Doppler VOR(redirected from VHF omnidirectional range)
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Doppler VOR[′däp·lər ¦vē¦ō′är]
A ground-based navigational aid operating at very high frequency and using a wide-aperture radiation system to reduce azimuth errors caused by reflection from terrain and other obstacles; makes use of the Doppler principle to solve the problem of ambiguity that arises from the use of a radiation system with apertures that exceed one-half wavelength; the system is so designed that its signals may be received on the equipment used for the narrow-aperture VOR (very-high-frequency omnidirectional radio range).
A VOR (very high frequency omnidirectional radio-range), which by using Doppler principles reduces the errors in bearings caused by the reflection of RF (radio frequency) energy from objects near the ground. In the Doppler VOR system, the carrier is amplitude modulated by the reference signal and frequency modulated by the variable signal. In Standard VOR systems, the situation is reversed; the carrier is frequency modulated by the reference signal and amplitude modulated by the variable signal.