Author Topic: Enhancement Requests  (Read 237609 times)

mo0g

Re: Enhancement Requests
« Reply #300 on: March 30, 2017, 10:28:34 am »

Mark,

You seem to be missing the point. We are NOT busting controlled airspace. We are flying perfectly legally in class G airspace, but are, responsibly, letting ATC know where we are by transponding and using the listening squawk to let them know that they can, if necessary, call up and speak to us or advise us of (usually) inbounds, which drop to 2,500 ft as they approach and enter the east stub of the CTA.

I am sure I am still missing something, what does PAW have to do with listening squawks and transponding, unless you do not have a radio equipped with a transponder?  If not, then obviously I see the value to you of that, but still not sure what the real value is of you being able to see CAT traffic via PAW, or worse (from my perspective) getting audio alerts about CAT traffic.

I trust the airspace classification to keep me (in class G) adequately separated from CAT (in CAS).  As you said, if there is an emergency and ATC need to route CAT through class G, then if they can talk to me or see me, it is obviously beneficial, to THEM.  If they could do neither then I am confident they would route the emergency so as not to conflict with me, based on unknown intentions etc.  I would not need PAW to save me from a collision in that scenario, I do not believe?  ATC would not route that traffic close enough to me to cause even a risk D airprox?

exfirepro

Re: Enhancement Requests
« Reply #301 on: March 30, 2017, 11:32:00 am »
I am sure I am still missing something, what does PAW have to do with listening squawks and transponding, unless you do not have a radio equipped with a transponder? If not, then obviously I see the value to you of that, but still not sure what the real value is of you being able to see CAT traffic via PAW, or worse (from my perspective) getting audio alerts about CAT traffic.

You've lost me here Mark - radios and transponders are usually two separate pieces of equipment. Many (if not most) GA have radio but no transponder and believe it or not, large swathes of the UK still don't have reliable Primary Radar coverage - especially at the low levels used by GA and in mountain valleys, etc, so GA - especially microlights, balloons, gliders, paramotors, etc, especially flying in these areas can be virtually invisible to ATC even with transponders! Although I use the listening squawk regularly, it isn't compulsory and in any case only lets ATC know you are listening on their frequency. It certainly doesn't oblige them to provide you with a traffic service outside controlled airspace, hence why PAW provides that service for you. Even if they can't see you, at least you can see them and take any necessary avoiding action before a conflict arises.

Quote
I trust the airspace classification to keep me (in class G) adequately separated from CAT (in CAS).As you said, if there is an emergency and ATC need to route CAT through class G, then if they can talk to me or see me, it is obviously beneficial, to THEM.  If they could do neither then I am confident they would route the emergency so as not to conflict with me, based on unknown intentions etc.  I would not need PAW to save me from a collision in that scenario, I do not believe?  ATC would not route that traffic close enough to me to cause even a risk D airprox?

Except that in most of the UK, CAT traffic routinely has to pass through 'uncontrolled' airspace to get into Controlled Airspace in the first place. This is the point where conflict can occur and outside controlled airspace there is no obligation on ATC to provide YOU with a traffic service even if they can see you. It is as much your responsibility to see and avoid the CAT traffic as it is for them to see and avoid you. PilotAware simply makes this process easier, safer and more reliable as I have outlined above.

Hope this clarifies things.

Regards

Peter
p.s. The simplest way to deal wth unwanted audio is to fit a simple mechanical volume control in the audio line between the PAW and your intercom or headset. Just remember to turn the volume back up again when you do want to hear it. P  ;)
« Last Edit: March 30, 2017, 11:49:34 am by exfirepro »

mo0g

Re: Enhancement Requests
« Reply #302 on: March 30, 2017, 12:07:08 pm »
No, I still dont get it.  Perhaps it is just because I have always flown club cessnas that I have been used to always having transponders.  Also that I have never had to share uncontrolled airspace with CAT at normal bimbling locations or altitudes (here and abroad).

Turning down the volume in my case is pointless, because I wanted PAW mainly for conspicuancy and awareness in and around my local area, being in and around CAS and therefore in and around rat runs.  If I only turned up the audio when not in the vicinity of CAT then I would be missing all those alerts.

