ENVIRONMENT GENERATOR FOR COHERENT RADAR HYBRID SIMULATOR

RECENT ADVANCES IN DIGITAL TECHNOLOGY HAVE OPENED UP THE POSSIBILITY OF DEVELOPING AN AFFORDABLE ENVIRONMENT SIGNAL GENERATOR BASED ON DISTRIBUTED PROCESSING ELEMENTS. SUCH A SYSTEM, WHICH COULD INTERFACE WITH THREAT RADAR SIMULATORS AS WELL AS ACTUAL RADAR SYSTEMS, WOULD BE MODULAR AND COULD BE DESIGNED TO BE EASILY RECONFIGURED FOR DIFFERENT RADARS AND MODES. IN THIS PROPOSAL WE DESCRIBED THE SYSTEM TRADE ISSUES THAT SHOULD BE CONSIDERED FOR DEVELOPING SUCH A SYSTEM. THE MAJOR ISSUES ARE SIGNAL FIDELITY AND HOW THE SIGNAL GENERATOR SHOULD BE INTERFACED TO THE RADAR SYSTEM UNDER TEST. SINCE THE INTERFACE IS LIKELY TO BE IN AN ANALOG FORMAT AT SOME IF OR RF, THE DIGITAL SIGNALS WILL PROBABLY BE CONVERTED TO ANALOG. IN THE PAST, SUCH CONVERSION HAS BEEN A PROBLEM WITH COMMERCIALLY AVAILABLE HARDWARE. HOWEVER, WE DESCRIBED A NEW DIGITAL QUADRATURE MODULATION TECHNIQUE THAT OVERCOMES SUCH PROBLEMS; THE TECHNIQUE IS CAPABLE OF SUPPRESSING ALL SPURIOUS COMPONENTS TO WELL BELOW -60 DB, WHICH IS REQUIREMENT OF MODERN COHERENT RADARS. MOST THREAT RADAR SIMULATORS ARE OF GROUND BASED RADARS. WE DESCRIBE THE SIGNAL GENERATION ISSUES FOR BOTH GROUND AND AIRBORNE RADARS, BECAUSE WITH A PROPERLY DESIGNED SYSTEM IT WILL BE POSSIBLE TO ACCOMMODATE BOTH, EVEN THOUGH THE TECHNIQUES FOR CREATING CLUTTER SIGNALS ARE VERY DIFFERENT FOR THE TWO SYSTEMS.