An Ultrahigh-Resolution Positioning Algorithm for Satellite Ultra-Long-Duration Data Based on Synthetic Aperture Technique

In satellite synthetic aperture positioning (SAP), the curvature of the Earth's surface and the curved orbit lead to nonlinear and asymmetric instantaneous Doppler frequencies, especially when dealing with signals of very long durations. This phenomenon significantly affects the accuracy of cen...

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Bibliographic Details
Published in:IEEE transactions on geoscience and remote sensing 2024, Vol.62, p.1-12
Main Authors: Wang, Yuqi, Sun, Guang-Cai, Zhang, Xu, Yang, Jun, Wang, Anyi, Xing, Mengdao, Yang, Xiaoniu
Format: Article
Language:English
Subjects:
Algorithms
Azimuth
Chirp
Data acquisition
Doppler effect
Doppler sonar
Duration
Earth surface
Estimation
Frequency estimation
Frequency modulation
History
Nonlinear instantaneous Doppler compensation
Orbits
Radiation sources
Satellites
Signal resolution
synthetic aperture positioning (SAP)
Synthetic apertures
ultrahigh-resolution positioning
zero-Doppler moment estimation
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Summary:In satellite synthetic aperture positioning (SAP), the curvature of the Earth's surface and the curved orbit lead to nonlinear and asymmetric instantaneous Doppler frequencies, especially when dealing with signals of very long durations. This phenomenon significantly affects the accuracy of center frequency estimation and radiating source positioning. This study presents an ultrahigh-resolution positioning algorithm designed to process ultra-long-duration data collected by a single satellite. Initially, a method for estimating the zero-Doppler moment based on sub-aperture chirp rates is proposed to obtain an unbiased estimate of the radiation source's center frequency. Subsequently, a nonlinear instantaneous Doppler compensation method is proposed, utilizing the estimated center frequency and chirp rates to enhance the coherence of the long-duration data. Furthermore, a long coherent positioning is suggested to generate an ultrahigh-resolution positioning image. Ultimately, the efficacy of the proposed algorithm is validated through simulations and acquired data.
ISSN:0196-2892
1558-0644
DOI:10.1109/TGRS.2024.3386618