CHRIS (Compact High Resolution Imaging Spectrometer) sira group sira electro-optics Dr Mike Cutter EO & Technology Business Manager

sira group sira electro-optics CHRIS/PROBA – low cost mission CHRIS  Design concept- programmable hyperspectral  Spectral range - VNIR  Spatial sampling - 17 perigee PROBA Platform  Small satellite (100kg) – launched October 2001  Agile 3-axis stabilised platform - roll, pitch & yaw  Provides multi-angle observations & motion compensation Mission Objectives  Obtain selected land and littoral images  Obtain multi-view angle measurements (aerosols, BRDF)  Evaluate in-orbit performance - precursor mission

sira group sira electro-optics Scene Radiance Information The radiance field is at least 7 dimensional  (  v,  s, ,, x, y, t ) Angular (BRDF) Spatial Information Temporal Information Spectral Information

sira group sira electro-optics MVA Data from CHRIS/PROBA PROBA:  Along-track: five angles per overpass: 0°  36 ,  55 ground MVA = Multi-View Angle

sira group sira electro-optics Day n+y MVA data from CHRIS/PROBA Day n+x Day n By rolling the satellite ± 25º in the across-track direction it is possible to image a fixed point on the Earth surface at different sensor view angles. MVA = Multi-View Angle

sira group sira electro-optics Information from MVA Image Left: Nadir-view, multispectral composite (0.5µm, 0.65 µm and 0.85 µm) showing wheat (red), bare soil (blue) and oil seed rape (white). Right: Multi-angle composites (nadir + two oblique angles) at recorded 0.5 µm, 0.65 µm and 0.85 µm, respectively.

sira group sira electro-optics Instrument Design

sira group sira electro-optics CHRIS

sira group sira electro-optics Specification Image area13 km perigee Spatial sampling interval17 perigee Spectral range (nominal)415nm to 1050nm Spectral resolution1.25 to 11nm Spectral/Spatial registration+/ pixel Gain stage4 levels (albedo 0.5,1,2,4 levels) Digitisation 12 bits Signal-to-noise ratio albedo, 17m, 10nm) Data per (13x13 km 2 ) image 16.4Mbytes Mass/power< 14 kg/ 10 W primary power Volume790 x 260 x 200 mm 3

sira group sira electro-optics GSD/band number options

sira group sira electro-optics Platform Aspects

sira group sira electro-optics Platform Aspects Platform - ESA PROBA (Verhaert, Belgium) l Orbit km, sun-synch. (10.30am node) l Inclination97.97º, l Repeat period11 days l Dimensions800mm x 600mm x 600mm l Power/mass< 100 W/100 kg Pointing l Along-track 0 º, +/- 36º, +/-55º ground) l Across-track +/-25º ground) l Absolute pitch/roll/yaw< +/- 0.1º l Control of pitch/roll/yaw < +/ º/s (11% of imaging pitch rate) l Maximum pitch rate0.7º/s Down-link S-band: 1 Mbit/s (5 images/day) Ground StationRedu, Belgium

sira group sira electro-optics Observation Plan

sira group sira electro-optics Observation Programme Programme defined by CHRIS Steering Group (UK, ESA) AO issued by ESA in 2000 for first year mission. Observations  21 Core sites, 31 additional sites, 12 reserve sites  Approx. 60 PIs world wide Observation modes (5 off) excluding calibration  Mode 1: Low resolution – aerosols, 62 bands  Mode 2: High resolution – water, 18 bands  Mode 3: High resolution – land, 18 bands  Mode 4: High resolution – chlorophyll, 18 bands  Mode 5: Half swath/high resolution – land, 37 bands Observation logistics  Apply 48 hour cloud predictions to aid target selection Details:

sira group sira electro-optics Location of CHRIS Test Sites

sira group sira electro-optics Sample Images

sira group sira electro-optics Antwerpen

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sira group sira electro-optics Satellite Pitch Rates Spectral

sira group sira electro-optics New York

sira group sira electro-optics Current Status Platform Commissioning  Platform undergoing fine tuning wrt pointing  Platform processor intermittent issue being investigated  Reviewing options for improving operational approach Instrument Commissioning  Instrument performance assessment on-going  Data processing being validated for each imaging mode  Wavelength calibration (O 2 line) results being evaluated Downlink  Platform commanding approach being refined.  Reviewing options for utilising a Kiruna (polar) downlink. Data sets  Plan to issue sample data sets to PIs in August 2002

sira group sira electro-optics Acknowledgements  BNSC for partial funding of CHRIS  ESA for the launch opportunity, support for calibration activities, data processing, the planning tool and website.  Redu, ESOC (Belgium) for operational support  Verhaert (Belgium) for platform support  RSAC (UK) for preparation of the planning tool & jointly with ESSC the CHRIS website.  UK PIs: Prof. Mike Barnsley (BRDF), Swansea University Dr Jeff Settle (Aerosols), ESSC, Reading University Dr Samantha Lavender (Coastal), Plymouth University

sira group sira electro-optics The End