V.T. Lobach – Head of Department of Radio Engineering and Telecommunication Systems, Southern Federal University (Taganrog)
M.V. Potipak – Associate Professor, Department of Radio Engineering and Telecommunication Systems, Southern Federal University (Taganrog)
V.V. Bakhchevnikov – Post-graduate Student, Department of Radio Engineering and Telecommunication Systems, Southern Federal University (Taganrog)
M.I. Dulin – Head of Department for Preparation and Provision of Research and Development Work, JSC «Taganrog Scientific Research Institute of Communications»
A.V. Sheverda – Engineer, Department for Preparation and Provision of Research and Development Work, JSC «Taganrog Scientific Research Institute of Communications»
In the context of the general problem of natural resources study by non-contact methods, the exploration of the World Ocean, whose role in the life of humankind is continuously increasing, is of great importance. Rational and full use of natural resources, including resources of the seas and oceans, requires the development of modern technical means for their study. Significant place in the general problem of world's oceans study takes problem connected with remote sensing of sea waves parameters.
In this paper, the algorithm for sea waves height measurements is developed on the basis of cross-correlation function modulus es-timations for reflected signals with frequency diversity. It is shown, that the cross-correlation function is related to the root-mean-square deviation of sea wave heights, the antenna beamwidth, the aircraft flight altitude and the spatial diversity of the transmitting and receiving antennas.
The novelty of this work is to investigate the decorrelation effect of above listed parameters to sea waves height measurement error. A structural scheme has been developed in accordance with which a working model of a two-frequency radar gauge for sea wave height estimation has been designed and manufactured. The results of actual experiments and results, obtained by other authors show the perspective of a two-frequency measurement method at low altitudes.
The experimental results are qualitatively and quantitatively consistent with the results of the calculations. So, at a flying height of z0 = 100 m, with roll angles increase in the range of values (0−10°) the cross decorrelation of the reflected signals increases. With roll angles increase, the relative error of sea waves height measurements increases. The smaller measured wave’s height, the greater measurement error at the same values of roll angles.
Thus, implementation of this method shows that the total error in waves height measurements is determined by antenna viewing angle instability, oscillator frequency stability, signal-to-noise ratio, the error in flight altitude measuring, beamwidth of antenna and correlometer instrumental and methodical errors. In general, the total error is due to error in stabilizing the axis of antenna beam ∆β0 and finite averaging time Tу. For ∆β0 = 0,2° and Tу = 10 с, the total relative mean square error in measuring the height of sea waves can be 10…15%.
These results indicate the possibility of sea waves height measurements using this method with sufficient accuracy for practice.
- Zubkovich S.G. Statisticheskie xarakteristiki radiosignalov, otrazhenny’x ot zemnoj poverxnosti. M.: Sov. radio. 1968.
- Garnaker’yan A.A., Sosunov A.S. Radiolokacziya morskoj poverxnosti. g. Rostov n/Donu: Izd-vo RGU. 1978. 140 s.
- Garnaker’yan A.A., Lobach V.T. i dr. Korrelyaczionnaya funkcziya signala korotkovolnovogo diapazona, otrazhennogo ot morskoj poverxnosti // Texnika usileniya i preobrazovaniya radiosignalov. Taganrog: 1982. № 1. S. 11−16.
- Lobach V.T. Radiolokaczionnoe izmerenie secheniya prostranstvennogo e’nergeticheskogo spektra morskoj poverxnosti // Izvestiya TRTU. 2004. № 1. S. 1−7.
- Longnet-Higgins M.S. The propagation of shorts Surface waves on longer gravity waves // J. Fluid Mech. 1987. V. 177. P. 293−306.
- Lobach V.T., Potipak M.V. The use of stepped frequency signals for object coordinate measurement // IEEE 25th International Crimean Conference Microwave & Telecommunication Technology (CriMiCo). 2015. P. 1140−1141.
- Lobach V.T. Statisticheskie xarakteristiki radiolokaczionny’x signalov, otrazhenny’x ot morskoj poverxnosti. M.: Radio i svyaz’. 2006. 250 s.