Stennis Space Center NASA Scientific Data Purchase IKONOS

Stennis Space Center NASA Scientific Data Purchase IKONOS V&V Overview Mary Pagnutti 1 IKONOS V&V

NASA Scientific Data Purchase (SDP) Stennis Space Center • • Began with $50 Million appropriation for NASA purchase of scientific data sets for commercial sources Goal: Test new way of doing business; tap new sources of data Managed by NASA Commercial Remote Sensing Program, Stennis Space Center, MS Phased Approach – Phase I - simulated / prototypical data sets received and reviewed – Phase II - selection of products and data purchase over 3 years • Firm fixed price contracts - cash on delivery of data 2 IKONOS V&V

IKONOS SDP V&V Philosophy Stennis Space Center • Perspective: SDP is an experiment – Can the commercial sector provide useful, cost effective data to the science community? – Only one satellite (no backup), buy data while we can • Assumptions – – Space Imaging will attempt to provide high quality data NASA Stennis will trust but verify Releasing data in a timely fashion is important Feedback from users is important • Competition is developing – Earth Watch, Orbital, Russian Spin Data, West Indian Aerospace – Methodologies developed will be used again. 3 IKONOS V&V

IKONOS V&V Activities Stennis Space Center Shipment Verification (All acquired data sets) • • • Data Format Meta File Location / Coverage Cloud Cover General Statistics – mean – standard deviation – pixel histogram – fraction of saturated pixels • Auto Report generation • Thumbnail generation • Band-to-band registration • MODTRAN / radiance intercomparison • NIIRS evaluation when appropriate Performance Product V&V Product Characterization (Sample V&V data sets) Applications Utility (Sample V&V data sets) • Image Quality – Spatial – SNR • Geometric Accuracy – Positional Accuracy – DEM evaluation • Radiometric Performance – Spectral Characterization • University of Maryland assessment • Obtain feedback from ESE Researchers 4 IKONOS V&V

Joint Agency Commercial Imagery Evaluation (JACIE) Team Formed Stennis Space Center • Joint NASA / NIMA / USGS team focused on characterizing commercial remote sensing system performances • Overall performance assessment to meet each agency’s mission requirements – NASA - System Characterization – NIMA- Photogrammetry – USGS - Cartographic Assessment • Improved communications with industry – More productive interchanges between industry and government – Minimize duplication of effort – Reduction in costs incurred by industry and government IKONOS one meter panchromatic image of Jefferson Memorial in Washington, D. C. 5 IKONOS V&V

SDP IKONOS Characterization Team Stennis Space Center JACIE TEAM EOS Validation Teams U of Maryland U of Arizona S. Dakota State U SCIENCE USERS 6 IKONOS V&V

IKONOS Validation Sites Stennis Space Center Stillman Creek SDSU USGS-EDC Lake Tahoe Railroad Valley Morrison Quad. Konza Prairie Lunar Lake Beltsville Kaintuck Hollow Quad Ivanpah Sevilleta U of A WSMR Maricopa Big Springs SSC 7 IKONOS V&V

IKONOS Validation Sites Overview Stennis Space Center 8 IKONOS V&V

NASA Stennis Space Center, Mississippi Stennis Space Center Site: Scattered buildings within heavily wooded area, man-made reservoirs and canal. Elevation 5. 5 m - 10 m. 30. 388 degrees N, 89. 61 degrees W Purpose: Spatial, geometric and radiometric characterization, BRDF evaluation. Targets: • 2 orthogonal concrete edge targets (70 x 80 m oriented E-W, 80 x 80 m oriented N-S) 130 m concrete radial target (96. 4 deg arc, 0. 08 -5. 0 m range), 4 step concrete grayscale target (35 x 40 m each) • over 40 known GPS markers known to within 2 cm • 4 step gray tarps (20 mx 20 m each) IKONOS Image Area Concrete edge, radial and 4 step grayscale targets In-Situ Instrumentation: Cimel Sunphotometer, Shadowband Radiometer, ASD and GER Spectroradiometers, SSC Weather Station, Radiosonde balloon launch, Pyronometer, Goniometer. Radiometric Tarp Coupons Coincident Collects: IKONOS V&V Landsat 7 ATLAS image and showing known GPS points at SSC 9

Image Quality Characterization Stennis Space Center 10 IKONOS V&V

Big Springs, TX Edge Target Stennis Space Center • Three 15 m x 15 m squares • Northing and easting edges allow MTF analyses in two directions • Edges are aligned approx 8 deg off true north and true east IKONOS Panchromatic Band 11 IKONOS V&V

