ISSN 2070-7401 (Print), ISSN 2411-0280 (Online)
Sovremennye problemy distantsionnogo zondirovaniya Zemli iz kosmosa


Sovremennye problemy distantsionnogo zondirovaniya Zemli iz kosmosa, 2021, Vol. 18, No. 2, pp. 258-270

Evaluation of the characteristics of the reflected radar signal during bistatic sensing of the water surface in the presence of a river current

Yu.A. Titchenko 1 , V.Yu. Karaev 1 , M.S. Ryabkova 1 , K.A. Ponur 1 
1 Institute of Applied Physics RAS, Nizhny Novgorod, Russia
Accepted: 23.03.2021
DOI: 10.21046/2070-7401-2021-18-2-258-270
The advantage of bistatic remote sensing is the ability to carry out measurements in a region far from the receiver and emitter, while the scattering remains in the quasi-specular region and is described by the well-studied Kirchhoff approximation. This makes it possible to obtain an explicit relationship between the scattering characteristics and the parameters of the water surface, which opens possibilities for creating new algorithms for solving the inverse problem of retrieving the wave parameters. In addition, the power level of the received signal in the quasi-specular reflection region significantly exceeds the resonant scattering region, which makes it possible to use signals from satellite navigation systems reflected from the underlying surface for remote sensing tasks. This work is devoted to the presentation of an original approach for calculating the characteristics of microwave radiation directly reflected from wind waves formed in the presence of a constant current. Within the framework of this approach, the concepts of effective wind speed and direction, depending on the speed and direction of the current, are used to define the wave number spectrum of surface waves in the presence of a constant current. To set the frequency spectrum of the waves, the harmonic frequencies are additionally recalculated depending on the speed and direction of the current. The paper presents the dependence of the wave spectrum on the current velocity and on the angle between the wind and current directions. Next, the spectra are used to calculate the second order statistical moments of waves, which are necessary to calculate the Doppler spectrum (DS) of the reflected radiation. To calculate the DS, an approach is used that considers the speeds of the receiver and emitter, the antenna patterns of the receiving and emitting antennas, and depends on 6 second order statistical moments describing the reflecting surface. In this work, the dependences of the bistatic radar cross section, the width and shift of the DS of the reflected radiation on the azimuthal angle of the sensing plane and the wind direction are presented. An algorithm is proposed for retrieving the speed and direction of the current when measuring the characteristics of the DS of the from navigation satellites (GPS, GLONASS, etc.) signal reflected by the water surface on a bridge or offshore platform.
Keywords: scattering cross section, Doppler spectrum, Kirchhoff approximation, quasi-specular scattering, GLONASS, GPS, slope, vertical orbital velocity variance, bistatic sensing, current, wind, waves, wave spectrum
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  1. Avdeev V. A., Bakholdin V. S., Gavrilov D. A., Gerasimenko I. S., Dobrikov V. A., Ivanov A. A., Ivanov V. F., Koshkarov A. S., Sakhno I. V., Simonov A. B., Tkachev E. A., Uspenskii K. K., Shaldaev A. V., Shulzhenko A. V., A set of experiments on the reception of signals from the satellite radio navigation systems GLONASS/GPS reflected from the earth’s surface, Trudy Instituta prikladnoi astronomii RAN, 2012, No. 23, pp. 303–306 (in Russian).
  2. Bass F., Fuks I., Rasseyanie voln na statisticheski nerovnoi poverkhnosti (Wave Scattering from Statistically Rough Surfaces), Moscow: Nauka, 1972, 424 p. (in Russian).
  3. Karaev V. Yu., Titchenko Yu. A., Meshkov E. M., Panfilova M. A., Ryabkova M. S., Doppler spectrum of microwave signal backscattered by sea surface at small incidence angles, Sovremennye problemy distantsionnogo zondirovaniya Zemli iz kosmosa, 2019, Vol. 16, No. 6, pp. 221–234 (in Russian).
  4. Panfilova M. A., Karaev V. Yu., Using spaceborne precipitation radar data to investigate variations of slope variance of large-scale waves in a slick, Sovremennye problemy distantsionnogo zondirovaniya Zemli iz kosmosa, 2017, Vol. 14, No. 5, pp. 187–194 (in Russian).
  5. Ryabkova M. S., Karaev V. Yu., Panfilova M. A., Titchenko Yu. A., Meshkov E. M., Zuikova E. M., Doppler spectrum of a backscatter microwave signal: experiment on a river, Sovremennye problemy distantsionnogo zondirovaniya Zemli iz kosmosa, 2020, Vol. 17, No. 5, pp. 213–227 (in Russian).
