when exist metal or wall, about tdoa3

[justinleeyang]

hi,

If there is some metal or wall occlusion in the environment, the TDOA3 algorithm be used, and the positioning is very inaccurate?

[arnaud]

Hi,
Have you seen problems in that situation or are you just wondering if that would be a problem.

TDoA3 measures time of flight between anchors in order to achieve time synchronization, so as long as the inter-anchor time of flight is stable enough and the tag has direct line of sight with enough anchors, things should work quite well.

[estrategico]

I use the tdoa2 and tdoa3 in a room with mirrors on the wall and the system has very poor performance, specially when the CFs fly near to the walls (mirrors) and there was a zone where z axis seems to be higher than in others,(all the cfs rise a bit when they flought above that zone).

I change the location (no mirrors) same settings and the precision increase.

[arnaud]

Unfortunatly, hard reflection is known to he bard on the UWB tracking. Have you tried to place your anchors a bit further away from the walls and have you tried TDoA3? TDoA3 has a more random ranging pattern which might be able to help in that case.

[justinleeyang]

hi,

Inter-anchors are LOS, but tag and anchors maybe exist occlusion,

[kristoffer]

@justinleeyang as long as some anchors are LOS from the Crazyflie, it should work. One of the design goals of TDoA3 was actually to handle this type of situation. If the anchors that the Crazyflie receives, are at "good" locations, a position can be calculated.