EVALUATION OF CALIBRATION ACCURACY WITH HPS (HONGIK POLARIMETRIC SCATTEROMETER) SYSTEM FOR MULTI-BANDS AND MULTI-POLARIZATIONS.ppt

[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Objectives ,[object Object],[object Object],[object Object],IGARSS 2011

IGARSS 2011 Configuration of HPS system [1] P. O’Neill, et al, “Survey of L-Band Tower and Airborne Sensor System Relevant to Upcoming Soil Moisture Missions,” IEEE Newsletter Geosci. Remote Sensing , Jun. 2009. 1) Boom structure (8m) : movable platform 2) Head part : it’s consist of sensor (OMT+Ant.) and incident angle control 3) Sub-circuit : this circuit achieves two functions of frequency converting and switching for full-polarization 4) DAQ, Graphic User Interface : HPS is basically network analyzer based system, Agilent 8753E and controlled by GUI

Configuration : Head Part ,[object Object],IGARSS 2011 [2] J.-H. Hwang, S.-M. Park, S.-G. Kwon, Y. Oh, “Study on the calibration of a full-polarimetric scatterometer system at X- band (in Korean)”, KIEES , Apr. 2010. (2) Inclinometer sensor (2-axis) (1) Step motors (3ea) MOVE Ang. (A move =A n -A in ) Meas. Ang. (A (n+1) ) Input Inc.angle (A in ) No Yes Set position (destination) Meas. Curr. Ang. (A n ), n=0 (n+1) Meas. Ang. (A n ), n=1 A move

Configuration : sub-circuit ,[object Object],[object Object],IGARSS 2011 Tx-path Rx-path RF-cable 7m Pol. indicator

Configuration : GUI & DAQ IGARSS 2011 ,[object Object],[object Object],File header Full-pol. Measurement data Incidence angle

Innovative Ant. System for L-band (type 1) IGARSS 2011 ,[object Object],[3] J. -H. Hwang, S.G. Kwon, Y. Oh, “orthomode transducer using trapezoidal waveguide”, Patent in Korea , 10-2010-0090749 (in progress). ,[object Object],[object Object],Waveguide taper waveguide T-junction V-pol. H-pol. Common mode port < Commercial class 1 OMT > Waveguide taper V-pol. H-pol. Conducting post Total length = 75cm, < OMT with Compact T-junction> Reduced total size to about 56%

Innovative Ant. System for L-band (type 2) IGARSS 2011 ,[object Object],[object Object],[4] J. -H. Hwang, Y. Oh, “Compact OMT Using Single-Ridged Triangular Waveguide”, IEEE MWCL, 2011 . [5] J. -H. Hwang, S.G. Kwon, Y. Oh, “orthomode transducer using waveguide with 4-splitted triangular cross section”, Patent in Korea , 10-2010-0091816 (in progress). Stepped - horn antenna (length: 300mm, 1.26 λ 0 aperture: 450 × 450mm 2 ) Proposed new OMT (length: 560mm, 2.35 λ 0 )

System calibration (Single Target Cal. Tech.) IGARSS 2011 [5] K. Sarabandi, and F. T. Ulaby, “A convenient technique for polarimetric calibration of single-antenna radar systems,” IEEE Trans. Geosci. Remote Sensing , Nov. 1990. IGARSS 2011 ,[object Object],[object Object],s 0 : theoretical [S 0 ] of ref. target (sphere) m 0 : measured [M 0 ] of ref. target (sphere) m u : measured [M u ] of test target (C.R.) s pg : calibrated [S] of test target (C.R.) Mie exact solution 2DTST (2D target scanning technique) This method offers ‘well-aligned’ data

System calibration (2D Target Scanning Tech.) IGARSS 2011 ,[object Object],[4] J. -H. Hwang, S. -M. Park, Y. Oh, “Calibration Accuracy Enhancement in the Field Experiment with a Ground-Based Scatterometer”, IGARSS 2010, Aug. 2010. Scan resolution ~1˚ ,[object Object],Max point (-1,1) ~ boresight

System calibration (multi-bands/full-pol.) IGARSS 2011 ,[object Object],[object Object],After calibration, effective isolation levels improve more than about 10dB 9.4 9.5 9.6 9.7 9.8 9.9 -40 -30 -20 -10 0 10 freq. [GHz] X-Band 5.1 5.2 5.3 5.4 5.5 -40 -30 -20 -10 0 10 freq. [GHz] C-Band 1 1.1 1.2 1.3 1.4 1.5 -40 -30 -20 -10 0 10 freq. [GHz] RCS,  p q [dBsm] L-Band theory un-cal. cal. s v v s v h s h v s h h

IGARSS 2011 Cal. accuracy ~ 0.3dB ~ 0.4dB ~ 0.3dB ,[object Object],: RMS norm of residuals Evaluation of Cal. accuracy 9.4 9.5 9.6 9.7 9.8 9.9 -3 -2.5 -2 -1.5 -1 -0.5 0 0.5 freq. [GHz] 5.1 5.2 5.3 5.4 5.5 -1.5 -1 -0.5 0 0.5 1 freq. [GHz] 1 1.1 1.2 1.3 1.4 1.5 -6 -5 -4 -3 -2 -1 0 1 freq. [GHz] Rasiduals [dB] X-Band C-Band L-Band Cal. resid. un-cal. resid.

Evaluation of Cal. accuracy IGARSS 2011 ,[object Object],[object Object],*Note: It depends on meas. antenna radiation pattern: HPBW (29 ° /35°, 25°/29°, 12°/13° ), E-/H-. Phase error does not exceed about 7˚ in all frequency bands. 0 5 10 15 20 25 30 0 10 20 30 40 50 60 Off-Center Angle [deg] Cal.Error: mag [dB]  v v : [dB]  h h : [dB]  h h -  v v : [deg] 10 20 30 40 50 60 0 5 10 15 20 25 30 0 10 20 30 40 50 60 Off-Center Angle [deg]  v v : [dB]  h h : [dB]  h 10 20 30 40 50 60 h -  v v : [deg] 0 5 10 15 0 10 20 30 40 50 60 Off-Center Angle [deg]  v v : [dB]  h h : [dB]  h h -  v v : [deg] P hase error [deg] 10 20 30 40 50 60 X-Band C-Band L-Band Reliability zone ~ 6.5° ~ 5° ~ 3°

Concluding remarks IGARSS 2011 ,[object Object],[object Object],[object Object],[object Object],Thanks, do you have any questions??

Appendix 1. (off-center error rate) IGARSS 2011 ,[object Object],[object Object],< e.g., Off-center errors of X-band > where, ‘ corr.’ is correlation coefficient of centered and off-centered meas. data arrays of ref. target.

Appendix 2. : Backsacttering coef.( σ ˚) in tidal flat + pattern cal. [M 0 ] IGARSS 2011 C-band, 2010.08.16 Oyster field Mud area X-band, 2010.08.17 Oyster field Mud area C-band: oyster field X-band: mud area

EVALUATION OF CALIBRATION ACCURACY WITH HPS (HONGIK POLARIMETRIC SCATTEROMETER) SYSTEM FOR MULTI-BANDS AND MULTI-POLARIZATIONS.ppt

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EVALUATION OF CALIBRATION ACCURACY WITH HPS (HONGIK POLARIMETRIC SCATTEROMETER) SYSTEM FOR MULTI-BANDS AND MULTI-POLARIZATIONS.ppt