Patent ID: 7791531

Claim:
A VOR (Very High Frequency Omnidirectional Radio Range) monitoring receiving apparatus comprising: a receiving circuit configured to receive a field signal from a VOR apparatus, and output content of the field signal to a plurality of signal systems; a first monitoring receiving circuit provided in a first signal system included in the plurality of signal systems, and configured to monitor the content of the field signal; a second monitoring receiving circuit provided in a second signal system included in the plurality of signal systems, and configured to monitor the content of the field signal; a self-check signal generator configured to generate a self-check signal necessary to confirm whether the first and second monitoring receiving circuits normally operate; a VOR monitoring controller configured to detect an abnormality of the VOR apparatus based on monitoring results of the first and second monitoring receiving circuits; a switch configured to perform switching to alternately output the field signal and the self-check signal to the first and second signal systems; and a switch controller configured to receive a monitoring result from each of the first and second monitoring receiving circuits, determine whether a monitoring result from each of the first and second monitoring receiving circuits indicates monitored content of the field signal or monitored content of the self-check signal, output a determination result to the VOR monitoring controller, and control the switch to perform switching whenever a preset time elapses.