Hi all,
Is it possible fusion 2 sensor (GPS Velocity and Pitot sensor) for have an accurate Velocity measure ?
another
Is it possible fusion 2 sensor (GPS altitude and pressure sensor) for have an accurate Altitude measure?
Thanks
Michele
You need to be a member of diydrones to add comments!
Replies
Sensor fusion is possible with any arbitrary sensors. Sensor fusion is actually beneficial with sensors that have complementary strengths & weaknesses. I'm not sure that these are candidates for sensor fusion, because I'm not sure that they build on each other's strengths in typical drone situations.
Air pressure sensors:
Very accurate
Drift does not accumulate over short timescales, if shielded from wind / prop wash
No natural zero point - is currently calibrated to ground at initialization
Accuracy problems with nonlinear air pressure at high altitude
Natural height:millibar ratio varies based on elevation - can be calibrated to arbitrary value during settings tweaking
Pressure at a given altitude varies over several hours based on weather patterns.
GPS altitude reading:
Not very accurate
Drift does not accumulate, but is considerable at low altitudes
Greater accuracy possible with RTK if it's ever implemented as OSS
Natural zero point
I suppose you could correct for altitude ASL by using periodic GPS fixes, but this will probably only be useful in long duration, high altitude, or high-wind flights, where the benefit of the high relative accuracy of the altimeter is destroyed by meteorological pressure changes. GPS altitude needs to be far more precise relative to ground before it's used for drone landing, IMO.
While I know of people that want to attempt it... personally, I don't understand GPS velocity - airspeed sensor fusion. Winds are highly variable on seconds-long timescales, and sufficiently turbulent that dead reckoning is pointless. What precisely is the goal?