Getting position by TDoA

[SergeyLadanov]

Hi!
I found two functions in the project crazyflie-firmware for processing TDoA data, these are "kalmanCoreUpdateWithTDOA" (file mm_tdoa.c) and "kalmanCoreRobustUpdateWithTDOA" (file mm_tdoa_robust.c).
Which is better? In which cases should I use each of them?

[krichardsson]

Hi!

The two functions are called as part of the kalman filter when using the Loco system in TDoA mode, they should usually not be called by external code. kalmanCoreUpdateWithTDOA() is used if the parameter kalman.robustTdoais 0, while kalmanCoreRobustUpdateWithTDOA() is used when the parameter is non zero.

Which is better? In which cases should I use each of them?

In my experience the robust flavor is less noisy and more robust(!) but does not converge as easy when the estimated position is off. A middle ground is maybe to let the position first converge using the normal mode and then set the parameter to 1 to switch to the robust mode.

The robust mode also uses a bit more CPU power.

[SergeyLadanov]

Hi!
Thanks a lot!