Channel Imbalances and Along-Track Baseline Estimation for the GF-3 Azimuth Multichannel Mode

Shang, Mingyang; Qiu, Xiaolan; Han, Bing; Ding, Chibiao; Hu, Yuxin

doi:10.3390/rs11111297

Cited by 24 publications

(30 citation statements)

References 49 publications

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“…Inspired by the "Sign-Doppler Estimator" proposed by Madsen [14], Liu et al addressed the time-domain correlation method [15], and Feng et al addressed the azimuth correlation method [16]. Based on the real data acquired by Gaofen-3 (GF-3), we proposed the correlation method in the two-dimension frequency domain to estimate phase imbalance, range sampling time imbalance and along-track baseline, in the former work [17]. But all these methods treat the phase imbalance as a constant without considering the time-varying in azimuth and the space-varying in range.…”

Section: Introductionmentioning

confidence: 99%

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The Space-Time Variation of Phase Imbalance for GF-3 Azimuth Multichannel Mode

Shang

Qiu

Han

et al. 2020

IEEE J. Sel. Top. Appl. Earth Observations Remote Sensing

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Azimuth multichannel (AMC) synthetic aperture radar (SAR) is an advance technology that can prevent the minimum antenna area constraint and provide high-resolution and wide-swath SAR images. The calibration of phase imbalance is an important topic in AMC SAR signal processing since it has a significant impact on the image quality. For one SAR image, the phase imbalance is usually considered as a constant. However, because of the attitude errors, antenna position errors, target elevation, target motion and phase mismatch of the antenna pattern, the actual phase imbalance is time-varying in azimuth and space-varying in range. Even though the space-time variation of phase imbalances is too tiny to make little effect on the product quality, it is still meaning to study the variation. On the one hand, it is possible to quickly estimate the phase imbalance of the whole observing operation, and eliminate the influences of target motion, etc. on the phase imbalance. On the other hand, some parameters, such as motion, can be retrieved by phase imbalance. This paper first establishes the signal models between phase imbalances and attitude errors, antennal position errors and target elevation. Then, the signal model is verified by some simulations based on the parameters of Gaofen-3 (GF-3). In addition, the phase imbalance of the real data acquired by GF-3 is processed. Finally, based on the procession results of GF-3 real data, this paper makes some discussions and points out the direction for the future work.

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Section: Introductionmentioning

confidence: 99%

“…The phase imbalance not only affects the azimuth ambiguity-to-signal ratio (AASR) [17,21] but also can be used to retrieve some information about the imaging scene. In fact, the phase imbalance of AMC SAR just is the interferogram in the alongtrack interference (ATI) SAR [22][23][24][25].…”

Section: Introductionmentioning

confidence: 99%

The Space-Time Variation of Phase Imbalance for GF-3 Azimuth Multichannel Mode

Shang

Qiu

Han

et al. 2020

IEEE J. Sel. Top. Appl. Earth Observations Remote Sensing

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“…After MOCO, gain-phase error and time delay error between channels should be corrected. An azimuth cross correlation method is proposed in [15]- [17], which estimates the two different errors with a simple operation. However, as for phase error correction, the performance is dependent on the Doppler centroid frequency accuracy, and since phase error is estimated at range frequency domain, it cannot accommodate the range-variance of phase error effectively.…”

Section: Introductionmentioning

confidence: 99%

An Improved Airborne Multichannel SAR Imaging Method With Motion Compensation and Range-Variant Channel Mismatch Correction

Guo

Chen

Liu³

et al. 2020

IEEE J. Sel. Top. Appl. Earth Observations Remote Sensing

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To obtain high resolution and wide swath (HRWS) image, the azimuth multi-channel technique has been widely used in synthetic aperture radar (SAR) systems to overcome the contradiction between wide swath and high pulse repetition frequency (PRF). For high image quality, channel mismatch correction is an essential step in multi-channel SAR data imaging. However, in the case of airborne multi-channel SAR, motion errors will severely degrade the performance of channel mismatch correction. To deal with this problem, this paper proposes an improved airborne multi-channel SAR imaging method with motion compensation (MOCO) and range-variant channel mismatch correction. Firstly, motion errors are compensated based on resampling and phase compensation. Then the time delay error and constant gain-phase error between channels are estimated and corrected, followed by range-variant phase error correction based on a novel range-down-sampling method, which reduces the influence of motion errors on channel mismatch correction significantly. Finally, simulated and real data processing results are used to demonstrate the effectiveness of the proposed method.

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“…Channel imbalances, non-uniform sampling, and the presence of moving targets are the main causes of the Doppler spectrum aliasing. For the static scenes, unambiguous imaging can be achieved by estimating and compensating the amplitude and phase errors between different channels [5][6][7] and by the reconstruction algorithm, which solves the non-uniform sampling problem [8]. The first spaceborne demonstration experiment using the TerraSAR-X dual receiving antenna mode is elaborated in Reference [9], and the processing algorithms for the GF-3 dual-channel mode imaging are described in References [5] and [10].…”

Section: Introductionmentioning

confidence: 99%

“…For the static scenes, unambiguous imaging can be achieved by estimating and compensating the amplitude and phase errors between different channels [5][6][7] and by the reconstruction algorithm, which solves the non-uniform sampling problem [8]. The first spaceborne demonstration experiment using the TerraSAR-X dual receiving antenna mode is elaborated in Reference [9], and the processing algorithms for the GF-3 dual-channel mode imaging are described in References [5] and [10]. Nevertheless, the false targets still exist if there are moving targets and they are treated as stationary ones [10][11][12].…”

Section: Introductionmentioning

confidence: 99%

A Simultaneous Imaging Scheme of Stationary Clutter and Moving Targets for Maritime Scenarios with the First Chinese Dual-Channel Spaceborne SAR Sensor

et al. 2019

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The technique of azimuth multichannel synthetic aperture radar (SAR) system has become a potential solution to the irreconcilable conflict between high-resolution and wide-swath (HRWS) confronted with in a traditional SAR system. Unambiguous imaging, especially for a scene with moving targets, is one of the crucial research topics in the HRWS SAR system. This paper proposes a simultaneous imaging scheme of moving targets and stationary clutter for maritime scenarios. First, the moving target echoes are extracted from the stationary clutter. After that, two methods working in completely different principles are used to estimate the radial velocity of each moving target, and the estimated result is used for phase compensation. After that, the moving target echoes are added back to the stationary scene echo and sent to the reconstruction filter. Lastly, the reconstructed echo can be processed by the classical Chirp Scaling (CS) algorithm. Experiments are carried out using the Chinese GaoFen-3 dual-channel data. The estimated velocities of the moving targets are verified by automatic identification service (AIS) information, and the imaging results show that the false targets are effectively suppressed and the moving targets also return to their correct positions along the azimuth.

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Channel Imbalances and Along-Track Baseline Estimation for the GF-3 Azimuth Multichannel Mode

Cited by 24 publications

References 49 publications

The Space-Time Variation of Phase Imbalance for GF-3 Azimuth Multichannel Mode

The Space-Time Variation of Phase Imbalance for GF-3 Azimuth Multichannel Mode

An Improved Airborne Multichannel SAR Imaging Method With Motion Compensation and Range-Variant Channel Mismatch Correction

A Simultaneous Imaging Scheme of Stationary Clutter and Moving Targets for Maritime Scenarios with the First Chinese Dual-Channel Spaceborne SAR Sensor

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