1. Department of Optoelectronic Information Science and Engineering, Jiangsu University, Zhenjiang, China
2. Tianjin Navigation Instruments Research Institute, Tianjin, China
3. School of Opto-Electronic Information Science and Technology, Yantai University, Yantai, China
4. Department of Optoelectronic Information Science and Engineering, Nanjing University of Posts and Telecommunications, Nanjing, China