A Method for Separating the O/X Mode Signals in Vertical Ionograms Based on Improved U-Shaped Encoder-Decoder Network. - Hongchun Li; Chengfeng Zhang; Bo Yin; Xiaoyi Jia; Jiali Xu; Jiawei Xue; Mengfei Ma (IEEE Trans. Geosci. Remote. Sens., 2023)