A Method for Extracting Wave Height from First-Order Bragg Resonant Peak of High Frequency Surface Wave Radar Ocean Echo

Abstract

The invention discloses a method for extracting wave height from sea echo first-order Bragg harmonic peak of a high-frequency ground wave radar. The method comprises the steps of building a response curve of the Bragg wave spectrum value based on the wave height; calibrating the first-order peak power of a long-distance unit through the wave length subjected to second-order spectrum inversion and the first-order peak powder in a near distance unit of the radar, so as to calculate the wave height distribution in the long-distance unit. The method is mainly dependent on the unsaturation feature of the Bragg wave; the wave height is extracted from the first-order Bragg resonance peak; the first-order peak under the general ocean state is obviously more than that in the second-order spectrum, so that the wave height detection distance of the high-frequency ground wave radar can be greatly improved; meanwhile, the portable radar adopting a compact receiving antenna has the space resolution for obtaining the wave height; therefore, the development, popularization and application are greatly promoted.

Description

technical field [0001] The invention belongs to the technical field of high-frequency ground wave radar marine environment monitoring, and in particular relates to a method for extracting sea surface wave height by using the first-order Bragg resonance peak of high-frequency ocean echo. Background technique [0002] The main mechanism of the echo spectrum formed by the backscattering of high-frequency radio waves by ocean waves is the Bragg scattering effect, and its main components are the first-order and second-order Bragg scattering resonance peaks. The first-order peak is the line spectrum, which is produced by the in-phase intensification of the Bragg waves whose wavelength is half the wavelength of the radar wave; the second-order spectrum is located on both sides of the first-order spectrum and is mainly a continuous spectrum. At present, the wind and wave retrieval methods adopted by various types of high-frequency sea-state radar products in the world are mainly bas...

AI Technical Summary

Problems solved by technology

In addition, because the energy of the second-order spectrum is relatively weak and the spectrum range is wide, it is highly susceptible to noise and other disturbances. Even weak electromagnetic disturbances or echoes from ships on the sea surface may cause large wave height estimation errors

One way to improve the accuracy of wave height inversion is to expand the array aperture, but this is not conducive to the establishment and promotion of radar stations; another way is to increase the transmission power to improve the signal-to-noise ratio of the second-order spectrum, but due to the The existence of surface propagation Norton (Norton) attenuation factor makes this approach very inefficient, and the transmission power should not be too large due to radio management constraints

Therefore, under the framework of existing wave height inversion methods, high-frequency ground wave radars, especially portable radars, have distance limitations. They can only measure wave heights in offshore areas, and cannot achieve long-distance detection.

For portable radars, even for measuring wave heights in offshore areas, because the beam used for spatial scanning is very wide, it has almost no spatial resolution capability