While there was mystery surrounding the morning (GMT) launch of three Chinese Yaogan 30-01 military surveillance spacecraft from the Xiching launch site in late September 2017, another Long March 2C rocket has since delivered three more of the satellites from the same launch site, this time at 1810 GMT on 24 November.
While officially for peaceful electromagnetic measurements, these military satellites are believed to be an equivalent to the US ocean surveillance NOSS mission tracking naval ships, with this new batch offering a 12 hour observational update to the original September batch. Both batches were built by China Academy of Sciences Small Satellite Center and placed in to a 600km circular orbit at 35 degrees inclination.
There is a further launch of three satellites in the Yaogan 30 “China Noss” class is expected in December 2017 or early 2018.
NB: Note that an earlier satellite dubbed Yaogan 30 which was launched in May 2016 is a Jianbing-6 electro-optical reconnaissance satellite built by CAST.

Long March 2C launches three Yaogan 30 satellites. Courtesy: Xinhua