Effect of ionosphere refraction on spaceborne SAR imaging precision

Ionosphere has different stratification at different height, so it´s index of refraction varies with height. When radar´s echo signals transmit through the ionosphere, the real propagation path is not the ideal straight line, in fact, it will inflect to a certain extent. For the spaceborne synthetic aperture radar (SAR) system, the imaging precision has been decreased both in azimuth section and range section due to imprecise slant range history. In this paper, we simulate the real distance between satellite and the target according to Snell´s law, and analyze the effect of ionospheric refraction on spaceborne SAR imaging performance at L-band C-band and X-band.