Sea surface flow inversion method based on X waveband radar image

Abstract

The invention discloses a sea surface flow inversion method based on an X waveband radar image. The method comprises the following steps that: (1), sea clutter images in a time-space domain are collected and are used as a sequence, so that a sub-image sequence is obtained; (2), three-dimensional fourier transform is carried out on the sub-image sequence; (3), a band pass filer is constructed according to a dispersion relation; (4), correction is carried out on a non-linear influence of an image spectrum; (5), a degree of membership is calculated; (6), weighted calculation is carried out; (7),initial flow estimation carried out; (8), iteration flow estimation is carried out. Compared with a current flow inversion algorithm, the sea surface flow inversion method enables a flow inversion accuracy to be improved and especially a flow inversion accuracy at a slow flow speed to be improved; moreover, stability on an inversion result is improved. According to the invention, a dispersion relation band bass filter that depends on a maximum flow speed is utilized to carry out noise filtering on an image spectrum and the denoising capability is strong; besides, correction is carried out on the image spectrum to obtain a sea state spectrum, so that real sea state information can be reflected; and then, the sea state spectrum is utilized as one of weights of a least square method to calculate a flow, so that a flow inversion result approaches a real sea state.

Description

technical field [0001] The invention belongs to the technical field of sea wave parameter inversion, and in particular relates to a sea surface current inversion method based on an X-band radar image. Background technique [0002] Ocean currents are due to the long-term differences in temperature, density, and pressure of seawater between adjacent seas or the long-term effect of directional winds, which cause seawater to flow in a horizontal direction. It has a very close relationship with marine fishery, marine engineering construction, maritime navigation safety and military operations. [0003] When the X-band radar works in the short-pulse mode, the emitted electromagnetic waves meet the micro-scale waves on the sea surface and undergo Bragg scattering, which generates back echoes and is received by the radar receiver to form sea clutter images. Sea clutter images contain a wealth of information about waves and currents. Many domestic units have carried out related rese...

AI Technical Summary

Problems solved by technology

[0019] The current surface flow measurement algorithm has the following shortcomings: ① When the flow rate is low, the error of the measurement result is too large; ② The measurement result is unstable, and singular values ​​often appear, especially when the flow rate is low

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