  6. Ryabkova M. S., Karaev V. Yu., Panfilova M. A., Titchenko Yu. A., Meshkov E. M., Zuikova E. M., On the problem of the river flow influence on the Doppler spectrum of the reflected radar signal at small angles of incidence, Sovremennye problemy distantsionnogo zondirovaniya zemli iz kosmosa, 2021 (in Russian, in press).
  7. Sakhno I., Tkachev E., Gavrilov D., Uspensky K., Space vehicle of sea surface observation with use of signals from general navigation satellite systems, Izvestiya vyshikh uchebnikh zavedenii. Priborostroenie, 2009, Vol. 52, No. 4, pp. 34–39 (in Russian).
  8. Titchenko Yu. A., Karaev V. Yu., The method of determining the sea wave parameters by using a modified acoustic wave gauge, Izvestiya vyshikh uchebnikh zavedenii. Radiofizika, 2012, Vol. 55, No. 8, pp. 544–554 (in Russian).
  9. Titchenko Yu. A., Karaev V. Yu., Zuikova E. M., Meshkov E. M., Panfilova M. A., Ryabkova M. S., In-situ measurements of bistatic characteristics of radiation reflected by a water surface using a modified radar, Materialy Semnadtsatoi Vserossiiskoi otkrytoi konferentsii “Sovremennye problemy distantsionnogo zondirovaniya Zemli iz kosmosa” (Proc. 17th Open Conf. “Current Problems in Remote Sensing of the Earth from Space”), 11–15 Nov. 2019, Moscow: IKI RAN, 2019, p. 149 (in Russian).
  10. Fateev V. F., Ksendzuk A. V., Obukhov P. S., Krapivkin G. I., Timoshenko G. V., Korol G. N., Fateev O. V., Novikov V. A., Gerasimov P. A., Shakhalov K. S., Multi-position non-radiating SAR with GNSS GLONASS transmitters, Elektromagnitnye volny i elektronnye sistemy, 2012, Vol. 17, No. 5, pp. 62–68 (in Russian).
  11. Cardellach E., Fabra F., Nogués-Correig O., Oliveras S., Ribó S., Rius A., GNSS-R ground-based and airborne campaigns for ocean, land, ice, and snow techniques: Application to the GOLD-RTR data sets, Radio Science, 2011, Vol. 46, No. 6, Art. No. RS0C04, 16 p., DOI: 10.1029/2011RS004683.
  12. Clarizia M. P., Gommenginger C. P., Gleason S. T., Srokosz M. A., Galdi C., Di Bisceglie M., Analysis of GNSS-R delay-Doppler maps from the UK-DMC satellite over the ocean, Geophysical Research Letters, 2009, Vol. 36, No. 2, Art. No. L02608, 5 p., DOI: 10.1029/2008GL036292.
  13. Ghavidel A., Camps A., Impact of Rain, Swell, and Surface Currents on the Electromagnetic Bias in GNSS-Reflectometry, IEEE J. Selected Topics in Applied Earth Observations and Remote Sensing, 2016, Vol. 9, No. 10, pp. 4643–4649.
  14. Gleason S., Remote sensing of ocean, ice and land surfaces using bistatically scattered GNSS signals from low earth orbit: Doctoral Thesis, University of Surrey, Guildford, UK, 2006, 223 p.
  15. Hobiger T., Haas R., Löfgren J. S., GLONASS-R: GNSS reflectometry with a frequency division multiple access-based satellite navigation system, Radio Science, 2014, Vol. 49, No. 4, pp. 271–282.
  16. Huang N. E., Chen D. T., Tung C., Smith J., Interactions between Steady Won-Uniform Currents and Gravity Waves with Applications for Current Measurements, J. Physical Oceanography, 1972, Vol. 2, pp. 420–431.
  17. Jing C., Niu X., Duan C., Lu F., Di G., Yang X., Sea Surface Wind Speed Retrieval from the First Chinese GNSS-R Mission: Technique and Preliminary Results, Remote Sensing, 2019, Vol. 11(24), Art. No. 3013, 13 p., available at:
  18. Karaev V., Ryabkova M., Panfilova M., Titchenko Y., Meshkov E., Zuikova E., Application of doppler radar for measurement of current velocity at small incidence angles: the first experiments at the river, IGARSS 2020 —2020 IEEE Intern. Geoscience and Remote Sensing Symp., Waikoloa, HI, USA, 2020, pp. 5693–5696, DOI: 10.1109/IGARSS39084.2020.9323494.
