| 摘要 |
A navigation system having a plurality of transmitting stations each of which transmits a sequence of short repeating codes at a fast digital rate and superimposed thereon a long single code at a second slower digital rate, and of a duration equal to the duration of the sequence of short repeating codes, such that correlation of the long code in a receiver will yield an unambiguous timing signal relevant to the sequence of short repeating codes. One of said stations may be a master transmitting codes to which transmissions from other stations are locked, and its operation monitored and master status transferred to another station in the event of a fault. Transmitting stations may adjust their frequencies if a receiver detects interference. |
