Geebax
Captain
Australia
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Raf_IZ0QWM Posted at 4-22 06:55
Speaking of altitude, I'm seeing a lot of altitude issues around, probably introduced in the last release.
Some users are increasingly seeing negative altitude after take off, and even, if the drone takes off and then lands, the altitude has changed and does not return to 0.
All measurement systems have a degree of inaccuracy, and measurement of altitude is difficult to any degree of precision. The basic method is a barometer, the same technology as used by full size aircraft. DJI add to that with VPS or downwards sensors to measure altitude, but VPS is only good to about 30 Meters in altitude before it cuts out. GPS, on the other hand, is woefully inaccurate at any time, and that is why DJI do not use it. This from Wiki:
"Global Positioning System (GPS) receivers can also determine altitude by trilateration with four or more satellites. ... In hiking and climbing, it is common to find that the altitude measured by GPS is off by as much as 400 feet (122 metres) depending on satellite orientation." |
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