Method for removing non-linear phase pollution from sky wave OTHR (over-the-horizon radar) echo signal

A technology of over-the-horizon radar and nonlinear phase, which is applied to radio wave measurement systems and instruments, and can solve problems affecting detection performance and the influence of sky-wave over-the-horizon radar echo signals, achieving good stability and reducing errors Effect

Inactive Publication Date: 2012-12-26
HARBIN INST OF TECH
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  • Application Information

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Problems solved by technology

[0004] The purpose of the present invention is to provide a method for removing nonlinear phase pollution of sky-wave over-the-horizon radar echo signals, so as to solve the problems caused by nonlinear pha

Method used

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  • Method for removing non-linear phase pollution from sky wave OTHR (over-the-horizon radar) echo signal
  • Method for removing non-linear phase pollution from sky wave OTHR (over-the-horizon radar) echo signal
  • Method for removing non-linear phase pollution from sky wave OTHR (over-the-horizon radar) echo signal

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specific Embodiment approach 1

[0014] Such as figure 1 As shown, the sky-wave over-the-horizon radar echo signal non-linear phase pollution method is realized through the following steps:

[0015] Step 1: The sky-wave over-the-horizon radar echo signal is converted into sky-wave over-the-horizon radar time domain data to be processed by the data acquisition module;

[0016] Step 2: The data selection module converts the sky-wave over-the-horizon radar time domain data collected in step 1 into corresponding frequency domain data through FFT, selects a data window for the frequency domain data and intercepts the energy-concentrated area in the spectrum , perform IFFT on the intercepted frequency domain data to obtain new sky-wave over-the-horizon radar time domain data as processing data; first, assume that there is a radar echo signal X which is a signal from a certain resolution unit that is not polluted by the ionospheric phase The echo signal in a coherent accumulation period. Then the corresponding ech...

specific Embodiment approach 2

[0043] In order to verify the effectiveness of this method, the following simulations were carried out:

[0044] 1. Simulation analysis

[0045] The simulated sky-wave over-the-horizon radar sea surface echo signal data is used. Let the radar received echo be formula 8:

[0046] s(t)=s 1 ·exp(j2πf b t)+s 2 ·exp(-j2πf b t)+w(t)

[0047] where s 1 , s 2 —respectively positive and negative first-order sea clutter power amplitudes;

[0048] f b - Bragg frequency;

[0049] w(t)——Gaussian white noise.

[0050] The power spectrum corresponding to formula 8 is as follows figure 1 shown.

[0051] Table 1 Simulation experiment parameters of time domain correlation algorithm

[0052]

[0053]

[0054] On the basis of the ideal signal shown, phase pollution is added (generally the pollution function is considered to be a sine-like function), and the phase pollution function is defined here as follows:

[0055] γ(t)=A(t)sin(2πf(t)·t)

[0056] In the formula, A——amplitud...

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Abstract

The invention provides a method for removing non-linear phase pollution from a sky wave OTHR (over-the-horizon) radar echo signal, which relates to the field of the method for removing the non-linear phase pollution from the sky wave OTHR (over-the-horizon radar) echo signal and aims at solving the problems that the existing non-linear phase pollution has an effect on the sky wave OTHR echo signal and further reduces detecting performance under all kinds of conditions, especially under the lower signal-to-noise ratio. The method provided by the invention comprises the following steps that a data acquisition module collects to-be-processed sky wave OTHR time domain data; a data selecting module converts the to-be-processed sky wave OTHR time domain data; a pollution function computing module obtains a non-linear phase pollution function; and a signal correcting module obtains the sky wave OTHR echo signal after being subjected to removing the non-linear phase pollution. The method provided by the invention solves the problem of influence caused by the non-linear phase pollution in the sky wave OTHR radar echo signal, obviously reduces errors and has better effect under the lower signal-to-noise ratio. The method provided by the invention is used for processing the sky wave OTHR radar echo signal.

Description

technical field [0001] The invention discloses a method for removing nonlinear phase pollution of sky-wave over-the-horizon radar echo signals, and relates to the field of decontamination methods for sky-wave over-the-horizon radar echo signals. Background technique [0002] High-frequency sky-wave over-the-horizon radar (OTHR) uses the ionosphere's reflection of electromagnetic waves to detect targets, and its maximum detection range can reach more than 3000km. OTHR has the advantages of large monitoring range, long warning time, preventing low-altitude and ultra-low-altitude penetration, and being able to detect stealth targets. But OTHR still has some defects and problems to be solved. Because the ionospheric medium is affected by various environmental factors and is an unstable propagation medium, it has a great influence on the final detection results of OTHR. The ionospheric problem that OTHR is mainly concerned with is the impact of the ionosphere on the echo spectr...

Claims

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Application Information

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IPC IPC(8): G01S7/36G01S7/41
Inventor 位寅生崔岩许荣庆张晨
Owner HARBIN INST OF TECH
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