Environmental/Noise Effects on VHF/UHF UWB SAR

摘要

This paper presents a straightforward approach to estimating the impact of natural environmental noise on an overall system noise temperature for very high frequency/ultrahigh frequency synthetic aperture radar (VHF/UHF SAR), emphasizing the 30-600 MHz band. The most important external noise sources included are galactic noise, solar noise, and unintended man-made noise. In addition, the estimate of system noise temperature includes the effect of thermal noise due to ground and antenna losses as well as receiver noise. Atmospheric noise is generally much less than other sources in the band of interest here and so has not been specifically included. Similarly, thermal noise originating in atmospheric absorption losses is not significant in this band. We consider first the contributions of various sources to an overall sky temperature and then a model for estimating the effect of sky temperature on the system noise temperature of a practical, non-ideal, radar receiver.