PROBA V Multispectral Imager: Status

Transcription

1 PROBA V Multispectral Imager: Status A. Zuccaro Marchi, M. Taccola, J. Versluys, D. Beguin, Y. Stockman, M. François, R. Kassel, I. Torralba Elipe ICSO Ajaccio, Corse, France 09/10/2012

2 Content 1. Overview and Mission Objectives 2. The Vegetation Instrument 3. The Spectral Imager 4. Calibration-Verification activities 5. Spectral Calibrations 6. Geometrical Calibrations 7. Radiometric Calibrations 8. Stray-Light characterizations 9. Proba V Status summary 10.Acknowledgements ESA Presentation Alessandro Zuccaro Marchi ICSO Ajaccio, France 09/10/2012 TEC Slide 2

3 1: Project Set-up PROBA V: project performed under ESA GSTP Programme, with support from the Belgian Space Policy Office. Mass: 160Kg Volume: 765 x 730 x 840mm 3 Power consumption: 78W ave 140W peak 3-axis stabilized ESA Presentation Alessandro Zuccaro Marchi ICSO Ajaccio, France 09/10/2012 TEC Slide 3

4 1: Mission Objectives and Overview 1. Primary Mission Objectives a. Continuation of Vegetation Products Generation (SPOT 4 and 5) Daily Coverage of the Earth Latitudes between 35 and 75 North + Latitudes between 35 and 56 South Two-days Coverage of the Earth b. Spatial Resolution Latitudes between 35 North and 35 South GSD 1 km in VNIR and SWIR Design goal: 300m GSD in VNIR + 600m GSD in SWIR c. Operations shall start in 2013 to obtain an overlap with SPOT/VGT d. Mission Lifetime of 2.5 years, with extension up to 5 years 2. Secondary Mission Objective a. PROBA-V shall carry at least 2 Technology Demonstration Payloads ESA Presentation Alessandro Zuccaro Marchi ICSO Ajaccio, France 09/10/2012 TEC Slide 4

5 1: Orbit Selection Orbit selection is based on SPOT Vegetation mission 1.Driving requirements a. Global coverage requirements b. Minimum swath width of 2250 km c. LTDN between 10:30 and 11:30 2.Resulting orbital parameters a. Altitude: 820 km ± 10 km b. Eccentricity: 0 c. Inclination: SSO ESA Presentation Alessandro Zuccaro Marchi ICSO Ajaccio, France 09/10/2012 TEC Slide 5

6 1: Ground Sampling Distance ESA Presentation Alessandro Zuccaro Marchi ICSO Ajaccio, France 09/10/2012 TEC Slide 6

7 2: Vegetation Instrument VI Characteristics: 4 spectral bands: Blue, Red, NIR, SWIR Field of View = Established with 3 Spectral Imagers (SI), each with FoV = 34.6 Star Trackers mounted on the optical bench to minimise thermo-elastic deformations Earth-facing radiator Total instrument mass: 35 Kg. ESA Presentation Alessandro Zuccaro Marchi ICSO Ajaccio, France 09/10/2012 TEC Slide 7

8 3: Spectral Imager Based on Three Mirror Anastigmat design Parameter Focal Length Maximum Aperture Value 110 mm 18.5 mm M1 f/# 7 FOV Length Width Height Spectral bands Detectors ESA Presentation Alessandro Zuccaro Marchi ICSO Ajaccio, France 09/10/2012 TEC Slide x 10.8 mm x 5.5 VNIR 90 mm 110 mm 140 mm VNIR: µm (Blue) µm (Red) µm (NIR) SWIR: µm VNIR: 3 x 5200 pixels, 13 µm (E2V)- Quadric-linear TH1547 SWIR: 3 x 1024 pixels, 25 µm (Xenics)-mechanical butting (130 to 160 pixels overlap) M2 SWIR 25mm M3

