I’m new to learning about the Cramér Rao lower bound. Does the calculation of the CRLB imply that only particular estimation algorithms can be used (e.g. estimating delay and Doppler from a complex ambiguity surface) which satisfy the CRLB inequality? And, if I have additional algorithms to refine those estimates and get higher precision ones, could I ever do better than the CRLB?
Or in other words, does the CRLB always hold for any possible algorithm I come up with to compute/estimate the quantity of interest?