| 摘要 |
A navigational-aid apparatus and method involving the use, on a target station or a craft station, of at least two transmitters, separated by a base-line distance, of distinguishable sonic signals and a transmitter of radio or other electromagnetic signals and, on the craft station or the target station respectively, of three receivers for the sonic signals and a receiver for the electromagnetic signals, the receivers for the sonic signals being in two positions separated by a base-line distance, there being two receivers, one for each sonic signal, in one said position and a receiver for one of the said sonic signals in the other position, while the station having the said receivers is provided with timing means for determining the elapsed times between the reception of the electromagnetic signal and the reception of the respective sonic signals. |
