An ultra-wideband sensor transmits impulse radio signals over a predetermined time period, detects echo signals of the impulse radio signals by way of at least one sensor of the ultra-wideband sensor and generates a time-variant channel impulse response that describes the echo signals received by the at least one sensor as a function of a time at which the respective impulse radio signal of the predetermined time period was transmitted and a path delay, uses a predetermined selection method to ascertain at least one ascertained path delay, generates a signal characteristic of the time-variant channel impulse response for the at least one ascertained path delay, uses a predetermined comparison method to determine a similarity of the signal characteristic to a reference characteristic, and detects a predetermined movement pattern associated with the reference characteristic if the similarity meets a predetermined similarity criterion.