Near-field calibrating method for high frequency surface wave radar uniform straight line array receiving channel

Abstract

The invented near-field correction method includes the following steps: utilizing position information of radar antenna array and high-frequency sea-state radar marine echo characteristics to detect marine echo with single-bearing arrival angle, and utilizing single-bearing arrival angle marine echo and multiple signal classification algorism to estimate channel amplitude mismatch factor to implement amplitude correction; utilizing near-field single auxiliary signal source set on the extended line of antenna array and utilizing amplitude-corrected single-bearing arrival angle near-field arrival wave signal, position information of array unit antenna, bearing information of near-field auxiliary source and multiple signal classification algorism to estimate and obtain mismatch factor of channel phase so as to implement phase correction.

Description

technical field [0001] The invention relates to a near-field correction method for a single auxiliary source in a receiving channel of a uniform linear antenna array of a high-frequency surface wave radar. Background technique [0002] High-frequency surface wave over-the-horizon radar utilizes the characteristics of small diffraction and propagation attenuation of vertically polarized high-frequency electromagnetic waves on the conductive ocean surface, and can over-the-horizon detect moving targets such as ships, aircraft, and missiles that appear below the line of sight at sea level. In addition, the high-frequency surface wave over-the-horizon radar uses the first-order and second-order scattering mechanisms of the ocean surface for high-frequency electromagnetic waves to extract ocean dynamic parameters such as wind field, wave field, and flow field from radar ocean echoes, which can realize Large-scale, high-precision and all-weather real-time monitoring of the marine ...

AI Technical Summary

Problems solved by technology

However, the application range and practical effect of this method are limited, and it is not suitable for sea areas without known fixed reflectors (such as islands), and is still affected by adverse factors such as noise interference, ship echo, and multipath effects.

[0007] Some people in the radio wave propagation laboratory of Wuhan University have also proposed that the calibration of the radar receiving channel can be realized by using the ocean echo, but some auxiliary antennas and auxiliary channels (the so-called nonlinear array) need to be added, but this not only increases the antenna footprint, Moreover, the original limited antenna aperture is sacrificed, the cost is high, and the cost is high

Moreover, when the ocean is fully used for calibration, the premise is that the ocean echo characteristics must satisfy the theoretical model assumed by the researcher, and the relationship between these theories and the actual model is unknown, and the channel correction, especially the phase estimate, is incredible.

Theory and practice show that the phase error of the receiving channel has the greatest impact on the high-resolution algorithm, and its estimation and calibration are also the most difficult

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