9 3: SI: The TMA and FPA TMA telescope: two aspheric mirrors and one spherical Focal Plane Assembly: SWIR band and VNIR bands (spectral separation thru spectral windows) Mirrors produced through diamond turning process (~4 nm roughness) All made Aluminium 6061-T6 ESA Presentation Alessandro Zuccaro Marchi ICSO Ajaccio, France 09/10/2012 TEC Slide 9 The FPA

10 3: SI: VNIR and SWIR Detectors VNIR SWIR ESA Presentation Alessandro Zuccaro Marchi ICSO Ajaccio, France 09/10/2012 TEC Slide 10

11 3: SI: integration and baffling ESA Presentation Alessandro Zuccaro Marchi ICSO Ajaccio, France 09/10/2012 TEC Slide 11

12 4: Flowchart of Calibration-Verification activities At OIP facilities: Clean Room, class 100 Ambient temperature and pressure -Calibration of the SIs. At CSL facilities: FOCAL 3 vacuum chamber, in cleanroom class ambient and vacuum, and for three T -Verification of the VI. ESA Presentation Alessandro Zuccaro Marchi ICSO Ajaccio, France 09/10/2012 TEC Slide 12

13 5: Spectral Calibrations of SI: set-up Test Equipment: Set up for spectral measurements Monochromator EGSE The 4 SIs (3 +1 spare) Monochromator, with collimator, mounted on translation stage Test procedure: Each waveband is scanned with a suitably decided scan step (1, 2 or 5nm). SI on alignment table, mounted on the hexapod Rotation point ESA Presentation Alessandro Zuccaro Marchi ICSO Ajaccio, France 09/10/2012 TEC Slide 13

14 5: Spectral Calibration: measurements Spectral response in line with simulations, not always within requirements (green and red lines). Peak-to-peak VNIR bands in line with VGT-1,-2. Spectral mis-registration < 1nm (requirement) in Blue and Red for all SIs. Assessment on large variety of vegetation spectral responses done and corresponding effect NedR no impact on Science. ESA Presentation Alessandro Zuccaro Marchi ICSO Ajaccio, France 09/10/2012 TEC Slide 14

15 6: Geometrical Calibrations: set-up Test equipment: VI OBP mounted on the dummy PLP Star Tracker Baffles & Baffle holder Reference Cubes (RC) Collimator with movable slits Theodolites VNIR and SWIR ROE (EM or FM) Test procedure: MTF & IFOV: scan over few pixels in 5 FoVs (VNIR) and 9 FoVs (SWIR) LOS: measurements wrt RC SI inter-alignment: with theodolites Collimator with movable slit assembly MTF & IFOV: 0.1 pixel width slit in centre of collimator ESA Presentation Alessandro Zuccaro Marchi ICSO Ajaccio, France 09/10/2012 TEC Slide 15

16 6: Geometrical Calibrations of SI and VI 1. Across-track MTF for SIs Results: Centre FoV (goal) Edge FoV (goal)» Blue: 90% (81%) 42% (29%)» Red: 88% (78%) 36% (26%)» NIR: 83 % (72%) 25% (18%)» SWIR: 82 % (79%) 32% (26%) Results are better or comparable to VGT 2. MTF at VI level: in process. 3. FOV and IFOV at SI level: IFOV meets requirements. It is max around 0, minimum at edges. FOV across is max 34.7 for VNIR an 34.5 for SWIR; FOV along is < LOS at SI level: calculated, in Elevation & Azimuth. 5. LOS at VI level (LOS of the 3 SI wrt star tracker cubs): in process. 6. Distortion at VI level: in process. ESA Presentation Alessandro Zuccaro Marchi ICSO Ajaccio, France 09/10/2012 TEC Slide 16

17 7: Radiometric Model ESA Presentation Alessandro Zuccaro Marchi ICSO Ajaccio, France 09/10/2012 TEC Slide 17

