# Presentation: 517918

## VIIRS FU-1 Pre-launch Calibration and Characterization

**VIIRS FU-1 Pre-launch Calibration and Characterization**
**NPP Instrument Calibration Support Team/Element (NICST/E)**
**VIIRS/MODIS Science Teams Meeting**
**Hilton BWI Airport **
***May 15, 2008***** **

## References

**References**

- List of Ambient Phase I, II, and III Test Data
- Test IDs and Names; Data Collected/Processed
- List of NICST Data Analysis Reports
- Name: NICST_REPORT_YR_###q (q for quick report)
- Subject and Date Released
- List of NICST Technical Memos
- Name: NICST_MEMO_YR_###
- Subject and Date Released

**All NICST reports and memos are available from e-room **

## VIIRS Ambient Radiometric Calibration and Characterization (RC-01) 

**VIIRS Ambient Radiometric Calibration and Characterization (RC-01) **

**Objectives: characterize sensor radiometric response/gain, dynamic range, SNR/NEdT, and dual gain transition**
**RC-01 Part 1 for Thermal Emissive Bands**
**RC-01** **Part 2 for Reflective Solar Bands**
**RC-01** **Part 3 for DNB**
**RC-01** **Part 4 for Dual Gain Transitions**
**STR-504, 506, and 508**** **

## Radiometric Calibration Summary (RC-01) 

**Radiometric Calibration Summary (RC-01) **

- All detectors meet the SNR/NEdT requirements (specified at typical radiance/temperature)
- M12 D1 is out-of-family (OOF)
- Most spectral bands meet the dynamic range requirements
- Exceptions: M8 (HG), M1 (LG), and M2 (LG)
- Most dual gain bands meet the gain switching requirements
- Exception: M1 (HG to LG)

**RC-1 provides initial ambient baseline performance information  **
**RC-2 and RC-5 in TVAC will provide final verification of sensor performance**

## RSB Gains and SNR

**RSB Gains and SNR**

**Measured SNR for all VIIRS RSB bands meet the specified requirements at Ltyp **

**(Expected values from Y23503; SBRS gains from Y23579)**

## TEB Gains and NEdT

**TEB Gains and NEdT**

**A few detectors failed SNR/NEdT in run3 (det. 2, 9, 16 of M14; det. 8 of M16A)**

**Run 2 CFPA set at 79.2K**
**Run 3 CFPA set at 81.6K**

## OOF Detector: M12 D1

**OOF Detector: M12 D1**

***Detector 1 is OOF. But meets the spec.***

## Dynamic Range Compliance HAM A ASP A 

**Dynamic Range Compliance HAM A ASP A**

**SRV0465: RSB Dual Gain Band's High/Low gain transition within +20.0% to 0.0% of spec.**
**SRV0468: TEB Dual Gain Band's High/Low gain transition within +5.0K to 0.0K of spec. (M13: ****343-348K)**

## M8 Did Not Meet Dynamic Range Requirement

**M8 Did Not Meet Dynamic Range Requirement**

- Saturated before the specified maximum radiance** **

**Noticeable detector response variation**

- After ASP gain adjustment, M8 still failed dynamic range requirement (RC1 RUN2 and STR-508)

## Concerns (Ambient RC-01)

**Concerns (Ambient RC-01)**

- SIS100 stability impact on radiometric calibration
- IFA filter leak: red leakage through M1 filter could be 16% of M1 RC-1 signal, causing the gain to be over estimated (from NGST)
- SWIR bands M8, M9 and M11 had relatively large detector gain variations
- Most dual gain bands had large noisy behavior at their gain transitions (to be verified from new test)
- Path forward: Better characterize SIS monitor and make sure it works

**RC-1 provides initial ambient baseline performance information  **
**RC-2 and RC-5 in TVAC will provide final verification of sensor performance**

## Response Versus Scan-angle (RVS) Characterization (FP-10) 

**Response Versus Scan-angle (RVS) Characterization (FP-10) **

**Objectives: characterize RSB response versus scan angles (RVS); characterize TEB response versus scan angles (RVS)**
**FP-10 Part 1 for RSB**
**FP-10 Part 2 for TEB**

