Evaluating Two Array Autocalibration Methods with Multifrequency HF Radar Current Measurements

Chen Zhao Radio Ocean Remote Sensing Laboratory, School of Electronic Information, Wuhan University, Wuhan, China

Search for other papers by Chen Zhao in
Current site
Google Scholar
PubMed
Close
,
Zezong Chen Radio Ocean Remote Sensing Laboratory, School of Electronic Information, Wuhan University, Wuhan, China

Search for other papers by Zezong Chen in
Current site
Google Scholar
PubMed
Close
,
Gengfei Zeng Radio Ocean Remote Sensing Laboratory, School of Electronic Information, Wuhan University, Wuhan, China

Search for other papers by Gengfei Zeng in
Current site
Google Scholar
PubMed
Close
, and
Longgang Zhang Radio Ocean Remote Sensing Laboratory, School of Electronic Information, Wuhan University, Wuhan, China

Search for other papers by Longgang Zhang in
Current site
Google Scholar
PubMed
Close
Restricted access

We are aware of a technical issue preventing figures and tables from showing in some newly published articles in the full-text HTML view.
While we are resolving the problem, please use the online PDF version of these articles to view figures and tables.

Abstract

One pivotal factor affecting the accuracy of HF radar current measurements is the direction of arrival (DOA) estimation performance of the current signal. The beamforming technology or superresolution algorithm cannot always perform best in practical applications because of the phase errors existing in array channels. These phase errors, which cause uncertain estimation of DOA, lead to confused values in radial current maps. To solve this problem, this paper is focused on discussing the performances of two autocalibration methods using sea echoes for multifrequency high-frequency (MHF) radar current measurements. These two array calibration methods, based on maximum likelihood (ML) and multiple signal classification (MU), first seek single-DOA sea echoes and then gather them for array calibration using different cost functions. The ML and MU methods provide approximate mean phases, while the standard phase errors of the MU method are smaller. After array calibration using these two methods, the results show significant improvements in current retrievals. Comparisons between the MHF radar and ADCPs reveal that array calibration using the ML and MU methods also improves the estimation of radial currents clearly, with correlation coefficients over 0.93 and rms differences of 0.09–0.18 m s−1 at different operating frequencies and sampling locations. The performance of the bearing offset is also improved. Only small bearing offsets less than 10° exist in radial current measurements. Therefore, this paper demonstrates that array calibration is a crucial part for current measurements, especially for direction-finding HF radar.

Corresponding author address: Zezong Chen, School of Electronic Information, Wuhan University, Luojia Hill, Wuchang District, Wuhan, Hubei 430072, China. E-mail: chenzz@whu.edu.cn

Abstract

One pivotal factor affecting the accuracy of HF radar current measurements is the direction of arrival (DOA) estimation performance of the current signal. The beamforming technology or superresolution algorithm cannot always perform best in practical applications because of the phase errors existing in array channels. These phase errors, which cause uncertain estimation of DOA, lead to confused values in radial current maps. To solve this problem, this paper is focused on discussing the performances of two autocalibration methods using sea echoes for multifrequency high-frequency (MHF) radar current measurements. These two array calibration methods, based on maximum likelihood (ML) and multiple signal classification (MU), first seek single-DOA sea echoes and then gather them for array calibration using different cost functions. The ML and MU methods provide approximate mean phases, while the standard phase errors of the MU method are smaller. After array calibration using these two methods, the results show significant improvements in current retrievals. Comparisons between the MHF radar and ADCPs reveal that array calibration using the ML and MU methods also improves the estimation of radial currents clearly, with correlation coefficients over 0.93 and rms differences of 0.09–0.18 m s−1 at different operating frequencies and sampling locations. The performance of the bearing offset is also improved. Only small bearing offsets less than 10° exist in radial current measurements. Therefore, this paper demonstrates that array calibration is a crucial part for current measurements, especially for direction-finding HF radar.

Corresponding author address: Zezong Chen, School of Electronic Information, Wuhan University, Luojia Hill, Wuchang District, Wuhan, Hubei 430072, China. E-mail: chenzz@whu.edu.cn
Save
  • Barrick, D. E., and Lipa B. J. , 1986: Correcting for distorted antenna patterns in CODAR ocean surface measurements. IEEE J. Oceanic Eng., 11, 304309, doi:10.1109/JOE.1986.1145158.