  19. Li B., Yu B., Yang L., Yang D., Han H., Modeling and Simulation of GNSS-R Signals with Ocean Currents, China Satellite Navigation Conf. (CSNC) 2020 Proc., Vol. I, Singapore: Springer, 2020, pp. 99–110.
  20. Martin-Neira M., A Passive Reflectometry and Interferometry System (PARIS): Application to ocean altimetry, ESA J., 1993, Vol. 17, No. 4, pp. 331–355.
  21. Rodríguez E., Wineteer A., Perkovic-Martin D., Gál T., Stiles B. W., Niamsuwan N., Rodriguez Monje R., Estimating Ocean Vector Winds and Currents Using a Ka-Band Pencil-Beam Doppler Scatterometer, Remote Sensing, 2018, Vol. 10, No. 4, Art. No. 576, 59 p., available at:
  22. Rodríguez E., Bourassa M., Chelton D., Farrar J. T., Long D., Perkovic-Martin D., Samelson R., The Winds and Currents Mission Concept, Frontiers in Marine Science, 2019, Vol. 6, Art. No. 438, 8 p., DOI: 10.3389/fmars.2019.00438.
  23. Romeiser R., Runge H., Suchandt S., Sprenger J., Weilbeer H., Sohrmann A., Stammer D., Current Measurements in Rivers by Spaceborne Along-Track InSAR, IEEE Trans. Geoscience and Remote Sensing, 2007, Vol. 45, No. 12, pp. 4019–4031.
  24. Ruf C., Chang P., Clarizia M. P., Gleason S., Jelenak Z., Murray J., Morris M., Musko S., Posselt D., Provost D., Starkenburg D., Zavorotny V., CYGNSS Handbook, University of Michigan, Ann Arbor, Michigan Publishing, 2016, 143 p.
  25. Ryabkova M., Karaev V., Guo J., Titchenko Y. A., Review of Wave Spectrum Models as Applied to the Problem of Radar Probing of the Sea Surface, J. Geophysical Research: Oceans, 2019, Vol. 124, No. 10, pp. 7104–7134.
  26. Ryabkova M., Karaev V., Panfilova M., Titchenko Y., Meshkov E., Zuikova E., Study of the Doppler Spectrum of the Microwave Radar Signal Backscattered from the Water Surface at Low Incidence Angles in the Presence of a Constant Current: Experiment and Modeling, 2020 33rd General Assembly and Scientific Symp. Intern. Union of Radio Science, Rome, Italy, 2020, pp. 1–4, DOI: 10.23919/ursigass49373.2020.9232433.
  27. Titchenko Y., Bistatic Doppler spectrum of radiation reflected by a water surface, Russian J. Earth Sciences, 2020, Vol. 20, No. 6, pp. 1–8.
  28. Titchenko Y., Karaev V., Doppler Spectrum of Microwaves at Forward Scattering from the Sea Surface, IGARSS 2018 — 2018 IEEE Intern. Geoscience and Remote Sensing Symp., 2018, pp. 4127–4130, DOI: 10.1109/igarss.2018.8517326.
  29. Titchenko Y., Zuikova E., Karaev V., Meshkov E., Panfilova M., Ryabkova M., Bistatic doppler spectra of the signal reflected by rough water surface measured by modified monostatic radar, IGARSS 2020 — 2020 IEEE Intern. Geoscience and Remote Sensing Symp., Waikoloa, HI, USA, 2020, pp. 5713–5716, DOI: 10.1109/IGARSS39084.2020.9323093.
  30. Valenzuela G., Theories for interaction of electromagnetic and oceanic waves: A review, Boundary Layer Meteorology, 1978, Vol. 13, pp. 61–86.
  31. Wineteer A., Perkovic-Martin D., Monje R., Rodríguez E., Gál T., Niamsuwan N., Nicaise F., Srinivasan K., Baldi C., Majurec N., Stiles B., Measuring Winds and Currents with Ka-Band Doppler Scatterometry: An Airborne Implementation and Progress towards a Spaceborne Mission, Remote Sensing, 2020, Vol. 12, No. 6, Art. No. 1021, 18 p., available at:
  32. Zavorotny V. U., Voronovich A. G., Scattering of GPS Signals from the Ocean with Wind Remote Sensing Application, IEEE Trans. Geoscience and Remote Sensing, 2000, Vol. 38, No. 2, pp. 951–964, DOI: 10.1109/36.841977.
  33. Zavorotny V. U., Gleason S., Cardellach E., Camps A., Tutorial on Remote Sensing Using GNSS Bistatic Radar of Opportunity, IEEE Geoscience and Remote Sensing Magazine, 2014, Vol. 2, No. 4, pp. 8–45.