Influence of nonhomogeneous Earth on the rms phase error and beam‐pointing errors of large, sparse high‐frequency receiving arrays

Abstract

The performance of ground‐based high‐frequency (HF) receiving arrays is reduced when the array elements have electrically small ground planes. The array rms phase error and beam‐pointing errors, caused by multipath rays reflected from a nonhomogeneous Earth, are determined for a sparse array of elements that are modeled as Hertzian dipoles in close proximity to Earth with no ground planes. Numerical results are presented for cases of randomly distributed and systematically distributed Earth nonhomogeneities where one‐half of vertically polarized array elements are located in proximity to one type of Earth and the remaining half are located in proximity to a second type of Earth. The maximum rms phase errors, for the cases examined, are 18° and 9° for randomly distributed and systematically distributed nonhomogeneities, respectively. The maximum beampointing errors are 0 and 0.3 beam widths for randomly distributed and systematically distributed nonhomogeneities, respectively.