Abstract
A low-cost transportable software-based global positioning system reflectometry (GPS-R) scheme, which can measure sea-surface wave frequency, period, and speed, is proposed and described. We designed and implemented an appropriate software receiver to acquire and track GPS-R L1-band C/A code signals in near real time. At Lanyu, Taiwan, a research platform has been built with two software-based GPS-R receivers overlooking the seas in the east-northeast and southwest directions. Additionally, we propose applying the maximum entropy method for the spectral analyses of recorded time series of GPS-R signal acquisition data and derive the mean frequencies, periods, and speeds of random sea-surface waves. The derived sea-surface wave frequencies have been compared and validated against buoy measurements and Weather Research and Forecasting (WRF) model data around Lanyu Island. The results show that the buoy wave heights and the modeled WRF wave heights have linear correlation coefficients of 0.64 and 0.47, respectively, with the GPS-R wave frequency measurements. The observed coastal sea area has a maximum horizontal distance of approximately 20 km from station Lanyu (22.037°N, 121.559°E). Thus, the corresponding mapping products of the sea-surface wave period and speed are presented with wave propagation footprints of the first Fresnel zone sizes.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
Explore related subjects
Discover the latest articles, news and stories from top researchers in related subjects.Data availability
The 4.096-MHz I-Q data obtained on DOY 346, 2019, from the Lanyu-ENE and Lanyu-SW systems can be downloaded from http://isl.csrsr.ncu.edu.tw/en-us/data.html.
References
Borre K, Akos D, Bertelsen N, Rinder P, Jensen SH (2007) A software-defined GPS and Galileo receiver: a single-frequency approach. ISBN 978–0–8176–4390–4. Birkhauser
Clarizia PC, Ruf CS, Jales P, Gommenginger C (2014) Spaceborne GNSS-R minimum variance wind speed estimator. IEEE Trans Geosci Remote Sens 52(11):6829–6843. https://doi.org/10.1109/TGRS.2014.2303831
Goda Y (1990) Random waves and spectra, in Handbook of Coastal and Ocean engineering, Volume 1: Wave Phenomena and Coastal Structures. Edited by Herbich JB, 175–212, ISBN 0–872–01461–4. Gult Publishing Company, Houston
Hristov HD (2000) Fresnel zones in wireless links, zone plate lenses and antennas. ISBN 0–89006–849–6. Artech House, Inc., Norwood
Lin B, Katzberg SJ, Garrison JL, Wielicki BA (1999) Relationship between GPS signals reflected from sea surfaces and surface winds: Modeling results and comparisons with aircraft measurements. J Geophys Res 104(C9):20713–20727
Longuet-Higgins MS (1957) The statistical analysis of a random, moving surface. Phil Trans Roy Soc London, Ser A 966:321–387. https://doi.org/10.1098/rsta.1957.0002
Martín-Neira M (1993) A passive reflectometry and interferometry system (PARIS): application to ocean altimetry. ESA Journal 17:331–355
Mei CC (1990) Basic gravity wave theory, in Handbook of Coastal and Ocean Engineering, Volume 1: Wave Phenomena and Coastal Structures. Edited by Herbich JB, 1–62, ISBN 0–872–01461–4. Gult Publishing Company, Houston
Press WH, Teukolsky SA, Vetterling WT, Flannery BP (1992) Numerical Recipes in C: The Art of Scientific Computing, 2nd edn, ISBN 0-521-43108-5. Cambridge Univ Press, New York
Rice SO (1944) Mathematical analysis of random noise. Bell Syst Tech J 23:282–332. https://doi.org/10.1002/j.1538-7305.1944.tb00874.x
Rius A, Aparicio JM, Cardellach E, Martín-Neira M, Chapron B (2002) Sea surface state measured using GPS reflected signals. Geophys Res Lett 29(23):2122. https://doi.org/10.1029/2002GL015524
Trizna TB (1997) A model for Brewster angle damping and multipath effects on the microwave radar sea echo at low grazing angles. IEEE Trans Geosci Remote Sens 35(5):1232–1244. https://doi.org/10.1109/36.628790
Tsui JBY (2000) Fundamentals of Global Positioning System Receivers: A Software Approach. ISBN 0–471–20054–9. John Wiley & Sons, Inc., New York
Wickert J et al (2016) GEROS-ISS: GNSS REflectometry, Radio Occultation, and Scatterometry onboard the International Space Station. IEEE J Sel Topics Appl Earth Obs Remote Sens 9(10):4552–4581. https://doi.org/10.1109/JSTARS.2016.2614428
Zavorotny VU, Voronovich AG (2000) Scattering of GPS signals from the ocean with wind remote sensing application. IEEE Trans Geosci Remote Sens 35(3):951–964. https://doi.org/10.1109/36.841977
Acknowledgements
The work was supported in part by MOST 107-2111-M-008-030 and 106-2923-M-008-001-MY3 from the Ministry of Science and Technology, Taiwan, R.O.C., and in part by a grant from the Asian Office of Aerospace Research and Development of the U.S. Air Force Office of Scientific Research (AOARD/ARFL FA2386-18-1-0115). The authors also acknowledge the German Research Foundation (DFG) for funding project DEAREST (SCHU 1103/15-1). The authors would also like to express their indebtedness to the CWB, Taiwan, for providing the data and supporting space and utility to operate the GPS-R systems.
Author information
Authors and Affiliations
Corresponding author
Additional information
Publisher's Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Rights and permissions
About this article
Cite this article
Tsai, LC., Su, SY., Chien, H. et al. Coastal sea-surface wave measurements using software-based GPS reflectometers in Lanyu, Taiwan. GPS Solut 25, 133 (2021). https://doi.org/10.1007/s10291-021-01167-2
Received:
Accepted:
Published:
DOI: https://doi.org/10.1007/s10291-021-01167-2