Yu. O. Pedenko


Subject and Purpose. The paper is an effectiveness study of the root-MUSIC technique as applied to elevation angle measurements of low-altitude radar targets over the sea, specifically with account of the radio waves’ phase front sphericity. The purpose is to find out whether and how much can the measurement accuracy be improved through account of the phase front sphericity, as compared with the classical approach assuming a plane phase front.

Methods and Methodology. The work proceeds from computer simulation, considering a variety of sea roughness levels, and covers a range of radio wave reflection conditions from a nearly specular return to strong diff use reflection from the sea surface. The simulation involves a wide range of target distances within the far-field region with respect to the receive array.

Results. A new approach has been suggested for taking into account the phase-front sphericity of the radio waves arriving from the target. The level of errors of elevation angle measurements has been estimated and compared with such shown by the conventional root-MUSIC method which assumes a plane phase front for the waves reflected from the target. The comparison concerns a wide range of sea roughness levels and target separations.

Conclusion. It has been established that the proposed version of the root-MUSIC technique which takes wave front sphericity into account can significantly reduce the errors in elevation angle measurements for low-altitude targets.

Manuscript submitted 06.12.2021

Radio phys. radio astron. 2022, 27(2): 110-120


  1. Pedenko, Y., Reznichenko, N., Zuykov, V. and Labazov, S., 2020. The root-MUSIC method versus the amplitude sum-difference monopulse method in radar tracking of low-elevation targets over rough sea. In: 2020 IEEE Ukrainian Microwave Week (UkrMW). Kharkiv, Ukraine, 21—25 Sept. 2020. DOI:
  2. Marple, S.L., 1987. Digital spectral analysis: with applications. Prentice-Hall, Englewood Cliffs, NJ.
  3. Shakhtarin, B.I. and Kovrigin, V.A., 2005. Methods of spectral estimation of random processes: a training manual. Moscow: Gelios Publ. (in Russian).
  4. Barton, D.K. and Ward, H.R., 1969. Handbook of Radar Measurement. Prentice-Hall, Englewood Cliffs, NJ.
  5. Razskazovskiy, V.B., Pedenko, Yu.A., 2003. A model for millimeter- and centimeter-waves field over a sea surface designs for investigation the m ethods for low-fl ying targets elevation angle measurement. In: V.M. Yakovenko, ed. 2003. Radiofizika i elektronika. Kharkov: IRE NAS of Ukraine Publ. 8(1), pp. 22–33 (in Russian).
  6. Becкman, P., Spizzichino, A., 1963. Th e scattering of electromagnetic wave from rough surface. London: Pergamon press.
  7. Barton, D.K., 1974. Low-Angle Tracking. Proceedings of the IEEE, 62(1), pp. 687–704. DOI:
  8. Pedenko, Yu.A., 2013. The choice of root-MUSIC parameters for radar measurements of target elevation angles near sea surface. Radiofi z. Elektron., 4(18)(1), pp. 53–58 (in Russian).
  9. Pedenko, Yu.A., 2016. Radar elevation angle measurements of low-altitude targets over the sea by root-MUSIC method under interference from multipath and thermal noise оf direction finder. Radiofiz. Elektron., 7(21)(1), pp. 22–33 (in Russian).
  10. Pedenko, Yu.A., 2014. Measuring places angles over the sea using root-MUSIC method. Choice of solutions. Radiofiz. Elektron., 5(19)(4), pp. 33–41 (in Russian). DOI:


root-MUSIC, elevation angle, low-altitude target, elevation measuring errors, phase front sphericity, multipath, thermal noise, simulation

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