The radar computer measures each pulse and generates a power plot in which the maximum point is called the power centroid. The accuracy of the radar is a measure of its ability to locate the power centroid and align its antenna so that the centroid is on the antenna axis. Automatic Angle Tracking is accomplished by keeping the power centroid centered on the antenna axis as the target moves. Note that this implies that for best tracking the beamwidth should be larger than the target so that no target exists in adjacent beamwidths. If the target is bigger than the beamwidth of the radar, the power return will be about equal in several antenna orientations so that the power centroid will be broad in angle and thus degrade tracking accuracy.
Resolution is the ability to distinguish multiple targets.
When the computer generates the power plot, any pulse whose value is less than .707 of the power centroid is assumed to be from a different beamwidth due to the definition of beamwidth. Therefore, to resolve two targets there must be a point between them where the returned power is down to the half-power points. But that, by definition, is a separation equal to the beamwidth of the radar. The resolution for such a dual beam system is often given as the inter-section of the smallest dimension of each beam, but this is not to be confused with the resolution cell. For a dual beam TWS system, each transmitter has a res cell in which the power centroid of the target or targets will be located to within one beamwidth.