There are 30 years difference between cold war era satellite and the latest generation satellite A LOT of technology has advanced in between the time So Your knowledge about satellite is probably about 30 years behind
Rocket can be manufacture cheaper today and Nano satellite is all the rage now. Lidar is so common and cheap today that they are used in driver less car in combination with AI. Microwave radar has been miniaturize and use in brimstone missile. Supercomputer is reality and china has plenty of it So they have all the building block. All they have to do is getting lidar that can pierce 500 m into the sea in all weather
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Daily watch means the satellite pass over the area once a day.
A ship can travel 1000 km between the overpasses.