OCX ATTACHMENT B OCXPORD 418-XO-OCXPORD-0061_V_1_1 Updated.pdf

/GeoXO Flight Project OCX

OCXPORD

418-XO-OCXPORD-0061, RM Version, Geostationary Extended Observations (GeoXO) Ocean Color (OCX) Performance and Operational Requirements Document (PORD)

Version: 1.1 Printed by: rkhoover Printed on: Monday, September 20, 2021

No filter applied.

No sort applied.

Generated from DOORS 9.6.1.11

Contents

1 1Scope

1.1 1Identification

1.2 1Mission Review

1.3 1Document Overview

1.4 1Terminology

1.5 2Definitions

1.6 4Requirement Applicability

2 5Documents

2.1 5Applicable Documents

2.2 5Reference Documents

3 6Sensor Requirements

3.1 6Sensor Definition

3.1.1 6OCX Modes

3.1.1.1 6Safe Mode

3.1.1.2 7Normal Operational Mode

3.1.1.3 7Instrument Diagnostic Mode

3.1.1.4 8Outgas Mode

3.1.2 8On-Orbit Operations

3.1.2.1 8Operational Zones

3.1.2.1.1 8Performance Zone

3.1.2.1.2 8REMOVED Restricted Zone

3.1.2.2 9Imaging the Sun

3.1.2.3 9Eclipse

3.1.2.4 9Operations After Maneuvers

3.1.2.4.1 9Yaw Flip

3.1.2.4.2 9Stationkeeping

3.1.2.4.3 9Post Storage Activation

3.1.2.5 9Detector Operating Temperatures

3.2 9Normal Operational Mode Sensor Requirements

3.2.1 10Coverage

3.2.1.1 10Coverage Rate

3.2.1.2 10Flexible and Efficient Imaging Pattern

3.2.1.3 11Field of Regard

Project: GeoXO Flight Project OCX Module: OCXPORD Baseline Version: 1.1

Contents ii

3.2.1.4 11Simultaneity

3.2.1.5 11Data Latency

3.2.1.6 11Data Collection Overlap

3.2.2 12Channel Definitions, SNR, Dynamic Range

3.2.2.1 12Baseline

3.2.2.2 14System Spectral Response

3.2.2.2.1 14Spectral Response Envelope

3.2.2.2.2 14Within Channel Spectral Response Uniformity

3.2.2.2.3 15Reserved

3.2.2.3 15Reserved

3.2.3 15Spatial Resolution and Sampling

3.2.3.1 15System Modulation Transfer Function

3.2.3.2 15Spatial Response Uniformity

3.2.3.3 16Ringing from a Sharp Edge

3.2.4 16Image Navigation and Registration

3.2.4.1 16Star Sensing

3.2.4.2 16INR Performance Requirements

3.2.4.2.1 16Navigation

3.2.4.2.2 17Frame-to-Frame Registration

3.2.4.2.3 17Within Frame Registration

3.2.4.2.4 17Reserved

3.2.4.2.5 17Channel-to-Channel Registration

3.2.5 17Radiometric Accuracy and Precision

3.2.5.1 17REMOVED

3.2.5.1.1 17REMOVED

3.2.5.2 17Repeatability

3.2.5.2.1 17Pixel-to-Pixel

3.2.5.2.2 17Removed

3.2.5.2.3 18Removed

3.2.5.2.4 18Removed

3.2.5.2.5 18Removed

3.2.5.3 18Coherent Noise

3.2.5.4 18Calibration of Channels

3.2.5.5 19Spatial Uniformity of Data

3.2.5.6 19Crosstalk

3.2.5.6.1 19Channel-to-Channel

3.2.5.6.2 19Within Channel

3.2.5.7 20Blooming

Contents iii

3.2.5.8 20Quantization Step Size

3.2.5.9 20Reserved

3.2.5.10 20Polarization

3.2.5.10.1 20Polarization Control

3.2.6 20System Linearity

3.2.7 20Data Compression

3.2.7.1 21Lossless Data Compression

3.2.7.2 21Lossy Compression

3.3 21Design Requirements

3.3.1 21Reliability

3.3.2 22Mechanical Requirements

3.3.2.1 22Design Limit Loads

3.3.2.2 22Nonlinear Loads

3.3.2.3 22Yield Strength

3.3.2.4 22Ultimate Strength

3.3.2.5 22Structural Stiffness

3.3.2.6 22Unit Stiffness

3.3.2.7 23Material Properties

3.3.2.8 23Critical Members Design Values

3.3.2.9 23Redundant Members Design Values

3.3.2.10 23Selective Design Values

3.3.2.11 23Structural Reliability

3.3.2.12 24Mechanisms

3.3.2.13 24Pressurized Units

3.3.2.14 24Alignment Reference

3.3.3 24Thermal Requirements

3.3.3.1 24Temperature Limits

3.3.3.2 25Non Operational Temperature

3.3.3.3 25Thermal Control Hardware

3.3.3.4 25Dectector Cooling Margin

3.3.4 25Onboard Processors Requirements

3.3.4.1 25Flight Load Non-Volatile Memory

3.3.4.2 25Commandable Reinitialization

3.3.4.3 25Deterministic Power-on Configuration

3.3.4.4 26Fail-safe Recovery Mode

3.3.5 26Flight Software Requirements

3.3.5.1 26Language and Methodology

3.3.5.2 26Flight Software Upload

Contents iv

3.3.5.3 26Flexibility and Ease of Software Modification

3.3.5.4 26Version Identifiers

3.3.5.5 26Flight Processor Resource Sizing

3.3.5.6 27Software Event Logging

3.3.5.7 27Warm Restart

3.3.5.8 27Memory Tests

3.3.5.9 27Memory Dump

3.3.5.10 28Telemetry

3.3.6 28Power Requirements

3.3.6.1 28Power Regulators and Supplies

3.3.6.2 28Fuses

3.3.6.3 28Test Connectors

3.3.7 28Magnetic Properties

3.3.8 28Fluid Filter Margins

3.3.9 28Ground Support Equipment and Development Facilities

3.3.9.1 28Electrical System Test Equipment

3.3.9.2 29Flight Software Development Environment

3.3.9.3 29Shipping Container

3.3.9.4 30Instrument Emulator

4 31Design Verification Requirements

4.1 31Performance Operating Time and Trouble-Free Performance Testing

4.2 31Structural and Mechanical Verification Requirements

4.2.1 31Mechanical Test Factors and Duration

4.2.2 31Minimum Workmanship

4.2.3 31Testing in Flight Configuration

4.2.4 31Structural Proof Testing

4.2.5 31Modal Survey Characterization

4.2.6 32Structural Qualification

4.2.7 32Deployment and Articulation Verification

4.2.8 33Life Test

4.2.9 33Mechanical Clearance Verification

4.3 33Electromagnetic Compatibility Requirements

4.3.1 33General

4.3.2 33Electrostatic Arc-Discharge Susceptibility

4.3.2.1 33External Surface-to-Surface direct discharge

4.3.2.2 33Deep Dielectric Charging

4.3.2.3 33ESD Characteristics

Contents v

4.4 34Magnetic Properties

4.4.1 34General

4.5 34Thermal Requirements

4.5.1 34General

4.5.1.1 34Test Chronology

4.5.1.2 34Thermal Test Chronology

4.5.1.3 35Pressure

4.5.2 35Thermal Vacuum

4.5.2.1 35Transition Rates

4.5.2.2 35Corona Operation

4.5.2.3 35Hot and Cold Start Demonstrations

4.5.2.4 35Heater Verification

4.5.2.5 36Flight Temperature Sensor Verification

4.5.3 36Thermal Cycling

4.5.3.1 36Spacecraft Level TV Test

4.5.3.2 36Cumulative Cycles

4.5.3.3 36Instrument Level TV Cycling

4.5.3.4 36Unit Level TV Cycling

4.5.3.5 37Ambient Pressure Thermal Cycling Substitution

4.5.3.6 37Test Temperatures

4.5.3.6.1 37Mission Allowable Temperatures

4.5.3.6.2 37Qualification, Protoflight and Acceptance Temperatures

