1. School of Information and Electronics, Beijing Institute of Technology, Beijing 100081, China
2. Key Laboratory of Electronic and Information Technology in Satellite Navigation $($Beijing Institute of Technology$)$, Ministry of Education, Beijing 100081, China
Corresponding author (email@example.com
This work was supported by National Natural Science Foundation of China (Grant Nos. 61427802, 61471038, 61501032), Chang Jiang Scholars Program (Grant No. T2012122), 111 Project of China (Grant No. B14010), and China Scholarship Council (CSC).