I'd like to make an appeal for (at least) 2 more S2 uplink patches. My plan is that we be able to process interferometric uplink data to serve as a "where is the earth?" attitude determination technique. Attached is a sketch showing where 2 elements might be located. The baselines Bx & By are the maximum baselines that these antennas offer. The sinusoidal interferometer fringes have a periodicity on the sky (fringe spacing) of B/(lambda) in radians. For a B ~ 500mm at 3.4 GHz=88mm, the fringe spacing ~0.17 radians or ~10 degrees. With a S/N ~ 10, the angles can be measured to ~0.05 fringes, i.e. about a half degree.
The way I have sketched the interferometer, the S2 array elements on shorter baselines can be used to quickly resolve the 2pi interferometer ambiguities.
73, Tom
