Sensitivity of a direct sampling digital correlation receiver for aperture synthesis radiometry

This paper continues the authors´ investigation of a novel direct RF sampling digital radiometer (DSDR) that would be suitable for use in large L-band aperture synthesis sensors. The authors´ focus is to solve for the noise-equivalent sensitivity (NEΔT) of a two-element, correlation DSDR, which would generate the visibility samples for aperture synthesis. An outline of the discrete-time statistical NEΔT derivation is presented for typical Earth remote sensing design conditions. They find that a hypothetical 3-bit L-band DSDR could attain a sensitivity within 3.8% of the figure for an ideal analog correlation radiometer