You can see them with aerial or even satellite assets.
Assuming they are not heavily camouflaged. Forest branches and leaves also play havoc on ISR and this is why shoot and scooters like to hide on forests.
On the other hand, HIMARS rockets has proven vulnerable even to Buks, and China has its equivalent.
To find shoot and scooters, the trajectory has to be tracked by defense radars, traced to a possible grid location, send a loitering munition or UAV, discover. If loitering munition finds, strike. If UAV finds, you call a ballistic missile strike. Or even with a loitering munition, you can call a ballistic missile strike, use the loitering munition for damage verification, then expend the loitering munition on the survivors.
The whole kill loop needs to be accomplished within minutes.
Hmmm, obviously HIMARS launchers are not easy target to catch given what we've seen in Ukraine, and you can see how much effort PLA is putting into catching them in Taiwan just from watching this exercise.
Is the reverse also true for PHL-191 given it's larger size?
Thanks to optical cameras on long range munitions like Gerans, Gerbara, Italmas or even satellite linked FPV drones, the Russians appear to be in a kill streak against HIMARS, Patriots and the Ukrainian radar defense network.