  Autonomously retracing a manually-taught path is desirable for many
applications, and Teach and Repeat (T&R) algorithms present an approach that is
suitable for long-range autonomy. In this paper, ultra-wideband (UWB)
ranging-based T&R is proposed for vehicles with limited resources. By fixing
single UWB transceivers at far-apart unknown locations in an indoor
environment, a robot with 3 UWB transceivers builds a locally consistent map
during the teach pass by fusing the range measurements under a custom ranging
protocol with an on-board IMU and height measurements. The robot then uses
information from the teach pass to retrace the same trajectory autonomously.
The proposed ranging protocol and T&R algorithm are validated in simulation,
where it is shown that the robot can successfully retrace the taught trajectory
with sub-metre tracking error.
