STAP is essentially filtering in the space-time domain. This means that we are filtering over multiple dimensions, and multi-dimensional signal processing techniques must be employed. The goal is to find the optimal space-time weights in formula_1-dimensional space, where formula_2 is the number of antenna elements (our spatial degrees of freedom) and formula_3 is the number of pulse-repetition interval (PRI) taps (our time degrees of freedom), to maximize the signal-to-interference and noise ratio (SINR). Thus, the goal is to suppress noise, clutter, jammers, etc., while keeping the desired radar return. It can be thought of as a 2-D finite-impulse response (FIR) filter, with a standard 1-D FIR filter for each channel (steered spatial channels from an electronically steered array or individual elements), and the taps of these 1-D FIR filters corresponding to multiple returns (spaced at PRI time). Having degrees of freedom in both the spatial domain and time domain is crucial, as clutter can be correlated in time and space, while jammers tend to be correlated spatially (along a specific bearing).