## RVS Characterization Summary (FP-10) 

**RVS Characterization Summary (FP-10) **

- RSB RVS characterization meet the requirements (agree with SBRS results)
- TEB RVS characterization meet the requirements (agree with SBRS results)

**PVP 4.2.2.4.2 ****Characterize normalized RVS of RSB bands over full earth view scan to 0.3% or better (Pre-launch: 0.27%; change over life: 0.1%).**
**PVP 4.2.2.4.3 ****Characterize normalized RVS of TEB bands over full earth view scan to 0.2% (0.6% for M14) or better (Pre-launch 0.17% (0.57% for M14); change over life: 0.1%).**** ****	**** **

## VIIRS Scan Angles and AOI 

**VIIRS Scan Angles and AOI **

## FP-10 Part 1
RSB bands: 12 discrete scan angles: -65.4o, -55.5o, -51o, -45o, -38o, -30o, -20o, -8o, 6o, 22o, 38o, 55.5o.
SIS100 radiance monitor data collected
Relative humidity and temperature monitored

FP-10 Part 2
TEB bands: 12 distinct scan angles: -65.7o, -60.6, -55.5o, -51o, -45o, -38o, -30o, -20o, -8o, 6o, 22o, 35o
CFPA controlled using BTC
LABB and OBC BB data collected

- FP-10 Part 1
- RSB bands: 12 discrete scan angles: -65.4o, -55.5o, -51o, -45o, -38o, -30o, -20o, -8o, 6o, 22o, 38o, 55.5o.
- SIS100 radiance monitor data collected
- Relative humidity and temperature monitored
- FP-10 Part 2
- TEB bands: 12 distinct scan angles: -65.7o, -60.6, -55.5o, -51o, -45o, -38o, -30o, -20o, -8o, 6o, 22o, 35o
- CFPA controlled using BTC
- LABB and OBC BB data collected

**RVS Data Collection**

## RSB RVS (for all detectors) 

**RVS results agree well to within 0.1%**

**RSB RVS (for all detectors)**** **

## TEB RVS (band averaged) 

**TEB RVS (band averaged)***** ***

## RSB and TEB RVS Uncertainty

**RSB and TEB RVS Uncertainty**

- Both RSB and TEB RVS characterization meet the requirements
- (consistent with SBRS analyses and results)

- RVS uncertainty included
- (1) fitting residuals
- (2) measurement errors

## RVS Results and Issues

- SIS monitor approach was not satisfactory
**SIS stability and uncertainty are major concerns**
- Drifting correction approach works better for RSB RVS retrieval
- Results agree well with SBRS using the same approach
- Better understanding of SIS drifting mechanism and correction methodology needed
- Uncertainties of RSB and TEB RVS meet the requirements.
- HAM side difference is ~0.6% for M6-M7 and I2; ~0.4% for TEB bands
- Detector variation < 0.1% for RSB; and <0.4% for TEB
- Path forward:
- FU1: verify RSB RVS with witness samples; re-evaluate TEB RVS uncertainty assessment
- FU2: repeat measurements should be made at multiple scan angles.

**RVS Results and Issues**

## SIS monitor correction vs drifting correction

- Group 1      Group 2      Group 3

**SIS monitor correction vs drifting correction**

**SIS corrected**

## FU1 VIIRS Polarization Insensitivity for VisNIR BandsFP-11, STR-545, and STR-554

**FU1 VIIRS Polarization ****Insensitivity for VisNIR Bands****FP-11, STR-545, and STR-554**

**Test Objectives**
- Examine the insensitivity of the sensor to an input polarized light
- Measure polarization insensitivity for every VISNIR band and detector at discrete scan positions
- Characterize polarization insensitivity to uncertainty level (0.5%) specified in TP154640-103
**Spec. for polarization factor:**  3% for M1 and M7;  2.5% for all other VisNIR bands

## Data Analysis Status of Polarization Insensitivity for VisNIR Bands

**Data Analysis Status of Polarization Insensitivity for VisNIR Bands**

-  Tests using PSA as polarized light source
-  Data: run1 and run 2
-  Data analyzed and polarization parameters derived
-  Strong effect of non-uniformity of light source and other noises
-  Algorithms developed to correct the effect of the PSA but they still depend on how well the PSA is characterized
-  Tests using SIS with a polarizer sheet as polarized light source
-  Data: run2-STR-545 and run3-STR-554
-  Data analyzed and polarization parameters derived
-  No non-uniformity of the light source issue
-  The polarizer sheet might not provide perfect polarized light, waiting for SBRS’ investigation

