POSITION DETERMINING APPARATUS AND METHOD

摘要

An apparatus and method are disclosed for determining the position of a movable element (150). An elongated housing (110) is provided for positioning generally adjacent an edge of an area (10) in which the position of the movable element is to be determined. The housing (110) has a base portion (111) which contains a pair of spaced apart transducers (20) and (30) that are mounted in the surface of the base portion and face said area (10). An upper body portion (112) of the housing is disposed above the base portion (111) and protrudes in a cantilevered fashion toward said area (10), so that the transducers (20 and 30) are recessed from said area (10) beneath the protruding upper body portion (112) of the housing. Circuitry is provided for determining the position of the movable element from the respective transit times of energy propagating in either direction between the movable element (150) and the pair of transducers (20 and 30). At least a portion of the circuitry is contained within the upper body portion (112). An additional transducer is mounted in the recessed region beneath the protruding upper body portion (112), for speed of sound determining purposes. Also disclosed are techniques for increasing the accuracy of the position determination, data validation and screening the position determination data.