4.5.3.6.3 38Non-operating Temperatures

4.5.3.7 38Temperature test tolerances

4.5.3.8 38Plateau Criteria

4.5.4 38Thermal Balance (TB)

4.5.4.1 38TB Applicability

4.5.4.2 38Balance Points

4.5.4.3 38TB-Instrument Configuration

4.5.4.4 39TB Accuracy and Knowledge

4.5.4.5 39TB Steady State Criteria

4.6 39Test Condition Tolerances

4.6.1 39General

5 42Appendix 1

5.1 42Priority 1

6 43Acronyms

Contents vi

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OCXPORD2

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OCXPORD6

OCXPORD7

OCXPORD8

OCXPORD9

OCXPORD10

OCXPORD11

OCXPORD12

Object Number

1.1

1.1.0-1

1.2

1.2.0-1

1.2.0-2

1.2.0-3

1.2.0-4

1.3

1.3.0-1

1.4

1.4.0-1

418-XO-OCXPORD-0061, RM Version, Geostationary Extended Observations (GeoXO) Ocean Color (OCX) Performance and

Operational Requirements Document (PORD)

1 Scope

1.1 Identification

This Performance and Operational Requirements Document (PORD) sets forth the performance requirements for the National Oceanic and Atmospheric Administration (NOAA) Geostationary Extended Orbits (GeoXO) Ocean Color (OCX) instrument.

The OCX may incorporate additional capabilities described in Appendix 1.

1.2 Mission Review

The OCX is a multi-channel, UV through infrared, passive imaging radiometer used to measure environmental data as part of a 3-axis stabilized, geostationary weather satellite system. The OCX remotely collects imagery of the Earth’s coastal waters for harmful algal blooms, water turbidity, and general water quality, fisheries management, habitat quality/assessment/mapping, pollution tracking, biogeochemical processing in coastal regions, warnings and predictions.

The OCX objectives are as follows:

a) Provide new NOAA ocean color operational data that will be used by NOAA and other public and private agencies to produce forecasts of water quality pollution including turbidity and harmful algal blooms.

b) Provide ocean color operational data that will be used to expand knowledge of coastal waters and ocean processes in the exclusive economic zone

(EEZ).

The ocean color instrument provides data to the Ground System via the spacecraft communication system. The Ground System takes the data, spacecraft telemetry data, orbit determination data and other required information and autonomously generates radiometrically calibrated and navigated data (Level 1b data) for the NOAA users.

The Ground System will be developed by the Government but will implement algorithms developed by the OCX contractor to satisfy performance requirements.

The Ground System will calibrate and then resample the data to generate the fixed grid. Resampling requires that the raw imagery be adequately sampled to maintain radiometric accuracy after resampling.

1.3 Document Overview

This document contains all performance requirements for the OCX instrument and Ground Support Equipment (GSE). This document, the General Interface Requirements Document (GIRD), and the OCX Unique Instrument Interface Document (UIID) define all instrument to spacecraft interfaces for the OCX instrument.

1.4 Terminology

The term “TBD” means, “to be determined.” This is applied to requirements or values that have not been defined.

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OCXPORD14

OCXPORD15

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OCXPORD17

OCXPORD18

OCXPORD19

OCXPORD20

OCXPORD21

OCXPORD22

OCXPORD23

OCXPORD24

OCXPORD25

Object Number

1.4.0-2

1.4.0-3

1.4.0-4

1.4.0-5

1.4.0-6

1.4.0-7

1.5

1.5.0-1

1.5.0-2

1.5.0-3

1.5.0-4

1.5.0-5

1.5.0-6

418-XO-OCXPORD-0061, RM Version, Geostationary Extended Observations (GeoXO) Ocean Color (OCX) Performance and

Operational Requirements Document (PORD)

The contractor shall propose a requirement or value and provide a rationale for all TBD requirements. TBD requirement proposals shall be made in coordination with the government and may involve other contractors.

The contractor shall request approval from the government before proceeding with its proposed TBD requirement or value.

The term “TBR” means, “to be reviewed.” This is applied to requirements or values that are subject to review by the government and the contractor. The contractor shall review and suggest a modified value and rationale for all TBR requirements.

The “TBR” provides an indication that the value may change upon review.

TBR requirement proposals shall be made in coordination with the government and may involve other contractors.

The contractor shall request approval from the government before proceeding with its proposed TBR requirement or value.

The term “TBS” means, “to be supplied.” The government will supply TBS requirements. The Government will provide a date or milestone at which each TBS requirement will be supplied.

1.5 Definitions

Throughout this document, the following definitions apply (note that Appendix 1 has optional updates to some terms):

Accuracy: Refers to the error in a measurement, that is the difference between the measurement result and the object to be measured (the measured or true value).

It includes both systematic and random errors. Systematic errors must be estimated from an analysis of the experimental conditions and techniques. Random errors can be determined, and reduced, through repeated measurements under identical conditions.

Albedo: Refers to the fraction of the solar spectrum taken from the default MODTRAN solar irradiance file (newkur.dat) that is reflected by the Earth at the top of the atmosphere assuming a Lambertian surface (see OCX Radiance file for values).

All requirements/all performance requirements/all operational requirements: Refers to any performance characteristic or requirement in the OCX PORD, OCX UIID, and the GIRD.

Derived Noise Equivalent Delta Radiance (NEDN): Refers to the NEDN required to meet the Noise Equivalent Delta Temperature (NEDT) specification or Signal-to- Noise Ratio (SNR) specification.

