Design method for interferometer array. Measurement of the elevation angle of waves in the presence of a reflecting terrain

A design method is given for interferometer arrays that are required to measure the elevation angle of arrival of waves in the presence of near-horizontal specularly-reflecting ground, The array consists of a number of interferometers of different baselines whose phase measurements are used together to compute the elevation angle; only the fractions of cycles of phase are measurable and the constraints include size and cost. The design method considers the disposition of the individual interferometers and the way the elevation angle is computed from the phase measurements. The objective is an accurate estimate of elevation angle over a wide range of angles. The possible improvements that might result from measurements of amplitude as well as phase have been considered. One application might be to aircraft landing aids to improve the present international landing system (i.l.s.).