Space-varying phase self-focusing ISAR imaging method with maximum contrast

Abstract

The invention discloses a maximum contrast space-variant phase self-focusing ISAR imaging method. The method includes acquiring the ISAR echo data, and dividing the azimuth corresponding echo data and the distance corresponding echo data of the ISAR echo data to obtain M azimuth units and N distance units; determining the total number of slow time, and then obtaining the final focuse image of the ISAR echo data; calculating the final focus image contrast of the ISAR echo data, taking the final focus image contrast of the ISAR echo data as a cost function, respectively calculating the distance space-variant quadratic phase error coefficient estimate value of the nth distance unit, the azimuth space-variant phase error coefficient estimate value of the mth azimuth unit, and the quadratic phase error coefficient estimate value for the kth constant, and calculating the focus images of the mth azimuth unit and the nth distance unit; and obtaining the maximum contrast space-variant phase self-focusing ISAR image.

Description

technical field [0001] The invention belongs to the technical field of radar, and in particular relates to a maximum-contrast space-variable phase self-focusing ISAR imaging method, which is suitable for adaptively compensating distance-azimuth space-variant phase errors. Background technique [0002] Inverse Synthetic Aperture Radar (ISAR) imaging technology uses radar to transmit large-bandwidth signals to obtain high-range resolution, and obtains high-resolution azimuth through the synthetic aperture formed by the attitude change of the target relative to the radar line of sight; at the same time, ISAR imaging processing usually assumes that the target within a short period of time If the rotation angle is small and the rotation speed is uniform, the range-Doppler imaging can be realized through the Doppler analysis of the azimuth dimension. However, range-Doppler imaging processing does not consider the high-order phase modulation introduced by target rotation, and is us...

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Problems solved by technology

However, range-Doppler imaging processing does not consider the high-order phase modulation introduced by target rotation, and is usually only effective for small-angle imaging processing of stationary moving targets. That is to say, the traditional phase error compensation method has a relatively simple signal model. The influence of distance and azimuth space variation on focusing performance is neglected; for non-stationary moving targets and large imaging angles, the phase error of distance and azimuth space variation will cause the image to defocus, so that the ideal imaging result cannot be obtained

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