Z-Ranger and LPS Compatibility?

Firmware/software/electronics/mechanics
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wtse
Beginner
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Joined: Sun Apr 09, 2017 4:52 am

Z-Ranger and LPS Compatibility?

Post by wtse » Mon May 01, 2017 10:10 pm

I have a Crazyflie working with the Loco Positioning System and I recently ordered the new Z-Ranger deck as well. Are these two systems mutually exclusive, or will I be able to use the LPS for X and Y coordinates and the Z-Ranger for an accurate Z measurement?



arnaud
Bitcraze
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Joined: Tue Feb 06, 2007 12:36 pm

Re: Z-Ranger and LPS Compatibility?

Post by arnaud » Tue May 02, 2017 10:06 am

They 'should' already work together.

There has been an implementation of the Z-ranger as input for the Kalman filter a while ago. It requires to add the flag "UPDATE_KALMAN_WITH_RANGING". So your config.mk should look like that:

Code: Select all

ESTIMATOR=kalman
CFLAGS+=-DUPDATE_KALMAN_WITH_RANGING
Note that not everything is perfect since we still have this bug https://github.com/bitcraze/crazyflie-f ... issues/169 that makes it hard to fuse multiple kind of measurement, but anyway it works quite well and it has been tuned to blend with the LPS system when you start going higher: the noise model is setup in such a way that over 1.3m the standard deviation of the Z-ranger starts becoming worst than the standard deviation of the LPS https://github.com/bitcraze/crazyflie-f ... .c#L48-L53

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