EEZ East Region: Any spatial resolution element in the Atlantic along the US East or Gulf Coast including the Gulf of Mexico and within 400 km from the continental US shoreline, with inclusion of Puerto Rico in the Caribbean. This is a region of approximately 6110 km x 400 km in area without including Puerto Rico and 6300 km by 400 km including Puerto Rico EEZ.

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OCXPORD27

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OCXPORD29

OCXPORD30

OCXPORD31

OCXPORD32

OCXPORD33

OCXPORD34

OCXPORD35

Object Number

1.5.0-7

1.5.0-8

1.5.0-9

1.5.0-10

1.5.0-11

1.5.0-12

1.5.0-13

1.5.0-14

1.5.0-15

1.5.0-16

418-XO-OCXPORD-0061, RM Version, Geostationary Extended Observations (GeoXO) Ocean Color (OCX) Performance and

Operational Requirements Document (PORD)

EEZ West Region: Any spatial resolution element in the Pacific along the US West coast and within 400 km from the continental US shore plus any spatial resolution element in the Pacific along the Hawaii coast and within 400 km from the Hawaiian shore, plus approximately 2000 km of the observable southern Alaska coast from the GOES West slot (137 West) that falls within 400 km from the Alaskan shore.

This is a region of approximately 3600 km by 400 km in area plus 2000 km by 400 km in area for Alaska totaling 5600 km by 400 km in area.

Great Lakes: Any spatial resolution element in the Great Lakes. This is a region of approximately 900 km by 1250 km in area.

Detector sample or element: Refers to the output of a physical detector after the Analog-to-Digital (A/D) converter and Time Delay and Integration (TDI) processing, if applicable.

Eclipse: Defined as when the solar disk is completely occulted by the Earth or Moon, as viewed from the satellite.

Fixed Grid Format: Refers to the idealized georeferenced positions for pixel locations. The fixed grid has the following characteristics:

a) The fixed grid is rectified to a GRS80 geoid viewed from the idealized geostationary position.

b) The pixels have the same angular separation for East/West and North/South.

c) From the viewpoint of a right-hand coordinate system of the idealized geostationary satellite with its x-axis in the direction of the velocity and the z-axis pointed at nadir, the North/South angle is determined by a rotation about the x-axis and the East/West angle is determined by a rotation about the rotated y-axis.

d) The angular separation is 8.4 microradians for 300 m resolution.

e) The ideal sub-satellite point is at the corner of a pixel on the 8.4 microradians grid.

Fully Functional Configuration: Being able to perform the following functions: scene radiance measurement; radiometric calibration; star sensing; on-orbit monitoring of calibration sources and instrument response changes; acquisition of sensor health and status data; generation of sensor, calibration, monitoring, health and status data streams; and reception and execution of command and control data.

Frame: Collection of pixels from a contiguous region as commanded by a minimum bounding rectangle.

Navigation: Refers to the determination of the location of each pixel relative to a fixed reference, such as fixed-grid angle coordinates.

Registration: Refers to maintaining the spatial relationship between pixels within frames, between frames, and between channels.

Launch: The period of time between lift off and the separation of the satellite from the launch vehicle.

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OCXPORD37

OCXPORD38

OCXPORD39

OCXPORD40

OCXPORD41

OCXPORD42

OCXPORD43

OCXPORD44

OCXPORD45

Object Number

1.5.0-17

1.5.0-18

1.5.0-19

1.5.0-20

1.5.0-21

1.5.0-22

1.5.0-23

1.6

1.6.0-1

1.6.0-2

418-XO-OCXPORD-0061, RM Version, Geostationary Extended Observations (GeoXO) Ocean Color (OCX) Performance and

Operational Requirements Document (PORD)

Navigation Error: Refers to the angular error of locations in the resampled fixed-grid frame.

Pixel: Applies to data samples after resampling during the ground processing.

Polarization Sensitivity: Defined as the ratio of the difference between maximum and minimum output to the sum of the maximum and minimum output obtained when the plane of incoming 100% linearly polarized radiation is rotated through 180 degrees.

Precision: Refers to the standard deviation of a statistically meaningful number of samples of a measurement.

SNR: Refers to the Signal-to-Noise Ratio specification.

Transfer Orbit: The sequence of events that transpires to establish the GeoXO satellite on-station after the GeoXO satellite has separated from the launch vehicle.

Unit: A functional subdivision of a subsystem and generally a self-contained combination of items performing a function necessary for the subsystem's operation.

Examples are electronics unit and sensor unit.

1.6 Requirement Applicability

The requirements in this OCX PORD pertain to the OCX ‘system’, which may include motors, optics, detectors, signal processing electronics and software, and ground processing. The OCX contractor is not responsible for the whole Ground System, but certain specifications may require some level of ground processing after collection but before data distribution, i.e. decompression, re-sampling, and calibration.

All requirements apply over the entire life of the instrument. Data performance requirements, such as Modulation Transfer Function (MTF) and Image Navigation and Registration (INR), apply to data after all ground processing, except as indicated.

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OCXPORD50

Object Number

2.1

2.1.0-1

2.2

2.2.0-1

418-XO-OCXPORD-0061, RM Version, Geostationary Extended Observations (GeoXO) Ocean Color (OCX) Performance and

Operational Requirements Document (PORD)

2 Documents

2.1 Applicable Documents

The following form a part of this specification to the extent specified herein.

1. CCSDS Recommendation for Space Data System Standards, Image Data Compression, CCSDS 122.0-B-2, September 2017.

2. CCSDS Recommendation for Space Data System Standards, Low-Complexity Lossless and Near-Lossless Multispectral and Hyperspectral Image Compression, CCSDS 123.0-B-2, February 2019.

3. Structural Design and Test Factors of Safety for Spaceflight Hardware, NASA, Document Number NASA-STD-5001B, August 6, 2014

4. Removed

5. Removed

6. General Environmental Verification Specification For GSFC Flight Programs and Projects, Document Number GSFC-STD-7000A, April 22, 2013

7. NASA-STD-8719.24, NASA Expendable Launch Vehicle Payload Safety

Requirements (Base and Annex), 2018

8. Removed

9. OCX Radiances

2.2 Reference Documents

The following are reference documents.

1. GXI General Interface Requirements Document, Document number 418-XO-

GXIGIRD-0025

2. Report Concerning Space Data System Standards GREEN BOOK: LOSSLESS

MULTISPECTRAL AND HYPERSPECTRAL IMAGE COMPRESSION,

Informational Report CCSDS 120.2-G-1

3. SPECTRAL PREPROCESSING TRANSFORM FOR MULTISPECTRAL AND

HYPERSPECTRAL IMAGE COMPRESSION” Recommended Standard CCSDS 122.1-B-1.

