  We present a range-based solution for indoor relative localization by Micro
Air Vehicles (MAVs), achieving sufficient accuracy for leader-follower flight.
Moving forward from previous work, we removed the dependency on a common
heading measurement by the MAVs, making the relative localization accuracy
independent of magnetometer readings. We found that this restricts the relative
maneuvers that guarantee observability, and also that higher accuracy range
measurements are required to rectify the missing heading information, yet both
disadvantages can be tackled. Our implementation uses Ultra Wide Band, for both
range measurements between MAVs and sharing their velocities, accelerations,
yaw rates, and height with each other. We used this on real MAVs and performed
leader-follower flight in an indoor environment. The follower MAVs could follow
the leader MAV in close proximity for the entire durations of the flights. The
followers were autonomous and used only on-board sensors to track and follow
the leader.
