingless' targets is more complex and requires direct pilot action, i.e. active selection of detection range - which requires an understanding of how the system works, the experience to decide the most appropriate range for your current flying environment, and a clear understanding of the use of physical lookout to 'find' the reported aircraft. Mode S was therefore set to 'off by default' to allow new PAW users to get to know the system before deciding when and how they wish to use the Mode S 'option'.
Selection of detection range is of significant importance. Too long in a busy environment and you will receive constant alerts which can cause distraction and if the contacts are not 'found' can cause the user to start disbelieving the warnings (which are in fact always real, but probably came from a high power CAT transponder far too far away to be a risk - full 360 degree physical lookout up/down or level as advised by the relative altitude confirms this and allows it to be disregarded, unless it continues to approach). Too short on the other hand and you might not get that critical warning until it might be too late.
I agree that it would be beneficial if these settings once decided by the pilot were retained during update, or if not practicable, a warning to this effect needs to go in the Operating Manual. In any case it is important if using Mode S to recheck settings before each flight if your environment is likely to change.
Regards
Peter
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Thanks Peter,
Makes sense to me. I've been experimenting with the range and found that 'short' meant that I was visual with the target before the alert. 'Medium' gave a greater number of alerts, most of which must have been no threat due to great distances. But then I didn't see them so will never know. I will stick with 'Medium' for now.
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Hi Ian,
I also generally use the Medium Range setting unless I know I will be flying near CAT traffic e.g. when they are on left base into EGPH or if I'm doing a zone transit through the Edinburgh overhead, when I will select short range.
Unfortunately there is no easy way to filter out High Power CAT mode S except via the altitude and range filters. You will still get some 'rogue' alerts - note these are NOT FALSE ALERTS - from further away CAT aircraft, but soon learn to recognise these as such after a good 360 scan and can fairly quickly disregard them. Unless you are very near a large airport it's not usually too much of a problem.
Regards
Peter
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Just a thought - could the SIL / SDA flag settings, in conjunction with received signal strength, be used to indicate the likelihood of a CAT Mode S bearingless target return and therefore a likely low(er) probability of a "risk" aircraft"?
As I say, just a thought and I am not even sure if these flags would be set to in a CAT's Mode S transponder (with no ADS-B).
Or are there other flags that may differentiate between CAT and GA mode S transponders?
Tony Nowak
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Just a thought - could the SIL / SDA flag settings, in conjunction with received signal strength, be used to indicate the likelihood of a CAT Mode S bearingless target return and therefore a likely low(er) probability of a "risk" aircraft"?
As I say, just a thought and I am not even sure if these flags would be set to in a CAT's Mode S transponder (with no ADS-B).
Or are there other flags that may differentiate between CAT and GA mode S transponders?
Tony Nowak
Hi Tony,
Afraid not, SIL/SDA are sent as part of an Extended Squitter DF17 message - which is ADS-B
Mode-S does not contain this information.
Thx
Lee
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Hi Tony,
Lee just beat me to it. I was busy looking back through my test screen captures to check this. Unfortunately as Lee says SIL and SDA are only transmitted for ADSB, and even then with commercial units very infrequently, so this just wouldn't work.
Thanks for the suggestion though.
Regards
Peter
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The altitudes on the ADS-B and Mode S transmissions would match perfectly surely?
If altitudes on a Mode S and ADS-B target change to identical figures within 30 seconds of each other, you could assume that the they are one and the same target, and disregard the Mode S information until there is a disparity in altitude data for longer than a set period.
Complex logic, but just a thought as to how to reduce CAT "interference" ?
Assuming a bearingless Mode S target is also sending ADS-B as well that is. I would imagine nearly all CAT is using ADS-B is it not?
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If a transponder with ADSB transmits two packets then the mode S and ADSB would have the same hex code? I didn't think it did transmit twice? Hence a bearing less Mode S that also transmits ADSB, would not be bearing-less?
What we are discussing above is mode S only transmissions.
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So there aren't any flags in a Mode S (non ADS-B) transmission that could possibly help differentiate between CAT and GA?
I seem to recall setting various parameters in my Trig TT21which relates to my aircraft size and cruise speed etc. I don't think they were related to my ADS-B connection but don't have my manual to hand just at the moment.
