– The orbits of the March 12 satellites appear to match two previous launches of Yaogan-31 satellites on Jan. 29 and Feb. 24. Another clutch of satellites launched successfully in April 2018.
– All of these satellites share a similar orbit, but the additional launches likely decrease revisit times when a particular region is visible underneath the orbit of the satellites, which carries them over maritime regions such as the South Shetland Islands.
– The Yaogan-31 series of satellites are part of the Jian Bing 8 (JB-8) ELINT constellation. JB-8 satellites orbit at 1100km and are 63.4° inclined.
– 8 triplets have been launched – the last 3 expanded the constellation beyond the initial 3 orbital planes. With the launch of group 31-04, there are now 6 regularly-spaced orbital planes, indicating the constellation is now likely complete.
Western defense analysis suggests that Yaogan (“remote sensing”) satellites are military reconnaissance satellites and part of ISR systems for the People’s Liberation Army. Such satellites locate and track vessels by detecting and triangulating radio transmissions.