I. D. Zolotarev, V. A. Berezovskyi

Today for phase directionm finders a heterodyne frequency substitution circuit is often used that has a number of acvantages as compared to traditional two-channel direction finders. Due to the use of highly stable quartz heterodyne stable narrow-band filters can be applied in phase direction finder channels and therefore direction finding characteristics errors can be reduced. In known works the operation of such phase direction finder is analyzed in reference to one radiation source. An urgent task is the analysis of the operation of the direction finder with the frequency substitution in the presence of the simultaneous signal stream from several spaced radiation sources. In this situation there is direction finding characteristic deformation lowering the quality of the direction finding each of the radiation sources. The analysis of the phase direction finder operation in these conditions required the development of a matrix technique using the bilinear form for the signal notation. Based on the obtained matrix technique the paper shows the capability for solving the problem of several radiation sources direction finding parameter resolution.