I would like to use an ultrasonic transmitter and three receivers to be able to determine the position of the transmitter relative to the receivers. The distances to be measured are around 3-4 ft. I want to understand how the receivers orientation relative to the transmitter can affect the distance measurement. I attach some simple pictures for illustration, in the first one the receiver is placed directly in front of the transmitter and opposite which is the ideal situation. In the second picture the receiver is placed in front of the transmitter but it is facing away from it. In the third picture the receiver is within the beam angle but is facing almost tangent to the beam. Basically as long as the receiver is within the beam range does its orientation matter?