Consider a 1-dimensional toy problem. I have two sensors at different points along the $x$-axis. Somewhere away from the sensors, a disturbance is created which travels towards the sensors, first reaching sensor 1 and then sensor 2 at a later time. Both sensors produce samples over the entire time window, $W$. Both sensors are sampling at the same rate $f$. Using cross-correlation or other methods, what is the smallest time delay I can resolve?
My hunch is that the answer is given by the Cramer-Rao bound. If so, can someone give a simple intuition on how this bound is derived?