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Xiaoxiong Xiong - One of the best experts on this subject based on the ideXlab platform.
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Improvements in the calibration of the NOAA-20 VIIRS day-night band low Gain Stage using a solar diffuser
Sensors Systems and Next-Generation Satellites XXIV, 2020Co-Authors: Junqiang Sun, Xiaoxiong XiongAbstract:We aim to introduce and demonstrate several improvements that are applied to the on-orbit solar diffuser (SD) calibration of the day-night band (DNB) low Gain Stage (LGS) of the Visible Infrared Imaging Radiometer Suite (VIIRS) onboard the NOAA-20 satellite. The most important improvement is the expansion of the angular range, referred to “sweet spot”, from 4° to 7.8° in order to increase the number of fully-illuminated scans considered for the SD calculation. The increase in scan number enables the completion of on-orbit calibration using the SD within one orbit, compared with the multiple orbits approach, which is required in the current standard approach applied in operational DNB LGS calibration coefficients look-up tables (LUTs) updates. The NOAA-20 DNB LGS calibration coefficients have been derived with the new methodology and the results show a more stable, smoother, and less noisy trend when compared with the current standard approach. The results also demonstrate that the NOAA-20 VIIRS DNB overall on-orbit performance has been very stable.
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Intercomparison of the SNPP and NOAA-20 VIIRS DNB High-Gain Stage Using Observations of Bright Stars
IEEE Transactions on Geoscience and Remote Sensing, 2020Co-Authors: Truman Wilson, Xiaoxiong XiongAbstract:The Visible Infrared Imaging Radiometer Suite (VIIRS) on board the Suomi-NPP (SNPP) and NOAA-20 (N20) spacecrafts is a multispectral Earth-observing instrument with bands covering wavelengths from visible to long-wave infrared. Among these bands is a panchromatic day/night band (DNB) with a broad spectral response ranging from 500 to 900 nm, and a high dynamic range spanning over seven orders of magnitude, allowing for observations to take place during both daytime and nighttime. The DNB operates at three Gain levels, with low- and mid-Gain Stages and two high-Gain Stages (HGSs). The HGS is capable of detecting dim city lights during Earth-view observations at night as well as bright stars through the instrument space-view port. Since SNPP and N20 are at opposite points of the same orbit, each VIIRS instrument is able to observe the same stars with the DNB in successive orbits. This will allow us to make a direct comparison of the relative calibration of each instrument using stars over a range of spectral classes. In this article, we develop methodology for accurately identifying target stars in order to make proper comparisons between the DNB HGS of each instrument. We then take observations from multiple stars in order to compute the ratio in the measured irradiance for each instrument as a function of spectral class. For K-type stars, which have the least spectral change over the DNB wavelength range, we measure a calibration bias between the SNPP and N20 DNB HGS of approximately 4%, which is stable over the duration of the N20 mission.
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a new method for suomi npp viirs day night band on orbit radiometric calibration
IEEE Transactions on Geoscience and Remote Sensing, 2015Co-Authors: Shihyan Lee, Jeffrey Mcintire, Hassan Oudrari, Thomas Schwarting, Xiaoxiong XiongAbstract:The Suomi National Polar-orbiting Partnership Visible Infrared Imaging Radiometer Suite (S-NPP VIIRS) instrument contains a visible imaging band designed to produce imagery during both daytime and nighttime, which is called the day-night band (DNB). The DNB is a three-Gain-Stage backside-illuminated charge-coupled device (CCD) with four detector arrays that aggregate the individual CCD pixels into 32 different aggregation modes across scan, yielding imagery with a roughly constant horizontal sampling interval. The highest Gain Stage is over 100 000 times more sensitive than the lowest Gain Stage; the combination of the three Gain Stages allows for imagery with radiances ranging from 10 -10 to 10 -2 W · cm -2 · sr -1 . The initial DNB on-orbit calibration relies on monthly sensor special operations. This offline calibration approach results in discrete calibration and the loss of some science data. In this paper, we will present a new calibration method based solely on VIIRS onboard calibrators (OBCs). The calibrator data collected on the nighttime side of an orbit are used to determine the dark offset and the data collected over the daytime side of the orbit, and the day-night terminators are used to compute the cross-Stage Gain ratios. The results showed that the dark offset and the Gain ratio derived from the initial method could be biased up to ten digital numbers (DN) and 12%, respectively, due to nighttime airglow and Earth scene stray light. The calibration is also continuous as calibrator data are recorded for each scan. Because no special operation and offline analysis are required, this method was approved for VIIRS operational implementation to improve the DNB radiometric calibration and sensor on-orbit operations.