## Algorithms for Polarization Insensitivity 

- Fourier Analysis
-   is the polarization angle
- Oscillation

**Algorithms for Polarization Insensitivity **
**Data Analysis**

-  Only second order oscillation has information for the polarization effect
-  Other order oscillations
- due to light source and other noise

## Measured Response

**Measured Response**

**PSA**

**SIS with polarizer sheet**

## Amplitude of One-cycle Oscillation

**Amplitude of One-cycle Oscillation**

**PSA**

**SIS with polarizer sheet**

## Polarization Factor

**Polarization Factor**

**PSA**

**SIS with polarizer sheet**

**Uncertainty is definitely larger than 0.5%**

## Polarization Factor

**Polarization Factor**

**SIS with polarizer sheet**

**Polarization factors of band M1 (412 nm) are smaller than of band M2 (445 nm).  This is probably due to the non-fully polarization of light for band M1, an issue being currently investigated by SBRS. **

## Polarization Factor

**Polarization Factor**

**SIS with polarizer sheet**

**For band I1 (640 nm), the polarization factors are quite different for the two mirror sides at small AOI.  The differences between the two mirror sides also observed for polarization factors of bands M4 (555 nm) and  M5 (670 nm).  This phenomena were also observed in the polarization factors derived from the tests using the PSA to provide polarized light source.    **

## Polarization Factor

**Detector averaged polarization factor**

**HAM A**

**HAM B**

**Polarization Factor**

**SIS with polarizer sheet**

## Summary

***Summary***

-  All FU1 VIIRS polarization insensitivity test data (both with FP-11 and SIS with a polarizer sheet as light source) for VisNIR Bands are analyzed and the polarization parameters are derived from the measured data.
-  The derived polarization factors from all tests satisfy the VIIRS specification for the polarization factor.
-  The derived polarization factors are sensitive to detectors and also mirror side for a couple of bands.
-  The polarization parameters derived from the test using PSA to provide polarized light are significantly contaminated by effect of non-uniformity of the light source and other noise.  The uncertainty of the derived polarization factors are larger than the specification for the uncertainty level.
-  The light provided by the SIS with a polarizer sheet might not be a fully polarized light.  But the effect of the non-perfect polarized light on the derived parameters need to be corrected.  The uncertainty level of the derived polarization factors can not be assessed without the characterization of the polarization degree of the polarizer sheets used in the tests.

## The irradiance from earth and/or cloud albedo outside the sensor FOV will be the main source of stray light, and sensor rejection of this light should be demonstrated prior to launch
FP-12 test simulated stray light source comparable to the on orbit condition 
Test data was used for evaluation of temporal SLR performance against the specification
The original specification SRV0065 requires that stray light causes less than 1% change in response when sensor viewing an earth scene of typical radiance 

**FP-12: RSB Stray-Light Rejection (SLR) **** **

- The irradiance from earth and/or cloud albedo outside the sensor FOV will be the main source of stray light, and sensor rejection of this light should be demonstrated prior to launch
- FP-12 test simulated stray light source comparable to the on orbit condition
- Test data was used for evaluation of temporal SLR performance against the specification
- The original specification SRV0065 requires that stray light causes less than 1% change in response when sensor viewing an earth scene of typical radiance

## FP-12 Lamp Position at Nadir

***The lamp was placed behind ABC  ***

- A 1000w studio lamp was placed 120in away to provide uniform illumination over a solid angle cone
- Telescope was locked at three different scan angles: EOS (w/ cooled CFPA), Nadir (w/o BTC) and SV
-  At each scan angle, the ABC was aligned with sensor FOV to provide a dark view
- At each lamp position, the measurement was done with the lamp off, on and off
-  Sensor responses from all positions were summed and scaled to compensate for the spectral difference between earth albedo and the lamp.

