Detection performance of slowly and tangential moving targets (STMT) is a considerable problem in modern radar systems, especially in unwanted reflected signals. These STMT produce zero/near-zero Doppler frequency shifts which the moving target indicator processor automatically removes. One popular solution is applying the received echo after passing through matched filer (MF) through a moving target detector (MTD) with a clutter map processor. In this paper, an improved clutter map MTD processor is considered. It relays on passing the output from MF through a sidelobe suppression optimum filter (SLS-OF) before clutter map MTD to relieve the detrimental effect of the clutter returns. The performance of the intended processor is evaluated compared with the traditional MTD using equal length Barker and polyphase coded waveforms. The evaluation process involves calculating the average peak signal to sidelobe ratio (PLSR) and evaluating the detection performance through the receiver operating characteristic (ROC) curve. The enhancement PLSR for the two scenarios are 4dB and 6dB, respectively, which improves the detection performance of the proposed processor by 2 dB.