A baker's dozen magnitude approximations and their detection statistics
A. E. Filip · IEEE Transactions on Aerospace and Electronic Systems · 1976
Thirteen linear approximations to the square root of the sum of the squares operation are examined and compared as to their peak error, average error, mean-squared error, and, most importantly, for digital radar signal processing the increase in SNR (over an exact linear detector) needed to maintain a specified PD and PFA.