| 摘要 |
A ground installation for an aircraft landing system has an array of transmitting elements located on the arc of a circle. When the elements are activated sequentially either in one direction ("to") or the other ("fro"), a signal is transmitted which, when mixed with a reference signal, produces a wave train in the aircraft having varying beat frequency. Cross-correlating two wave trains, produced by consecutive to and fro excitations, to establish the time delay between them can be used to establish positional information for an aircraft. |