Burkhard Vogel - One of the best experts on this subject based on the ideXlab platform.
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The Cascoded Cathode Follower (CCF)
How to Gain Gain, 2013Co-Authors: Burkhard VogelAbstract:The CCF (cascoded CF) and its variants are presented in this chapter. It includes all relevant equations that allow calculating Gains, input and output resistances, Gain Stage transfer functions, and all noise aspects of the Gain Stage.
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Differential (Balanced) Gain Stage (DIF)
How to Gain Gain, 2013Co-Authors: Burkhard VogelAbstract:The DIF (differential or balanced Gain Stage) is presented in this chapter. It includes all relevant equations that allow calculating Gains, input and output resistances, Gain Stage transfer functions, and all noise aspects of the Gain Stage. Additionally, the treatment of the DIF generated correlated noise voltages takes place in a separate section.
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The Common Cathode Gain Stage (CCS)
How to Gain Gain, 2013Co-Authors: Burkhard VogelAbstract:The common cathode Gain Stage (CCS) is presented in this chapter. It includes all relevant equations that allow calculating Gains, input and output resistances, Gain Stage transfer functions, and all noise aspects of the Gain Stage.
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The Common Grid Gain Stage (CGS)
How to Gain Gain, 2013Co-Authors: Burkhard VogelAbstract:The common grid Gain Stage (CGS) is presented in this chapter. It includes all relevant equations that allow calculating Gains, input and output resistances, Gain Stage transfer functions, and all noise aspects of the Gain Stage.
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The Shunt Regulated Push–Pull Gain Stage (SRPP)
How to Gain Gain, 2013Co-Authors: Burkhard VogelAbstract:The shunt regulated push–pull Gain Stage (SRPP) is presented in this chapter. It includes all relevant equations that allow calculating Gains, input and output resistances, Gain Stage transfer functions, and all noise aspects of the Gain Stage.
Changyong Cao - One of the best experts on this subject based on the ideXlab platform.
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Correction of NOAA-20 VIIRS day/night band low-Gain Stage Gain calibration errors by scaling factors derived from prelaunch testing data
Earth Observing Systems XXV, 2020Co-Authors: Slawomir Blonski, Xi Shao, Wenhui Wang, Taeyoung Choi, Sirish Uprety, Changyong CaoAbstract:The operational VIIRS Day/Night Band (DNB) Low Gain Stage (LGS) Gain is calibrated by the onboard solar diffuser when it is fully illuminated by the Sun. Such calibration method relies on assumption of the same calibrator view and Earth view responses of the LGS. However, analysis of the NOAA-20 VIIRS DNB prelaunch testing data shows this assumption is not valid for all aggregation modes and detectors, consequently yielding striping in NOAA-20 VIIRS DNB daytime images collected by its LGS. Through applying scaling factors derived from the prelaunch testing data, the operational LGS Gain calibration errors are corrected and striping in the reprocessed DNB daytime images is reduced.
