A novel strategy for topside ionosphere sounder based on spaceborne MIMO radar with FDCD

A novel strategy for topside ionosphere sounder based on spaceborne Multiple-Input Multiple-Output (MIMO) radar is proposed, which takes advantage of frequency division and code division (FDCD) as a substitution for swept-frequency regime employed by the current ionosphere explorers, e.g., TOP side Automated Sounder (TOPAS). The azimuth resolution can be improved by 153 times compared with TOPAS by means of frequency division, producing two-dimensional electron density images. The signal-to-noise ratio (SNR) can be enhanced and complete orthogonality among channels at different frequencies can be achieved by code division, which uses Complete Complementary Sequence (CCS) as phase coding waveform. The simulation results show that root mean square (RMS) of normalized electron density measurements error of novel ionosphere sounder is as low as 1.7%.