Three-dimensional microwave imaging method for correcting multi-channel amplitude-phase error

Abstract

The invention discloses a three-dimensional microwave imaging method for correcting a multi-channel amplitude-phase error, and relates to the technology of microwave three-dimensional imaging. The three-dimensional microwave imaging method for correcting the multi-channel amplitude-phase error comprises the following steps of: obtaining a two-dimensional image for each two-dimensional receiving channel datum in original three-dimensional microwave echo data by using a two-dimensional imaging algorithm; taking a scaler target as a reference target in all the two-dimensional images, taking the maximum amplitude value of each channel reference target as a reference, and performing amplitude correction on all the channel data; obtaining an actual distance and a ideal distance between the reference target and each receiving antenna, and taking the actual distance and the ideal distance as a filter H1(f) for correcting multi-channel distance offset; transforming a signal to a distance-direction frequency domain via Fourier transformation, performing multiplication with the filter, and then transforming the signal after the multiplication back to the distance-direction time domain via Fourier inverse transformation; getting an unwrapping phase at the peak value of the reference target in each two-dimensional image, and performing subtraction with the ideal phase progress value calculated by the ideal distance to obtain a factor H2(i) for correcting the multi-channel phase error; performing the multiplication on the H2(i) and the data after the two-dimensional imaging to compensate the influence of the phase error; and obtaining a three-dimensional image which is focused well in a target area by using a back-projection algorithm along the row-crossing direction Y.

Description

technical field [0001] The invention relates to the technical field of microwave three-dimensional imaging, in particular to a microwave three-dimensional imaging method for correcting multi-channel amplitude and phase errors for array antennas. Background technique [0002] Array antenna microwave 3D imaging system is a new microwave 3D imaging technology, such as figure 1 As shown, the imaging system forms a synthetic aperture in the direction of motion (azimuth direction X) through the movement of the carrier platform (such as aircraft, satellite, ground orbit, etc.); ) array antenna, forming an array synthetic aperture; in the propagation direction of the electromagnetic wave, the broadband signal is transmitted and then pulse compressed; the three-dimensional resolution imaging of the observation area / target is realized. [0003] Since the array antenna microwave 3D imaging system is a multi-channel system, there are unpredictable inter-channel amplitude and phase erro...

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Problems solved by technology

[0005] The purpose of the present invention is to disclose a microwave three-dimensional imaging method for correcting multi-channel amplitude and phase errors, which can correct the amplitude and phase errors of the echo data of the array antenna to obtain a three-dimensional image, so as to solve the problem between multiple transmitting and receiving channels of the array antenna microwave imaging system. Due to the different characteristics of each antenna and the differences in channel amplitude and phase caused by transmission lines and microwave switches in each channel, there is a problem that direct imaging processing cannot focus imaging

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