ASPECT AND INCIDENCE ANGLE SENSITIVITY IN ERS-1 SAR DATA

Large variations in backscattering coefficients were observed on ERS-1 SAR images acquired from ascending and descending orbits, within 36 h ours, over an agricultural area and under stable winter conditions. Th ree possible causes were investigated: (1) environmental factors; (2) SAR processor instability; and (3) aspect and incidence angle sensitiv ity. The look direction (aspect angle) accounted for a 1.5 dB differen ce in backscattering coefficients. The remaining variations were relat ed to the incidence angle. A correction model is proposed.