Enhancement Requests

[Admin]

Lee the same question was asked here http://forum.pilotaware.com/index.php/topic,435.0.html. In there I think you misunderstood the question to be about transmission, when it was about how PAW receivers handle a mode S reception and P3i from the same aircraft.

Hi Ian

Thanks I will go back and check
Effectively the index into the internal database is the ICAO code, each database entry gathers as much information that it can, alt, pos etc. Then when sending to the nav device it decides how to represent the data.
So for example, if it receives Mode-S and P3I, then it has position, ground speed, track, squawk code, ICAO, altitude barometric and gnss. So this is NOT represented as bearingless, because we have appended the P3I data to the Mode-S.
Unless there is a bug here, this should only provide a single representation in the nav device.

Hope that makes sense ?

Thx
Lee

[Admin]

I am so glad I put that tracking feature in 

Thanks for the data, so this is what I have found
I found the following Aircraft

At some point 2 different ICAO codes were using the same FlightID, one Mode-S
and the other P3I/ADS-B, the ICAO codes are 87EA65 and 401FF2
$GPGGA,103857,5113.014,N,00008.432,W,2,05,1.0,57.0,M,-34.0,M,,*49
$PFLAA,3,-387,-302,7,1,87EA65!GBJWZ,0,,0,,8*1D
$PFLAA,3,0,0,5,1,401FF2!GBJWZ,,,,,0*15

I looked on ginfo for these codes, and G-BJWZ is
Hex: 401FF2
Which matches the Mode-S signature, but something with Hex Code 87EA65 is transmitting either P3I or ADS-B

So what is more interesting, I found the following other traces ALSO configured as FlightID GBJWZ, but only one of each, the above were many traces
$PFLAA,3,8,13,10,1,D3D090!GBJWZ,0,,0,,8*1E
$PFLAA,3,-235,-33,-3,1,D300F0!GBJWZ,224,,3,,8*03
$PFLAA,3,-153,503,100,1,DEE488!GBJWZ,81,,22,,8*4B
$PFLAA,3,21,306,-4,1,ED49E0!GBJWZ,75,,20,,8*79

I wonder if someone was trying to configure their PilotAware and inputing different HEX codes ?

Thx
Lee

[Keithvinning]

Perhaps a shared PAW being used in many school aircraft. With the reg being changed but the ICAO code not.

[T67M]

I've checked with the person who installed the PAW in G-BJWZ and he hadn't realised that the ICAO code needed to be configured as well as the registration, so it was using one of the automatically allocated codes. This has now been corrected... but doesn't explain the other four ICAO codes which Lee spotted in the log file. The aircraft is privately owned, and was in flight, so I'm pretty sure that no-one was configuring its PAW when I made the screen grab!

At least the main concern is understood and resolved.

[Ian Melville]

Thanks Lee, I broadly knew how it worked, but thanks for the details.

[gilest]

The voice alerts directly from the PAW are fantastic. A really brilliant addition but can I add my vote to the request to provide some sort of filtering for stationary or ground based devices - ideally selectable in the configuation.

1. If the PAW device is stationary (or very low ground speed <20kts?) can it be set not to announce traffic warnings when receiving traffic from other nearby transmitters. While great for testing, it would be distracting to get traffic alerts from other aircraft, while sitting on the ground not moving. If optional in the configuration then I guess helicopter or other aircraft capable of flying at very low ground speeds pilots could decide to enable?

2. Similarly if the PAW device is stationary should it transmit PAW signals? I assume another PAW device will pick up the stationary transmitter and will just be clutter or may even be seen as a traffic threat to other aircraft flying low overhead. I assume that if stationary the transmitting aircraft is not a threat. Again this could be an optional setting for helicopters or paramotors etc. This is not tested so apologies if this is how it currently works.

