Abstract: A system for measuring distance in a gas or liquid operating medium has an even number of ultrasonic signal transmitters (12, 14), and a single ultrasonic signal receiver (16). The ultrasonic signal transmitters are adapted to transmit ultrasonic signals to a target (18) in the operating medium. Each of the transmitters and receiver are so spaced apart in a geometrically symmetrical planar array within an acoustically attenuating substrate medium, and each of the transmitted ultrasonic signals are so pulse driven in an acoustically symmetrical relationship, that opposing ultrasonic signals transmitted through the substrate medium by symmetrically opposed transmitters are cancelled at the receiver and a signal for measuring distance to the target is formed at the receiver by combination of the transmitted signals through the operating medium.