Hi Steve,
I guess Pozyx it’s only TWR so it’s not suitable for swarm application, Ciholas seems a high quality product but I don’t know much about it or how to use it in ArduPilot.
BTW we just presented our research and development dedicated to Ardupilot with UWB localization for swarm applications.
We are now accepting requests from the community in order to close the final version and propose it in a Kickstarter soon.
This UWB system is based already on Ardupilot and the position is calculated directly by the drone’s FC onboard. Our aim is to integrate it perfectly inside Ardupilot and develop it even more, release the code in order it could become a valid tool for all the community. In the above blog post there is a section about the UWB system and some details. We develop it because we need to use it every day with our Ardupilot luminousbees’s swarm for creative application.
We have a google form for collecting all the requests and suggestions https://forms.gle/ZjYc4HuLyF29zY8g6
If you like to ask some questions about our UWB system you could write in the ArduBee blog post.