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improved algorithm for determining the visible infrared imaging radiometer suite day night band high Gain Stage dark offset free from light contamination
Applied Optics, 2019Co-Authors: Sirish Uprety, Slawomir Blonski, Bin Zhang, Changyong CaoAbstract:Dark offset is one of the key parameters for Visible Infrared Imaging Radiometer Suite (VIIRS) Day/Night Band (DNB) high-Gain Stage (HGS) radiometric calibration, whose accuracy strongly impacts applications of DNB low-light detection for Earth observation at nighttime. Currently, DNB observation of the VIIRS onboard calibrator blackbody (OBCBB) view, together with its observation of deep space during the spacecraft pitch maneuver performed early in the mission, has been used to compute the HGS dark offset continuously. However, the relationship between the DNB OBCBB data and the Earth view (EV) data is unclear due to electronic timing differences between these two views. It is questionable whether the DNB OBCBB data can monitor the EV HGS dark offset change. Through comprehensive analysis of the DNB OBCBB data and EV data acquired from the monthly special acquisitions known as the VIIRS recommended operating procedures (VROPs), we have shown that the OBCBB data can only track the dark current component of the DNB HGS EV dark offset, instead of the total dark offset. The DNB observation of deep space during the spacecraft pitch maneuver was also contaminated by starlight. With such background, in this paper we propose an improved algorithm for determining the DNB HGS dark offset. By combined use of the DNB OBCBB data and the DNB VROP data, the generated DNB HGS dark offset is both free from light contamination and capable of tracking continuous drift. The improved algorithm could potentially improve the DNB radiometric performance at low radiance level. Our results provide a solid theoretical basis for dark offset calibration of the VIIRS DNB onboard Suomi National Polar-Orbiting Partnership satellite and the following Joint Polar Satellite System satellites.
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Improved algorithm for determining the Visible Infrared Imaging Radiometer Suite Day/Night Band high-Gain Stage dark offset free from light contamination.
Applied optics, 2019Co-Authors: Sirish Uprety, Slawomir Blonski, Bin Zhang, Changyong CaoAbstract:Dark offset is one of the key parameters for Visible Infrared Imaging Radiometer Suite (VIIRS) Day/Night Band (DNB) high-Gain Stage (HGS) radiometric calibration, whose accuracy strongly impacts applications of DNB low-light detection for Earth observation at nighttime. Currently, DNB observation of the VIIRS onboard calibrator blackbody (OBCBB) view, together with its observation of deep space during the spacecraft pitch maneuver performed early in the mission, has been used to compute the HGS dark offset continuously. However, the relationship between the DNB OBCBB data and the Earth view (EV) data is unclear due to electronic timing differences between these two views. It is questionable whether the DNB OBCBB data can monitor the EV HGS dark offset change. Through comprehensive analysis of the DNB OBCBB data and EV data acquired from the monthly special acquisitions known as the VIIRS recommended operating procedures (VROPs), we have shown that the OBCBB data can only track the dark current component of the DNB HGS EV dark offset, instead of the total dark offset. The DNB observation of deep space during the spacecraft pitch maneuver was also contaminated by starlight. With such background, in this paper we propose an improved algorithm for determining the DNB HGS dark offset. By combined use of the DNB OBCBB data and the DNB VROP data, the generated DNB HGS dark offset is both free from light contamination and capable of tracking continuous drift. The improved algorithm could potentially improve the DNB radiometric performance at low radiance level. Our results provide a solid theoretical basis for dark offset calibration of the VIIRS DNB onboard Suomi National Polar-Orbiting Partnership satellite and the following Joint Polar Satellite System satellites.
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The Terra Vega Active Light Source: A First Step in a New Approach to Perform Nighttime Absolute Radiometric Calibrations and Early Results Calibrating the VIIRS DNB
