Doppler VOR has an improvement with respect to siting effects compared to the conventional VOR, although the Doppler VOR is costly to install.
SSB Doppler VOR is preferred to be operated because of simple and low cost construction, but the SSB Doppler VOR has the systematic bearing error caused by undesired amplitude modulation which results from the rotating sideband antenna pattern distorted by the counterpoise.
This paper describes an analytical study on the systematic error sources and the error reduction methods by means of compensating signal radiation.
The summary flight test results are also presented and discussed in relation to the effectiveness of the error reduction method.
