A High-Resolution Imaging Method of Ionosonde Based on Spatial-Frequency 2-D Spectrum Estimation Technology

Abstract

The ionosonde is one of the most widely used ionospheric detection devices. It has significant implications for the study of space physics and wireless communication technology. To solve the problem of low resolution with traditional iososonde imaging method, this letter proposes a high-resolution 2-D spatial-frequency spectral estimation imaging method. By reconstructing the echo signal matrix and constructing the guidance vector that simultaneously reflects the range and motion characteristics of the target, high-precision estimation of the range-Doppler spectrum is achieved in 2-D Capon estimation. The analysis of experimental sporadic-E (Es) sounding data of August 13, 2021 in Wuhan ( $114^{\circ } 22^{\prime } $ E, $30^{\circ } 30^{\prime } $ N), China, demonstrates its ability of the precise measurement for single-layer echoes and the identification ability for multilayer fine structures. This method further enhances the potential of traditional ionosonde for precise observation and analysis of the ionosphere.