MDPI AG, 2019Co-Authors: Robert E. Ryan, Changyong Cao, Slawomir Blonski, Mary Pagnutti, Kara Burch, Larry Leigh, Timothy Ruggles, David Aaron, Dennis HelderAbstract:A fully automated, National Institute of Standards and Technology (NIST)-traceable artificial light source called Terra Vega has been developed to radiometrically calibrate the Visible Infrared Imaging Radiometer (VIIRS) Day Night Band (DNB) working in high Gain Stage (HGS) mode. The Terra Vega active point source is a calibrated integrating sphere that is only a fraction in size of a VIIRS DNB pixel. As such, it can be considered analogous to a ground-based photometric reference star. Vicarious calibrations that employ active point sources are different than those that make use of traditional extended sources and can be applyed to quantify the brightness of artificial light sources. The active source is successfully fielded, and early results indicate that it can be used to augment and validate the radiometric calibration of the VIIRS DNB HGS sensor on both the Suomi National Polar-orbiting Partnership (NPP) and NOAA-20 satellites. The VIIRS DNB HGS sensor can benefit from this technology as on-board calibration is challenging and hinges on transferring low Gain Stage (LGS) calibration using a solar diffuser to the medium Gain Stage (MGS) and HGS via regions of overlap. Current vicarious calibration methods that use a lunar-illuminated extended source estimate the HGS radiometric accuracy to within 8-15%. By comparison, early results and analysis showed that Terra Vega is stable to about 1%. Under clear dark night conditions, predicted top-of-atmosphere radiance from Terra Vega ranged between 1–11% of VIIRS measured values. Terra Vega’s excellent stability opens up new opportunities to validate and develop nighttime imaging applications based on point sources
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Feasibility demonstration for calibrating Suomi-National Polar-Orbiting Partnership Visible Infrared Imaging Radiometer Suite day/night band using Dome C and Greenland under moon light
Journal of Applied Remote Sensing, 2016Co-Authors: Shi Qiu, Changyong Cao, Xi Shao, Sirish UpretyAbstract:The day/night band (DNB) of the Visible Infrared Imaging Radiometer Suite (VIIRS) onboard Suomi National Polar-orbiting Partnership (Suomi-NPP) represents a major advancement in night time imaging capabilities. DNB covers almost seven orders of magnitude in its dynamic range from full sunlight to half-moon. To achieve this large dynamic range, it uses four charge-coupled device arrays in three Gain Stages. The low Gain Stage (LGS) Gain is calibrated using the solar diffuser. In operations, the medium and high Gain Stage values are determined by multiplying the Gain ratios between the medium Gain Stage, and LGS, and high Gain Stage (HGS) and LGS, respectively. This paper focuses on independently verifying the radiometric accuracy and stability of DNB HGS using DNB observations of ground vicarious calibration sites under lunar illumination at night. Dome C in Antarctica in the southern hemisphere and Greenland in the northern hemisphere are chosen as the vicarious calibration sites. Nadir observations of these high latitude regions by VIIRS are selected during perpetual night season, i.e., from April to August for Dome C and from November to January for Greenland over the years 2012 to 2013. Additional selection criteria, such as lunar phase being more than half-moon and no influence of straylight effects, are also applied in data selection. The lunar spectral irradiance model, as a function of Sun–Earth–Moon distances and lunar phase, is used to determine the top-of-atmosphere reflectance at the vicarious site. The vicariously derived long-term reflectance from DNB observations agrees with the reflectance derived from Hyperion observations. The vicarious trending of DNB radiometric performance using DOME-C and Greenland under moon light shows that the DNB HGS radiometric variability (relative accuracy to lunar irradiance model and Hyperion observation) is within 8%. Residual variability is also discussed.
Sirish Uprety - One of the best experts on this subject based on the ideXlab platform.
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Correction of NOAA-20 VIIRS day/night band low-Gain Stage Gain calibration errors by scaling factors derived from prelaunch testing data
Earth Observing Systems XXV, 2020Co-Authors: Slawomir Blonski, Xi Shao, Wenhui Wang, Taeyoung Choi, Sirish Uprety, Changyong CaoAbstract:The operational VIIRS Day/Night Band (DNB) Low Gain Stage (LGS) Gain is calibrated by the onboard solar diffuser when it is fully illuminated by the Sun. Such calibration method relies on assumption of the same calibrator view and Earth view responses of the LGS. However, analysis of the NOAA-20 VIIRS DNB prelaunch testing data shows this assumption is not valid for all aggregation modes and detectors, consequently yielding striping in NOAA-20 VIIRS DNB daytime images collected by its LGS. Through applying scaling factors derived from the prelaunch testing data, the operational LGS Gain calibration errors are corrected and striping in the reprocessed DNB daytime images is reduced.