Image Quality Characterization, cont’d. Stennis Space Center 12 IKONOS V&V

Uniform Sites Selection for SNR Stennis Space Center • Utilize NASA Scientific Data Purchase Earth. Sat Databuy African Map with Sites – TM data for Africa – 30 meter GSD data – Develop algorithms to find most uniform scenes for Radiometry & SNR estimates Libya TM Scene Tight Gaussian Histogram Indicate Uniform Scenes IKONOS V&V 13

Geometric Accuracy Characterization Stennis Space Center * 90% circular error 14 IKONOS V&V

Geometric Accuracy Assessment Stennis Space Center • USGS EROS Data Center – Brookings, South Dakota (SDSU) – Sioux Falls, South Dakota (EDC) – Each site surveyed 50+ points throughout 11 x 11 km scene • USGS – Morrison Quad – Kaintuck Hollow Quad – Utilize USGS database for both sites • NASA CRSP – Stennis Space Center – Utilize site survey & Geodetic Targets Brookings South Dakota Fast Static Survey Checked to less than five cm. horizontal using two Trimble 4000 ssi units over B Order monuments. IKONOS V&V 15

Radiometric Performance Characterization Stennis Space Center 16 IKONOS V&V

Radiometric Performance Characterization, cont’d. Stennis Space Center 17 IKONOS V&V

Radiometric Performance Characterization, contd. Stennis Space Center 18 IKONOS V&V

Radiometric Vicarious Calibration Approaches Stennis Space Center • Reflectance Method – Measurement of ground reflectance and atmospheric properties allows prediction of Top-of-the-Atmosphere (TOA) radiance estimates – Typically require ground teams and a great deal of coordination • Radiance Method – Coincident collect with well characterized airborne or satellite system 19 IKONOS V&V

Reflectance Method Stennis Space Center Commercial Satellite Radiosonde Balloon Spectroradiometer Sun Photometer Method: Utilize ground reflectance measurements (Spectroradiometer) and atmospheric measurements (Sun Photometer & Radiosonde) to determine 20 radiometric accuracy of new commercial satellite systems (IKONOS) IKONOS V&V

Radiance Method Stennis Space Center Commercial Satellite Well Characterized System (Aircraft or Satellite) Method: Utilize coincident airborne or spaceborne calibrated imagery (e. g. Landsat 7) to determine radiometric accuracy of new commercial satellite systems (IKONOS) IKONOS V&V 21

IKONOS Characterization Status Stennis Space Center • Spatial Characterization – – – • Geometric Characterization – – • Three acquisitions have been made (received std original imagery only) Four SI archive images have been acquired Two acquisitions are pending collection Awaiting two precision original images All but one image has been evaluated Three acquisitions have been made (received std original imagery only) Two acquisitions are pending collection (same as above) Two DEM acquisitions scheduled for spring 2001 Two have been evaluated Radiometric Characterization – Six acquisitions have been made and evaluated (received std original imagery only) – Two acquisitions are pending collection (same as above) 22 IKONOS V&V

IKONOS Characterization Summary Stennis Space Center Preliminary Findings: • Geometric Characterizations show imagery is well within specification • Spatial Characterizations indicate imagery meets MTF and SNR specifications • Radiometric Characterizations indicate potential concerns with the red and NIR bands • No serious issues associated with on-board compression have been found 23 IKONOS V&V

Stennis Space Center Backup 24 IKONOS V&V

IKONOS Sensor Facts from SI Web Site Stennis Space Center 25 IKONOS V&V

IKONOS Sensor Facts from SI Web Site, cont’d. Stennis Space Center 26 IKONOS V&V

IKONOS Sensor Facts from SI Web Site, cont’d. Stennis Space Center 27 IKONOS V&V

IKONOS Sensor Facts from SI Web Site, cont’d. Stennis Space Center 28 IKONOS V&V

Stennis Target Stennis Space Center Positive Systems Image Expanded View of Target Edge. Target: 70 x 80 meters and 70 x 70 meters 8: 1 contrast ratio 29 IKONOS V&V

Edge Response Stennis Space Center Focal plane array undersamples edge with classical cross section sampling Solution: Sample tilted edge to improve sampling Foot Print 30 IKONOS V&V

Edge Response Relationship to Line Spread Function Stennis Space Center 31 IKONOS V&V

Modulation Transfer Function Stennis Space Center • MTF is a measure of an imaging system’s ability to recreate the spatial frequency content of scene MTF is the magnitude of the Fourier Transform of the Point Spread Function / Line Spread Function. 1. 0 MTF Cut-off Spatial frequency 32 IKONOS V&V

SNR Estimate Example Results Stennis Space Center Histograms of Mean/Std of 5 x 5 Pixel Blocks TM data IKONOS V&V Location of Histogram Peak is a measure of the SNR 33

