VARIABLE RESOLUTION RADAR FOR TROPOSPHERIC SOUNDERS

摘要

A radar sounder for plotting and studying the refractive structure of atmospheric strata close to the ground is described. The radar comprises means for linearly modulating and vertically radiating a beam of microwave energy. The beat frequency produced in the receiver by the heterodyning of the outgoing with the returning frequencies, is a function of the elevation of the strata from which the reflections occur. Importantly, the degree of resolution of the radar of this invention can be varied from coarse to fine without altering the duty cycle or the total amount of radiated power. Coarse resolution is preferred for searching for the important principal refractive layers from ground to high altitude, while fine resolutions is necessary for examining the fine structure of the selected layer. Of extreme importance is the ability of the radar sounder of this invention to observe structures close to the ground as this is the range where refractive index variations are the greatest.