Signal-to-noise ratio loss in an MTI cascaded with coherent integration filters

An analysis of the effect of an MTI on detection by coherent integration is given. It is shown that for detection of targets in regions of no clutter, preceding coherent integration filters by an MTI can degrade performance. This degradation of performance is expressed both as a decrease in SNR and as a reduction in detection probability. Formulas for the output SNR are derived for the case where a conventional delay-line-canceller digital MTI is cascaded with a coherent integrator that is implemented using the discrete Fourier transform. Comparison of the output SNR as a function of Doppler frequency are made for several values of the number of delays in the MTI. Averaging SNR over Doppler frequency is not performed.