GP941E 11/01
02.11.01
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GPS receivers operating without a local differential beacon The altitude accuracy from satellite-based systems
will not be as good as accuracy in lat/long, because satellite geometry is not as favourable for obtaining accura-
te altitude fixes compared to horizontal position. This effect may be increased by less-than-ideal antenna posi-
tioning in some gliders. Lat/long fix accuracy is not affected and is typical of that for a 12 channel GPS system,
but data analysts and NAC officials should allow for the above when comparing the GPS altitude and pressure
altitude records.
Maximum Altitudes Recorded in the IGC file.
Pressure Altitude. The recorder is designed to have a pressure altitude capability up to 10km (32,808ft). Above
this altitude, figures may be recorded but accuracy is not guaranteed.
GNSS altitude. The GP 941 has 16-bit resolution and the maximum positive recorded value is theoretically
32,767m (107,503ft). However, US limitations on the recording of GPS altitude by non-military GPS receivers
may limit recording to 60,000ft (18,288m).
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