4. General Specification for Assemblies, Moving Mechanical, for Space and Launch Vehicles, Document Number MIL-A-83577B, February 1, 1988

5. Space Mechanisms Handbook, Document Number NASA TP-1999-206988

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OCXPORD60

OCXPORD61

OCXPORD62

Object Number

3.1

3.1.1

3.1.1.0-1

3.1.1.0-2

3.1.1.0-3

3.1.1.0-4

3.1.1.0-5

3.1.1.0-6

3.1.1.1

3.1.1.1.0-1

3.1.1.1.0-2

418-XO-OCXPORD-0061, RM Version, Geostationary Extended Observations (GeoXO) Ocean Color (OCX) Performance and

Operational Requirements Document (PORD)

3 Sensor Requirements

3.1 Sensor Definition

3.1.1 OCX Modes

The OCX shall execute commands to individually enable and disable each autonomous function.

Rationale: Autonomous capability needs to be able to be disengaged as well.

The OCX shall initiate all commanded mode transitions in no more than 20 seconds after receipt of command.

Rationale: Mode transitions should occur rapidly for operators.

The OCX shall make limits and triggers of autonomous functions changeable by command.

Rationale: Autonomous functions should be controlled by operators if there is a special need to do so.

The OCX shall transition from its current mode to any other mode without causing permanent damage to itself.

Rationale: Mode transitions should occur without damage.

The OCX shall indicate the mode of the instrument in housekeeping telemetry.

Rationale: Knowledge of instrument modes is needed for data processing.

The OCX shall provide command and housekeeping telemetry functions in all powered modes.

Rationale: Command and housekeeping telemetry is necessary for monitoring instrument health at all times.

3.1.1.1 Safe Mode

The OCX shall implement a Safe Mode.

Rationale: The OCX needs a Safe Mode to enable straightforward storage.

The OCX shall be in a thermally and optically safe configuration for an indefinite period of time while in Safe Mode.

Rationale: Safe Mode of instrument enables a thermally and optically safe configuration for storage.

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OCXPORD69

OCXPORD70

OCXPORD71

OCXPORD72

Object Number

3.1.1.1.0-3

3.1.1.2

3.1.1.2.0-1

3.1.1.2.0-2

3.1.1.3

3.1.1.3.0-1

3.1.1.3.0-2

3.1.1.3.0-3

3.1.1.3.0-4

3.1.1.3.0-5

418-XO-OCXPORD-0061, RM Version, Geostationary Extended Observations (GeoXO) Ocean Color (OCX) Performance and

Operational Requirements Document (PORD)

The OCX shall enter Safe Mode upon detection of internal faults capable of causing permanent damage to the instrument.

Rationale: The OCX needs to employ the Safe Mode after fault detection to ensure that there is time for recovery.

3.1.1.2 Normal Operational Mode

The OCX shall be in a fully functional configuration while in Normal Operational Mode.

Rationale: Normal mode is used for observations that require full functionality.

The OCX shall meet all performance requirements while in Normal Operational Mode without receiving commands or data loads for a minimum of 7 days.

Rationale: Autonomy is required for a period of 7 days, without impacting performance.

3.1.1.3 Instrument Diagnostic Mode

The OCX shall implement an Instrument Diagnostic Mode.

Rationale: Diagnostic mode is needed for diagnosing anomalies.

The OCX shall be in a fully functional configuration while in Instrument Diagnostic Mode.

Rationale: Diagnostic mode must be fully functional.

The OCX shall by command send selected channels while in Instrument Diagnostic Mode.

Rationale: Diagnostic mode will afford commandable channel engagement for diagnosing anomalies.

The OCX shall by command send the individual measurement in those cases where TDI data is digitally processed off the focal plane while in Instrument Diagnostic Mode.

Rationale: Diagnostic mode will send data from TDI if employed to help in validation and in assessing anomalies.

The OCX shall by command send data from all detectors while in Instrument Diagnostic Mode.

Rationale: Diagnostic mode will send data from all detectors to help in validation and in assessing anomalies.

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OCXPORD73

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OCXPORD77

OCXPORD78

OCXPORD79

OCXPORD80

OCXPORD81

OCXPORD82

OCXPORD83

OCXPORD84

OCXPORD85

Object Number

3.1.1.3.0-6

3.1.1.3.0-7

3.1.1.3.0-8

3.1.1.3.0-9

3.1.1.4

3.1.1.4.0-1

3.1.1.4.0-2

3.1.2

3.1.2.1

3.1.2.1.1

3.1.2.1.1.0-1

3.1.2.1.1.0-2

3.1.2.1.2

418-XO-OCXPORD-0061, RM Version, Geostationary Extended Observations (GeoXO) Ocean Color (OCX) Performance and

Operational Requirements Document (PORD)

The OCX shall by command send the same data both compressed and uncompressed if the data is capable of being compressed while in Instrument Diagnostic Mode.

Rationale: Diagnostic mode will send compressed and uncompressed to help in validation and in assessing anomalies.

The OCX shall by command send all bits from the A to D converter while in Instrument Diagnostic Mode.

Rationale: Diagnostic mode will send all bits to help in validation and in assessing anomalies.

The OCX shall by command perform electronic in-flight calibration.

Rationale: Diagnostic mode electronic in-flight calibration will help in validation and in assessing anomalies.

The OCX shall by command send dwell data (increased samples per second of a particular telemetry measurand) while in Diagnostic Mode.

Rationale: Diagnostic mode dwell data will help in validation and in assessing anomalies.

3.1.1.4 Outgas Mode

The OCX shall sublimate and evaporate contaminants from hardware to prevent contamination from jeopardizing performance while in Outgas Mode.

Rationale: Diagnostic mode will have an outgas capability to ensure that the instrument has contaminants removed before operations.

The post-launch outgas period shall be no longer than 14 days.

Rationale: Outgassing should occur relatively quickly to afford time for PLT testing in 6 months.

3.1.2 On-Orbit Operations

3.1.2.1 Operational Zones

3.1.2.1.1 Performance Zone

Reserved

The OCX shall meet all performance requirements for all pixels whose solar zenith angle (SZA) is less than 70 (TBR) degrees.

Rationale: SNR, on-orbit calibration, and accuracy are met in well-illuminated conditions during the day and may degrade in performance outside this region.

Solar zenith angle is the angle measured off local zenith to the moving sun’s position.

3.1.2.1.2 REMOVED Restricted Zone

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OCXPORD92

OCXPORD93

OCXPORD94

OCXPORD95

OCXPORD96

OCXPORD97

OCXPORD98

OCXPORD99

OCXPORD100

Object Number

3.1.2.2

3.1.2.2.0-1

3.1.2.3

3.1.2.3.0-1

3.1.2.4

3.1.2.4.1

3.1.2.4.1.0-1

3.1.2.4.2

3.1.2.4.2.0-1

3.1.2.4.3

3.1.2.4.3.0-1

3.1.2.5

3.1.2.5.0-1

3.1.2.5.0-2

3.2

418-XO-OCXPORD-0061, RM Version, Geostationary Extended Observations (GeoXO) Ocean Color (OCX) Performance and

Operational Requirements Document (PORD)

3.1.2.2 Imaging the Sun

The OCX shall survive imaging of the sun without sustaining damage.

