Optimal imaging in single-channel radiometers with scanning antenna V.K. Volosyuk, D.Sc.; V.V. Pavlikov, PhD; S.S. Zhyla, PhD-student Zhukovsky National Aerospace University, "KhAI"
Using the results and ideas of the previous scientific works a wide class of radiometers has been investigated. Optimal algorithms of radiobrightness or brightness temperature restoration as function of angular coordinates in scanning single-channel radiometers has been synthesized. All radiometers can be divided into scanning radiometers with stable predetection section and radiometers with unstable predetection section. The simplest of them is a total power scanning radiometer. Investigation results of such system has shown the next fundamental operations: spatial matched filtering, time matched filtering, time decorrelation, square detection, averaging, internal noise compensation and spatial decorralation. On the base of these operations a block diagram of radiometer are designed. Using Fisher information matrix limit errors of estimation and potential fluctuation sensitivity are derived. Because of transfer characteristic fluc¬tuations total power radiometer is not used in practice.
For reducing systematic errors and increasing estimates precision radio- metric systems with modulation of the desired signal are offered in practice. By the maximum likelihood method an optimal chopper radiometer, an optimal zero type radiometer and a modified chopper radiometer are synthesized. Operations in optimal chopper radiometer and optimal zero type radiometer are based on subtraction intensities in the next periods of modulation function. Unlike the last modified chopper radiometer performs dividing powers in the next periods of modulation function. Such approach completely eliminate all instabilities in ra¬diometer predetection section. Also for these radiometers limit errors of estimation and potential fluctuation sensitivity are derived and block diagrams arc designed.