Spaceborne SIMO-SAR for Three-Dimensional Ionospheric Irregularity Sounding

Ionospheric irregularity sounding is of significant importance in compensating for ionospheric scintillation effects on satellite communication, navigation, and remote sensing systems at lower frequencies, i.e., L band, P band, etc. A novel spaceborne nadir-looking single input and multiple outputs synthetic aperture radar (SAR) scheme is proposed for three-dimensional (3D) sounding of ionospheric irregularities. The 3D radar echo signal model is developed by examining the ionospheric effects on electromagnetic radar waveforms. These echoes can be used to produce 3D global maps of the distribution of ionospheric irregularities by means of a novel 3D SAR image formation algorithm. The effectiveness of the proposed SAR system was verified by means of computer simulations. The simulation results show that the proposed system has the capability to generate a 3D high-precision image of ionospheric irregularities with an altitude resolution as high as 0.9 km, an along-track resolution as high as 0.4 km, and an across-track angular resolution of 0.25 degrees.