I want to assess performance of a 4 and 5 antennas (arranged in the form of circular array), by calculating different parameters such as CRB and RMSE. However, as I have seen in theory, a number of different formulas and methods are implemented. Moreover, what I learnt till now is that you have to deduce a different CRB formula for different scenario. Is there some basic guide or some instructions which can point me in the right direction for calculating CRB as per given antenna design?