**FP-12 Lamp Position at Nadir**

## Summary of FP-12 Results

**Summary of FP-12 Results**

- After the initial run, the test data indicated that most of M-bands did not meet the original requirement, and an EFR was generated to formally track the non-compliance results
- The run 2 results show that bands M2-M7, and M11 do not meet the original requirement, but meet the proposed requirement RDW053A
- Path Forward: evaluation and approval of waiver request

## Waiver of SRV0065 –W053 

**Waiver of SRV0065 –W053**

-  It is said that based on heritage mirror roughness knowledge, the predicted results showed non-compliance for VisNIR.
- For M8, M9 and M11, the SLR requirement makes SNR at Ltyp more stringent than the sensor SNR specification.
- Previous RDWs w053 was based on the initial modeling, a less matures models. RDWs w053A was proposed

##  Preliminary Results 

** ****Preliminary Results **

-  Ratio stands scattered radiance to the original spec.
-  Bands with the ratio >1.0 are non-compliant

## Summary of Near Field Response (NFR)

**Summary of Near Field Response (NFR)**

- FP-14 test was conducted with a single vertical slit scanning across IFA w/wo ND, and bandpass filters were used for VisNIR
- The objective is to estimate the ability of the sensor to measure the radiance from one region the earth scene which differs from the adjacent regions. An example
- - a bright cloud scanned by the sensor might introduce scattered radiation that would corrupt the radiometric measurements of an adjoining dark region
- The processed test data w/ selected collects are the same as the Raytheon
- The preliminary results of the data analysis indicate that at least bands M4, M12, M13 and M16 are non-compliant
- The largest margin between the existing specification and the measured data is found in TEB band M12 > 750%
- Ghosting signals are found in TEB which makes it difficult to assess the NFR.

## FP-14 – NFR for all spectral bands
       Dynamic crosstalk artifacts are found in many VisNIR collected without BPF. Ghosting artifacts are found in TEB 
STR541 – Emissive Band Filtering
       An extended test for TEB to use bandpass filter to generate a narrow width light. Unfortunately, the artifacts were still presented, though the SNR was improved. The second run was conducted with the lamp level as high as possible to maximize SNR. This data is used in the FP-14 analysis.
STR546 – Aperture Blocking
      To confirm the source of artifacts was within VIIRS and not a result of the test setting. Measurements were made with the aperture open, left half blocked, right half blocked and fully blocked. Unfortunately the results didn’t give a sufficient explanation.
STR547 – TMC Source with Slit & Single Point Reticles
        To confirm that the ScMA was not the source of the artifacts. The results still exhibited the artifacts. Requested by Eric Johnson, a few sets of data were collected with the single point reticle positioned over detectors 2, 8, 9 & 13 individually. The data allows to derive a more representative PSF to generate a scan & track response for the ScMA data. NGST used this data alone with FP-14 to derived ghost coefficients.
EFR3326
      Engineering Failure Report 3326 was opened to track the investigation of artifacts in the FP-14 data.

**FP-14 – NFR for all spectral bands**
**       **Dynamic crosstalk artifacts are found in many VisNIR collected without BPF. Ghosting artifacts are found in TEB
**STR541 – Emissive Band Filtering**
-        An extended test for TEB to use bandpass filter to generate a narrow width light. Unfortunately, the artifacts were still presented, though the SNR was improved. The second run was conducted with the lamp level as high as possible to maximize SNR. This data is used in the FP-14 analysis.
**STR546 – Aperture Blocking**
-       To confirm the source of artifacts was within VIIRS and not a result of the test setting. Measurements were made with the aperture open, left half blocked, right half blocked and fully blocked. Unfortunately the results didn’t give a sufficient explanation.
**STR547 – TMC Source with Slit & Single Point Reticles**
-         To confirm that the ScMA was not the source of the artifacts. The results still exhibited the artifacts. Requested by Eric Johnson, a few sets of data were collected with the single point reticle positioned over detectors 2, 8, 9 & 13 individually. The data allows to derive a more representative PSF to generate a scan & track response for the ScMA data. NGST used this data alone with FP-14 to derived ghost coefficients.
**EFR3326**
-       Engineering Failure Report 3326 was opened to track the investigation of artifacts in the FP-14 data.

