A precipitation sensor including a cantilevered sensor member having a cantilevered portion and an upper and a lower surface extending on opposite sides of the cantilevered portion. The invention further relates to a photopolymer formulation comprising the methacrylate of the invention as well as to use of said photopolymer formulation for producing holographic media. An output switching module is arranged to switch from a first output mode in which model estimations of the tracking module are forwarded, to at least a second output mode in which only reliable outputs are forwarded, in response to information indicating the detection of a target maneuver being received from the detector.