Abstract: The position estimation system (220, 226, 222) for estimating a position of an object (224) in a room (200) works by an ultrasound emitter (220) emitting an ultrasound pulse (201), which is reflected at least once on a reflecting object (232), after which an ultrasound receiver (226) detects an ultrasound signal (300) comprising at least the reflection and possibly also a line of sight transmission. Either the emitter or the receiver is attached to the object. A processor estimates the position of the object (224) on the basis of the ultrasound signal (300), by a calculation dependent on properties of the ultrasound signal (300) or by matching the ultrasound signal (300) with templates for object (224) positions, obtained by measurement or by simulation of the ultrasound pulse (201) transmission in the room (200).