Azimuth-to-Frequency Mapping in Airborne SAR Data Corrupted by Uncompensated Motion Errors

Perna, Stefano; Zamparelli, Virginia; Pauciullo, Antonio; Fornaro, G.

doi:10.1109/lgrs.2013.2260721

Cited by 32 publications

(25 citation statements)

References 16 publications

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“…Due to the residual azimuth-dependent motion error, ϑ 0 is calculated in (18), and a method of PTA is introduced to compensate ϑ 0 by modifying the AMF function. According to [17], the modified AMF function H AMF (K x , r) is expressed as:…”

Section: Flowcharts Of One-step and Two-step Moco-based Imaging Algormentioning

confidence: 99%

“…Besides, the original MOCO methods only take range-dependent motion error into account, and the residual azimuth-dependent motion error should also be considered, which is nonignorable for high-resolution airborne MMW SAR imaging with wide swath. The existed azimuth-dependent MOCO algorithms [14][15][16][17][18] could precisely compensate the azimuth-dependent motion error and modify the azimuth matched filtering function in order to eliminate the influence of azimuth-variant motion error.…”

Section: Introductionmentioning

confidence: 99%

“…The one-step MOCO-based imaging algorithm is investigated, which compensates rangedependent motion error before RCMC in order to suppress the residual envelope and phase error of RCM range profile. Moreover, according to the analytical expression of the residual spatial variant error, an accurate azimuth match filtering (AMF) function is modified by precise topography-and aperture-dependent motion compensation (PTA) [17], which compensates the residual azimuthdependent motion errors remained by RCMC. In this paper, the conventional two-step MOCO-based imaging algorithm is introduced for comparison, theoretical analysis to the superiority of one-step MOCO would be adequately verified by simulated and real-measured data experiments.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Range cell migration correction analysis of one-step and two-step motion compensation for millimeter-wave airborne SAR imaging

Wang

Zhang

et al. 2016

EURASIP J. Adv. Signal Process.

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Conventional two-step motion compensation (MOCO) method is widely adapted for airborne synthetic aperture radar (SAR) imaging due to its conciseness combining with the SAR focusing procedure. For two-step MOCO, rangeindependent compensation is processed before range cell migration correction (RCMC), and the range-dependent phase correction is implemented after RCMC. However, the accuracy of RCMC would be seriously decreased by the residual range-dependent phase, which is a fatal problem for high-resolution millimeter-wave (MMW) SAR imaging. In this paper, an extensive investigation on the RCMC accuracy is provided by establishing an accurate formula expression between the range cell migration error and the residual range-dependent phase error. One-step MOCObased SAR imaging algorithm is investigated by compensating the range-dependent motion error before RCMC, so the presence of range cell migration error would be significantly suppressed. What is more, a modified azimuth match filtering (AMF) function is given by precise topography and aperture-dependent motion compensation (PTA) method to overcome the residual azimuth-dependent phase error in the azimuth compression stage. Both simulated and real-measured MMW SAR data sets are used to validate the analysis for high-resolution airborne SAR imaging.

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Section: Flowcharts Of One-step and Two-step Moco-based Imaging Algormentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Range cell migration correction analysis of one-step and two-step motion compensation for millimeter-wave airborne SAR imaging

Wang

Zhang

et al. 2016

EURASIP J. Adv. Signal Process.

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“…To perform the spectral mapping of the residual errors, the PTA makes use of the well-known azimuth-to-frequency relationship between the azimuth (Doppler) frequency of the SAR impulse response of a target and its relative azimuth position with respect to the illuminating antenna [15]. However, it can be shown [18] that the azimuth-to-frequency mapping used by the original PTA in [15] is not fully appropriate, because it does not account for the presence of the residual motion errors themselves. More specifically, in [18] it is provided the analytical derivation, based on the stationaryphase method [1], of the correct azimuth-to-frequency mapping to be used.…”

Section: Introductionmentioning

confidence: 99%

“…However, it can be shown [18] that the azimuth-to-frequency mapping used by the original PTA in [15] is not fully appropriate, because it does not account for the presence of the residual motion errors themselves. More specifically, in [18] it is provided the analytical derivation, based on the stationaryphase method [1], of the correct azimuth-to-frequency mapping to be used.…”

