No, bear with me here for a moment. We all know that one round, on time and on target, is worth more than a battery twelve half an hour late and five miles down the valley. But one thing I've been noticing lately is that more and more, the US is moving toward GPS targeting for precision-guided munitions — cruise missiles, tactical surface-to-surface missiles, even artillery shells. And I'm not at all sure this is a good idea.
The good part of this is that, if the GPS system is working, all these weapons become capable of reliably striking within a few feet of their targets, so long as you know with good accuracy EXACTLY where the target is. But the key part of that is the clause "when the GPS system is working". The recent Chinese ASAT test makes two things very clear — first, that they can kill satellites with a ground-launched weapon, and secondly, that they have no qualms whatsoever about filling up near-earth space with junk and debris.
So consider this scenario. China makes a move against Taiwan. The US threatens military intervention. China fires off a salvo of thirty or so ASATs and splashes twenty or thirty satellites, mostly their own old satellites, in orbits that intersect those of the GPS satellites. They haven't fired on any US asset, so it's not a directly hostile act against the US. But over the next twenty four to forty eight days, impacts with debris disable a large proportion of the satellites in that orbital region, including a large proportion of the GPS constellation. Perhaps if if the debris could doesn't disable enough, they directly fire on several of the remaining GPS satellites, taking out enough of the GPS constellation that there's no longer enough satellites visible at any given time to obtain GPS fixes.
And the US military's entire arsenal of GPS-targeted precision guided munitions stops working. Suddenly they're not precision-guided any more. Inertially-guided cruise missiles still work, but GPS-targeted weapons like ATACSM lose the ability to strike their targets.
It seems to be to be a very bad idea to base your entire munitions strategy on a relatively fragile resource that one of your major potential enemies has already demonstrated the ability to disable or destroy. I sincerely hope the Pentagon is thinking about this.