    • Search Google Scholar
    • Export Citation
  • Chapman, R. D., Shay L. K. , Graber H. C. , Edson J. B. , Karachintsev A. , Trump C. L. , and Ross D. B. , 1997: On the accuracy of HF radar surface current measurements: Intercomparisons with ship-based sensors. J. Geophys. Res., 102, 18 73718 748, doi:10.1029/97JC00049.

    • Search Google Scholar
    • Export Citation
  • Chavanne, C., Janeković I. , Flament P. , Poulain P.-M. , Kuzmić M. , and Gurgel K.-W. , 2007: Tidal currents in the northwestern Adriatic: High-frequency radio observations and numerical model predictions. J. Geophys. Res., 112, C03S21, doi:10.1029/2006JC003523.

    • Search Google Scholar
    • Export Citation
  • Chen, Z., Zhao C. , Jiang Y. , and Hu W. , 2011: Wave measurements with multi-frequency HF radar in the East China Sea. J. Electromagn. Waves Appl., 25, 10311043, doi:10.1163/156939311795253902.

    • Search Google Scholar
    • Export Citation
  • Cosoli, S., Mazzoldi A. , and Gačić M. , 2010: Validation of surface current measurements in the northern Adriatic Sea from high-frequency radars. J. Atmos. Oceanic Technol., 27, 908919, doi:10.1175/2009JTECHO680.1.

    • Search Google Scholar
    • Export Citation
  • Crombie, D. D., 1955: Doppler spectrum of sea echo 13.56Mc./s. Nature, 175, 681682, doi:10.1038/175681a0.

  • De Paolo, T., and Terrill E. , 2007: Skill assessment of resolving ocean surface current structure using compact-antenna-style HF radar and the MUSIC direction-finding algorithm. J. Atmos. Oceanic Technol., 24, 12771300, doi:10.1175/JTECH2040.1.

    • Search Google Scholar
    • Export Citation
  • Emery, B. M., Washburn L. , and Harlan J. A. , 2004: Evaluating radial current measurements from CODAR high-frequency radars with moored current meters. J. Atmos. Oceanic Technol., 21, 12591271, doi:10.1175/1520-0426(2004)021<1259:ERCMFC>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Fernandez, D. M., Vesecky J. , and Teague C. , 2006: Phase corrections of small-loop HF radar system receive arrays with ships of opportunity. IEEE J. Oceanic Eng., 31, 919921, doi:10.1109/JOE.2006.886238.

    • Search Google Scholar
    • Export Citation
  • Flores-Vidal, X., Flament P. , Durazo R. , Chavanne C. , and Gurgel K.-W. , 2013: High-frequency radars: Beamforming calibrations using ships as reflectors. J. Atmos. Oceanic Technol., 30, 638648, doi:10.1175/JTECH-D-12-00105.1.

    • Search Google Scholar
    • Export Citation
  • Friedlander, B., and Weiss A. J. , 1988: Eigenstructure methods for direction finding with sensor gain and phase uncertainties. ICASSP88: 1988 International Conference on Acoustics, Speech, and Signal Processing, Vol. 5, IEEE, 26812684.

  • Graber, H. C., Haus B. K. , Chapman R. D. , and Shay L. K. , 1997: HF radar comparisons with moored estimates of current speed and direction: Expected differences and implications. J. Geophys. Res., 102, 18 74918 766, doi:10.1029/97JC01190.

    • Search Google Scholar
    • Export Citation
  • Hisaki, Y., 2014: Inter-comparison of wave data obtained from single high-frequency radar, in situ observation, and model prediction. Int. J. Remote Sens., 35, 34593481, doi:10.1080/01431161.2014.904971.

    • Search Google Scholar
    • Export Citation
  • Kim, K. C., 2004: Calibration and validation of high frequency radar for ocean surface current mapping. M.S. thesis, Dept. of Oceanography, Naval Postgraduate School, 74 pp.