**FP-14 Test Overview**

## Ghosting signal in STR-541

**Ghosting signal in STR-541**

- Artifact signal of ~0.2% (FP-14: 0.5%) is seen on the detector when the slit is scanned across the IFA
- Artifact is angularly dependent in scan direction
-  Ghosting is confirmed from the Dewar by a 2D-modeling

**The ghosting is observed in bands M12-M13, and M15-M16**

**Scattered response: dn/dn_max**
**Ø: angular distance in degree**

## M13 Analyzed Result (Preliminary)

- Two sets of test data, one saturated and one unsaturated, are stitched together to generate the relative response for each detector.
- The stitched data are used to verify and refine NFR H-S models, which are used to evaluate the sensor performance.

**M13 Analyzed Result (Preliminary)**

## NGST 2D Ghosting from FP-14 and STR-547

**NGST 2D Ghosting from FP-14 and STR-547**

## Waiver w004

**Waiver w004**

-  It is said that requirement is too stringent for a few bands, since the large contrast ratio between Lmax and Ltyp never occur in the same earth scene.
-  New requirements is under developing. To date no mutually agreeable changes have ever been identified.

## ERF 3326 Conclusions
Root cause is known-reflection and rejected light comes from Dewar window
NGST SDR sesults suggest no substantial impact in Emissive band SDR SST
NGST impact on assessment of EDRs VIIRS Cloud Mask and Aerosols are in progress

Path Forward
NGST investigate VIIRS Cloud Mask and Aerosols EDR
Need independent verification of artifact Ghosting is a small impact to SST EDR

- ERF 3326 Conclusions
- Root cause is known-reflection and rejected light comes from Dewar window
- NGST SDR sesults suggest no substantial impact in Emissive band SDR SST
- NGST impact on assessment of EDRs VIIRS Cloud Mask and Aerosols are in progress
- Path Forward
- NGST investigate VIIRS Cloud Mask and Aerosols EDR
- Need independent verification of artifact Ghosting is a small impact to SST EDR

**NGST EFR 3326 Investigation****Ghosting impact on SDR **

## FP13 Crosstalk
Measure the crosstalk signal under both static and dynamically scanning conditions
Part 1 uses the Three Mirror Collimator (TMC) and Part 2 uses the Scatter Measurement Assembly (ScMA) to cover the low gain region of the VisNIR dual gain bands. 
Include both polychromatic illuminations
Verify compliance with crosstalk requirements for all spectral bands. 

**FP13 Crosstalk**
- Measure the crosstalk signal under both static and dynamically scanning conditions
- Part 1 uses the Three Mirror Collimator (TMC) and Part 2 uses the Scatter Measurement Assembly (ScMA) to cover the low gain region of the VisNIR dual gain bands.** **
- Include both polychromatic illuminations
- Verify compliance with crosstalk requirements for all spectral bands.

**STR Crosstalk**
- FPA and In-band crosstalk: STR351, STR352, STR358, STR359, STR405 and STR406
- Crosstalk survey tests to investigate the presents xtalk artificial after rework of ASPs and VNIR FPA
- Provided preliminary assessment of crosstalk mechanisms
- Optical Crosstalk/Filter Leakage for VisNIR
- In-band dynamic xtalk for all spectral bands

**VIIRS FU1 Crosstalk**

## FP13 Reticle Spatial Patterns 

**FP13 Reticle Spatial Patterns**

## STR Crosstalk Overview

**STR Crosstalk Overview**

## Analyzed Data Checklist

**Analyzed Data Checklist**

- Completed STR351, STR352, STR358, STR359, and STR406 crosstalk analysis
- Completed FP-13 point-to-point static and dynamic crosstalk analysis for all spectral bands
- Identified crosstalk root cause, as well as the major send detectors
- Derived and delivered static point-to-point crosstalk influence coefficients for all VIIRS spectral bands in dn, radiance, and CNR spaces for cases of:
- For HG --> HG
- For LG --> HG
- Fixed LG --> Fixed LG
- Results comparison between similar tests are in progress

## Summary of  STR Optical Crosstalk

**Summary of  STR Optical Crosstalk**

- Significant optical crosstalk is evident from
- M1, M3 and I1 into M4
- M4 into M5
- High optical crosstalk is associated with TMC BPF blocking sides, as well as IFA filter leak
- Filter orientation recommendation for FP-13 after STR-406 was made by NGST on Sept 26, 2007
- Optical crosstalk/leak is measurable for receiver bands M1, M2, M4, M5 and M6 at difference spectral ranges
- M1: 770-830nm
- M2: 370-390nm
- M4: 428-432, 460-470 and 700-720 nm
- M5: 460-470, 570-585, and 770-830nm
- M6: 370-390, 460-470, 500-520nm
- Compared with  STR-443 data (component level), STR-406 (system level) shows improvement in spectral range >700nm
- Optical crosstalk map was derived and released

