Abstract: A remotely controllable position indicator system arranged to determine the relative position of two bodies and their relative orientation. A movable remote control device is controllable to transmit command radiation signals. A fixed reference station executes commands represented by the command radiation signals. The remote control device has a transmitter while the reference station has a receiver or receivers which monitors the intensity of the radiation received and distinguishes the source of the radiation. A computer is programmed to determine the direction of the reference station from the remote control device using a comparison of monitored intensity of radiation received from the transmitter to give the direction of the receiver from the directional transmitter. One or more of the transmitters is controllable to transmit command signals and the receiver is arranged to receive the command signal.