DIGITAL NULL-STEERING PROCESSOR FEATURING A VARIABLE NULLING THRESHOLD

DEGRADATION OF COMMUNICATION AND DATA LINKS BY THE PRESENCE OF INTENTIONAL AND UNINTENTIONAL INTERFERING SIGNALS IS A MAJOR PROBLEM IN TACTICAL ENVIRONMENTS. THE USE OF HIGH SPEED DIGITAL PROCESSORS TO CONTROL ADAPTIVE NULLING ARRAYS AND INTERFERENCE CANCELLERS IS A NECESSARY COMPLEMENT TO CURRENT SPREAD SPECTRUM AND FILTERING TECHNIQUES. THIS PROGRAM FEATURES THE DEVELOPMENT OF A HIGH SPEED DIGITALPROCESSOR WHICH COMBINES THE NORMALLY MUTUALLY EXCLUSIVE FEATURES OF FAST CONVERGENCE AND DEEP NULLING, WHILE PROVIDING DYNAMIC OPTIMIZATION OF THE SIGNAL TO NOISE RATIO. THE PROPOSED METHOD OF DYNAMIC S/J+N OPTIMIZATION IS TO VARY A NULLING THRESHOLD LEVEL. SIGNALS OF POWER LEVELS BELOW THE THRESHOLD ARE NOT NULLED BY THE PROCESSOR/ NULL-FORMING ARRAY. THE ATTRACTIVE FEATURE OF THIS METHOD OF DESIRED SIGNAL PROTECTION IS THAT IS REQUIRES NEITHER DIRECTION OF ARRIVAL NOR WAVEFORM APRIORI INFORMATION, TWO QUANTITIES THAT OFTEN ARE NOT AVAILABLE IN TACTICAL SITUATIONS. THE KEY TECHNICAL OBJECTIVES ARE TO DEVELOP AN ALGORITHM WITH THE FEATURES DESCRIBED ABOVE, AND TO DEVELOP THE NECESSARY RF/DIGITAL ARCHITECTURE TO IMPLEMENT IT A LOW COST. THE SIMULTANSOUS ACQUISITION OF ALL THESE PERFORMANCE CHARACTERISTICS WOULD ADVANCE THE STATE-OF-THE-ART SIGNIFICANTLY.