Radar exploration of Venus

[摘要] The feasibility of studying Venus by radar was demonstrated on the tenth of March, 1961, when an echo from Venus was first detected in real time.The spectrum of the echo may be expected to be broadened by the doppler shifts produced by any rotation Venus might have.In order to measure this broadening, a novel technique for accurate spectral estimation of this extremely weak signal was devised, analyzed and implemented.The results of the measurements indicate that Venus rotates only once for each of its years, so that one hemisphere always faces the sun.In addition, the spectral measurements together with some polarization measurements enable one to infer some scattering properties of the surface.Time of flight measurements were also made, using a cross-correlation technique.These, compared with standard astronomical tables, provide a new value for the Astronomical Unit.The standard deviation of these measurements is only a few parts in 10^7.

[发布机构] University:California Institute of Technology;Department:Engineering and Applied Science

[关键词] Electrical Engineering