Sky wave radar ionospheric pollution correction method and system

Abstract

The invention relates to a sky wave radar ionospheric pollution correction method and system. According to the characteristics of ionospheric pollution, a spline function is selected as a kernel function of parameterized time-frequency transformation, kernel function parameters are estimated for signals after ionospheric pollution, a pollution sequence is estimated through the kernel function, andpollution correction is conducted. For ionospheric pollution under the multimode propagation condition, a mode of filtering after correction is adopted, and pollution correction is completed throughmultiple iterations. The sky wave radar ionospheric pollution correction method and system provided by the invention can be suitable for pollution under a multimode condition, and the correction precision is improved.

Description

technical field [0001] The invention relates to the field of sky-wave radar ionosphere pollution correction, in particular to a sky-wave radar ionosphere pollution correction method and system. Background technique [0002] The sky-wave over-the-horizon radar works in the short-wave band (3-30MHz), and uses the reflection effect of the ionosphere on short-wave electromagnetic waves to complete over-the-horizon detection of air or sea / ground targets thousands of kilometers away. Due to its "looking down" working method, sea / ground clutter interferes seriously when detecting sea / ground targets. Sea / ground targets move slowly. To detect targets from strong sea / ground clutter, a long accumulation time is required to obtain sufficient Doppler resolution and separate clutter and targets in the Doppler domain. For sea / ground target detection, typical coherent accumulation times are 10-40s. During this time frame, the ionospheric channel is fluctuating. The fluctuation of the ion...

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Problems solved by technology

The method based on singular value decomposition is to use the invariance of the pollution frequency in a short period of time, construct the Hankel matrix with the extracted characteristic signal for singular value decomposition, reduce the rank by retaining large singular values, suppress the noise component, and then use matrix block, The extraction and correction of pollution signals are realized after operations such as feature decomposition. The problem with this method is that it is sensitive to noise

[0007] In addition, due to the increase of the Doppler component of the received signal in the multi-mode situation, the current pollution correction methods are all aimed at the single-mode propagation situation, and are not applicable to the pollution in the multi-mode situation

The key problem of ionospheric pollution correction is the analysis of the time-frequency structure of the pollution signal. The difficulty lies in the fact that multi-component signals make the analysis of the time-frequency structure of the pollution signal affect each other, making it difficult to accurately analyze

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