Recent changes in TDoA

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Recent changes in TDoA

Post by arnaud »

We are currently working at making TDoA a supported ranging mode out of the box. In doing so we have developed a new anchor protocol (called TDoA2) and the corresponding tag/receiver implementation for the Crazyflie. We have merged some change to master so I though I would try to explain a bit the status (as of 2017-12-14 morning) and what we plan in the near future for anyone currently using the master branch of Crazyflie firmware or the LPS node firmware.

First of all the way we work: we try as much as possible to keep the master branches of the repos in sync. This means that if we make an incompatible change to a protocol it will be pushed to both sides the same day. For TDoA2 we achieved that by working on branches and then merging the branches in master of the Crazyflie firmware and the LPS node firmware.

Last week we have merged the new TDoA2 protocol in the master branch of both crazyflie and node, it means that now when you compile the Crazyflie with TDoA support, you need an anchor with TDoA2 protocol. The latest node master has it. We have removed the previous TDoA protocol in the process.

We have implemented anchor position set from TDoA and automatic mode switching in the Crazyflie, this means that it is now possible to build a clean Crazyflie firmware with empty and to setup the system as described in the LPS getting started but now with anchors set as TDoA instead of TWR (the LPS tools has been updated for that).

In the very near future we will implement outlier rejection in the Crazyflie and a new LPP packet to set the ranging mode in the anchor via the radio. Then we will most likely publish a new stable version of all the Firmwares. It is very likely that the protocol will not change so if you do not care about changing the ranging mode of the system using the radio you can flash your nodes now and start using the new TDoA mode, otherwise you might have to flash you nodes again in a week :).
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