RADIO DIRECTION FINDER

PURPOSE:To achieve a stable and accurate azimuth measurement by enhancing accuracy of an average value by controlling the average count according to fluctuation of azimuth measurement result and by selecting measurement result with the average value as a center. CONSTITUTION:An azimuth signal is generated by phase difference between elements at a sequential switching azimuth detector 4 by an antenna switcher 2 from reception signal from an azimuth antenna element 1 where a plurality of antenna elements #1 - n are placed in circular shape and reference azimuth signal is generated by a switching signal generator 5. Then, the arrival azimuth of electric waves is measured by an azimuth measuring equipment 6 by comparison. At this time, an average value is calculated by an average circuit 8 according to measurement result of the measuring equipment 6 and a deviation value indicating condition of fluctuation is calculated by a deviation value calculation circuit 9 from it and the measurement result. The average count is controlled by setting procedures using an average count control circuit 10 based on it for improving accuracy of the average value. Also, measurement result is selected according to allowance range which is preset 11 by a screening circuit 12, thus enabling measurement result which fluctuated extremely due to noise, mixed signal, etc., to be excluded.