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Old 20th Nov 2022, 10:11
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TheOddOne
 
Join Date: Sep 2004
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Our ADS-B 'out' derived from our Garmin transponder gives GNSS-derived speed over the ground and GNSS-derived altitude referenced to World Geophysical Survey 1984 (WGS84). This is somewhat different from baro-derived altitude which is also different from 'real' altitude.This is in the UK with no enhancements the raw ADS-B as other places benefit from. I guess velocity can be derived from the track shown on various web sites that track ADS-B.
Other more sophisticated ABS--B units can give more information, but nowhere near as much as Mode Select (known as Mode 'S').
When you look at some of the accident analysis both from Youtube people such as Juan Browne and official sources, they sometimes show a timeline of horizontal and vertical speeds derived from ADS-B, but as separate traces. The recent tragedy involving test flying a C208 is a case in point.
TOO


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