A Robust Motion Compensation Approach for UAV SAR Imagery

Zhang, Lei; Qiao, Zhijun; Xing, Mengdao; Yang, Lei; Bao, Zheng

doi:10.1109/tgrs.2011.2180392

Cited by 167 publications

(86 citation statements)

References 33 publications

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“…Only the space-independent range error is considered in Equation (4). Regrading that its is space-variant, interested readers can refer to [24] for solutions.…”

Section: Signal Modelmentioning

confidence: 99%

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

et al. 2018

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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.

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“…Only the space-independent range error is considered in Equation (4). Regrading that its is space-variant, interested readers can refer to [24] for solutions.…”

Section: Signal Modelmentioning

confidence: 99%

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

et al. 2018

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“…Rotary has almost the same design concepts with helicopter except it is designed with single rotor or multi rotors. A rotary UAV system with single rotor has the same structure with a manned helicopter while rotary with multi rotor has more than one motor (Lin et al, 2011;David et al, 2009;Zhang et al, 2012). Fixed wing UAV needs momentum energy to move from one point to the next point, while rotary UAV can lift up or hover, stay still in one position and landing on a computer or operator commands.…”

Section: Introductionmentioning

confidence: 99%

Multi Rotor Uav at Different Altitudes for Slope Mapping Studies

Tahar

2015

Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci.

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ABSTRACT:Most of consultation work only involves a small area, especially for slope mapping studies. The objective of this study is to evaluate the accuracy of slope mapping results from different altitudes at semi-undulated area and undulated area. Multi-rotor UAV is used as an instrument for data acquisition for this study. The images of slope were captured from five different altitudes in the same study area. All images were processed using photogrammetric software to produce digital elevation models and digital orthophoto. In this study, slope map from all different altitudes were identified and recorded for analysis purposes. It was found that the accuracy of slope is increase when altitude is increase. In conclusion, the condition of slope such as semi-undulated and undulated area did have an influence on the slope accuracy.

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“…However, one of the problems is that the data rate of INU or GPS is usually much lower than the azimuth sampling frequency, while the interpolation may bring about extra errors and reduce the precision. The other commonly used way to obtain the motion error is to estimate the trajectory deviation directly from the raw data [7][8][9][10][11][12][13][14][15][16][17]. It is based on the concept that the uniformly azimuth-sampled data without motion errors has its intrinsic coherence, while the motion error is random.…”

Section: Introductionmentioning

confidence: 99%

“…And the forward velocity variation and the displacement in line of sight (LOS) affect respectively the lower and higher order terms of the Doppler frequency, so that they can be extracted sequentially. According to this, several algorithms [11] are proposed, such as the reflectivity displacement method (RDM) [12], the phase gradient algorithm (PGA) [13,14,16] and the phase retrieval [17] methods.…”

Section: Introductionmentioning

confidence: 99%

Along-Track Motion Compensation for Strip-Map Sar Based on Resampling

Ma¹,

Bai²,

Liang³

et al. 2014

PIER M

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Abstract-The airborne or vehicle-based SARs are very vulnerable to the influences of airflows or road conditions so as to deviate from the predicted trajectory, which undermines the uniformity of the azimuth sampling. As a result, the SAR image quality can get impaired in varying degrees. Since the SAR systems are sensible to the track deviation, the motion compensation (MOCO) algorithms are always applied as pre-processing of SAR raw data. In this paper, mainly with regard to the motion error caused by the forward velocity variation, a 'resampling MOCO' algorithm is proposed as an auxiliary of the widely used bulk MOCO. The simulation result has verified that the performance of the fundamental bulk MOCO algorithm is greatly improved utilizing the proposed method.

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A Robust Motion Compensation Approach for UAV SAR Imagery

Cited by 167 publications

References 33 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

Multi Rotor Uav at Different Altitudes for Slope Mapping Studies

Along-Track Motion Compensation for Strip-Map Sar Based on Resampling

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