Polarimetric Calibration of the Ku-Band Advanced Polarimetric Radar Interferometer

Baffelli, Simone; Frey, Othmar; Werner, Charles; Hajnsek, Irena

doi:10.1109/tgrs.2017.2778049

Cited by 21 publications

(34 citation statements)

References 55 publications

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“…In addition to this, The anomaly which hinders this comparability of measurements from different polarisation channels is known as channel imbalance representing the imbalance both in amplitude and phase (Van Zyl & Kim, 2011). Moreover, The anomalies introduced in PolSAR data due to improper channel isolation are commonly known as crosstalk (Baffelli et al, 2018). According to Freeman et al (1992), the sensor calibration alone can not entirely avoid all these issues.…”

Section: Manuscript Submitted To Earth and Space Sciencementioning

confidence: 99%

A Computationally Efficient Hybrid Framework for Polarimetric Calibration of Quad‐Pol SAR Data

Maiti

Kumar

Tolpekin³

et al. 2021

Earth and Space Science

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Polarimetric Synthetic Aperture Radar (PolSAR) calibration is an essential preprocessing step that must be performed to ensure that the data quality is adequate. This, in turn, helps to minimise the propagation of errors in any further data processing or information extraction. Crosstalk and channel imbalance are two major distortions found to be present in the uncalibrated polarimetric SAR data. The PolSAR calibration mainly aims to reduce these two distortions revealing the true scattering pattern of the targets. In this regard, Quegan's algorithm and Ainsworth algorithm are two widely used algorithms for the PolSAR calibration. In this research, the accuracy and efficiency of these two algorithms have been thoroughly compared using suitable metrics. It has been shown that the Ainsworth algorithm performs better than Quegan's in terms of accuracy at the cost of poor computational efficiency. The data quality metrics also highlight the better calibration accuracy of the Ainsworth algorithm. The issue of higher computational complexity has been effectively addressed by coupling both of these algorithms. Evidently, the computational cost has been reduced in the case of the proposed algorithm. The polarisation orientation angle (POA) shift is another distortion caused by the topographic variations present in the target scene. Therefore, correction of POA shift has been incorporated in this research by coupling it with the PolSAR calibration. Subsequently, the improvement in the scattering has been observed. In essence, the proposed algorithm coupled with the correction of POA shift rectifies the major polarimetric distortions with adequate accuracy and computational efficiency.

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Section: Manuscript Submitted To Earth and Space Sciencementioning

confidence: 99%

A Computationally Efficient Hybrid Framework for Polarimetric Calibration of Quad‐Pol SAR Data

Maiti

Kumar

Tolpekin³

et al. 2021

Earth and Space Science

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“…It is well known that polarimetry can provide highly profitable information in different applications of radar imaging of natural media, such as rough, bare, and vegetated soil, snow, and glaciers: The availability of polarimetric data provided by recent SAR satellite missions has strongly pushed studies based on spaceborn, large scale, data [4]. On the other hand, so far in GB-SAR imaging, this approach has been 2 of 22 rarely used, and only a few case studies have been discussed in the literature [5][6][7][8]. The main reason of this lack of research is probably due to the fact that commercial terrestrial radars do not provide multi-polarization capability, and they usually operate in single co-polar configuration (mostly vertical).…”

Section: Introductionmentioning

confidence: 99%

Ku Band Terrestrial Radar Observations by Means of Circular Polarized Antennas

Luzi

Dematteis

2019

Remote Sensing

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This paper reports some experimental results obtained by means of a commercial apparatus used by many researchers and users, where a pair of novel and specifically developed circular polarized antennas, designed to operate with Ku band-terrestrial radar interferometers, are used alternatively to the most conventional linear vertical polarized horns provided by the manufacturer of the apparatus. These radar acquisitions have been carried out to investigate for the first time the potential of circular polarization (CP) configurations for terrestrial radar interferometers (TRI) applications, aiming at improving monitoring of landslides, mines, and semi-urban areas. The study tries to evaluate whether the circular polarization response of natural and man-made targets can improve the interpretation of the radar images, with respect to the standard approach used in terrestrial radar interferometry, usually carried out in co-polar vertical polarization. The goal is to investigate how different polarization combinations, in terrestrial radar interferometry, affect the coherence and amplitude dispersion of natural media, potentially improving the identification of stable scatter.

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“…Spaceborne- [11], [18], [19], airborne- [10], [20], and ground-based [21] polarimetric SAR must be calibrated to obtain the true information of the objects under study. Calibration techniques of polarimetric SAR usually are based on point targets [10], [11], [19].…”

mentioning

confidence: 99%

“…Since the point targets with known PSM are only valid around them, a number of calibration targets need to be artificially deployed to achieve the calibration. To overcome the shortcomings of point targets, the polarimetric calibration techniques using distributed targets with good scene flexibility and adaptability, such as rainforest, grassland, and so on, were presented in [18], [20], [21]. Meanwhile, it is convenient to maintain and update the polarization characteristics of the system.…”

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Calibration of a Polarimetric MIMO Array With Horn Elements for Near-Field Measurement

Kong

2020

IEEE Trans. Antennas Propagat.

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Polarimetric multiple input and multiple output (MIMO) radar is capable of acquiring target's high-resolution images and polarization scattering matrix (PSM). In this article, calibration of a polarimetric MIMO array of an instrumentation radar for near-field measurement is achieved at X-band by using a rotatable double-antenna polarimetric active radar calibrator (RODAPARC) and a metal cylinder quickly and accurately. The theoretical PSM of the RODAPARC with different antenna rotation angles is derived from Huygens' radiation electric field which is applicable to different bistatic angles. A polarimetric signal model is adopted to reduce the impact of the RODAPARC on calibration. Experimental studies are conducted on a polarimetric MIMO array which is measured and divided into quasi-monostatic and bistatic transceiver channels for assessment on the calibration performance. Promising calibration results are obtained with a polarization isolation improvement of about 16 dB and great reduction of the polarization channel gain error less than ±0.5 dB in amplitude and ±3 • in phase. The calibrated polarization signatures for classic objects are consistent with the theoretical results. Index Terms-Multiple input and multiple output (MIMO) radar, polarimetric active radar calibrator (PARC), polarimetric calibration. I. INTRODUCTIONW ITH the explosive development of multiple input and multiple output (MIMO) technology, more and more MIMO radars have been presented in [1]-[6]. MIMO is an enabling technique capable of imaging a target using only one snapshot [6], which is different from rail synthetic aperture radar (SAR) and turntable inverse synthetic aperture radar (ISAR). Polarimetric MIMO radar images the target rapidly, while also providing the polarization scattering matrix (PSM) of the target. Crosstalk and polarization channel gain error distort the receive signal in polarimetric radars. This distortion will be more serious for polarimetric MIMO radars in terms of multiple transceiver channels. Therefore, polarimetric calibration serves an important role in polarimetric MIMO radars.According to the different polarimetric calibrators, polarimetric calibration can be divided into passive [7]-[9] and Manuscript

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Polarimetric Calibration of the Ku-Band Advanced Polarimetric Radar Interferometer

Cited by 21 publications

References 55 publications

A Computationally Efficient Hybrid Framework for Polarimetric Calibration of Quad‐Pol SAR Data

A Computationally Efficient Hybrid Framework for Polarimetric Calibration of Quad‐Pol SAR Data

Ku Band Terrestrial Radar Observations by Means of Circular Polarized Antennas

Calibration of a Polarimetric MIMO Array With Horn Elements for Near-Field Measurement

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