The features of aircraft direction finding are considered by estimating the Doppler frequency that occurs during periodic circular reading of radio signals coming from aircraft radio stations to the annular antenna array of an automatic direction finder. The possibilities of forming and measuring the Doppler frequency of received radio signals are shown, the basic initial data for constructing the proposed variant of measuring the bearing of aircraft with radio emission sources are presented. The results of estimating the permissible values of the distance between neighboring elements and the radius of the antenna array ring, as well as the sensitivity of the phase difference and the Doppler frequency of the radio signals of neighboring elements to a change in direction to the radio source are presented.