I will continue to use PAW but not the audio function as, unfortunately, traffic into and out of LHR and LGW is continuous and I would only want to know about other GA as I, personally, do not need to be warned about potential conflict with that traffic.

exfirepro

Re: Enhancement Requests
« Reply #303 on: March 30, 2017, 12:34:03 pm »
Hi Mark,

Swings and roundabouts unfortunately. Believe me, having done a lot of experimental testing against CAT at fairly close range, both on the ground and while passing through the EGPH overhead, I can fully appreciate your position. Just that I am concerned about deliberately excluding known potential risks. You can bet someone will get it wrong and imagine the backlash.

As I say, best IMO to run close altitude filters in your Nav programme for ADSB and close Mode C/S altitude filter in PAW together with Short or Ultra Short (accepting a higher level of risk) for Mode C/S, together with audio at low volume. You will be surprised at how well your ears and brain can filter unwanted alerts after they get used to them providing the volume level is kept low. You never know, Lee may come up with another option down the line.

Safe flying

Regards

Peter
« Last Edit: March 30, 2017, 12:38:44 pm by exfirepro »

Keithvinning

Re: Enhancement Requests
« Reply #304 on: March 30, 2017, 08:42:38 pm »
Hi Mark

I sympathise your dilemma.

When I fly betwixt Heathrow and Gatwick. I close down PilotAware Radar to +/-2000 ft and Mode C/S to +/500 ft ultra short and find that the problem you are having is not a problem.

This works for me.

Recognising that altimeters are at best +/- 50 accurate, so only expect ANY analogue or electronics systems to be accurate within +/- 100ft. So giving a conservative element for inaccuracy I consider 200ft separation good.

If it still is troublesome to you then set the PilotAware RADAR to +/-1000 ft and the same with your navigation software.

If you then fly close or across the TMZ and are troubled by the additional information that  PilotAware voice alert information gives you turn it down. At this point you will be, hopefully, on a listing squawk or unique squawk and the ATC will let you know of any conflicts or  infringement that you have made.

 

Paul_Sengupta

Re: Enhancement Requests
« Reply #305 on: April 01, 2017, 03:48:38 pm »
No, I still dont get it.  Perhaps it is just because I have always flown club cessnas that I have been used to always having transponders.  Also that I have never had to share uncontrolled airspace with CAT at normal bimbling locations or altitudes (here and abroad).

You'd be surprised. You're near Farnborough, yes? They have aircraft up to BBJ (737) size going in there. What about Biggin and their new 03 instrument approach over two of Redhill's VRPs? Ever experienced an airliner going in or out of Lasham? What about further down west - Exeter? Newquay?

GeoffreyC

Re: Enhancement Requests
« Reply #306 on: April 03, 2017, 10:52:52 pm »
I agree with all the discussion about the problems of filtering out CAT traffic.  I'd rather know about it if it is a potential conflict.

My comment though is having used PAW for the first time in anger I found I was getting quite a lot of alerts from traffic on the ground.  I had set the Mode C/S separation to +/- 2000 feet and was flying along at circa 1500 feet which is fairly normal, but found I kept on getting audio alerts for aircraft that were 1300 feet below me,  1100 feet below, etc.
Now I'd prefer to fly with a 2000 feet separation range if possible rather than 1000 feet separation because I'd like more advance warning of something climbing up to meet me,  but getting alerts off stationary ground based traffic was distracting to say the least.

So is it possible to either:
- Have a +/- 1500 feet separation option?
- Have some "smarts" in the separation detection based upon the height PAW is at,  say +/- 2000 if PAW > 2000 feet, but if PAW is between 1000 and 2000 feet then apply -1000/+2000 - this would filter out a large number of the 'below but stationary' traffic

My preference would be the latter

exfirepro

Re: Enhancement Requests
« Reply #307 on: April 04, 2017, 12:53:42 am »
My comment though is having used PAW for the first time in anger I found I was getting quite a lot of alerts from traffic on the ground.

Geoffrey,

You say.....

Quote
I had set the Mode C/S separation to +/- 2000 feet and was was flying along at circa 1500 feet which is fairly normal, but found I kept on getting audio alerts for aircraft that were 1300 feet below me,  1100 feet below, etc.

...so they could quite clearly have just taken off and were potentially climbing towards you.

