Autonomous on-board data processing and instrument calibration software for the SO/PHI

Albert, K.; Hirzberger, J.; Busse, D.; Lange, Tobias; Kolleck, M.; Fiethe, B.; Suárez, D. Orozco; Woch, J.; Schou, J.; Rodríguez, J. Blanco; Gandorfer, A.; Guan, Yejun; Carrascosa, J. P. Cobos; Expósito, D. Hernández; Iniesta, J. C. del Toro; Solanki, S. K.; Michalik, H.

doi:10.1117/12.2311718

Cited by 5 publications

(5 citation statements)

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“…The statistical mode of HELIX + inverts the data with varying starting conditions, and we regard the variation of the results as a measure of the inaccuracy inherent in the inversion of the data set, amounting to 21.9 G, 1.34 • , 1.37 • , and 14.5 m/s for | B|, γ, φ and v LOS , respectively. The errors in the inversion results, introduced to the SDO/HMI data by the on-board processing of SO/PHI (Albert et al, 2019), are 33.64 G, 2.56 • , 1.92 • , and 19 m/s for the same parameters, which are slightly higher than what we find in the current study. This is due to the different input data, as well as the earlier version of the processing pipeline.…”

Section: Discussioncontrasting

confidence: 71%

“…In Albert et al (2019) we have done a similar analysis on a data set acquired by the Helioseismic and Magnetic Imager on-board the Solar Dynamics Observatory (SDO/HMI; Schou et al, 2012), using an earlier version of the SO/PHI data reduction pipeline. In that study, we compared the errors from the processing to a statistical analysis performed with the He-Line Information Extractor inversion code (HELIX + ; see Lagg et al, 2004).…”

Section: Discussionmentioning

confidence: 99%

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Accuracy Analysis of the On-board Data Reduction Pipeline for the Polarimetric and Helioseismic Imager on the Solar Orbiter Mission

et al. 2023

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Context: Scientific data reduction on-board deep space missions is a powerful approach to maximise science return, in the absence of wide telemetry bandwidths. The Polarimetric and Helioseismic Imager (PHI) on-board the Solar Orbiter (SO) is the first solar spectropolarimeter that opted for this solution, and provides the scientific community with science-ready data directly from orbit. This is the first instance of full solar spectropolarimetric data reduction on a spacecraft.Methods: In this paper, we analyse the accuracy achieved by the on-board data reduction, which is determined by the trade-offs taken to reduce computational demands and ensure autonomous operation of the instrument during the data reduction process. We look at the magnitude and nature of errors introduced in the different pipeline steps of the processing. We use an MHD sunspot simulation to isolate the data processing from other sources of inaccuracy. We process the data set with calibration data obtained from SO/PHI in orbit, and compare results calculated on a representative SO/PHI model on ground with a reference implementation of the same pipeline, without the on-board processing trade-offs.Results: Our investigation shows that the accuracy in the determination of the Stokes vectors, achieved by the data processing, is at least two orders of magnitude better than what the instrument was designed to achieve as final accuracy. Therefore, the data accuracy and the polarimetric sensitivity are not compromised by the on-board data processing. Furthermore, we also found that the errors in the physical parameters are within the numerical accuracy of typical RTE inversions with a Milne-Eddington approximation of the atmosphere.Conclusion: This paper demonstrates that the on-board data reduction of the data from SO/PHI does not compromise the accuracy of the processing. This places on-board data processing as a viable alternative for future scientific instruments that would need more telemetry than many missions are able to provide, in particular those in deep space.