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improved algorithm for determining the visible infrared imaging radiometer suite day night band high Gain Stage dark offset free from light contamination
Applied Optics, 2019Co-Authors: Sirish Uprety, Slawomir Blonski, Bin Zhang, Changyong CaoAbstract:Dark offset is one of the key parameters for Visible Infrared Imaging Radiometer Suite (VIIRS) Day/Night Band (DNB) high-Gain Stage (HGS) radiometric calibration, whose accuracy strongly impacts applications of DNB low-light detection for Earth observation at nighttime. Currently, DNB observation of the VIIRS onboard calibrator blackbody (OBCBB) view, together with its observation of deep space during the spacecraft pitch maneuver performed early in the mission, has been used to compute the HGS dark offset continuously. However, the relationship between the DNB OBCBB data and the Earth view (EV) data is unclear due to electronic timing differences between these two views. It is questionable whether the DNB OBCBB data can monitor the EV HGS dark offset change. Through comprehensive analysis of the DNB OBCBB data and EV data acquired from the monthly special acquisitions known as the VIIRS recommended operating procedures (VROPs), we have shown that the OBCBB data can only track the dark current component of the DNB HGS EV dark offset, instead of the total dark offset. The DNB observation of deep space during the spacecraft pitch maneuver was also contaminated by starlight. With such background, in this paper we propose an improved algorithm for determining the DNB HGS dark offset. By combined use of the DNB OBCBB data and the DNB VROP data, the generated DNB HGS dark offset is both free from light contamination and capable of tracking continuous drift. The improved algorithm could potentially improve the DNB radiometric performance at low radiance level. Our results provide a solid theoretical basis for dark offset calibration of the VIIRS DNB onboard Suomi National Polar-Orbiting Partnership satellite and the following Joint Polar Satellite System satellites.
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Improved algorithm for determining the Visible Infrared Imaging Radiometer Suite Day/Night Band high-Gain Stage dark offset free from light contamination.
Applied optics, 2019Co-Authors: Sirish Uprety, Slawomir Blonski, Bin Zhang, Changyong CaoAbstract:Dark offset is one of the key parameters for Visible Infrared Imaging Radiometer Suite (VIIRS) Day/Night Band (DNB) high-Gain Stage (HGS) radiometric calibration, whose accuracy strongly impacts applications of DNB low-light detection for Earth observation at nighttime. Currently, DNB observation of the VIIRS onboard calibrator blackbody (OBCBB) view, together with its observation of deep space during the spacecraft pitch maneuver performed early in the mission, has been used to compute the HGS dark offset continuously. However, the relationship between the DNB OBCBB data and the Earth view (EV) data is unclear due to electronic timing differences between these two views. It is questionable whether the DNB OBCBB data can monitor the EV HGS dark offset change. Through comprehensive analysis of the DNB OBCBB data and EV data acquired from the monthly special acquisitions known as the VIIRS recommended operating procedures (VROPs), we have shown that the OBCBB data can only track the dark current component of the DNB HGS EV dark offset, instead of the total dark offset. The DNB observation of deep space during the spacecraft pitch maneuver was also contaminated by starlight. With such background, in this paper we propose an improved algorithm for determining the DNB HGS dark offset. By combined use of the DNB OBCBB data and the DNB VROP data, the generated DNB HGS dark offset is both free from light contamination and capable of tracking continuous drift. The improved algorithm could potentially improve the DNB radiometric performance at low radiance level. Our results provide a solid theoretical basis for dark offset calibration of the VIIRS DNB onboard Suomi National Polar-Orbiting Partnership satellite and the following Joint Polar Satellite System satellites.
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Feasibility demonstration for calibrating Suomi-National Polar-Orbiting Partnership Visible Infrared Imaging Radiometer Suite day/night band using Dome C and Greenland under moon light
Journal of Applied Remote Sensing, 2016Co-Authors: Shi Qiu, Changyong Cao, Xi Shao, Sirish UpretyAbstract:The day/night band (DNB) of the Visible Infrared Imaging Radiometer Suite (VIIRS) onboard Suomi National Polar-orbiting Partnership (Suomi-NPP) represents a major advancement in night time imaging capabilities. DNB covers almost seven orders of magnitude in its dynamic range from full sunlight to half-moon. To achieve this large dynamic range, it uses four charge-coupled device arrays in three Gain Stages. The low Gain Stage (LGS) Gain is calibrated using the solar diffuser. In operations, the medium and high Gain Stage values are determined by multiplying the Gain ratios between the medium Gain Stage, and LGS, and high Gain Stage (HGS) and LGS, respectively. This paper focuses on independently verifying the radiometric accuracy and stability of DNB HGS using DNB observations of ground vicarious calibration sites under lunar illumination at night. Dome C in Antarctica in the southern hemisphere and Greenland in the northern hemisphere are chosen as the vicarious calibration sites. Nadir observations of these high latitude regions by VIIRS are selected during perpetual night season, i.e., from April to August for Dome C and from November to January for Greenland over the years 2012 to 2013. Additional selection criteria, such as lunar phase being more than half-moon and no influence of straylight effects, are also applied in data selection. The lunar spectral irradiance model, as a function of Sun–Earth–Moon distances and lunar phase, is used to determine the top-of-atmosphere reflectance at the vicarious site. The vicariously derived long-term reflectance from DNB observations agrees with the reflectance derived from Hyperion observations. The vicarious trending of DNB radiometric performance using DOME-C and Greenland under moon light shows that the DNB HGS radiometric variability (relative accuracy to lunar irradiance model and Hyperion observation) is within 8%. Residual variability is also discussed.
