PilotAware

British Forum => Technical Support => Topic started by: hairgoneJohn on September 07, 2020, 03:12:04 pm

Title: Adding own encoder output to radar sceen
Post by: hairgoneJohn on September 07, 2020, 03:12:04 pm
Hi

Just a small enhancement request.  Would it be possible to add the aircraft's own encoder altitude being broadcast as a quick way of checking if the encoder is out of adjustment?  Older mode c units don't show it.

cheers
Title: Re: Adding own encoder output to radar sceen
Post by: Admin on September 07, 2020, 04:44:29 pm
If it is Mode-S, then yes, as the ICAO Code can be used in order to validate the transponder
if it is Mode-C, then no, there is no way of knowing the Altitude emitted is from your own transponder

Thx
Lee
Title: Re: Adding own encoder output to radar sceen
Post by: hairgoneJohn on September 07, 2020, 09:09:09 pm
Ok. Thanks.

So how does the pilotaware know which signal to ignore if using the mode-c +filter setting if the user has a mode-c transponder?
Title: Re: Adding own encoder output to radar sceen
Post by: Admin on September 07, 2020, 09:23:04 pm
So how does the pilotaware know which signal to ignore if using the mode-c +filter setting if the user has a mode-c transponder?
Aaah, now that would be a trade secret, and took a long time to work out
In simple terms, it learns, from your flight profile
It does get fooled sometimes, for example
very steep climb descent
Pressure differential between cabin and outside
Long periods of no ground interrogation

Thx
Lee
Title: Re: Adding own encoder output to radar sceen
Post by: hairgoneJohn on September 08, 2020, 04:37:34 pm
Ok Lee

I'll bite !

If you know which return to ignore then you must know it's reported altitude?
Title: Re: Adding own encoder output to radar sceen
Post by: Admin on September 08, 2020, 08:10:15 pm
Ok Lee
I'll bite !
If you know which return to ignore then you must know it's reported altitude?

Its altitude must be within +/- 100ft, mode c encoders only have 100ft accuracy, mode s is 25ft IIRC
To be clear it is not the baro which is accurate to 100ft, but the 12bit binary encoding used for transmission
Thx
Lee