With the latest TLE data, it is confirmed Yaogan-40 is the third gen (1st Gen= YG-9ABC/16ABC/17ABC/20ABC/25ABC; 2nd Gen: YG-31 Group 1 to 4) Naval Ocean Surveillance System using tree satellites operating in a triangular formation separated from each other by about 120 km. 9 and 31 are in similar orbits, of around 1,100 by 1,050 km inclined by 63.4° but 40 at 851 by 854, 63.4° inclined, giving it a global view instead of just SCS & TW strait. 40 sats also bigger than the others, as launched by CZ-7A instead of LM-4C. As for 9&31, I'am expecting SSF to launch a new serie of optical sats (maybe also with a serie of SAR sats) to trail each 40 triplet for target confirmation.
NOSS give the ability not only to track warships on the open ocean, but also to directly target ships with weapons. I'am pretty sure SSF/PLAN also have adopted the “sensor-to-shooter” approach like USN has done decades ago. Instead of the NOSS satellites data being sent to the SSF/PLAN HQ and then to the ships, the information would be made automatically available to the weapons control stations in ships, subs, and aircraft; PLAN ships and aircraft exchanging tactical data in near realtime. This approach meant that more data could be delivered in useable form. This concept required that the satellite systems collect, process, and automatically report the information. I believe this is one of the key space system allowing PLAN anti-ship missiles to reach beyond the sensor range of their launching ships. And as PLA is shifting from a regional system to a global system, it means the era of anti-ship missile strike beyond 2IC is coming.
Note that, SSF also operate YG-32 (only 2 group launched) another NOS System using 2 sats instead of 3 in each group. Current US latest gen of NOSS (called Intruder) also used 2 sats for radar emissions triangulation.