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Proceedings Paper

Compensating algorithm of nonlinear phase errors using scan filter in SAIL
Author(s): Nan Xu; Liren Liu; Wei Lu
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Paper Abstract

The phase errors due to the nonlinear chirp of tunable laser reduce the range resolution in synthetic aperture imaging ladar(SAIL). The compensating algorithms establishing matched and nonmatched reference paths were developed, and the phase errors were compensated in the whole echo pulse. In this paper a compensating algorithm by scan filtering is proposed. Compared to the compensation in the whole echo pulse, this compensating algorithm promotes precision and range resolution. Every echo pulse includes different echo components from all target points in footprint. The heterodyne signals of these different echoes are scan filtered from the heterodyne signal of one whole echo pulse in the spectrum. The phase errors of these heterodyne signals are measured by phase shifting algorithm in nonmatched reference path and compensated separately. Then the compensated signals are combined into whole heterodyne pulse and compressed in range. After all echo pulses are compressed in range the azimuth compensation and compression is followed. The mathematical flow of this algorithm is established. The simulation of the airborne SAIL model validates the feasibility, and the BW of range compression decreases obviously. The effects of width of the scan filter and nonlinear chirp are discussed. The conclusion of adequate width of the scan filter is given finally.

Paper Details

Date Published: 1 September 2009
PDF: 8 pages
Proc. SPIE 7442, Optics and Photonics for Information Processing III, 74420Z (1 September 2009); doi: 10.1117/12.824682
Show Author Affiliations
Nan Xu, Shanghai Institute of Optics and Fine Mechanics (China)
Liren Liu, Shanghai Institute of Optics and Fine Mechanics (China)
Wei Lu, Shanghai Institute of Optics and Fine Mechanics (China)

Published in SPIE Proceedings Vol. 7442:
Optics and Photonics for Information Processing III
Khan M. Iftekharuddin; Abdul Ahad Sami Awwal, Editor(s)

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