Simulating a UWB transmitter and receiver within a 3D space

Good day,

I'm attempting to create an indoor positioning system with UWB tags and anchors using the time-difference-of-arrival method.

Could anyone help or give me hints where to start with creating a transmitter that can transmit a pulse that can be picked up by a receiver?

As well as how to have it occur within a 3D space.

Thank you very much.