Rationale: Imaging of the sun or unexpected loss of pointing control that points at the sun must not results in damage to the instrument.

3.1.2.3 Eclipse

(Reserved)

3.1.2.4 Operations After Maneuvers

3.1.2.4.1 Yaw Flip

The OCX shall meet all radiometric, coverage and INR requirements within 30 minutes after the spacecraft interface has returned to being within specification following a yaw flip.

Rationale: If the spacecraft executes a yaw flip, the instrument recovery will occur in this duration after the interface is restored to nominal conditions.

3.1.2.4.2 Stationkeeping

The OCX shall meet all radiometric, coverage and INR requirements within 2 minutes (TBR) after the spacecraft interface has returned to being within specification following spacecraft stationkeeping maneuvers.

Rationale: If the spacecraft executes a different maneuver than a yaw flip, the instrument recovery will occur in this short duration after the interface is restored to nominal conditions.

3.1.2.4.3 Post Storage Activation

The OCX shall meet all requirements within 2 days (TBR) of turn on after post storage activation.

Rationale: After activation, OCX will cool for operations in this time listed here.

3.1.2.5 Detector Operating Temperatures

The OCX detector set-point temperature shall be selectable by command to ensure radiometric performance during degradation at end of life.

Rationale: This provide for set point temperature adjustments near the operating temperature range that may be needed due to gain changes or troubleshooting.

Knowledge uncertainty of the OCX detector temperature shall be less than +/- 0.1 K.

Rationale: OCX may be thermally sensitive due to its detectors and thermal telemetry will provide information for potential corrections and troubleshooting.

3.2 Normal Operational Mode Sensor Requirements

Page 10 of 44 Printed Monday, September 20, 2021

ID

OCXPORD101

OCXPORD102

OCXPORD103

OCXPORD104

OCXPORD105

OCXPORD106

OCXPORD107

OCXPORD108

OCXPORD109

Object Number

3.2.1

3.2.1.1

3.2.1.1.0-1

3.2.1.1.0-2

3.2.1.1.0-3

3.2.1.1.0-4

3.2.1.2

3.2.1.2.0-1

3.2.1.2.0-2

418-XO-OCXPORD-0061, RM Version, Geostationary Extended Observations (GeoXO) Ocean Color (OCX) Performance and

Operational Requirements Document (PORD)

3.2.1 Coverage

3.2.1.1 Coverage Rate

Note that these coverage requirements define a capability and not a definitive operational scenario. Rather, NOAA anticipates operating OCX in an asynchronous manner that uses information from other instruments and models to identify potential regions for scanning/stepping by OCX. To perform its tasks, commanding of OCX for these targeted observations will be based on priorities and availability.

The OCX shall acquire concurrently within 3 hours:

a) Coverage Regions: Either EEZ East Region (EEZE) plus Great Lakes (GL), or EEZ West Region (EEZW). Note that EEZE+GL is larger than EEZW.

b) Any other observations required to meet radiometric and INR requirements

Rationale: When covering the driving EEZE plus Great Lakes, the coverage including all calibrations will take 3 hours or less to ensure a timely coverage rate for the instrument that may be used to cover smaller areas in proportionally smaller times.

Nominally coverage from OCX on the GeoXO Imager satellite (GeoI) at 75 W (GeoI- East) will cover EEZE plus Great Lakes and OCX on GeoI-West at 137 W will cover

EEZW.

The OCX shall interrupt current operations by issued command and start the acquisition of a new frame, after a frame coordinate upload, within 30 seconds.

Rationale: The OCX must be commandable to cover regions of interest. Regions will be covered with the same instrument coverage rate, with smaller areas taking proportionally less time.

All corresponding EEZE+GL frames in consecutive revisits shall be spaced at an average time of no more than 3 hours with peak deviation of no more than +/- 30 seconds.

Rationale: The OCX revisit of the entire region should be repeatable if commanded with a regular cadence with limited temporal deviation to support operations.

3.2.1.2 Flexible and Efficient Imaging Pattern

The OCX sensor shall observe an area of commanded size anywhere within the field of regard when commanded.

Rationale: Permits flexible tasking of OCX to regions of interest.

The scan area and geographic location shall be selectable from one frame to the next.

Rationale: Permits flexible tasking of OCX to regions of interest.

Page 11 of 44 Printed Monday, September 20, 2021

ID

OCXPORD110

OCXPORD111

OCXPORD112

OCXPORD113

OCXPORD114

OCXPORD115

OCXPORD116

OCXPORD117

OCXPORD118

OCXPORD119

OCXPORD120

OCXPORD121

Object Number

3.2.1.2.0-3

3.2.1.2.0-4

3.2.1.2.0-5

3.2.1.3

3.2.1.3.0-1

3.2.1.4

3.2.1.4.0-1

3.2.1.4.0-2

3.2.1.5

3.2.1.5.0-1

3.2.1.5.0-2

3.2.1.6

418-XO-OCXPORD-0061, RM Version, Geostationary Extended Observations (GeoXO) Ocean Color (OCX) Performance and

Operational Requirements Document (PORD)

The OCX shall be designed such that the Earth-scanning patterns are fully programmable on-orbit.

Rationale: Permits flexible tasking of OCX to regions of interest.

The OCX shall accept fixed grid coordinates for all imaging patterns.

Rationale: Permits mapping to fixed grid.

The OCX shall set the center location of each frame to Fixed Grid Frame coordinates specified by command.

Rationale: Permits centering on fixed grid point for ease of Fixed Grid mapping.

3.2.1.3 Field of Regard

Reserved

3.2.1.4 Simultaneity

Corresponding pixels in all spectral channels shall be calculated from detector samples that are collected within 20 seconds of each other.

Rationale: Spectrally simultaneous observations provide observations of the same features and avoid artifacts in resulting data.

All adjacent pixels shall be calculated from detector samples collected within 7 minutes (TBR) of each other.

Rationale: This somewhat limits shearing to some extent in an image composed of multiple individual observations, but is constrained by the need to provide hyperspectral coverage at 300 meter resolution over a large area.

3.2.1.5 Data Latency

The OCX shall contribute to the total data latency for the Level 1b product of no more than 5 minutes for calibrated, navigated radiances.

Data latency is measured from the time the instrument collects all samples for an earth scene (or frame) to the time the data is available for dissemination on the ground as Level 1b data. The OCX contribution to data latency includes delay of delivery of data to the spacecraft and delay due to ground algorithm processing (i.e., any resampling and INR).