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Section: Discussioncontrasting

confidence: 71%

Section: Discussionmentioning

confidence: 99%

Accuracy Analysis of the On-board Data Reduction Pipeline for the Polarimetric and Helioseismic Imager on the Solar Orbiter Mission

et al. 2023

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“…Finally, because of its role in a deep-space mission with limited telemetry, SO/PHI is designed to autonomously process and conduct a full scientific analysis onboard. This functionality is achieved by a specifically tailored software (Albert et al 2018(Albert et al , 2020 and a newly designed device, the electronic inverter of the radiative transfer equation (RTE) for polarized light (Cobos Carrascosa 2016;Cobos Carrascosa et al 2016). The recorded and the processed data both undergo compression using conventional procedures before they are downlinked (Hernández Expósito et al 2018).…”

Section: Overview Of the So/phi And Sdo/hmi Instrumentsmentioning

confidence: 99%

Comparison of magnetic data products from Solar Orbiter SO/PHI-FDT and SDO/HMI

Moreno Vacas,

Orozco Suárez,

Strecker

et al. 2024

A&A

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The Polarimetric and Helioseismic Imager (SO/PHI), on board the Solar Orbiter mission, is the first photospheric magnetograph and tachograph to observe the Sun from outside the Sun-Earth line. The Full Disc Telescope (FDT) of SO/PHI, images the whole solar disk with a spatial resolution that varies with the distance between the Sun and the spacecraft. To check for consistency between the magnetic field strength ($B$), the field inclination (gamma ), the line-of-sight (LoS) magnetic component ($B_ LoS $) and the field azimuth (phi ), inferred by SO/PHI-FDT and the Helioseismic and Magnetic Imager (HMI), on board Solar Dynamics Observatory (SDO), and obtain linear correlation coefficients among them. We use data from both instruments obtained on 8 March 2022, when the angle between SDO and Solar Orbiter was $3.4^ circ $ and the solar disk showed four developed active regions. Before comparing the magnetic field products of both instruments we perform a precise alignment of the data, including a matching of the plate scale. Further, in order to improve the homogeneity of the compared data products, the SDO/HMI data were convolved with the SO/PHI-FDT point spread function (PSF). The linear correlation coefficients are obtained through a linear regression of SDO/HMI to SO/PHI-FDT. The two instruments yield comparable magnetic field data products. The slope coefficients for a linear fit are 1.37 for $B$, 1.11 for gamma , 1.35 for $B_ LoS $ and 1 for the azimuth. The corresponding fit offsets are $-94$ G, $-9.8^ circ $, $5.2$ G and $0.1^ circ $, respectively. The agreement between both instruments is significantly better when we take into account the different spatial resolution of both instruments. The fitting results vary slightly depending on the analyzed active region except for one of the four active regions, which shows larger differences and has been excluded from the comparison. The comparison of the LoS magnetic field products from SDO/HMI at 45 s and 720 s with SO/PHI-FDT shows a slope value of 1.17, with the offset less than $6$ G, in both cases.

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“…However, the processing of the data also happens on-board. This is due to the difficulties imposed by the telemetry limitations present in SO orbit (Albert et al, 2018).…”

Section: Imaging Detectors For Solar Spectropolarimetermentioning

confidence: 99%

Development of a proof-of-concept spectropolarimeter in the framework of the GSST mission: Characterization and performance analysis of a sCMOS image sensor

Barbosa

Carlesso²,

Vieira³

2022

Front. Astron. Space Sci.

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Camera characterization is critical for solar observation instruments such as spectropolarimeters. This paper presents the characterization of the proof-of-concept spectropolarimeter sCMOS image sensor. The report is divided into two parts. The first is to analyze the behavior of each pixel due to changes in the camera’s operation mode. Analyze the camera’s sensor cooling, shutter, and corrections and filters. The second part is the characterization of the camera, analyzing linearity, gain, and polarization effects. For this first phase of the project, the commercial sCMOS image sensor successfully acquired images of the Stokes parameters in an agile manner. However, a new camera with less non-linearity will be necessary for the project’s next phase.

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Autonomous on-board data processing and instrument calibration software for the SO/PHI

Cited by 5 publications

References 10 publications

Accuracy Analysis of the On-board Data Reduction Pipeline for the Polarimetric and Helioseismic Imager on the Solar Orbiter Mission

Accuracy Analysis of the On-board Data Reduction Pipeline for the Polarimetric and Helioseismic Imager on the Solar Orbiter Mission

Comparison of magnetic data products from Solar Orbiter SO/PHI-FDT and SDO/HMI

Development of a proof-of-concept spectropolarimeter in the framework of the GSST mission: Characterization and performance analysis of a sCMOS image sensor

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