Tony Nowak
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Hi Doc/ Tony / Ian,
If it was easy, we would have done it, believe me.
Yes, as Ian says, with an aircraft fitted with ADSB and Mode S, we get two sets of data, but Lee then filters out the Mode S using the 'hex' address, as the ADSB gives us exact positional data which are then presented to your nav system.
The problem arises with straight Mode S, which is used by a significant proportion of GA, as well as by a significant proportion of CAT instead of ADSB. Having no positional information (except altitude) we have to assess and present risk information based solely on the strength of the received signal. The problem is that signal is generated from a transponder the output of which can vary from about 70watts minimum at the antenna (e.g. Trig TT21 or similar) up to 500watts at the antenna for CAT. That's before we take into account significant variation between the fit of even the same transponder in individual aircraft, which can be considerable. The only reliable filter to differentiate between a close GA signal or a further out CAT one is the human eyeball I'm afraid.
Regards
Peter R
Mode S Development Tester
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ADSB usage. From the table I guess that only three aircraft
are ADSB equipped.
Am I correct?
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Yes
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ADSB usage. From the table I guess that only three aircraft
are ADSB equipped.
Am I correct?
Eric,
At first sight, Keith is correct - the rest of your traffic screen entries 'appear' to be Mode S. The significant factor is normally the fact that containing no positional information PAW cannot display any DISTance from the contact aircraft to your PAW.
Whilst I have experienced lots of 'non-ADSB' CAT aircraft, including Dash-8s and other FlyBe aircraft in particular, I am very suspicious that so many 'CAT' aircraft - including Boeing 737s, 747s and 787s at such high altitudes would not be fitted with ADSB out equipment.
If they were on the ground, knowing your proximity to Blackpool Airport, I would suspect that some of these - for example the bottom two - were Ground Transmissions from otherwise ADSB equipped aircraft (which appear on PAW in the same manner as if they were Mode S), but most of these are, as I say at high altitude.
I wonder if there is something else going on here. Perhaps Lee might be able to shed some light on this.
Regards
Peter
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Hi Lee,
Then what about trying to use the "aircraft category" and "speed" flags to differentiate between CAT and GA mode S bearingless targets?
I have asked Trig about these and it seems all Mode S transponders will have this data.
From Trig:
"The aircraft category is reported whenever the flight ID is changed, when it’s interrogated, and is squittered every 5 seconds (if the aircraft is ADS-B equipped).
The airspeed is reported when replying to a Mode S interrogation (usually from a TCAS).
The aircraft category is reported in the “Aircraft Identification and Category” extended squitter message in the “Emitter Category” field.
The airspeed is reported in the “Long Air-Air Surveillance” message in the “RI” field."
I remember setting these values when I got my Trig TT21
Tony
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Hi Tony,
Don't wish to rain on your parade, but the parameters you mention are all part, I believe, of the ADS-B message, and will be absent if the aircraft is only Mode S i.e. Is not transmitting ADS-B Extended Squitter and is therefore only " bearingless" in this particular case.
Regards,
Chris
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Hi Chris,
The info from Trig tech support seemed to suggest the data wasn't only for when ADS-B was configured/enabled.
I had to make those settings when I first installed my transponder (3 years ago) well before I decided to add the ADS-B capability.
Tony
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Hi Tony,
It funny but the darned Becker BXP 6401 Mode S transponder our flying group purchased in 2010/2011 didn't require us to make any of those settings. It's meant to be capable of outputting ADS-B ES if a GPS source is connected. All we had to do was connect the pre programmed address module which carries the 24bit unique code. It just seems to show how much further Trig are ahead of the game, I suppose. However I still think the parameters that you had to program were probably a precursor for you to add ADS-B Out functionality. This is evidenced but the term "squittering" that appears several times in the quote you posted from Trig and only applies to ADS-B Extended Squitter which is overlaid on top of basic Mode S, if so enabled.
Regards,
Chris
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The signal strength is very low on those A/C that show no distance.
Maybe some of the position data is corrupted hence not showing the distance?
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Yes, I've found this, if the signal strength is low, it won't be able to get a position.
Usually lower than this though, in the single digits.