Operation mode for topside ionospheric sounding based on space-borne high frequency synthetic aperture radar

Topside ionospheric sounding is significant for scientific research, especially on forecasting of some astronomical disasters. Current ionospheric topside sounding radars have low range resolution of tens of kilometers, but nearly have no azimuth resolution. The concept of synthetic aperture radar (SAR) is introduced to topside ionospheric sounding for improving the azimuth resolution. The operation mode based on space-borne high frequency SAR (HF-SAR) is presented in this paper. Theoretical analysis indicates that the azimuth resolution can be improved to tens of meters. The satellite orbit parameters are selected, and the main parameters of the radar system are preliminarily designed. The technique of Displaced Phase Centers Antenna (DPCA) is utilized to solve the confliction between the radar detection range and the pulse repetition frequency.