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Vicarious calibration of S-NPP/VIIRS day-night band
Earth Observing Systems XVIII, 2013Co-Authors: Xi Shao, Changyong Cao, Sirish UpretyAbstract:The Day Night Band (DNB) of the Visible Infrared Imaging Radiometer Suite (VIIRS) onboard the Suomi National Polar-orbiting Partnership (S-NPP) satellite provides imagery of clouds and other Earth features over illumination levels ranging from full sunlight to quarter moon. In order to cover this extremely broad measurement range, the DNB employs four imaging arrays that comprise three Gain Stages. The low Gain Stage (LGS) Gain values are determined by solar diffuser data. In operation, the medium and high Gain Stage values are determined by multiplying the LGS Gains by the medium Gain Stage (MGS)/LGS and high Gain Stage (HGS)/LGS Gain ratios, respectively. This paper demonstrates a scheme of using DNB observation of ground vicarious sites under lunar illumination at night to independently verify the radiometric accuracy of HGS of DNB. We performed vicarious calibration of DNB when S-NPP flies above the vicarious site such as Dome C in Antarctic and Greenland in northern hemisphere at night and the moon illuminates the site with lunar phase being more than half moon. Lunar spectral irradiance model as a function of Sun-Earth-Moon distances and lunar phase is used to assist the determination of top-of-atmosphere reflectance at the vicarious site. Analysis of the vicariously-derived reflectance from DNB observations show agreement with the reflectance derived from Hyperion observations of the vicarious sites.
Shihyan Lee - One of the best experts on this subject based on the ideXlab platform.
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a new method for suomi npp viirs day night band on orbit radiometric calibration
IEEE Transactions on Geoscience and Remote Sensing, 2015Co-Authors: Shihyan Lee, Jeffrey Mcintire, Hassan Oudrari, Thomas Schwarting, Xiaoxiong XiongAbstract:The Suomi National Polar-orbiting Partnership Visible Infrared Imaging Radiometer Suite (S-NPP VIIRS) instrument contains a visible imaging band designed to produce imagery during both daytime and nighttime, which is called the day-night band (DNB). The DNB is a three-Gain-Stage backside-illuminated charge-coupled device (CCD) with four detector arrays that aggregate the individual CCD pixels into 32 different aggregation modes across scan, yielding imagery with a roughly constant horizontal sampling interval. The highest Gain Stage is over 100 000 times more sensitive than the lowest Gain Stage; the combination of the three Gain Stages allows for imagery with radiances ranging from 10 -10 to 10 -2 W · cm -2 · sr -1 . The initial DNB on-orbit calibration relies on monthly sensor special operations. This offline calibration approach results in discrete calibration and the loss of some science data. In this paper, we will present a new calibration method based solely on VIIRS onboard calibrators (OBCs). The calibrator data collected on the nighttime side of an orbit are used to determine the dark offset and the data collected over the daytime side of the orbit, and the day-night terminators are used to compute the cross-Stage Gain ratios. The results showed that the dark offset and the Gain ratio derived from the initial method could be biased up to ten digital numbers (DN) and 12%, respectively, due to nighttime airglow and Earth scene stray light. The calibration is also continuous as calibrator data are recorded for each scan. Because no special operation and offline analysis are required, this method was approved for VIIRS operational implementation to improve the DNB radiometric calibration and sensor on-orbit operations.
