The loco positioning system TDoA mode allows a tag, ie. the Crazyflie 2.0, to find its position only by listening to the packets transmitted by the anchors. This has the advantage of not putting any hard-limit to the number of tags since adding tags does not add bandwidth requirement to the positioning radios.

To get your Crazyflie to fly with TDoA position estimation you need to:

1. Flash the latest master branch of the lps-node-firmware in the anchors.
2. Setup your anchors to maximize the size of the convex hull formed by the anchor. This is best achieved by placing 8 anchors on the corners of a rectangular cuboid.
3. Configure your system following the LPS getting started guide.
4. Configure the LPS nodes in TDoA by opening the serial console and pressing “m” for mode and “3” for TDoA mode.
5. Compile and use a recent version of the Crazyflie firmware and Crazyflie 2.0 NRF firmware from the master branch. The default build will include TDoA and the Crazyflie will automatically be set in TDoA mode if the TDoA anchors are detected

Note that TDoA is much more sensitive to anchor placement than TWR. It is mostly important that you fly within the convex hull formed by the anchors or as close as possible to it. Going out of the convex hull will quickly reduce the positioning accuracy.

Once TDoA is setup and working, you can fly your Crazyflies using the same scripts both in Python and in ROS as when flying with TWR.