ADVANCED NULLING TECHNIQUES

IT IS PROPOSED TO DEVELOP A SET OF ADVANCED ADAPTIVE NULLING ALGORITHMS TO ENABLE SENSOR ARRAYS TO OPERATE EFFECTIVELY IN A RAPIDLY CHANGING ELECTROMAGNETIC ENVIRONMENT CHARACTERIZED BY SPREAD-SPECTRUM SIGNALS AND SOPHISTICATED JAMMERS. AS ENVISIONED THE ADVANCED ADAPTIVE NULLING ALGORITHM WILL CONSIST OF TWO ELEMENTS: (1) A QUICK REACTION CAPABILITY (QRC) THAT ENABLES THE ARRAY TO RESPOND RAPIDLY TO SUDDEN CHANGES IN THE ELECTROMAGNETIC ENVIRONMENTS, AND (2) A FOLLOW-ON RAPIDLY-COVERGENT ITERATIVE ALGORITHM. THE QRC ALGORITHM WILL PROVIDE A MODIFIED (ALBEIT SUB-OPTIMUM) WEIGHT VECTOR TO EFFECTIVELY SUPPRESS NEW INTERFERENCE AFTER ONE OR A SMALL NUMBER OF ARRAY SAMPLES (MANY FEWER THAN REQUIRED BY THE SMI METHOD). THE FOLLOW-ON ITERATIVE COMPONENT WILL RAPIDLY BRING THE MODIFIED WEIGHT VECTOR CLOSE TO THE OPTIMUM VALUE NOTWITHSTANDING MODEST EQUIPMENT MISALIGNMENT (CONVERGENCE MUCH MORE RAPID THAN STEEPEST DESCENT). TO ASSURE HARDWARE COMPATIBILITY OF THE ALGORITHMS, AN EXAMPLE HIGHLEVEL DESIGN WILL BE DEVELOPED. THE DESIGN WILL INCLUDE THREE DIFFERENT MEASURES OF REQUIRED DIGITAL PROCESSING HARDWARE.