Phase error correction in synthetic aperture imaging

摘要

A method for phase error correction in a synthetic aperture (SA) imaging system is configured to image a target region of a scene from a platform in relative movement with respect to the scene. The method includes acquiring target SA data from the target region and reference SA data from a reference region of the scene, using a SA acquisition unit. One or more phase correction factors are determined from the reference SA data based on an assumption that the reference region has a known topography. The phase correction factors are representative of uncompensated optical-path-length fluctuations along the optical path between the reference region and the SA acquisition unit mounted on the platform. A phase correction is applied to the target SA data based on the phase correction factors so as to obtain phase-corrected target SA data. A SA imaging system implementing the method is also disclosed.

主权项

1. A method for phase error correction in a synthetic aperture (SA) imaging system configured for imaging a target region of a scene from a platform in relative movement with respect to the scene, the SA imaging system comprising an SA acquisition unit on the platform, the SA acquisition unit comprising a target transmitter and a reference transmitter; the method comprising the steps of:
a) directing a target optical signal onto the target region with the target transmitter and collecting target return echoes produced by reflection of the target optical signal from the target region, thereby acquiring target SA data, and directing a reference optical signal onto a reference region with the reference transmitter and collecting reference return echoes produced by reflection of the reference optical signal from the reference region, thereby acquiring reference SA data; b) determining one or more phase correction factors from the reference SA data based on an assumption that the reference region has a known topography, the one or more phase correction factors being representative of uncompensated optical-path-length fluctuations along a round-trip optical path between the reference region and the SA acquisition unit; and c) applying a phase correction to the target SA data based on the one or more phase correction factors so as to obtain phase-corrected target SA data.