Long/Lat coord.?
To any of our good guys out there, I’d look directly above what square one. Way up above that square.
If there’s a geosynchronous satellite there, or one appears above it at some later date, the square is likely somehow related to it.
Just a guess.
Here’s one:
40°27’19.74”N 93°23’31.72”E
They’re located at the border of two provinces: Gansu and Xinjiang.