3. Some sort of optional filter to switch off audible voice alerts when manoeuvring or close to the ground or on final etc at known airfields. I guess this could be simply unplugging the PAW audio out but would one forget to plug in again!! So maybe an optional filter based around proximity to ones manually inputed home airfield(s). If one inputted the altitude (asl) and GPS location of an airfield then a user could choose to optionally disable voice alerts when say within 1km or 500ft of the airfield(s). Just an idea? :-)

For interest what is the criteria for "same level' when annoucing traffic alerts? Within 1000ft? I was getting "same level 1,2,3 o'clock" warnings from aircraft flying between 500-1000ft all above me when I was on the ground (testing in the garden!). Assume this is ADSB traffic as no PAW transmissions seen and the directional warning I assume means the aircraft must be transmitting GPS location - so not Mode S. Also I assume they were flying above 500ft all as I live in a village and aircraft we are light GA aircraft several km from the nearest airfield! I see there is a setting for Mode-S sensitivity but there does not seem to be something similar for PAW and ADSB traffic.

4. Therefore following on from above what about a setting to adjust the altitude difference that triggers audible traffic warnings for low, high and same level traffic?

Hopefully this is helpful and will provoke some thought and discussion for possible future improvements.

[Admin]

Hi Giles,

All good feedback.

For interest what is the criteria for "same level' when annoucing traffic alerts? Within 1000ft? I was getting "same level 1,2,3 o'clock" warnings from aircraft flying between 500-1000ft all above me when I was on the ground (testing in the garden!)

The voice alerts give either 'above', 'level' or 'below'.
This is not indicating relative height, but the elevation to the horizon.
So if you think about it, an aircraft 10km away at 1000ft above is going to appear as though it is 'level'.

The algorithm calculates if the angle to the horizon is +/- 20 degrees or less, this depicts 'level' and the other cases are either 'above' or 'below'

Thx
Lee

[gilest]

Ok. That makes sense. So if +/-20 deg between PAWs then level, so the further apart the greater the height difference to still be level.

[Admin]

Ok. That makes sense. So if +/-20 deg between PAWs then level, so the further apart the greater the height difference to still be level.

Thats correct, but ADS-B as well as P3I (PAW)
Thx
Lee

[gilest]

Thats correct, but ADS-B as well as P3I (PAW)

What about Mode-S. Does that not give a level (but obviously not a direction) too? Also your thoughts on my suggestions to limit voice alerts and P3I transmissions when a PAW is stationary?

[exfirepro]

Hi Giles,

To keep them simple and 'different' from the 'position based' ADS-B/P3i alerts, Mode S alerts, based predominantly on the strength of the received signal, take the form 'Traffic- Notice', followed by 'Traffic - Alert' and 'Traffic - Danger', if the target continues to get closer. This is accompanied by a visual warning on your nav system screen which includes the target's relative altitude. No positional information is given in the audio warning.

In the case of ADS-B / P3i the warning is 'Traffic - X o'clock (with reference to your track) - 'Level' or 'Above' or 'Below -  (at) Y kilometres.  it is not a 'Level' as in 'a flying height'. Again the relative altitude of the target is displayed next to the (moving) aircraft symbol on your nav system display.

You have obviously read the earlier posts in this thread about audio alerts on the ground, which we are trying to decide the best way to deal with, without simply 'turning them off' and letting pilots taxi out into for example the path of an un-noticed and perhaps non-radio aircraft on final. (Preferably without having to manually operate a screen based on/off switch when your attention should be elsewhere). Lee has already incorporated user selectable filters which control the Mode S alerts and updated settings are currently under test which should improve things. In a similar vein, the P3i transmitter can be turned off by selecting 'Base Station' mode in [Config], (edit: I have just been told that I was misinformed - that this is NOT correct. At the present time, selecting 'Base Station' DOES NOT turn off the P3i transmitter)...but this is not something we would encourage in active aircraft anyway as the inbounds may still benefit from a reminder that you are there on the taxi way or threshold.

Unfortunately, the simple sounding 'solutions' all have their flaws, but Lee is working on it and your contribution to the discussion is very much appreciated.

Regards

Peter

[gilest]

Hi Peter. Thanks. That is really helpful to know how the Audio Alerts work. I had assumed that mode S used the relative altitude to calculate a level, above, below warning. Is that something in the pipeline?

audio alerts on the ground, which we are trying to decide the best way to deal with, without simply 'turning them off' and letting pilots taxi out into for example the path of an un-noticed and perhaps non-radio aircraft on final.

