So in short, how do the PN sequences became and remain synchronized
through time?
Thanks.

The E&WW article used a Delay Locked Loop, 3 decoders, one fed with the
actual PN secquenc, one with a leading version and one with a lagging
version. The error signal was used to correct the PN clock.

What some military radios use is that the receiver hops much slower than the
transmitter before achieving synchronisation, so I will catch a signal at
some time.

Wim