Rationale: Latency between the last observation of the input data to the Level 1b processing and the availability of the data for further processing should be as short as practical.

3.2.1.6 Data Collection Overlap

Page 12 of 44 Printed Monday, September 20, 2021

ID

OCXPORD122

OCXPORD123

OCXPORD124

OCXPORD125

OCXPORD126

Object Number

3.2.1.6.0-1

3.2.2

3.2.2.1

3.2.2.1.0-1

3.2.2.1.0-2

418-XO-OCXPORD-0061, RM Version, Geostationary Extended Observations (GeoXO) Ocean Color (OCX) Performance and

Operational Requirements Document (PORD)

The OCX shall generate each pixel from detector samples contained in a single collection.

Rationale: Requirement limits resampling from different collections at different times.

3.2.2 Channel Definitions, SNR, Dynamic Range

3.2.2.1 Baseline

The OCX shall collect hyperspectral data in the range 0.350 – 1.02 um.

Rationale: A large number of narrow adjacent spectral samples allows for flexibility for current and future algorithm development to distinguish algal species.

The OCX SNR shall be greater than or equal to 600:1 between 0.350 and 0.890 um, with achievable SNR reported up to 1.02 um for the “Minimum” albedo in the minimum albedo table below.

Rationale: These SNR values are needed to detect water leaving radiance properties to enable higher level product generation.

Minimum Albedo Table

Nominal Center

Wavelength (um)

Minimum Albedo

(fractional percent)

0.350 0.112

0.360 0.105

0.370 0.098

0.380 0.092

0.390 0.087

0.400 0.082

0.410 0.078

0.420 0.074

0.430 0.070

0.440 0.066

0.450 0.063

0.460 0.060

0.470 0.057

0.480 0.053

0.490 0.050

0.500 0.046

0.510 0.044

0.520 0.042

0.530 0.040

0.540 0.038

0.550 0.036

Page 13 of 44 Printed Monday, September 20, 2021

ID

OCXPORD126

Object Number

3.2.2.1.0-2

418-XO-OCXPORD-0061, RM Version, Geostationary Extended Observations (GeoXO) Ocean Color (OCX) Performance and

Operational Requirements Document (PORD)

0.560 0.035

0.570 0.033

0.580 0.032

0.590 0.031

0.600 0.029

0.610 0.028

0.620 0.026

0.630 0.025

0.640 0.024

0.650 0.023

0.660 0.023

0.665 0.023

0.670 0.022

0.675 0.022

0.680 0.022

0.685 0.021

0.690 0.021

0.700 0.021

0.710 0.020

0.720 0.020

0.730 0.020

0.740 0.019

0.750 0.019

0.760 0.019

0.770 0.018

0.780 0.018

0.790 0.017

0.800 0.017

0.810 0.017

0.820 0.017

0.830 0.016

0.840 0.016

0.850 0.016

Page 14 of 44 Printed Monday, September 20, 2021

ID

OCXPORD126

OCXPORD127

OCXPORD128

OCXPORD129

OCXPORD130

OCXPORD131

OCXPORD132

OCXPORD133

Object Number

3.2.2.1.0-2

3.2.2.1.0-3

3.2.2.2

3.2.2.2.1

3.2.2.2.1.0-1

3.2.2.2.1.0-2

3.2.2.2.2

3.2.2.2.2.0-1

418-XO-OCXPORD-0061, RM Version, Geostationary Extended Observations (GeoXO) Ocean Color (OCX) Performance and

Operational Requirements Document (PORD)

0.860 0.015

0.870 0.015

0.880 0.015

0.890 0.015

0.900 0.015

0.910 0.015

0.920 0.016

0.930 0.017

0.940 0.018

0.950 0.017

0.960 0.016

0.970 0.016

0.980 0.016

0.990 0.016

1.000 0.016

1.010 0.016

1.020 0.016

1.030 0.016

All OCX channels shall have sufficient dynamic range for measurements between 0 to Nmax, defined as 110% albedo solar spectrum, without saturation of any detector element.

Rationale: Dynamic range of Earth scene signals need to be observed without saturation.

3.2.2.2 System Spectral Response

3.2.2.2.1 Spectral Response Envelope

OCX shall collect hyperspectral data with spectral resolution of 0.010 um at 0.670 to 0.680 um, with at least 2 spectral samples (TBR) per spectral resolution element.

Rationale: Finer spectral resolution of 0.010 um in this region is driven by chlorophyll-a detection, with at least Nyquist sampling for the 0.010 um preferred.

Chlorophyll line is centered at 0.677 um and spans from about 0.665 to 0.690 um.

OCX shall collect hyperspectral data with spectral resolution of 0.020 um (TBR) at wavelengths shorter than 0.750 um, except for those described in OCXPORD130, and 0.020 um (TBR) at wavelengths 0.750 um, with at least 2 spectral samples per spectral resolution element.

Rationale: Spectral resolution of 0.020 um in these regions is driven by other features, with at least Nyquist sampling for the 0.020 um preferred. (CCR X00031)

3.2.2.2.2 Within Channel Spectral Response Uniformity

The variation in radiance measured between the 1% (TBR) as-built response points in each spectral channel due to residual spectral differences over the focal plane shall be less than the derived noise for all channels, when viewing the simulated

Page 15 of 44 Printed Monday, September 20, 2021

ID

OCXPORD133

OCXPORD134

OCXPORD135

OCXPORD136

OCXPORD137

OCXPORD138

OCXPORD139

OCXPORD140

OCXPORD141

OCXPORD142

Object Number

3.2.2.2.2.0-1

3.2.2.2.3

3.2.2.3

3.2.3

3.2.3.1

3.2.3.1.0-1

3.2.3.1.0-2

3.2.3.2

3.2.3.2.0-1

3.2.3.2.0-2

418-XO-OCXPORD-0061, RM Version, Geostationary Extended Observations (GeoXO) Ocean Color (OCX) Performance and

Operational Requirements Document (PORD) upwelling radiance data sets in supplied water leaving radiance spectrum (with the assumption that clouds have Lambertian reflectance with an albedo not less than 50%).

Rationale: Spectral artifacts in the Level 1b data should not be larger than the noise level.

3.2.2.2.3 Reserved

3.2.2.3 Reserved

3.2.3 Spatial Resolution and Sampling

3.2.3.1 System Modulation Transfer Function

The spatial resolution is defined by the sensor system sinusoidal MTF. The following MTF values (exact specification is in cycles/rad) are consistent with 0.3 kilometer resolution in all channels. The spatial frequencies, when referenced to kilometers, are measured at nadir.

The OCX MTF shall meet the requirements in the MTF Requirements Table over the coverage area, in both East/West and North/South directions, after any ground processing, in the presence of jitter, when averaged over all resampling phases of the detector sample grid to pixel grid, and after any lossy compression/ decompression.

