Mavic crash against wall

[InvisibleName]

I think taking off with 10 satellites is part of the problem. Personally, I would take off with at least 14. Around the forum some people say not below 11. It's not just the number of satellites, but their position. Satellites close to the horizon aren't likely to be good for navigation. The more you have, the more accurate your fix will be. I often get 17 flying here in Arizona, and that's a comfortable, reliable number.

10 satellites is enough, but not if his compass was not aligned due to external magnetic interference. The first check after power up is to ensure that the drone heading indicator is actually aligned with the physical direction of the drone. Magnetic interference can make this become misaligned, hence, simplistically, north is south etc.

This is discussed in great detail elsewhere on this forum. It could be the number 1 reason for fly always & crashes!

@sar104 is far more knowledgeable on this subject than me!!

 

[7thstring]

Thanks but however regardless of sats, what about collision detection? I don't see the two as related... I mean, if I purposedly direct it against the wall it refuses to, so why it did that by ignoring the same inputs from his very sensors?

 

[InvisibleName]

Thanks but however regardless of sats, what about collision detection? I don't see the two as related... I mean, if I purposedly direct it against the wall it refuses to, so why it did that by ignoring the same inputs from his very sensors?

I guess it depends on how fast it was flying at the wall

 

[melmartin]

They could well be related. If the positioning information was wrong, or compass was off, and the AC thought it was pointing south, but was really pointing northwest, for example, it seems it could easily slam into a wall it thought was elsewhere. I have no idea how the DJI software algorithms work, but often accidents are a cascading sequence of events, so one problem gets passed along to another software module, and chaos results. There are many examples of this in the forums. It's all speculation until someone analyzes the logs.

 

[7thstring]

I guess it depends on how fast it was flying at the wall

How fast does it go with RTH? I guess it was between 5km/h and 10km/h. Had I known the "sports mode" trick earlier I could have easily avoided the collision ("pause" didn't do anything).