Microwave over-the-horizon radar echo chart calculating method

A technology of over-the-horizon radar and graph computing, applied in radio wave measurement systems, instruments, etc., can solve the problems of over-the-horizon sea clutter interference, sea surface reflection, radar blind spots, etc., and achieve the effect of evaluating sea surface echo power

Active Publication Date: 2017-05-31
中国电波传播研究所 +1
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Problems solved by technology

Microwave over-the-horizon radar relies on the atmospheric waveguide propagation effect to detect targets at several or tens of times the distance of conventional microwave over-the-horizon radars, but there are also problems such as over-the-horizon sea clutter interference and radar blind spots. Sea clutter itself Due to the change of the beam direction and grazing angle due to the atmospheric super-refraction effect, not only the downward beam will have sea surface reflection, but the upward beam smaller than the critical angle will also generate trans-horizon sea clutter due to the refraction of the atmospheric waveguide to the sea surface. , in the atmospheric waveguide, there are multi-path interference of radio waves and synthesis of multi-path sea clutter. In addition, the detection of targets by conventional microwave radar is limited to within the line of sight, and the radar beam directly illuminates the target, while microwave over-the-horizon radar The irradiation of distant targets is often the indirect irradiation after multiple refractions and reflections of the atmospheric waveguide, and the target characteristics such as RCS and fluctuation characteristics are different from the general research results

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Embodiment 1

[0059] Embodiment 1, in the development process of the microwave over-the-horizon radar, parameters such as the height and strength of the ocean-atmosphere waveguide or the atmospheric refractive index profile are set in the laboratory. The expression of the atmospheric modified refractive index profile of the evaporation waveguide is:

[0060]

[0061] In the formula, M(0) and M(z) are the atmospheric corrected refractivity at sea surface and height z respectively, h 1 =h t =z EDH is the height of the evaporation waveguide, the roughness length z 0 =1.5×10 -4 .

[0062] Compute the sea surface grazing angle for atmospheric duct conditions, such as Figure 5 shown. Further, the sea surface scattering coefficient is obtained by using the clutter model, and the RCS of the corresponding resolution unit is obtained from the radar parameters.

[0063] Calculate the basic propagation loss considering the influence of the environment, and extract the propagation factor F: ...

Embodiment 2

[0068] Embodiment 2, during the use of microwave over-the-horizon radar, based on the monitoring equipment of marine hydrometeorological parameters, the oceanic atmospheric temperature, humidity, pressure, wind speed and direction, and sea surface temperature are obtained, and the evaporation waveguide prediction model such as the P-J model is selected to calculate the evaporation waveguide height , intensity and atmospheric refractivity profiles. The P-J model is the most widely used prediction model for evaporation waveguide. Jeske uses the potential refractive index instead of the atmospheric refractive index, the potential temperature instead of the ordinary temperature, and the potential water vapor pressure instead of the usual water vapor pressure. The atmospheric stability and Monin are determined by the overall empirical Richardson number. -Obukhov similar length, based on the assumption that the bit refractive index is conserved and is a similar variable, the evaporat...

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Abstract

The invention discloses a microwave over-the-horizon radar echo chart calculating method, which comprises the following steps: 1) determination of relevant parameters, target parameters and environment parameters of a microwave over-the-horizon radar; 2) prediction of characteristic parameters of an evaporation waveguide and measurement of characteristic parameters of a surface waveguide; 3) calculation of an atmosphere waveguide or atmosphere refraction propagation sea surface glancing angle; 4) calculation of an atmosphere waveguide or atmosphere refraction propagation factor; 5) calculation of a sea clutter and target echo power diagram; and 6) simulation of a dynamic radar echo chart. The disclosed microwave over-the-horizon radar echo chart calculating method takes influence, formed under ocean hydrological conditions, of atmospheric duct propagation on sea surface echoes and target echoes into full consideration under the actual microwave over-the-horizon radar working environment, provides an actual radar beam sea surface grazing angle calculating method under the atmospheric refraction or atmospheric duct condition on the basis of radar system parameters and marine hydrometeorological parameters, and with relevant sea clutter models being combined, can effectively predicate and estimate the sea surface echo power.

Description

technical field [0001] The invention relates to the technical field of radar target detection and environmental characteristics, in particular to a method for calculating echo patterns of ship-borne or shore-based microwave over-the-horizon radar. Background technique [0002] The inhomogeneity of the tropospheric atmosphere makes the propagation path of electromagnetic waves in the atmospheric medium bend, refract, and scatter. Four typical atmospheric refraction effects are as follows: figure 1 shown. Describe the shape and characteristics of radio wave propagation under the conditions of under-refraction, normal or standard refraction, super-refraction and atmospheric ducting. Atmospheric super-refraction and atmospheric waveguide are the target detection mechanism of the microwave over-the-horizon radar in the present invention. [0003] The variation pattern of the vertical profile of atmospheric refractivity is a key parameter to determine the type of refraction in t...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01S7/41
CPCG01S7/414
Inventor 康士峰湛希张玉生王红光岳永威韩杰郭相明曹仲晴
Owner 中国电波传播研究所
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