Spectrum-Oriented FFBP Algorithm in Quasi-Polar Grid for SAR Imaging on Maneuvering Platform

Yang, Lei; Zhao, Lifan; Zhou, Song; Bi, Guoan; Yang, Huan

doi:10.1109/lgrs.2017.2676118

Cited by 19 publications

(16 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…FFBP is the most classic TDBP that is capable of achieving a comparative accuracy of BP and simultaneously maintaining a high computational efficiency. The conventional FFBP usually performs in the polar coordinates in which the range of the frequency variation can be compacted into a narrower bandwidth so that the Nyquist sampling rate, as well as the number of BP operations can be dramatically reduced [12,17]. Different from the BP algorithm, FFBP performs in a recursive manner.…”

Section: Fast Factorized Back-projectionmentioning

confidence: 99%

“…In Equation (12), the first exponential term gives the ground scatterer at the quasi-polar coordinates (ρ k , x k ), while the last exponential term shows the effect from the motion error. The first term in the error exponent represents the motion error effect from the airborne radar motion deviation in the radial direction, while the second term gives that in the along-track direction.…”

Section: Motion Error Effectsmentioning

confidence: 99%

“…Generally, for SAR data, they inherently have coherence, which means the amplitude and phase modulation of the data have a coherent relationship. In other words, the range profile migration and the phase modulation should have a fixed relationship [12,13]. Thanks to the coherence, we can exploit the analytical form of the relationship between the APE and NsRCM error functions.…”

Section: Coherent Relationship Between Ape and Rcmmentioning

confidence: 99%

“…When no navigational data are available or only low accuracy data are available, the proposed algorithm still has the capability to compensate the error in a data-driven manner. To facilitate the FFBP SAR IFP with the data-driven error auto-calibration, the novel FFBP implementation in a quasi-polar grid is employed [13], and the data are transformed into the 2D wavenumber domain asS(k ρ , k x ) in Equation (12). For the following motion error compensation, the data are further transformed into the range-compressed domain by a range IFT.…”

Section: Processing Proceduresmentioning

confidence: 99%

“…SAR working in strip-map mode with the radar Line-of-Sight (LoS) in broadside can directly utilize iso-Doppler lines to achieve a large Doppler bandwidth, and accordingly, respect squint SAR data, recently, FTDBP algorithms have been developed to incorporate data-driven auto-calibrations [12,13,19,23]. They are capable of facilitating the processing of the SAR data collected at a high-squint angle.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Coherent Auto-Calibration of APE and NsRCM under Fast Back-Projection Image Formation for Airborne SAR Imaging in Highly-Squint Angle

et al. 2018

Self Cite

View full text Add to dashboard Cite

Synthetic Aperture Radar (SAR) imaging with a non-zero (forward) squint angle is capable of providing a longer time for reaction than that of the broadside mode. However, due to the large squint angle, there will be severe coupling between range and azimuth samples in the echoed data, which is known as the problematic Range Cell Migration (RCM) in the SAR community. Especially when the SAR sensor mounted on an airborne platform encounters unexpected motion deviations/errors, the coupling becomes more complicated, and it is difficult to differentiate the systematic RCM for the SAR Image Formation Processing (IFP) and the non-systematic RCM error to be compensated. To this end, a novel and accurate SAR imaging algorithm is proposed in this paper to facilitate the processing of airborne SAR data collected at a high-squint angle. Firstly, the proposed algorithm is established under a Fast Time-Domain Back-Projection (FTDBP) framework for the SAR IFP. FTDBP paves the way to avoid the complicated processing for the systematic RCM as for the conventional SAR IFP in the Doppler processing manner. It is capable of generating a high-resolution SAR image efficiently under more general geometries and configurations. Secondly, regarding the non-systematic RCM errors, the proposed algorithm realizes the compensation by correcting both the Non-systematic Range Cell Migration (NsRCM), as well as Azimuthal Phase Error (APE) in a coherent manner. It is consequently capable of auto-calibrating the effects of the motion error completely without being dependent on the airborne navigation unit. Finally, both simulated and raw data collected by the airborne squinted SAR are applied to evaluate the proposed algorithm. Comparisons with conventional algorithms are carried out to reveal the superiority of the proposed algorithm.

show abstract

Section: Fast Factorized Back-projectionmentioning

confidence: 99%

Section: Motion Error Effectsmentioning

confidence: 99%

Section: Coherent Relationship Between Ape and Rcmmentioning

confidence: 99%

Section: Processing Proceduresmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Coherent Auto-Calibration of APE and NsRCM under Fast Back-Projection Image Formation for Airborne SAR Imaging in Highly-Squint Angle

et al. 2018

Self Cite

View full text Add to dashboard Cite

show abstract

Wavenumber‐domain autofocus algorithm for helicopter‐borne rotating synthetic aperture radar

Zhang

Liao

Zhu

et al. 2018

IET signal process.

View full text Add to dashboard Cite

Helicopter-borne rotating synthetic aperture radar (ROSAR) enjoys fast imaging property as the synthetic aperture obtained by rotor rotation. However, ROSAR data processing is usually a challenging task due to severe range cell migration (RCM) and motion error. To solve this problem, an enhanced phase gradient autofocus (PGA) algorithm based on helicopterborne ROSAR wavenumber-domain imaging approach is proposed in this study, which alleviates the imaging performance degradation due to the RCM and motion error. With even small motion error induced in the wavenumber domain, the influence of motion error will become evident after performing Stolt interpolation, which induces serious image defocusing and degradation. Hence, the authors further propose the PGA-based ROSAR motion compensation scheme, which combines quadratic term correction with phase gradient estimation, and well-focused ROSAR images can be obtained via iterative processing. Several results of simulated experiments are presented to validate the proposed method for helicopter-borne ROSAR imaging.

show abstract

A modified design method of pulse repetition frequency for synthetic aperture radar system based on the single point equivalent squint model

Liang

Zhang

et al. 2021

IET Radar Sonar & Navi

View full text Add to dashboard Cite

Pulse repetition frequency (PRF) is an essential parameter in synthetic aperture radar (SAR). However, a small PRF value will cause spectrum ambiguity and a large value will increase the computational complexity. In highly squinted SAR imaging with maneuvering platform, the traditional PRF design methods used are airborne and space borne. SAR systems perform with a low precision because of the complex geometric configuration and system deviations. In order to adapt to the maneuvering platform SAR system, a modified design method of PRF is proposed in this paper. First, the azimuth spectrum of echoes is analyzed by establishing the SAR geometry base on the single point equivalent squint (SPES) model. Subsequently, the calculation of azimuth bandwidth is transformed into an optimization problem, and the lower limit of PRF is obtained by the Golden Section Method. Besides, the criteria of spectrum unambiguity and time sequence constraints in PRF design is also discussed in detail. Simulation experiments demonstrate the feasibility and accuracy of the proposed method.This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.

show abstract

Spectrum-Oriented FFBP Algorithm in Quasi-Polar Grid for SAR Imaging on Maneuvering Platform

Cited by 19 publications

References 17 publications

Coherent Auto-Calibration of APE and NsRCM under Fast Back-Projection Image Formation for Airborne SAR Imaging in Highly-Squint Angle

Coherent Auto-Calibration of APE and NsRCM under Fast Back-Projection Image Formation for Airborne SAR Imaging in Highly-Squint Angle

Wavenumber‐domain autofocus algorithm for helicopter‐borne rotating synthetic aperture radar

A modified design method of pulse repetition frequency for synthetic aperture radar system based on the single point equivalent squint model

Contact Info

Product

Resources

About