A delegation headed by Zhan Wenlong (vice president of CAS) and Zhou Dejin (director of Bureau of Science Communication) came to NTSC for investigation and guidance on April 20, 2015, together with Yang Xingke (secretary of party committee of Xi'an Branch, CAS) and Li Baoguo (vice director of Xi'an Branch, CAS). Accompanied by Guo Ji, director of NTSC, Zhan Wenlong and his group visited both Xi'an and Luonan satellite navigation proving grounds, and asked about the grounds’ functional orientation, transmitting and receiving frequency, navigation signal system and ground transportation control system in great detail.