MINIATURE ORTHOGONAL MAGNETIC SENSOR

KVH INDUSTRIES PROPOSES TO DEMONSTRATE THE FEASIBILITY OF DEVELOPING A MINIATURIZED ORTHOGONAL MAGNETIC SENSOR ASSEMBLY WHOSE VOLUMETRIC DIMENSION, INCLUDING SHIELD, WILL NOT EXCEED 10 CM(3). THE UNIT HAS AS OBJECTIVES A SENSITIVITY OF 1 NANOTESLA WHILE OPERATING AT FLUX DENSITIES OF UP TO 20 OERSTED. FURTHERMORE, THE SYSTEM DRIFT AT ROOM TEMPERATURE IS NOT TO EXCEED 1 NANOTESLA WITHIN A 60 MINUTE PERIOD. THE PROPOSED APPROACH TRANSFORMS THE PROBLEM OF DETECTING AN AMPLITUDE NULL INTO DETECTING A PHASE TRANSITION THROUGH THE USE OF A VERY HIGH GAIN AC AMPLIFIER WITH A LINEAR LIMITER AND A BANDPASS FILTER. THE EFFORT WILL DESIGN A SYNCHRONOUS PHASE DETECTOR WITH MINIMUM OFFSET AND SWITCHING NOISE THAT HAS A STABLE LOW PASS FILTER WITH MINIMUM RIPPLE IN THE PASS BAND AND A STOP BAND ATTENUATION OF AT LEAST 40 DB BELOW MINIMUM SIGNAL. THE ENTIRE MEASUREMENT SYSTEM WILL BE IN THE FEEDBACK LOOP. BIAS CURRENT WILL BE GENERATED TO INCREASE RESOLUTION AND STABILITY. ELECTRONIC CONTROL WILL BE VIA A MICROPROCESSOR WITH DATA OUTPUT AS A THREE BYTE WORD. A PROOF-OF-PRINCIPLE MODEL WILL BE DELIVERED.