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EXAMPLE FULL CALIBRATION TEST OF CERF RADAR

EXAMPLE FULL CALIBRATION TEST OF CERF RADAR. ERIC WALTON CERF RADAR AMTA 2012 10-1-2012. FULL CALIBRATION EXAMPLE. LET US DO A FULL CALIBRATION TO REFERENCE SPHERES AND USING EXACT SPHERE RCS FOR REFERENCE.

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EXAMPLE FULL CALIBRATION TEST OF CERF RADAR

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  1. EXAMPLE FULL CALIBRATIONTEST OF CERF RADAR ERIC WALTON CERF RADAR AMTA 2012 10-1-2012

  2. FULL CALIBRATION EXAMPLE LET US DO A FULL CALIBRATION TO REFERENCE SPHERES AND USING EXACT SPHERE RCS FOR REFERENCE. H. L. Thal Jr., “Exact Circuit Analysis of Spherical Waves,” IEEE Transactions on Antennas and Propagation, vol. AP-26, No. 2, March 1978. SET OF TEST TARGETS AND REFERENCE SPHERES APPROX 20 INCHES RADAR 1-12 GHZ RIDGED WAVEGUIDE HORNS STYROFOAM COLUMN

  3. FULL CALIBRATION EXAMPLE MEASURE TARGETS OF INTEREST (S21 VS. FREQ.) SUBTRACT BACKGROUND (EMPTY TARGET SUPPORT) TRANSFORM TO TIME DOMAIN ZERO OUT ALL EXCEPT TARGET ZONE TRANSFORM BACK TO FREQUENCY DOMAIN NORMALIZE TO REFERENCE SPHERE MULTIPLY BY EXACT RCS OF REFERENCE SPHERE Note units of complex voltage and complex meters.

  4. FULL CALIBRATION EXAMPLE FOR THE FOLLOWING EXAMPLE, WE WILL USE A 3.5 INCH DIAM. SPHERE AS THE REFERENCE, AND A 2.5 INCH DIAM. SPHERE AS THE TARGET OF INTEREST. THAT WAY, WE CAN DOUBLE CHECK OUR ACCURACY BY COMPARING THE CALIBRATED 2.5 INCH MEASURED RCS VALUES WITH THE EXACT SOLUTION FOR THE 2.5 INCH SPHERE TARGET. The set of measurements on the different targets took place over a period of approximately 1 hour.

  5. FULL CALIBRATION EXAMPLE NOTE THE I/Q BALANCE NOTE THE GAIN DROP-OFF OF THE RADAR NOTE THE RESULT OF SUBTRACTING THE EMPTY SUPPORT DATA.

  6. FULL CALIBRATION EXAMPLE INCREASING NOISE NOTE THE RESULT OF SUBTRACTING THE BACKGROUND AND THEN NORMALIZING TO (DIVIDING BY)THE REFERENCE SPHERE DATA.

  7. FULL CALIBRATION EXAMPLE ESPECIALLY REMOVE THE DIRECT HORN TO HORN COUPLING TERM SET ALL OUTSIDE THIS TARGET ZONE TO ZERO NEXT WE TRANSFORM THE SUBTRACTED & NORMALIZED DATA TO THE TIME DOMAIN.

  8. FULL CALIBRATION EXAMPLE PLOT OF THE EXACT RCS (DBSM) OF THE 3.5 INCH SPHERE DATA.

  9. FULL CALIBRATION EXAMPLE(FINAL CALIBRATION RESULT) NOTE THE AGREEMENT BETWEEN THE CALIBRATED TARGET AND THE EXACT CALCULATION.

  10. FULL CALIBRATION EXAMPLE WE CAN ALSO DO THIS FOR A 0.75 INCH DIAM SPHERE AS A TARGET. NOTE AGREEMENT

  11. FULL CALIBRATION EXAMPLE IN THIS CASE, THE TARGET OF INTEREST IS A 50 CALIBER BULLET (NOSE ON) 0.75 “ D SPHERE EXACT BULLET WE INCLUDE THE EXACT RCS OF THE 0.75 INCH DIAM. SPHERE AS A REFERENCE.

  12. FULL CALIBRATION EXAMPLE WE ALSO DID A MOM CALCULATION FOR THAT 50 CAL BULLET (Thanks; THE HONG LEE)

  13. FULL CALIBRATION EXAMPLE Overlay theoretical with experimental RCS (DBSM). BROADSIDE RCS (DBSM) NEAR NOSE ON BULLET RADAR DATA FREQ NOT “TOO” BAD. 

  14. FULL CALIBRATION EXAMPLE • CONCLUSIONS; • WE CAN BUILD A STEP FREQUENCY SYNTHESIZED RADAR USING MODERN MIXED SIGNAL MICROCHIPS FOR LESS THAN $2000. • IT IS FULLY SOFTWARE CONTROLLED. • USB INTERFACE TO LAPTOP • FULLY PROGRAM CONTROLLED IN MATLAB (IN OUR CASE) • WE CAN MEASURE RADAR TARGETS VERSUS FREQUENCY AND TRANSFORM THE RESULTS TO THE TIME DOMAIN. • WE CAN PERFORM FULL CALIBRATIONS ON THE DATA TO YIELD RADAR SCATTERING IN DBSM. • WITH GOOD DYNAMIC RANGE • AND GOOD TIME STABILITY. • WE CAN ALSO USE THIS RADAR IN THE SINGLE FREQUENCY MODE TO MEASURE DOPPLER.

  15. FULL CALIBRATION EXAMPLE QUESTIONS? DR. ERIC K. WALTON THE OHIO STATE UNIVERSITY ELECTROSCIENCE LABORATORY 1330 KINNEAR ROAD COLUMBUS, OHIO 43212 Walton.1@osu.edu Office 614/292-5051; cell 614/537-5609

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