This type of alert should only occur with 'bearingless' Mode C or S aircraft, where the alerts are based on received signal strength as well as relative altitude, because their position and distance are otherwise unknown. Whilst your suggestion for an 'automatically variable' relative altitude filter certainly has some merit, in order to effectively provide the 'variable' relative altitude filtering you are suggesting, PAW would have to take account not only of your current altitude, but the height of the ground you are flying over, which we cannot possibly do for the whole of the UK, let alone further afield. Without this information, rising ground would rapidly bring aircraft on the ground back into an 'alert' situation and falling ground would drop climbing aircraft out of your chosen alert bracket without you even being aware this was happening.

I have also just been looking at your post over in the 'Altitude Filter' thread. You seem to have at least 27 contacts showing on your XC Soar screen at the same time, with nothing inside 6 miles from you, so can I ask how you know the aircraft were all on the ground? What Mode CS Detect 'Range' setting are you using? Do you know that you can considerably reduce the bearingless target alerts by trying a shorter Range setting - we normally operate on 'Short Range', or 'Medium Range' if we need/want a bit more warning, but accepting that we will get more alerts. If operating near or transiting over a major airport (as I did yesterday), I would go down as far as 'Ultra-Short' Range, or alternatively turn the volume down a bit lower and live with the alerts for the short period of the transit.

Hope this helps

Regards
Peter
« Last Edit: April 04, 2017, 01:24:12 am by exfirepro »

Paul_Sengupta

Re: Enhancement Requests
« Reply #308 on: April 04, 2017, 01:03:55 am »
On the XC Soar radar display, everything further than the outer ring gets put on the outer ring, so all those around the outside are further away than the selected maximum range.

Certainly in the south east of England, with the London airports and airspace, 27 contacts on ADS-B isn't that many. From my house in Guildford with my antenna in the loft, I've seen over 100 contacts at once. You can receive more in the air. Even with my tiddly little antenna that I'm using for transponder receiving, I can pick up over 40 contacts at once in the air.

exfirepro

Re: Enhancement Requests
« Reply #309 on: April 04, 2017, 01:11:57 am »
Hi Paul,

Yes I fully appreciate that fact, but multiple ADSB contacts are unlikely to present a significant audio alert problem, unless all inbound at the same time, which from the screen doesn't seem to be the case. Geoffrey is complaining about multiple alerts from targets on the ground, which is why I am suggesting that he may be running too wide a Mode CS Detect Range.

Regards as always

Peter


GeoffreyC

Re: Enhancement Requests
« Reply #310 on: April 04, 2017, 08:11:11 am »
You say.....

Quote
I had set the Mode C/S separation to +/- 2000 feet and was was flying along at circa 1500 feet which is fairly normal, but found I kept on getting audio alerts for aircraft that were 1300 feet below me,  1100 feet below, etc.

...so they could quite clearly have just taken off and were potentially climbing towards you.

This type of alert should only occur with 'bearingless' Mode C or S aircraft, where the alerts are based on received signal strength as well as relative altitude, because their position and distance are otherwise unknown. Whilst your suggestion for an 'automatically variable' relative altitude filter certainly has some merit, in order to effectively provide the 'variable' relative altitude filtering you are suggesting, PAW would have to take account not only of your current altitude, but the height of the ground you are flying over, which we cannot possibly do for the whole of the UK, let alone further afield. Without this information, rising ground would rapidly bring aircraft on the ground back into an 'alert' situation and falling ground would drop climbing aircraft out of your chosen alert bracket without you even being aware this was happening.
Hi Peter,  thanks for your reply,  glad that my idea potentially has merit  ;)

The alerts I received (and there were a few of them as I was flying) were bearingless CS targets because all I was warned of was the target altitude.  I think I had the mode CS range set to the recommended setting of 'Short', but I will check this.
You're right, as I never saw any of the warning aircraft I am surmising that they were aircraft on the ground based upon my altitude and their relative altitude,  and they could have been aircraft that were taking off and so were becoming a danger.   With some kind of offset altitude alert +2000/-1000 or smarter logic like I suggested based upon my own altitude I feel that I would have had less false positives which has to be a good thing.  The last thing I want is to become complacent and start ignoring alerts because I am receiving too many of them.

