WO maneuvering target tracking techniques are compared in this note. The first, called input estimation, models the maneuver as constant unknown input, estimates its magnitude and onset time and then corrects accordingly the state estimate. The second models the maneuver as a switching of the target state model, where the various state models can be of different dimension and driven by process noises of different intensities, and estimates the stale according to the interacting multiple model (IMM) algorithm While the first requires around 20 parallel filters, it is shown how the latter, implemented in the form of the IMM, performs equally or better with 2 or 3 fillers.@en