TDoA geometrical assumptions

Hi to everybody,

I am going to test EVB1000 for TDoA positioning.
From my understanding the anchors should be placed in the corners of a rectangular or in points distributed in an area.
Unfortunately my anchors are quite close with each other (10cm) and are placed on a line.
Does someone know if TDOA can work in this scenario?
Maybe it is possible to measure the distance along one axis.



Hi Francesco,
Yes. It is possible to measure distance along one axis. But only within two anchors (the anchors and your device are placed on one line, and your device are placed only between that two anchors). TDOA location isn’t possible beyond (outside) two anchors. I guess that’s not your case cause the distance between your anchors small enough.
Maybe you should use two way ranging method instead of TDOA.

I would use TWR and TDMA but my system is quite complex.
There are two main constraints:

  1. the first is that the anchors are placed on a line and are close with each other,
  2. the second one is that the whole system can have 1, 2 or 3 groups of anchors, each one with the constraint 1).

Unfortunately the the areas covered by each group of anchors overlap.

I think that scenario could be difficult to manage using TWR an TDMA without knowing how the system is deployed (with 1, 2 or 3 groups of anchors).
So I would investigate the TDoA since it solves the overlap area problem but my concern is the TDoA accuracy given the constraint 1).
Could you help me on this issue?


francescoaru, how many anchors do you have in one group? Do you need 2D or 3D location?

There are 3 anchors in one group and we need 2D location.