MTF Requirements Table

All Channels

Spatial Period

(km/cyc)

Spatial Frequency

(cyc/rad)

System MTF

2.4 15000 0.90

1.2 30000 0.73

0.8 45000 0.53

0.6 60000 0.32

Rationale: MTF for OCX is scaled to be consistent with GXI.

3.2.3.2 Spatial Response Uniformity

Effects of co-registration and jitter may be ignored for the purposes of evaluating these requirements.

The normalized radiance difference due to spatial response differences between corresponding pixels in any two spectral channels located X (continuous variable) microradians from an edge of a 1000 by 1000 microradian or larger target with radiance equal to Nmax surrounded by a large region of radiance equal to or less

Page 16 of 44 Printed Monday, September 20, 2021

ID

OCXPORD142

OCXPORD143

OCXPORD144

OCXPORD145

OCXPORD146

OCXPORD147

OCXPORD148

OCXPORD149

OCXPORD150

OCXPORD151

OCXPORD152

Object Number

3.2.3.2.0-2

3.2.3.3

3.2.3.3.0-1

3.2.4

3.2.4.1

3.2.4.1.0-1

3.2.4.2

3.2.4.2.0-1

3.2.4.2.0-2

3.2.4.2.1

3.2.4.2.1.0-1

418-XO-OCXPORD-0061, RM Version, Geostationary Extended Observations (GeoXO) Ocean Color (OCX) Performance and

Operational Requirements Document (PORD) than 5% Nmax shall be less than 4% of the step function for an rms over the sampling-to-edge phasing and the channel-to-channel relative phasing. The values of X include all distances between +84 microradians and -84 microradians.

Rationale: Requirement limits signal contamination from bright scene regions into dark scene regions.

3.2.3.3 Ringing from a Sharp Edge

For both the North/South and East/West edges, the OCX shall not overshoot the top of an edge or undershoot the bottom of edge by more than 2% of the height of the edge where:

a) The height and the overshoot/undershoot are measured in radiance units.

b) The edge delineates a 10% albedo region from a 90% albedo.

c) The overshoot is averaged over all resampling phases of the detector sample grid to fixed-grid and edge position to detector sample grid.

Rationale: Requirement limits ringing response or overshoot near a sharp edge.

3.2.4 Image Navigation and Registration

3.2.4.1 Star Sensing

If autonomous star sensing is required to meet navigation requirements, the OCX shall have an on-board star catalog provided by the OCX vendor, which is loadable and modifiable from the ground and covers a span of two weeks.

Rationale: If employed, star sensing will require a star catalog and not rely on operators.

3.2.4.2 INR Performance Requirements

All INR requirements listed herein refer to location error of the fixed-grid pixels; i.e., the requirements apply to the end-to-end system, taking all instrument, spacecraft, and ground processing effects into account. Unless otherwise specified, all INR requirements in this document are specified as North/South and East/West angles, in microradians, 3-sigma, and refer to all hours of operation as defined by the operational zones.

In the context of OCX INR, 3-sigma error is defined to be equal to the 99.73rd percentile of the absolute values of all INR error observations collected over each 24-hour period from local noon to local noon. When INR requirements are temporarily suspended, due to Sun/Earth geometry or maneuver outages (including recovery time), the raw errors during the requirements suspension period should be ignored.

3.2.4.2.1 Navigation

Navigation error is the angular location knowledge error of pixels or features in a frame.

Page 17 of 44 Printed Monday, September 20, 2021

ID

OCXPORD153

OCXPORD154

OCXPORD155

OCXPORD156

OCXPORD157

OCXPORD158

OCXPORD159

OCXPORD160

OCXPORD161

OCXPORD162

OCXPORD163

OCXPORD164

OCXPORD165

OCXPORD166

OCXPORD167

OCXPORD168

Object Number

3.2.4.2.1.0-2

3.2.4.2.2

3.2.4.2.2.0-1

3.2.4.2.3

3.2.4.2.3.0-1

3.2.4.2.4

3.2.4.2.5

3.2.4.2.5.0-1

3.2.4.2.5.0-2

3.2.5

3.2.5.1

3.2.5.1.1

3.2.5.2

3.2.5.2.1

3.2.5.2.1.0-1

3.2.5.2.2

418-XO-OCXPORD-0061, RM Version, Geostationary Extended Observations (GeoXO) Ocean Color (OCX) Performance and

Operational Requirements Document (PORD)

The OCX navigation error shall not exceed max of 3.2 microradians (TBR), 3-sigma, per axis.

Rationale: This uses same Government methodolody as the PRAD.

3.2.4.2.2 Frame-to-Frame Registration

Frame-to-frame registration error shall not exceed a max of 2.7 microradians (TBR), 3-sigma, per axis. Frame-to-frame registration error is the difference in navigation error for any given pixel in two consecutive frames within the same channel.

Rationale: This uses same Government methodolody as the PRAD

3.2.4.2.3 Within Frame Registration

Within a frame in the same channel, any two pixels shall be separated by the known fixed distance to within a max of 3.2 microradians (TBR), 3-sigma, measured radially.

Rationale: This uses same Government methodolody as the PRAD

3.2.4.2.4 Reserved

3.2.4.2.5 Channel-to-Channel Registration

Channel-to-channel registration error, or co-registration, is the difference in navigation errors between spectral channels for any given pixel in the same frame.

Co-registration errors between any two spectral channels shall not exceed 1.7 (TBR) microradians, on a 3-sigma, per axis basis.

Rationale: This uses same Government methodolody as the PRAD

3.2.5 Radiometric Accuracy and Precision

3.2.5.1 REMOVED

3.2.5.1.1 REMOVED

3.2.5.2 Repeatability

3.2.5.2.1 Pixel-to-Pixel

For all channels, while viewing a stable, uniform calibration source over expected geostationary environmental conditions and calibration frequency, the OCX shall have a pixel-to-pixel repeatability less than the derived NEDN. Channels will be characterized as if viewing a 100% albedo calibration source.

Rationale: Pixel-to-pixel repeatability should be less than the required noise level to not interefere with scene data collection.

3.2.5.2.2 Removed

Page 18 of 44 Printed Monday, September 20, 2021

ID

OCXPORD169

OCXPORD170

OCXPORD171

OCXPORD172

OCXPORD173

OCXPORD174

OCXPORD175

OCXPORD176

Object Number

3.2.5.2.3

3.2.5.2.4

3.2.5.2.5

3.2.5.3

3.2.5.3.0-1

3.2.5.4

3.2.5.4.0-1

3.2.5.4.0-2

418-XO-OCXPORD-0061, RM Version, Geostationary Extended Observations (GeoXO) Ocean Color (OCX) Performance and

Operational Requirements Document (PORD)

3.2.5.2.3 Removed

3.2.5.2.4 Removed

3.2.5.2.5 Removed

3.2.5.3 Coherent Noise

For all channels, while viewing a stable, uniform calibration source over expected geostationary environmental conditions and calibration frequency, the OCX shall have no spatial coherent noise spectral component exceedances. The spatial coherent noise is defined as the variation in the 2-D Fourier transform of the pixel output of a square region of 0.042 radian by 0.042 radian following all calibration, sampling and detrending. An exceedance is defined as any spatial frequency whose scaled Fourier coefficients are greater than 25 percent of the derived NEdN. The scaled Fourier coefficients are defined using the following equations to scale the amplitude to match the amplitude of a single harmonic.

