Skydemon altitude with PAW

[piperflyer2]

Hello everyone!

Started using my new (to me) PAW and have an issue with the displayed ALT in skydemon. When it's connected to the PAW it displays a red triangle in the ALT box indicating its accuracy. I then connect to my garmin GLO and it has an ALT with a difference of 70ft with a blue triangle in the box. I was wondering how accurate the GPS ALT is with PAW?

(Tested outside with clear sight of sky)

[exfirepro]

Hi piperflyer,

That’s because SkyDemon reports height above MSL via GPS, NOT Altitude, which has to be based on barometric pressure. PilotAware uses a combination of GPS and Barometric pressure so that it can accurately report Relative Altitude* between aircraft using only PAW and those transmitting Mode C, Mode S or ADSB via a transponder (or CAP1391 devices such as SkyEcho). If we only used GPS, relative altitude from a transponder to your PAW could be ‘out’ by several hundreds of feet.

*Relative Altitude is the difference in altitude between your own aircraft and any other reported traffic, and needs to be consistent whether that traffic is reporting via GPS, transponder, or transponder derived ADSB.

For a fuller explanation please see page 77 of the current SkyDemon User Guide (available on the SkyDemon website)..

Regards
Peter

[Admin]

Hi piperflyer

how long had the system been up and running ?
It may need to download the almanac if this was the first time boot.

Also if you go the the home status page, what was shown for number of satellites inview / fix

Thx
Lee