Future military microwave radar systems will evolve into multifunction radar with simultaneous functions for surveillance, tracking and recognition. Resolution and accuracy of direction-of-arrival (DOA) estimation will be enhanced and performance against jamming and clutter will be increased. This is made possible by the development of digital array antennas and modern signal processing which utilizes DOA information. This report presents such signal processing together with its possibilities in multifunction radar. The report also covers signal processing for current radar systems which are equipped with auxiliary antennas. The contents of the report is based on our own research and on literature surveys. The purpose of the report is both dissemination of knowledge and reporting of the work performed at FOA. The report is directed to the persons at FOA/FOI which take part in the discussions of the future Swedish defence or plan the activity at FOA/FOI. It is also directed to technically minded persons at the Swedish Defence Materiel Administration, in the Swedish Armed Forces and in the defence industry.