  • Kohut, J. T., and Glenn S. M. , 2003: Calibration of HF radar surface current measurements using measured antenna beam patterns. J. Atmos. Oceanic Technol., 20, 13031316, doi:10.1175/1520-0426(2003)020<1303:IHRSCM>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Laws, K. E., Fernandez D. M. , and Paduan J. D. , 2000: Simulation-based evaluations of HF radar ocean current algorithms. IEEE J. Oceanic Eng., 25, 481491, doi:10.1109/48.895355.

    • Search Google Scholar
    • Export Citation
  • Laws, K. E., Paduan J. , and Vesecky J. , 2010: Estimation and assessment of errors related to antenna pattern distortion in CODAR SeaSonde high-frequency radar ocean current measurements. J. Atmos. Oceanic Technol., 27, 10291043, doi:10.1175/2009JTECHO658.1.

    • Search Google Scholar
    • Export Citation
  • Lipa, B. J., and Barrick D. E. , 1983: Least-squares methods for the extraction of surface currents from CODAR crossed-loop data: Application at ARSLOE. IEEE J. Oceanic Eng., 8, 226253, doi:10.1109/JOE.1983.1145578.

    • Search Google Scholar
    • Export Citation
  • Liu, Y., Weisberg R. H. , and Merz C. R. , 2014: Assessment of CODAR SeaSonde and WERA HF radars in mapping surface currents on the West Florida shelf. J. Atmos. Oceanic Technol., 31, 13631382, doi:10.1175/JTECH-D-13-00107.1.

    • Search Google Scholar
    • Export Citation
  • Parks, A. B., Shay L. K. , Johns W. E. , Martinez-Pedraja J. , and Gurgel K.-W. , 2009: HF radar observations of small-scale surface current variability in the Straits of Florida. J. Geophys. Res., 114, C08002, doi:10.1029/2008JC005025.

    • Search Google Scholar
    • Export Citation
  • Shay, L. K., Graber H. C. , Ross D. B. , and Chapman R. D. , 1995: Mesoscale ocean surface current structure detected by high-frequency radar. J. Atmos. Oceanic Technol., 12, 881900, doi:10.1175/1520-0426(1995)012<0881:MOSCSD>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Shay, L. K., Martinez-Pedraja J. , Cook T. M. , Haus B. K. , and Weisberg R. H. , 2007: High-frequency radar mapping of surface currents using WERA. J. Atmos. Oceanic Technol., 24, 484503, doi:10.1175/JTECH1985.1.

    • Search Google Scholar
    • Export Citation
  • Solomon, I. S. D., Gray D. A. , Abramovich Y. I. , and Anderson S. J. , 1999: Receiver array calibration using disparate sources. IEEE Trans. Antennas Propag., 47, 496505, doi:10.1109/8.768785.

    • Search Google Scholar
    • Export Citation
  • Wu, X., Cheng F. , Yang Z. , and Ke H. , 2006: Broad beam HFSWR array calibration using sea echoes. Proceedings of 2006 CIE International Conference on Radar (CIE '06), S. Wu, Ed., IEEE, 3 pp., doi:10.1109/ICR.2006.343480.

  • Wyatt, L. R., 2012: Shortwave direction and spreading measured with HF radar. J. Atmos. Oceanic Technol., 29, 286299, doi:10.1175/JTECH-D-11-00096.1.

    • Search Google Scholar
    • Export Citation
  • Wyatt, L. R., Green J. J. , Middleditch A. , Moorhead M. D. , Howarth J. , Holt M. , and Keogh S. , 2006: Operational wave, current, and wind measurements with the Pisces HF radar. IEEE J. Oceanic Eng., 31, 819834, doi:10.1109/JOE.2006.888378.

    • Search Google Scholar
    • Export Citation
  • Zhao, C., Chen Z. , Jiang Y. , Fan L. , and Zeng G. , 2013: Exploration and validation of wave–height measurement using multifrequency HF radar. J. Atmos. Oceanic Technol., 30, 21892202, doi:10.1175/JTECH-D-12-00178.1.

    • Search Google Scholar
    • Export Citation
All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 637 444 200
PDF Downloads 171 46 3