GPS Accuracies Stennis Space Center • Trimble Pathfinder or Geo Explorer – – Raw - 10 meters Coarse mode corrected - 5 meters per measurement reading Coarse mode corrected - averaging data 2 meter Fine mode corrected - averaging 10 minutes of differentially corrected data gives sub-meter Pathfinder Geo Explorer IKONOS V&V 34

Radiometric Error Associated with Finite Size Tarp Stennis Space Center Finite Size of Tarp will limit Radiometric Accuracy Simulated 20 m Tarp Image with 4 m GSD with MTF @ Nyquist of 0. 1 Insert Measured Reflectances Figures Cross Sectional Plot of Response For typical background/tarp reflectances, the error at the center pixels will be less than a few percent 35 IKONOS V&V

CRSP Tarp Sample Data Stennis Space Center Tarp Sample Data Reflectance Data Tarp Samples are Spectrally Flat Over Region of Interest 36 IKONOS V&V

GPS Accuracies Stennis Space Center • Trimble 4000 ssi Survey grade GPS units – Static survey- 5 mm + 1 ppm in base line distance. – Fast Static - Based on conditions and Satellite geometry – Real Time Kinematic (RTK) - less than five centimeters horizontal and vertical Brookings South Dakota Fast Static Survey Checked to less than five cm. horizontal using two Trimble 4000 ssi units over B Order monuments. IKONOS V&V 37

Radiometric Vicarious Calibration Background Stennis Space Center • Radiometric stability of remote sensing data is critical for long term studies • On-orbit calibration sources are not always stable or reliable • Methods which independently verify the radiometric calibration of remote sensing data are essential • Vicarious calibrations use natural well characterized scenes 38 IKONOS V&V

CRSP Radiometric Tarp Sample Examination Stennis Space Center <5% 20% Samples were obtained of the 4 grayscale radiometric tarps procured by CRSP. These samples were tested in the laboratory under conditions similar to those encountered in the field. These tests were performed to evaluate specified reflectivity values. 30% 4” tarp Samples 50% 39 IKONOS V&V

Desired Calibration Site Characteristics Stennis Space Center • Bright and Uniform – High reflectance minimizes atmospheric uncertainties – Uniformity allows statistically meaningful results • Stable – Long term studies are facilitated with stability • Low Precipitation and Cloud Cover – Maintains stability and increases chance of acquisition • Large – Several swath widths in extent or more to avoid adjacency effects 40 IKONOS V&V

Tarp Deployment at SSC Stennis Space Center 41 IKONOS V&V

SDP Shipment Verification Stennis Space Center • Shipment content and media count • Mission document review • Approximate geographic coverage • Comparison with original task order • File readability • General image quality • 100% visual inspection of JPEG quicklooks • Discrepancy report (As Needed) • Shipment tracking database • Shipment verification report 42 IKONOS V&V

NASA IKONOS V&V Focus IKONOS Data Product Characterization 1 m GSD PAN Quantitative System Characterizations: Stennis Space Center 4 m GSD MS • MTF and spatial resolution • SNR estimates • Geometric accuracies of imagery • Radiometric accuracies of products • Band-to-band registration of multispectral products • Intercomparison of IKONOS, Landsat 7 and other satellite imagery 43 IKONOS V&V

IKONOS Spectral Characterization Stennis Space Center 44 IKONOS V&V

IKONOS Spectral Bandpasses Stennis Space Center Provided by Space Imaging 45 IKONOS V&V

Well Characterized Site Method Stennis Space Center Calibrated Satellite Commercial Satellite Method: Utilize well characterized satellite systems (Landsat-7), not necessarily coincident, and well characterized sites (African deserts) to determine the radiometric accuracy of new commercial satellite systems (IKONOS) 46 IKONOS V&V

NASA CRSP Tarps Stennis Space Center • Portable radiometric characterization of 4 m class GSD systems and smaller • MTF characterization of 1 m class GSD systems and smaller • SNR estimation on 1 m class GSD systems • Fiducial markers for remote uniform sites 47 IKONOS V&V

CRSP Tarp Specifications Stennis Space Center • Size and Shape • – 20 m x 20 m • Reflectivity – – – • Spectral Range 400 -1000 nm Tarp 1 < 5 % Tarp 2 20 -25 % Tarp 3 30 -40 % Tarp 4 50 -55 % Spatial Uniformity Spectral Uniformity – <10% variation/100 nm band • Deployability – Less than 2 hours with 2 people in less than 3 m/s wind • Maintainability – Meet Specifications for 60 Deployments or two years which ever comes first – Standard deviation of 9 equally space reflectivity measurements <1% of absolute reflectance 48 IKONOS V&V