Guangjian Yan Huazhong Ren Ronghai Hu Kai Yan 0001 Wuming Zhang A portable Multi-Angle Observation System. 6916-6919 2012 IGARSS https://doi.org/10.1109/IGARSS.2012.6352572 conf/igarss/2012 db/conf/igarss/igarss2012.html#YanRHYZ12