Audio alerts

[Ian Melville]

After The comments that people were driving around with PAW units in the car, I gave it a try today. It was not a good idea to set the mode S to test(noisy mode). My ears are still ringing from the non-stop alerts on the drive to Heathrow 

I changed to the other extreme  for the return home. With the high level of alerts it appeared that the alerts were queued and often given after the threat had move quite some distance. It was also apparent that there was no priority for nearest threats. For example.
I was close to the threshold. There were three aircraft on final at 5, 7 and 10km. 7km was called first, then 10. The third was. Called last by which time the threat was approx 3km and closing fast. Inter spaced with these three calls there were others for aircraft heading away from me.

Is it possible to prioritise the alerts? And perhaps discard the more distant ones in a target rich environment?

Before anyone Says this is an unrealistic test, i would argue not as there was less than 15 aircraft in the vercinity, no more than a good fly in.

[Admin]

Hi Ian

Very complicated subject this ....

After The comments that people were driving around with PAW units in the car, I gave it a try today. It was not a good idea to set the mode S to test(noisy mode). My ears are still ringing from the non-stop alerts on the drive to Heathrow 

Not a good idea, that is simply there for S/W test 

I changed to the other extreme  for the return home. With the high level of alerts it appeared that the alerts were queued

This is correct, when an alert meets a threshold it is queued to the audio sub-system, but if another message is in the queue, then that must complete first.

and often given after the threat had move quite some distance.

Threats are issued immediately, there is no delay.
Are you referring to precise (ADS-B/P3I) or imprecise (Mode-S) threats ?
If it is imprecise then it is based upon signal strength, which has a correlation to distance but not a direct relation.

It was also apparent that there was no priority for nearest threats.

Highest priority threats are issued first.
If it is a precise threat, then the order is closest first, if it is imprecise, it is signal strength first.
So, are you referring to precise or imprecise traffic ?

For example I was close to the threshold. There were three aircraft on final at 5, 7 and 10km. 7km was called first, then 10. The third was. Called last by which time the threat was approx 3km and closing fast. Inter spaced with these three calls there were others for aircraft heading away from me.

OK, this is ADS-B traffic ?
At the distance specified were they within the height boundary ?
are you aware of the warning zones
HIGH - (3km +/- 500ft)
MEDIUM - (5km +/- 1000ft)
LOW - (10km +/- 2000ft)

Is it possible to prioritise the alerts? And perhaps discard the more distant ones in a target rich environment?

hmm this is possible I guess by having multiple message queues rather than a single message queue

Before anyone Says this is an unrealistic test, i would argue not as there was less than 15 aircraft in the vercinity, no more than a good fly in.

TBH, I think once you get to this situation, then you could be overwhelmed with information, this is why there have been a lot of requests to disable alerts when in the viscinity of the airfield for arrival/departure

Thx
Lee

[Ian Melville]

Lee, all alerts were Precise ADSB

I may have missed something, but you appear to contradict yourself. If the alerts are queued, than the cannot be issued immediately. The queue will have to be cleared first?

Not sure about the height boundary. They were all on the same ILS so in theory, if one was within the boundary then they all will be?

Cheers
Ian

[Admin]

Hi Ian

I may have missed something, but you appear to contradict yourself. If the alerts are queued, than the cannot be issued immediately. The queue will have to be cleared first?

Sorry, maybe I was not clear.
PilotAware is a Multi Threaded Application, so the Audio system is running all the time awaiting messages.
The detection system, sends messages into the queue (immediately) when they occur, now of course if I send 5 messages 200ms apart,
there is a latency due to the amount of time the audio system takes to output each message, the messages will NOT overlap
No way around that in the current setup.

What I was suggesting was that I manage 3 audio queues, so that the audio system always reads from the highest priority queue, rather than having a high priority message queued behind a low priority message, in a single message queue.

This is actually quite complicated - but do-able.

Thx
Lee

[Ian Melville]

That tally with my thoughts on the process. 3 queues sounds like a good plan, would that apply to mode S notice, alert and danger as well?

Cheers
Ian