Influence of inhomogeneous ground parameters on HF direction finding

The array manifold with ground parameters is derived for the HF direction finding (DF) error caused by the inhomogeneous ground parameters. Two kinds of circular array manifolds concluded of horizontal polarization and vertical polarization are given. The DF error is simulated with the MUSIC method for the two kinds of DF array. Simulation results show that there is obvious DF error of azimuth angle in the non-uniform boundary zone; on non-uniform ground with low conductivity, there is a significant DF error with the change in relative dielectric constant of the ground, which can reach 2°–3°; the DF error of vertical polarization array is about 1°–2° greater than the error of horizontal array. During construction of HF direction finding station, it is necessary to select areas with high conductivity, and lay a metal grid on the ground to eliminate DF errors caused by changes in ground parameters.