N j kj NljxlkX

)1)(1( 1 ),(),(

Ni

N e /2

M j kj MjlXklX

)1)(1( 12 ),(),(

Mi

M e /2

NM

X X a where x(j,l) are the radiances, N and M are the image size in pixels and Xa are the scaled Fourier coefficients. Detrending allows the removal of scene trends by subtracting the filtered scene using a square box car filter that is 10% of the minimum scene dimension. Edge effects of detrending may be reduced by using a symmetric boundary condition.

Note: The width of bin is defined by the fixed grid spacing. Channels will be characterized as if viewing a 100% albedo calibration source.

Rationale: Coherent noise in a Level 1b product should be less than the one fourth of the noise level to avoid interference.

3.2.5.4 Calibration of Channels

The OCX shall have an on-board optical path calibration capability.

Rationale: An on-board calibration capability of high quality improves near real time calibration accuracy compared to that of vicarious calibration. Additionally, vicarious calibration will also be used.

The OCX shall have a calibration capability for all channels that provides accuracy with traceability to NIST of +/- 1.0% (TBR) or less in the earth albedo measurements for scenes from 3% (TBR) albedo through 100% (TBR) albedo.

Rationale: Traceability to NIST (as documented in the SOW) provides improved

Page 19 of 44 Printed Monday, September 20, 2021

ID

OCXPORD176

OCXPORD177

OCXPORD178

OCXPORD179

OCXPORD180

OCXPORD181

OCXPORD182

OCXPORD183

OCXPORD184

OCXPORD185

OCXPORD186

Object Number

3.2.5.4.0-2

3.2.5.4.0-3

3.2.5.4.0-4

3.2.5.5

3.2.5.5.0-1

3.2.5.5.0-2

3.2.5.6

3.2.5.6.1

3.2.5.6.1.0-1

3.2.5.6.2

3.2.5.6.2.0-1

418-XO-OCXPORD-0061, RM Version, Geostationary Extended Observations (GeoXO) Ocean Color (OCX) Performance and

Operational Requirements Document (PORD) absolute accuracy for near real time calibration. Calibration of water leaving radiance necessitates calibration accuracy that remains linear down to low albedo levels. Tight absolute accuracy improves the quality of ocean color science as the ocean color signal is a small fraction of the total top of atmosphere scene.

The OCX shall have a calibration capability for all channels that provides drift in calibrated radiances of no more than 0.5% (TBR) over the OCX lifetime.

Rationale: Instrument degradation over the lifetime, if not corrected in processing, may be misunderstood and changing geophysical parameters over time.

Degradation of the instrument and correction method(s) need to be understood and reported to the Government for use in near real time through the instrument vendor calibration algorithms (updating calibration coefficients)

The OCX shall have a calibration capability for all channels that provides RMS repeatability of 0.2% or less. This requirement is met when no fewer than N independent calibrations are performed as closely as possible together in time and the RMS variation in each calibration coefficient is less than the specified level. N is the number of calibrations required to state at the 90% confidence level that the requirement has been met.

Rationale: Short term RMS repeatability of this level ensures high quality relative accuracy calibration.

3.2.5.5 Spatial Uniformity of Data

The OCX shall have less than 0.3% (TBR) change in response in the calibrated pixel data over the field of regard while viewing a stable, uniform calibration source over expected geostationary environmental conditions and calibration frequency.

Channels will be characterized as if viewing a 100% albedo calibration source.

Rationale: Calibrated data needs to spatial uniform so that variations in the data are not misinterpreted to be real signal variations.

3.2.5.6 Crosstalk

3.2.5.6.1 Channel-to-Channel

The OCX channel-to-channel (electrical, optical, spatial, spectral) crosstalk shall be less than the derived NEDN. Channel-to-channel crosstalk is defined as the change in any channel output when one channel's illumination is changed from 0.1 Nmax to a radiance of Nmax while all other channels remain illuminated at a radiance level less than 0.1 Nmax.

Rationale: Crosstalk between any spectral channels needs to be less than the noise level to minimize spectral artifacts in the data that may be misunderstood to be real features in the data.

3.2.5.6.2 Within Channel

Non-adjacent pixel to pixel within channel cross talk, not including diffraction, shall be less than the derived NEDN. Within channel crosstalk is defined as the change in any non-adjacent pixel when one pixel’s radiance is changed from 0.1 Nmax to a

Page 20 of 44 Printed Monday, September 20, 2021

ID

OCXPORD186

OCXPORD187

OCXPORD188

OCXPORD189

OCXPORD190

OCXPORD191

OCXPORD192

OCXPORD193

OCXPORD194

OCXPORD195

OCXPORD196

OCXPORD197

OCXPORD198

Object Number

3.2.5.6.2.0-1

3.2.5.7

3.2.5.7.0-1

3.2.5.8

3.2.5.8.0-1

3.2.5.9

3.2.5.10

3.2.5.10.1

3.2.5.10.1.0-1

3.2.6

3.2.6.0-1

3.2.7

3.2.7.0-1

418-XO-OCXPORD-0061, RM Version, Geostationary Extended Observations (GeoXO) Ocean Color (OCX) Performance and

Operational Requirements Document (PORD) radiance of Nmax while all other pixels in the same band remain illuminated at a radiance level less than 0.1 Nmax.

Rationale: Crosstalk within a spectral channel needs to be less than the noise level to minimize artifacts in the data that may be misunderstood to be real features in the data.

3.2.5.7 Blooming

In all directions from the edge of a 500 by 500 microradian bright target at twice Nmax, all detector outputs in all channels shall recover to normal operation within 24 microradians (TBR).

Rationale: Specular solar glint regions are limited to within this spatial distance from the solar sub-point.

3.2.5.8 Quantization Step Size

The quantizing step size for all detector samples shall be less than half the derived

NEDN.

Rationale: Signal quantization by the analog to digital converter should not be the driver in the noise budget in order to avoid having discrete jumps in signal level that can lead to digital artifacts (blocky) data.

3.2.5.9 Reserved

3.2.5.10 Polarization

3.2.5.10.1 Polarization Control

Channels shall have less than 4% polarization sensitivity to the incoming light at all Earth-viewing angles.

Rationale: Polarization sensitivity should be small to limit signal variations with angle.