## STR 406 Optical Crosstalk Overview 

**STR 406 Optical Crosstalk Overview**

**xxx**

**xxx**

**xxx**

**xxx**

**xxx**

**xxx**

**xxx**

**xxx**

**Scanned**
**Slit**

- Objective: Evaluate optical leakage through VisNIR IFA
-   slit illumination using The TMC
- 8 OOB spectral filters and 7 VisNIR BPF were used
- ~972 microradian slit width (approx 2.5 M-Band IFOV)
- TMC SIS is at 23,000 (max)

## FU1 Optical Crosstalk 

**FU1 Optical Crosstalk**

## Dynamic Crosstalk Tests

**Dynamic Crosstalk Tests**

_**Vertical KE Orientations**_

**STR w/ KE Reticle**
**STR358: vertical KE for VNIR **
**STR405: vertical KE for  **
**               ****SMWIR & LWIR **
**STR352: horizontal KE**
** ****Illumination of lower number detectors**
** ****Obscuration of higher number detectors**
** ****6 track positions of horizontal knife edge**

_**Horizontal Knife Edge**_

**Single Slit Reticle****TR359:  5 TMC BB Levels for SMWIR and LWIR, 9 BP filters: M8, M9, M10/I3, M12, M13, M14, I4 and I5;****STR351:  5 TMC SIS Levels,  7 VNIR BP filters: M1, M3, M4-M7/I2, and I1**** FP-13: three TMC SIS source levels 4000, 4500, and 25000 fl****FP-13 w/ Open Reticle**** Highest TMC source level for VisNIR bands**

**Single vertical slit**

**Dynamically scanned **
**256 scans each collect**

## Preliminary Summary of Dynamic Crosstalk

**Preliminary Summary of Dynamic Crosstalk**

- Generally in radiance space:
- Improvement is made in dynamic crosstalk in FU1 compared with EDU data after bond wire additions
- Dynamic crosstalk are observed only in VisNIR when sender bands are M4, M5, I1, and I2/M7
- Dynamic crosstalk in radiance space is impacted by gain state. Low gain has smaller coefficients.
- Dynamic crosstalk is proportional/linear to the source level
- Detector variations and I-band sub-sample difference are measurable

## Dynamic Crosstalk Signal from STR-351 

-  TMC SIS level 23000 fl
-  De-register dn vs. sample number for the middle detector
-  Low gain has lower dynamic crosstalk than that of the auto HG
-  Dynamic crosstalk is evident
-  Optical crosstalk is also observed in receiver bands M1 and M5-M7

**Dynamic Crosstalk Signal from STR-351**

## Dynamic Crosstalk in Radiance (Preliminary) 

**Dynamic Crosstalk in Radiance (Preliminary) **

-  Improvement was made in dynamic crosstalk after bond wire additions
-  In general, FU1 has smaller dynamic crosstalk than EDU

## Averaged Crosstalk Coefficient vs. Gain State

**Averaged Crosstalk Coefficient vs. Gain State**

- Auto HG has higher dynamic crosstalk coefficient than that of LG state

##          Crosstalk vs. SIS Level

**         ****Crosstalk vs. SIS Level**

- Amplitude of dynamic crosstalk in radiance ratio is proportional/linear to the source level

## Optical Crosstalk coefficients 

**Optical Crosstalk coefficients **
**From FP-13 Four-opening and KE (1)**

- Optical crosstalk is also observed in dynamic tests

## Electrical Static P-to-P Crosstalk from FP-13 

**Electrical Static P-to-P Crosstalk from FP-13**** **

-  Part 1 uses the Three Mirror Collimator (TMC) and Part 2 uses the Scatter Measurement Assembly (ScMA) to cover the low gain region of the VisNIR dual gain bands.** **
-  Verify sensor compliance with crosstalk requirements for all spectral bands.

