Need position estimate

Hi everyone

I have the problem:

Need position estimate

each time i want to arm the copter in loiter mode.

we use a small 4in copter with gps bn220, no compass activate.

in loiter mode, its mandatory to have a compass to can arm?

i have deactivate all arming checks, all ek3_gps_checks bitmask and the same result.

need position estimate.


Generally yes and to fly in Loiter. Read this Compass-less Operation


in similar drone we have, compassless, but with optical flow sensor and lidar tfmini, we can arm in loiter and have good positioning, always in indoors.

we have trying to test the throw mode in a similar small drone, sensorless, with gps, and we have a lot of problems with the position estimate warning.

any solution to test the throw mode without compass? only with a bn220 gps?


Hi PVR2022,

I’m trying to build exactly the same, optical flow + lidar controlled drone for indoor position hold. I have a GPS added recently but I still get this position estimate error. I also don’t have a compass. Could you explain what were the settings you used to make it work? Or even post the params?

I use ArduCopter V4.2.2 (4fcfa4b2).
22_08_16 Arducopter v4.2.2 MatekH743.param (19.8 KB)

uh o, looks like im having the same issue and im not seeing any solutions ! :S … anybody have any luck figuring this out ?

I also had that problem and solved it by setting RGNFND1_GNDCLEAR to the same distance that the sensor registers when the copter is on the ground. Hope it solves your problem too

We are building an indoor flying drone with a LW20/C
Lidar height sensor
and HEREFLOW optical position sensor. The drone already completed the autotune. Hereflow sensor inflight calibrated. Does anyone successfully fly your drone indoors and hover and hold the position at ±3cm?

We think the height holding is acceptable but not the xy position holding. We tried firmware versions, 4.3.3, 4.3.2, and 4.2.3.

Are there any parameters we can try to look into and improve? Is there anything from the flight log we can analyse to narrow down the cause? Is there a better indoor flight mode than Loiter flight mode? Which firmware do you use?

4.2.3 flight log
4.2.3 flight log 2

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