I do agree, having a database of altitude information within PAW would be impracticable, and so I thought of the smart range logic as being an achievable alternative.

I have also just been looking at your post over in the 'Altitude Filter' thread. You seem to have at least 27 contacts showing on your XC Soar screen at the same time, with nothing inside 6 miles from you, so can I ask how you know the aircraft were all on the ground?
This is the other issue I faced, that XCsoar doesn't offer any ability to filter out traffic so is I believe showing everything that PAW is detecting, regardless of range or height,  and is plotting them on the 6 mile+ ring which makes for a display that is impossible to use.   When I click on some of these individual aircraft I could see that in several cases they were jets flying thousands of feet above me,  but with so many aircraft plotted and XCSoar not offering any ability to filter based upon range or height, I can't separate the proverbial wheat from the chaff. 

I guess this comes from XCSoar being originally developed for gliders where the low power FLARM would only collect alerts from fairly near aircraft.  PAW picks up stuff miles away and so the display is now overloaded.

exfirepro

Re: Enhancement Requests
« Reply #311 on: April 04, 2017, 09:01:18 am »
Geoffrey,

The other thing that occurs to me that you may not be aware of is that if you are flying close to (i.e. within a few miles of) a major airport, you will experience very strong 'Mode S' signals from CAT traffic 'on the ground' due to their significantly higher power transponder responses to ground radar while taxiing. Unless you are running the Ultra Short Range Mode CS Detect setting, this traffic is likely to trigger alerts at a distance where it is still extremely difficult or impossible to see the aircraft, simply because of the significantly higher signal strength.

Experience of the alert patterns will help you recognise the difference between this type of traffic and incoming GA and allow you to safely disregard these alerts after carrying out a proper visual scan.

Regards

Peter

Admin

Re: Enhancement Requests
« Reply #312 on: April 04, 2017, 02:55:22 pm »
- Have some "smarts" in the separation detection based upon the height PAW is at,  say +/- 2000 if PAW > 2000 feet, but if PAW is between 1000 and 2000 feet then apply -1000/+2000 - this would filter out a large number of the 'below but stationary' traffic

Hi Geoffrey,
Unfortunately ModeC/S use barometric altitude.
So there is no way of knowing the height above ground, its only height difference to a reference pressure of 1013.25mb

Thx
Lee

GeoffreyC

Re: Enhancement Requests
« Reply #313 on: April 04, 2017, 04:13:14 pm »
Hi Geoffrey,
Unfortunately ModeC/S use barometric altitude.
So there is no way of knowing the height above ground, its only height difference to a reference pressure of 1013.25mb

Thx
Lee

Hi Lee,

I was assuming from the GPS data that PAW knows its height above MSL?

The suggestion was to expand the list of mode CS separation ranges that PAW can select from to give more filtering choice,  currently +/- 500,  +/- 1000, +/- 2000 with say 3 additional entries:
+/- 1500 .... works the same as the existing filters based upon difference in barometric height
+2000/-1000 ..... larger range filter for traffic approaching from above than below
"Smart filter 2000" .... +/- 2000 if GPS data height is > 2000,  +2000/-1000 if GPS data height is < 2000

Maybe this isn't a common request or others haven't noticed ground based aircraft causing alerts.  At the time I received these alerts I was flying outside and to the North of Luton CAS and there was no other airfields in sight or on the map.  So maybe it was ground based CAT at Luton that PAW was picking up and reducing the mode CS sensitivity would filter these out,  but if possible I'd like to not have to keep changing the settings whilst flying - taking gloves off etc is a hassle in a flexwing.

Just my 2p suggestion

Cheers, Geoffrey

Admin

Re: Enhancement Requests
« Reply #314 on: April 04, 2017, 04:23:52 pm »
The suggestion was to expand the list of mode CS separation ranges that PAW can select from to give more filtering choice,  currently +/- 500,  +/- 1000, +/- 2000 with say 3 additional entries:
+/- 1500 .... works the same as the existing filters based upon difference in barometric height
+2000/-1000 ..... larger range filter for traffic approaching from above than below
"Smart filter 2000" .... +/- 2000 if GPS data height is > 2000,  +2000/-1000 if GPS data height is < 2000

Hi Geoffrey,
Additional bands are reasonably easy to add
Lets see what others think

Thx
Lee