## Summary from P-to-P Static Crosstalk

**Summary from ****P-to-P**** Static Crosstalk**

- VisNIR FPA:
- Dominant sender detectors are 3, 8, and 13 from MB and 5/6, 15/16, 25/26 from IB
- Significant readout crosstalk from ROIC are observed which is N MB-detector away from the sender detector in track direction (N= 0, 2, and ±10/11)
- For HG-->HG, high in-band optical scattering (in track direction) extended over ±5~ ± 8 adjacent MB detectors
- For LG-->HG and LG-->LG, optical scattering to adjacent bands (in scan direction) is the dominant effect
- LG-->HG exhibits higher electrical crosstalk in the dn ratio. This may associated with the gain bit transition from the ASP board
- Sub-sample differences are measurable
- Limited source levels didn’t provide evidence of crosstalk linearity. The FP-15/FP-16 tests are appropriate tests for the linearity investigation
- LWIR FPA:
- No measurable readout crosstalk
- No measurable dominant sender detectors
- S/MWIR FPA:
- Relatively small but noticeable readout crosstalk which is N MB detector away from the sender detector (N= 0, 1, ±10)
- Relatively small but noticeable dominant detectors are 8 and 13
- Odd, even detectors and sub-sample differences are measurable

## Summary of Out of Spec. Bands/Detectors

**Summary of Out of Spec. Bands/Detectors**

-  Current P-to-P crosstalk testing has both electrical and optical components
-  Optical artifacts in the test set up are leading to high uncertainties in the electric crosstalk measurements
-  Given a severe sensor specification, many receiver detectors in all spectral bands are not compliant
-  For most of bands, majority of out of spec detectors (P-to-P) have crosstalk to Noise Ratio (CNR) less than 1.
-  However, crosstalk should be summed over all senders, which leads to CNR values much higher that the spec. of 0.5NEdL.
-  A completed comprehensive crosstalk influence tables can be found in the eRoom:
- _https://collab2.st.northropgrumman.com/eRoom/PayloadSensors/VIIRS/0_8452F_

## Readout Crosstalk  from ROIC 

- Three types of ROIC crosstalk,
- which are preferentially located
- in the track field at 0, 2, ±10 and
- ±11 M-band detectors away
- from the sender detector:
- a negative dip response usually less than 1.5dn and is associated with sender band in-band pixels
- a positive anomalous signal peak which is associated with cross-band pixels
- a pair of positive & negative or negative & positive anomalous signal peaks which also occurs for cross-band pixels.

**Readout Crosstalk ** **from ROIC**

**dn vs. detector number**

##  Adjacent band and In-band optical artifacts 

-  **Adjacent band and In-band optical artifacts**

-    U3102155 Collect 18 Bands M16A det 9

## Crosstalk Assessment

**Crosstalk Assessment**

- Crosstalk influence coefficients are derived in dn, radiance and noise (crosstalk to noise ratio) spaces

- dnSND: dn of the sender detector
- dnREC:dn of the receiver detector
- gSND: radiometric gain of the sender detector
- gREC: radiometric gain of the receiver detector
- LMAX: the maximum radiance for the sender band
- σREC-DARK: standard deviation of the receiver detector for the shutter closed scans only.

- Verification is made between the sensor crosstalk compliance against the requirement SRV0631 to the 0.2% Ltyp or 0.5 noise:

## Major Crosstalk Sender Det. in Band M1  

**Major Crosstalk Sender Det. in Band M1 **

**Dominant detectors: M-band detectors: 3, 8, and 13**
**                                    ****I-band detectors: 5,6, 15,16 and 15,16**

- The identified dominant sender detectors from dn and radiance space are consistent

## Dual-gain band crosstalk 

**Dual-gain band crosstalk**

-  When sender is in LG state, optical scattering/artifacts to adjacent bands are dominant
-  Fixed LG has the smallest crosstalk influence coefficient

## Identifying Out of Spec. detector

**Identifying Out of Spec. detector**

**Detectors with Normalized spec. >1.0 do not meet baseline requirement**

## Path forward

**Path forward**

- NGST and NASA continue to assess crosstalk impact on FU1 SDR/EDR
- NASA science community recommends insertion of re-manufactured IFA in FU1 at the earliest opportunity
- NASA science community recommended hardware ROIC rework but probably not possible for FU1

