Coherency is a state. My question is if that state can be achieved by just tuning the individual clocks/locations based on GPS as a master. And, there's other tricks, with all the inter-satellite communication [1].
replyAnd, there's a contextual difference here between civilian GPS and military GPS. Much of the precision in the existing GPS satellites is to support the military use of GPS, with intentionally error injected into the civilian side.
And, by the nature of the hostile environment the military operates, military craft don't have as strong of a reliance on something that's ephemeral, like a GPS signal on a battlefield.
What you describe is very normal in telecom and has been for a long time. 4G, 5G, etc are all totally dependent on every device syncing to the one higher up in the chain. These days typically a digital control loop is used to tune a high frequency voltage-controlled oscillator which feeds a counter. An event (like GPS PPS, or an ethernet frame arriving on the cable) is extracted from the signal and the counter generates a timestamp. The chips to do this are incredibly cheap and the performance is hard to comprehend.
replyhttps://www.ti.com/product-category/clocks-timing/clock-netw...