Track File : Post Processor : New Version (0.2)

[DaveStyles]

Hi Alan,

Good point, I don't think modeS was considered, too busy working out the 3 dimensional maths for the other targets.

We'll discuss the track files with Lee. I think it's fair to say that's a loophole in the current post processor. We wanted to get it up as people are beginning to get PAW to PAW hits and it's an easy way to see who, where and what sort of distances.

Plenty of refining to be done, but OK for a first release.

[AlanG]

No problem Dave,
as yourself and others are saying it is useful in its current form, especially when looking for known contacts.  I was just curious where it was taking info from to give any indication of Mode S position & direction when the fields in the $PFLAA sentences are effectively blank.  I would have only expected a possible altitude comparison. 
As you say, a work in progress.  Be assured my comments were not intended as a criticism.

Regards
Alan

[DaveStyles]

all feedback is good feedback ! Glad you pointed it out tbh
regards, Dave.

[Ian Melville]

I haven't much time to analyse it full but I did two flight yesterday from Enstone with PAW running in our group PA17 G-AWKD. The first in the morning only went a short way to the north west. The second in the afternoon was across to Daventry area. I used the audio alerts rather than checking the screen, as I only had an iPhone.

The Track Log shows I got an other PAW at 19Km, which came as close as 12Km. Not close enough to trigger an alert. Which showed to be an Eurofox. First contact 14:21UTC

Had quite a lot of 'Danger' Mode S alerts at my level, but saw nothing. It did pick up a Puma on converging course, almost Head on, a just a few 100 foot above me. But was just a split second before I saw it, approx. 3 miles away.

Dipole antenna was velcored to rear cabin bulkhead (a fabric panel).

Need to chew the data a bit more.

[exfirepro]

Hi Ian,

What Mode S range setting are you using? Also what vertical separation do you have selected? I suspect most of the Mode S contacts which you 'weren't seeing' were probably high power transponders e.g. CAT. Unfortunately this is an issue we have to live with, with Mode S, though reducing your separation level to say +/- 1000ft removes most of these. Changing to a shorter 'Range' would also help, but might have meant you saw the Puma before you got the alert. Just a question of balancing your settings to flying conditions.

Regards

Peter

[Ray McKeown]

Why is this contact showing as nearly 8 million metres away?   Probably 8km? 

[Admin]

Hi Ray

Why is this contact showing as nearly 8 million metres away?   Probably 8km?

I think I would like to see the entry in the .trk file first, it could be the post processor which is wrong, it could also be the input data.
These are the messages sent to the NAV tool, I could imagine if the GPS was bad at this point it would think a received signal was further than it really was.

If you can provide access to the track file, I will take a look at some point.

Thx
Lee

[Ray McKeown]

Thanks Lee, have emailed the trk file to support address

Regards, Ray

[DaveStyles]

Why is this contact showing as nearly 8 million metres away?   Probably 8km?

I'm waiting for someone to ask which antenna you are using to get that range !

[Admin]

Hi Ray,

Why is this contact showing as nearly 8 million metres away?   Probably 8km? 

The A/C in question G-PYPE, does this have an ADS-B in addition to PilotAware fitted ?
Also what version of PilotAware is being run ?

Thx
Lee

[Ray McKeown]

Yes he is broadcasting ADS-B OUT from a Funke Xpdr.  I believe he is running latest release albeit on a B+ 1. He's disappeared off to France but I'll email to confirm release level.

Regards, Ray

[Ian Melville]

Hi Ian,

What Mode S range setting are you using? Also what vertical separation do you have selected? I suspect most of the Mode S contacts which you 'weren't seeing' were probably high power transponders e.g. CAT. Unfortunately this is an issue we have to live with, with Mode S, though reducing your separation level to say +/- 1000ft removes most of these. Changing to a shorter 'Range' would also help, but might have meant you saw the Puma before you got the alert. Just a question of balancing your settings to flying conditions.

Regards

Peter

Hi Pete,
I had +/- 2000, and off the top of my head the medium setting. I am away from Home not until Sunday, so cannot be more precise. Today took the range to the next shorter (not the shortest Ultra Short) and could see an approaching mode S only helicopter blasting through the circuit, at circuit height  ,but he was less than a Km away before PAW spotted him. I also did not see the Reds who passed to the south, close to Enstone, visually or on PAW.

One thing I did notice is the OSF motor glider, which is S only kept appearing and disappearing from my Skydemon screen. We were doing circuits at the same time.

[exfirepro]

Hi Pete,
I had +/- 2000, and off the top of my head the medium setting. I am away from Home not until Sunday, so cannot be more precise. Today took the range to the next shorter (not the shortest Ultra Short) and could see an approaching mode S only helicopter blasting through the circuit, at circuit height  ,but he was less than a Km away before PAW spotted him. I also did not see the Reds who passed to the south, close to Enstone, visually or on PAW.

One thing I did notice is the OSF motor glider, which is S only kept appearing and disappearing from my Skydemon screen. We were doing circuits at the same time.

Hi Ian,

Alan G and I usually run with the Medium or Short Range Mode S settings these days. We developed 'Ultra Short' to deal with close proximity to high-power CAT Mode S or high power CAT ground radar signals, which otherwise swamp the Mode S triggers, causing continuous Danger Alerts, but would only use this setting if operating from or very close to a big CAT airfield - not likely in a flexwing, but you never know. Generally Zone Transits, including through the overhead, can be done quite satisfactorily using Medium or Short Range.

WRT the Reds - they may of course not have been transponding.

In the circuit, Mode S (or PAW for that matter) are more susceptible to being blocked by both your engines/bodies/ bodywork/whatever. You won't of course get any specific position information for Mode S anyway, but they will generally be visible for enough of the circuit so you know they are there. The signals are, however, often reliable throughout the circuit. It depends to a fair degree on the construction of each aircraft and the quality of the installation.

Best Regards

Peter

[Ian Melville]

I could not find the messages where the breaking of the Post processor was discussed.

I have tracked it down to sentences that have no hex code or call sign. e.g.

$PFLAA,2,0,0,1022,1,,,,,,0*44

I assume this was an attempt include Mode A/C targets? If the line was changed to something like the sentence below, then it will work again.

$PFLAA,2,0,0,1022,1,ModeAC!ModeAC,,,,,0*44

Cheers
Ian

[Admin]

I think the issue is the sentences which incorporate
$PAWRT, ....

This is a hint to the post processor to indicate what data is received for the A/C
Mode-C
Mode-S
Mode-S (ES)
P3I
Flarm (from Flarm-IN)

Thx
Lee