## Backup References

**Backup References**

## Ambient phase I&II Data Check List

**Ambient phase I&II Data Check List**

**>800 GB data has been  Processed**

## Ambient phase III Data Check List 

**Ambient phase III Data Check List**

**>32.5 GB data has been  Processed**

## Released Data Analysis Reports During Phase I Test  

**Released Data Analysis Reports During Phase I Test **** **

## Released Data Analysis Reports During Phase II Test  

**Released Data Analysis Reports During Phase II Test****  **

## Released Data Analysis Memos (1) 

**Released Data Analysis Memos (1) **

## Released Data Analysis Memos (2)

**Released Data Analysis Memos (2)**

## Backup RVS

**Backup RVS**

## SIS Monitor Data

**SIS Monitor Data**

**Anomalies in I1 and M5-M6**

**PVP: Source drift should <=0.2%**

- Compensation of variations in SIS-100 output for the same lamp configuration was expected
- Compensation of dn variation was failed
- Anomalies in SIS monitor data were not fully understood, especially drifting in the blue regions

##           Test Environment Conditions

**Absolute Humidity**

- SBRS M9_RVS_Data_V2.xls (Nov.14 2007)

- * From Kameron Rausch

- * From Kameron Rausch

**         **** ****Test Environment Conditions**

- M9 variation > 1%, likely due to changes of relative humidity and temperature of test environment

##           Response Drifting over Time (hour)   

**         **** ****Response Drifting over Time (hour)**** **

**PVP 4.2.2.4.2** **: Sensor gain drafting is expected <=0.1%**

-   SBRS proposed approach for drifting correction
-   #	Four -8o repeated measurements were used
-   #	Quadratic interpolation between data collects for each band (exception: M9)
-   #	Sensor and/or source drifting?

**M1-M3 drifted 1.1-1.6%**** **

## Backup Crosstalk

**Backup Crosstalk**

## Backup Significant VisNIR Crosstalk Pairs 

**Backup Significant VisNIR Crosstalk Pairs **

-  Most out of spec. detector pairs are the results of adjacent band optical artifacts
-  Major sender detectors are M-band det. 3, 8, and 13; and I-band 5&6,15&16, and 25&26
-  A completed and comprehensive crosstalk influence coefficient tables can be found in the eRoom

**CNR>1: Crosstalk is the dominant effect over noise**

## Significant SMWIR and LWIR Crosstalk Pairs 

**Significant SMWIR and LWIR Crosstalk Pairs **

## backup

**backup**

## Results w/ OOB Filter

**Results w/ OOB Filter**

**S = 0.2022 mm**

-  Spectral overlap cause optical leak is
- not crosstalk
-  Optical crosstalk is measurable for bands
- M1, M2, M4, M5 and M6
- -M1: 770-830nm
- -M2: 370-390nm
- -M4: 428-432, 460-470 and 700-720 nm
- -M5: 460-470, 570-585, and 770-830nm
- -M6: 370-390, 460-470, 500-520nm

## Comparison of Crosstalk coefficients 

**Comparison of Crosstalk coefficients **
**between four-opening and KE (2)**

- Two set of crosstalk coefficients are on the
-   same order
- The discrepancy may caused by different
-   test configurations

- M6 data from 4-openings may use substitute band

## TABLE 2: SRV0055 Dynamic Range Requirement (Wm-2sr-1mm-1)

**TABLE 2: SRV0055 Dynamic Range Requirement (Wm-2sr-1mm-1)**

##  Sensitivity requirements for VIIRS Sensor reflective bands

** ****Sensitivity requirements for VIIRS Sensor reflective bands**

- The units of spectral radiance for Ltyp are wm-2sr-1mm-1.
- The SNR column shows the minimum required (worst-case) SNR that applies at the end-of-scan. Elsewhere in the scan, aggregation will yield a larger SNR.
- Within the same gain setting, at radiances larger than Ltyp, the SNR will be larger than what is specified in this table.

## Backup: Band Averaged dn vs. Position in run 1 

**Backup: Band Averaged dn vs. Position in run 1**** **

- The scattered radiance at position 16 takes about 54 - 63% of the sum of all positions for VNIR bands: caused NICST initial results is twice larger than the SBRS results
-  Position 16 data was excluded after we learned a ABC baffle was remove and caused this anomaly. The updated results agree with the SBRS results