Angular jitter in an amplitude comparison monopulse radar due to turbulence

Calculations are presented of the bias and spread of the angle estimator of an amplitude comparison monopulse radar caused by propagation through a layer that contains random index of refraction fluctuations. These fluctuations, caused by irregularities between a target and a receiver, bias the angle estimator towards boresight and cause a spread in the measurements of both on- and off-boresight angles. To illustrate the general results simplified expressions are given for Gaussian antenna patterns, targets near boresight, and a simple power-law irregularity spectrum. Comparisons with other models of angular jitter show that the mean square angular fluctuation observed with an amplitude comparison monopulse radar is closely related to the angular fluctuation, which is predicted when the averaging effect of a radar aperture is considered.