A method of enhancing the detectability of a height change with an air pressure sensor and a sensor unit for determining a height change

A sensor unit (2) comprising a pressure sensor (9) is worn by a person. A fall of the person causes a height change as well an orientation change of the pressure sensor. To enlarge the detectability of the fall the air pressure is positioned such that in a pre-fall condition the contribution of an error to the sensor's measurement is maximal. This error is caused by gravity acting on the membrane of the sensor.