Primarily for general aviation discussion, but other aviation topics are also welcome.
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By rikur_
FLYER Club Member  FLYER Club Member
#1675174
On bearingless targets, isn't the squawk a clue ... if it's squawking 7000 it's unlikely to be an airliner 15nm away.

I realise it's still guesswork.... but I'm still on the fence as to whether it's entirely unhelpful
#1675180
rikur_ wrote:On bearingless targets, isn't the squawk a clue ... if it's squawking 7000 it's unlikely to be an airliner 15nm away.
I realise it's still guesswork.... but I'm still on the fence as to whether it's entirely unhelpful


In this instance it would have been a pretty bad idea to perform a PFL, with this other aircraft passing below.
Regarding 7000 this is a Mode-A code, and these do not (generally) overlap the Mode-C altitude codes
Neither can the Mode-A and Mode-C codes from the same aircraft be (easily) associated, without some pretty comprehensive machine learning algorithms :thumright

This snapshot gives an indication of how we use machine learning techniques to perform the association between Mode A/C/S unrelated responses
Image

Apologies for the thread drift ...
Thx
Lee
User avatar
By rikur_
FLYER Club Member  FLYER Club Member
#1675186
leemoore1966 wrote:.
Regarding 7000 this is a Mode-A code, and these do not (generally) overlap the Mode-C altitude codes
Neither can the Mode-A and Mode-C codes from the same aircraft be (easily) associated, without some pretty comprehensive machine learning algorithms :thumright

You've lost me there... I squawk 7000 mode C a lot of the time? I know it's unverified, but altitude is still encoded.
This snapshot gives an indication of how we use machine learning techniques to perform the association between Mode A/C/S unrelated responses
Image

I fear my role as head of technogobbledygook is under threat
#1675190
rikur_ wrote:I fear my role as head of technogobbledygook is under threat


:D

Its all confusing isnt it
7000 (general conspicuity) is a ModeA response to a ModeA interrogation

ModeC responses are determined by your altitude encoder (unrelated to what you dial in), a ModeC response is only sent in response to a ModeC interrogation

Botn of these codes are nothing more than a 4 digit octal number

They are generally arranged so the codes don’t overlap, this reduces the confusion of misinterpretation of A->C and vice versa

There are occasions where they do overlap, and that confuses the interpretation regarding wheter the code is a squawk, or an altitude, we use a lot of techniques to disentangle this issue

Thx
Lee
Last edited by leemoore1966 on Thu Feb 14, 2019 11:15 pm, edited 1 time in total.
#1675191
That ring on the map that you're so keen to glance at? Utter, utter guesswork. You might think it means distance but it doesn't. Being red as opposed to green also means very little.


In your replies so far, Tim, you have omitted to comment on the vertical information that I have referred to as being useful. Is there a reason for deliberately ignoring that?

It's evident you don't like bearingless targets. Whether that is because you truly find the information totally useless (including the vertical, which I suggest is not useless) or because you've pinned your flag to the UAT weather mast and that, for the users of PAW etc, means choosing between weather or bearingless targets, I don't know.

I have no issue with anybody continuing to use traffic annunciations from any other device if they suit your needs better


Thank you.
User avatar
By Tim Dawson
SkyDemon developer
#1675218
The vertical would be incredibly useful if you knew where the other aircraft was.

I’m just trying to stimulate debate and would love someone to come along and convince me why bearingless targets are useful and not a distraction.
#1675227
I am more that happy to be corrected but I believe the Mode S/MLAT being developed by PAW and Co will be transmitted using the same GDL90 'link' as the bearingless targets i.e. they are bearingless targets that have had a fair bit of work done to them to take away the bearingless bit but the choice will still be bearingless & Mode S MLAT or UAT weather. Please let me know if I am talking bolleaux.

Will SD be able to use the same thought process as an ADSB target to produce its intelligent audio or will bearingless target audio have to be added and then modified because the MLAT targets are, basically, bearingless with added extras?

If we don't get any bearingless audio does that mean we won't get any MLAT audio either?

As for the debate on whether or not people find bearingless targets useful or not does that mean that you won't add a 'simple' audio alert to announce the appearance of one unless you can be convinced that some pilots find the information useful? Would it not be a fairly easy (for the clever people like you) to add an on/off option if people didn't want to be alerted aurally? I'm not saying it needs to be the full roast dinner but just something, as I suggested previously, to draw your eyes to the screen when one appears instead of it sitting there unnoticed because we're looking elsewhere.
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By rikur_
FLYER Club Member  FLYER Club Member
#1675229
@leemoore1966
I think we're perhaps talking at crossed purposes, probably due to lax terminology on my part.

Where I'll confess to finding bearingless targets useful is where it supplements other context.
Therefore if e.g. I'm returning to the airfield and get a couple of bearingless targets for mode-S equipped club aircraft at 1000ft (i.e. I can see registrations) , it's a pretty good guess that they're in the circuit. Similarly if I get the reg of the tug from the neighbouring gliding airfield, I've a pretty good idea where he will be. In all these cases, I know they're not a B747 15nm away.

It's perhaps the depiction of these as circles and relative altitudes that's the issue - invariably I find myself reverse calculating the relative altitude to work out the other parties actual altitude (and if climbing/descending) to give myself a clue as to whether they're likely to be circuit traffic, whether they're e.g. climbing into conflict or level below etc.
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By Tim Dawson
SkyDemon developer
#1675235
Paul, you’d have to ask Lee about how he intends to tell apps about traffic whose position has been estimated by MLAT. In the trial so far I believe he has used a field of uncertainty which proved to be inappropriate when we briefly implemented it, as many transponders are conservative in their use of that field.

We could, and may, give verbal traffic information on multilaterated targets. In fact by default we would, because we may not even know they’ve been multilaterated. But the first instance where we tell someone there’s traffic at 9 o’clock two miles and it turns out to be at 3 o’clock half a mile, because it turns out its position was only guesswork, I will very strongly wish to turn it off.
Shoestring Flyer liked this
#1675267
@Cub - I'm afraid that you are wrong about the Chinook being fitted with ADSB.

I run 360Radar and I'm supplying the MLAT data to Lee for use in the PilotAware trials. We have a network of over 800 groundstations across the UK carrying out MLAT calculations in realtime. In the 3 years that it's taken to build this system I've never once seen a Chinook transmit ADSB. To know where they are we need to MLAT them using their Mode S responses.

The only RAF aircraft currently fitted with ADSB are the Voyagers, A400s, some Tucanos, some of the C17 fleet and the new Phenoms.

No Chinooks are fitted with ADSB, just Mode S and (presumably) military Mode 5 along with the rest of the military fleet.

EDIT: added C17s that I'd forgotten about !
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User avatar
By buzzthetower
FLYER Club Member  FLYER Club Member
#1675316
I find the bearingless warnings on PAW quite useful. As Lee pointed out, if you set the altitude filter to something sensible for GA, then many of those warnings are for GA in your close vicinity. I had a simple red ring once that had my eyes on stalks and managed to catch an extra 300 pulling out the bottom of a loop right in front of me. I then very nearly had an immediate brown ring moment but I do believe that little bit of advanced warning saved us both as I was pre-primed to take avoiding action (more so than a good constant scan out the window).
Paul_Sengupta, Ridders, PaulSS and 1 others liked this
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