Section: Introductionmentioning

confidence: 99%

Precise azimuth-to-frequency mapping for effective and efficient compensation of motion errors in airborne SAR

Perna

Berardino

Esposito

et al. 2013

2013 IEEE International Geoscience and Remote Sensing Symposium - IGARSS

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In this work we focus on the Precise Topography- and Aperture-dependent algorithm, briefly PTA, proposed in the recent literature to remove the residual errors still affecting airborne SAR data focused with standard two-step Motion Compensation algorithms. More specifically, we first show that the azimuth-to-frequency mapping used by the PTA procedure is not fully appropriate, because it does not account for the presence of the residual motion errors themselves. Then, we show how to calculate the correct azimuth-to-frequency mapping able to fully account for the presence of the residual motion errors. Finally, we show how to modify the original PTA in such a way to properly exploit the correct azimuth-to-frequency mapping previously discussed. © 2013 IEEE

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Comparison of two‐step and one‐step motion compensation algorithms for airborne synthetic aperture radar

2015

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Airborne synthetic aperture radar (SAR) image quality considerably degrades because of motion errors. High-precision motion compensation (MOCO) is necessary in an advanced SAR data processing scheme. In the case of ultra-high resolution, the conventional twostep MOCO algorithm introduces significant range cell migration correction (RCMC) error which causes a loss to resolution. Another method named one-step MOCO can avoid RCMC error, improving image quality obviously. Meanwhile, one-step MOCO can well integrate with the standard Omega-K algorithm succinctly. A comparison of the two MOCO algorithms is demonstrated by analysing the RCMC error. Point targets simulation has validated the proposed research. Introduction: Motion errors are mainly due to atmospheric turbulence, degrading the final image quality considerably in terms of geometric and radiometric resolution losses [1, 2]. Moreover, the effect of motion errors increases for ultra-high resolution imaging. Therefore, motion compensation (MOCO) requires to be studied in depth as the key procedure in airborne synthetic aperture radar (SAR) processing. MOCO approaches based on motion measurement data can correct motion errors effectively [3-7]. The representative algorithm is the two-step MOCO which was proposed based on the chirp scaling algorithm (CSA) in [3]. It consists of first-order MOCO and second-order MOCO. The former is range-independent part and applied before range cell migration correction (RCMC). The latter should be performed at a point where the azimuth signal has not been compressed with RCMC already completed, which is essential to achieve a precise residual range-dependent MOCO. Commonly, the Omega-K algorithm (OKA) is more ideal than the CSA. However, when combined with two-step MOCO, the second-order MOCO is not suitable in the OKA, for the reason that Stolt interpolation completes residual RCMC and residual azimuth compression in company. To overcome this problem, Reigber et al. [2] proposed an extended OKA. Unfortunately, when processing ultra-high resolution SAR data, the result of two-step MOCO is not satisfactory. Even small residual rangedependent errors will result in significant deviations of RCMC. For the reason that range compression can be performed first in the OKA, not as it is in the CSA, another MOCO approach in [6, 7] is more suitable. The two parts of two-step MOCO merge into one, which takes place before RCMC with range compression already completed. By contrast, we call this method one-step MOCO. One-step MOCO compensates integrated range-dependent error directly, to achieve a precise MOCO and accurate RCMC for ultra-high resolution imaging. This Letter first analyses the RCMC error. On this basis, we make a comparison between two-step and one-step MOCOs. Finally, point targets simulation has validated the proposed research.

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Azimuth-to-Frequency Mapping in Airborne SAR Data Corrupted by Uncompensated Motion Errors

Cited by 32 publications

References 16 publications

Range cell migration correction analysis of one-step and two-step motion compensation for millimeter-wave airborne SAR imaging

Range cell migration correction analysis of one-step and two-step motion compensation for millimeter-wave airborne SAR imaging

Precise azimuth-to-frequency mapping for effective and efficient compensation of motion errors in airborne SAR

Comparison of two‐step and one‐step motion compensation algorithms for airborne synthetic aperture radar

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