This report reviews the performance of operational ASR's, discusses each type of clutter with which the target must compete, examines presently employed methods of overcoming clutter and several state-of-the-art techniques which have not found their way into the ASR's for one reason or another. It concludes by describing two radars, one at S-band and one at UHF, which are believed to come closest to fulfilling ASR requirements in advanced ARTS facilities. The major improvements in performance will be derived from the use of linear optimum signal processing. Further gains will be achieved through the use of adaptive thresholds. STC will combat bird clutter. The radar will incorporate proper shaping of the antenna pattern so that aircraft off the peak of the antenna elevation beam will not be at a disadvantage compared to moving clutter at the peak. The recommended radar concepts also include radial velocity determination by Doppler measurement. This should prove of value in maintaining target tracks and in discrimination against ground vehicles.