| 摘要 |
<p>Tactical radio navigation systems provide bearing information to an interrogating aircraft in response to pairs of interrogation pulses received at a beacon transponder, the system also provides distance measuring and identification information. To provide the required bearing information, pulses radiated from the central antenna array are modulated at a 15 Hz frequency and by 135 Hz frequency, by parasitic elements rotating around a stationary central array. Broadband operation of the system is provided by a distribution pattern of the 135 Hz parasitic elements mounted radially from the central antenna array on a dielectric disc. Nine groups of radially displaced 135 Hz elements are circumferentially arranged around the dielectric disc and each element of a group is tailored to a particular frequency band in the frequency spectrum allotted to radio navigation systems.</p> |
