CHRIS IGARSS02

CHRIS (Compact High Resolution Imaging Spectrometer): 

CHRIS (Compact High Resolution Imaging Spectrometer) siragroup siraelectro-optics Dr Mike Cutter EO & Technology Business Manager

CHRIS/PROBA – low cost mission: 

CHRIS/PROBA – low cost mission CHRIS Design concept - programmable hyperspectral Spectral range - VNIR Spatial sampling - 17 m @ 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

Scene Radiance Information: 

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

MVA Data from CHRIS/PROBA: 

MVA Data from CHRIS/PROBA PROBA: Along-track: five angles per overpass: 0°, ±36°, ±55° @ ground MVA = Multi-View Angle

MVA data from CHRIS/PROBA: 

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

Information from MVA Image: 

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.

Slide7: 

Instrument Design

CHRIS: 

CHRIS

Specification: 

Specification Image area 13 km square @ perigee Spatial sampling interval 17 m @ perigee Spectral range (nominal) 415nm to 1050nm Spectral resolution 1.25 to 11nm Spectral/Spatial registration +/- 0.05 pixel Gain stage 4 levels (albedo 0.5,1,2,4 levels) Digitisation 12 bits Signal-to-noise ratio 200 (@ 0.2 albedo, 17m, 10nm) Data per (13x13 km2) image 16.4Mbytes Mass/power < 14 kg/ 10 W primary power Volume 790 x 260 x 200 mm3

GSD/band number options: 

GSD/band number options

Slide11: 

Platform Aspects

Platform Aspects: 

Platform Aspects Platform - ESA PROBA (Verhaert, Belgium) Orbit 570- 730 km, sun-synch. (10.30am node) Inclination 97.97º, Repeat period 11 days Dimensions 800mm x 600mm x 600mm Power/mass < 100 W/100 kg Pointing Along-track 0 º, +/- 36º, +/-55º (@ ground) Across-track +/-25º (@ ground) Absolute pitch/roll/yaw < +/- 0.1º Control of pitch/roll/yaw < +/- 0.015º/s (11% of imaging pitch rate) Maximum pitch rate 0.7º/s Down-link S-band: 1 Mbit/s (5 images/day) Ground Station Redu, Belgium

Slide13: 

Observation Plan

Observation Programme: 

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: WWW.PROBA-CHRIS.ORG.UK

Location of CHRIS Test Sites: 

Location of CHRIS Test Sites

Slide16: 

Sample Images

Antwerpen: 

Antwerpen

Satellite Pitch Rates: 

Satellite Pitch Rates Spectral

New York: 

New York

Current Status: 

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 (O2 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

Acknowledgements: 

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

Slide26: 

The End WWW.PROBA-CHRIS.ORG.UK