From my personal prospective (and as an active pilot) by far the primary purpose of PAW is to provide a "see and be seen" tool while flying cross country - where a combination of high closing speeds, poor aircraft visibility and other cockpit distractions create a potential collision risk. In my personal opinion "electronic" ground based traffic warnings are not so necessary, as other aircraft are much easier to be seen and pilots more attuned to the risks during taxi, take off and landing phases. In my opinion audible warnings may even contribute negatively due to the distraction, complacency and the tendency to manually switch off the PAW. However I realise that is my opinion and may not be held by others - however a configurable setting would allow individual choice.

in active aircraft as the inbounds may still benefit from a reminder that you are there on the taxi way or threshold.

The same comments as above. In this critical phase I want to be focused on the landing area and circuit traffic not to be distracted by someone inbound 10km out transmitting mode S! Maybe a simple audio mute is the solution.

Anyway it is great to be able to enter the debate and I really applaud the work you are all doing in this critical safety area.

[Admin]

Thanks for all the input, should probably moved the Audio/Mode-S/ADS-B/P3I onto a separate thread, but this is what I think we are coming to ....

Firstly the audio messages of 'above/level/below' indicate an angle to the horizon of
above = greater than +20degrees
level = between +20 and -20 degrees
below = less than -20 degrees

This can only be calculated with ADS-B/P3I - simple trigonometry, you need a distance and relative altitude.

For Mode-S, all you have is relative altitude, but no distance, therefore it is impossible to calculate the angle to the horizon, consider the angle to the horizon of +500ft at a distance of 100m and 1000m - completely different.
The altitude difference could be added for Mode-S altitude if it is valuable, but this would be of the form
"Notice, traffic, 500ft above", thus not indicating elevation to the horizon
Phew!

I think I am hearing two requirements for muting the audio :-

1. A manual mute: I like this idea with a configurable timeout, in other words mute for X minutes, then automatically re-enable, or mute permanantly (or pull out the plug!)
This could solve the issue of Taxi, Take off & Landing

2. Ground speed filter: if my speed is less than X Kns, then mute the audio.
This can only address the issue of Taxi & Take-off

These could both be config options, and in the case of Helicoptor, Paraglider, Hanglider, the speed option may not be a good choice.

Thx
Lee

[gilest]

Lee. Thanks for quick response.

For Mode-S, all you have is relative altitude, but no distance, therefore it is impossible to calculate the angle to the horizon, consider the angle to the horizon of +500ft at a distance of 100m and 1000m - completely different.
The altitude difference could be added for Mode-S altitude if it is valuable, but this would be of the form
"Notice, traffic, 500ft above", thus not indicating elevation to the horizon

I think this is a great idea. Giving height adds a huge amount to the message. Roughly where to look vertically but more importantly with the decision whether to climb or descend.

Thinking about ADS-B/P3I alerts the perfect solution would be to announce relative height if "level" and within short range ie in danger of collision - then even if not visual one can decide whether to climb or descend. Maybe getting too complex but think it would be very useful safety aid.

1. A manual mute: I like this idea with a configurable timeout, in other words mute for X minutes, then automatically re-enable, or mute permanently (or pull out the plug!) This could solve the issue of Taxi, Take off & Landing

My only comment is if a software mute how this would be accessed? Going into the configuration of the PAW in-flight is tricky. I feel a hardware mute is best, but implementing a time out would be difficult! Maybe just pulling the plug is simplest/best solution here! ;-)

2. Ground speed filter: if my speed is less than X Kns, then mute the audio.

Personally I really like this idea and I think this should also apply to P3I transmissions (both optionally from config).

Interestingly (as I am sure you know) the procedure for Mode S transponders is to leave on standby mode until entering the runway threshold or in the case of aircraft that have a sensor on the undercarriage until after take-off and similarly on landing to switch back to standby after vacating the runway or having touched down. It seems to me that this procedure is equally relevant to PAW but due to the lack of easily accessible controls on the PAW device that a more intelligent process is needed ie the speed filter.

These could both be config options, and in the case of Helicoptor, Paraglider, Hanglider, the speed option may not be a good choice.

Absolutely

Giles

[grahambaker]

I'd like to be able to filter out audio warnings for traffic greater than a certain distance away. Hearing 'Traffic noticed' every time an airliner gets airborne 75 miles away is a bit pointless, frankly.

BTW Mode S Ground Mode and Standby are not the same thing, AFAIUI.  Standby means your transponder effectively is switched off, but powered up. Ground Mode means it still responds, but with a flag set (I think).