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The sensitivity of synthetic aperture radiometers for remote sensing applications from space
Author(s) -
Le Vine David M.
Publication year - 1990
Publication title -
radio science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.371
H-Index - 84
eISSN - 1944-799X
pISSN - 0048-6604
DOI - 10.1029/rs025i004p00441
Subject(s) - radiometer , aperture synthesis , sensitivity (control systems) , remote sensing , synthetic aperture radar , aperture (computer memory) , antenna (radio) , microwave , computer science , signal (programming language) , antenna aperture , noise (video) , radiometry , time delay and integration , optics , electronic engineering , physics , acoustics , geology , telecommunications , radiation pattern , computer vision , engineering , image (mathematics) , interferometry , programming language
Aperture synthesis offers a means of realizing the full potential of microwave remote sensing from space by helping to overcome the limitations set by antenna size. The result is a potentially lighter, more adaptable structure for applications in space. However, because the physical collecting area is reduced, the signal‐to‐noise ratio is also reduced and may adversely affect the radiometric sensitivity. Sensitivity is an especially critical issue for measurements from low Earth orbit because the motion of the platform (about 7 km/s) limits the integration time available for forming an image. The purpose of this paper is to develop expressions for the sensitivity of remote sensing systems which use aperture synthesis. The objective is to develop basic equations general enough to be used to obtain the sensitivity of the several variations of aperture synthesis which have been proposed for sensors in space. The conventional microwave imager (a scanning total power radiometer) is treated as a special case, and the paper concludes with a comparison of three synthetic aperture configurations with the conventional imager.