18 7: Radiometric Calibrations Test procedure for SI: Linearity, Radiometric Resolution: Light measurements vs. IT. SNR: Light measurements vs. FOV. VI, mounted on test set up ST Master RC orientation Intergrating sphere, with stabilized, calibrated light source 3 fields/spectral band/si Fixed radiance level (L2) Test procedure for VI: Dark/light measurements for variation of gain, IT, field, T (25C, -10C, -25C). Outputs: dark noise, Flat field, model s parameters, SNR, Linearity. ESA Presentation Alessandro Zuccaro Marchi ICSO Ajaccio, France 09/10/2012 TEC Slide 18 Rotation point Radiometric Calibrations of VI are foreseen in the next two weeks. Spectral Band Blue 39 Red 10 NIR 4 Spectral Radiance (ToA, W/m2.sr.µm) L1 L2 L3 L NEdR (W/m2.sr.µ m) L2 (reference) SWIR

19 ESA Presentation Alessandro Zuccaro Marchi ICSO Ajaccio, France 09/10/2012 TEC Slide 19

20 ESA Presentation Alessandro Zuccaro Marchi ICSO Ajaccio, France 09/10/2012 TEC Slide 20

21 ESA Presentation Alessandro Zuccaro Marchi ICSO Ajaccio, France 09/10/2012 TEC Slide 21

22 ESA Presentation Alessandro Zuccaro Marchi ICSO Ajaccio, France 09/10/2012 TEC Slide 22

23 8: Stray-light modelling at ESTEC Analytical model considering main contributors to degradation of image quality: Scattering from mirrors due to surface roughness Surface roughness BRDF obtained after data from mirror samples. Scattering from mirrors due to particles contamination Scattering due to aperture stop around M2 (for SWIR) ghost images. Total PSF built from these data The CSL Facility will manage to measure: a. In-field stray-light with 10-8 at ±10px from illuminated pixel b. Out-of-field stray-light with sensitivity up to Measure of Stray Light: a. 9 Fields between 0º and 30º across; 4 fields between 0º and 8º along track ESA Presentation Alessandro Zuccaro Marchi ICSO Ajaccio, France 09/10/2012 TEC Slide 23 b. Blue, Red, VNIR, SWIR lines

24 8: Stray Light measurements at ESTEC BRDF measurements done at ESA in the TEC-MMO Optics Lab. BRDF setup: Complete Angle Scatter Instrument (CASI): = 633nm Angles of Incidence: 5 and 45 Two spatial spot locations on sample Two sample orientations (vert. & hor.) Spot size approx. 2-4mm M3 M1 M2 Clean room class ESA Presentation Alessandro Zuccaro Marchi ICSO Ajaccio, France 09/10/2012 TEC Slide 24

25 8: Stray-Light Simulations The straylight forward model describes how a 2-D flux distribution at the instrument entrance that cover the entire instantaneous FOV (34.6 x 5.5 ) is turned into a 2-D flux distribution in the focal plane (and not just on the detector line) TMA instantaneous FOV Detector line in focal plane Straylight correction model under development in ESA. ESA Presentation Alessandro Zuccaro Marchi ICSO Ajaccio, France 09/10/2012 TEC Slide 25 Decision to use it will be taken after analysis of on-ground calibration results.

26 9: Proba V Status summary 1. The mission design fulfils the ESA objectives. 2. PROBA-V will ensure the continuation of the SPOT/Vegetation image data towards the Vegetation Users Community. 3. Status of the Calibration Campaign: a. At SI level: spectral, geometrical, radiometric. Done. b. At VI level: geometrical, radiometric. To be completed soon. c. At VI level: Stray-light calibrations. Foreseen in 1 month. d. Commissioning plan. 4. Short term activities: a. Acceptance of the Vegetation Instrument (October 2012) b. System validation finalisation (November 2012) c. System environmental test campaign (Dec Jan 2013) 5. Launch campaign for VEGA VERTA-1: Mid March 2013 ESA Presentation Alessandro Zuccaro Marchi ICSO Ajaccio, France 09/10/2012 TEC Slide 26

27 Acknowledgements The authors wish to acknowledge the efforts of all the people involved, now and in the past, to the development of PROBA V mission, within ESA as well as from all the companies that actively participated to this challenging technological mission. THANK YOU ESA Presentation Alessandro Zuccaro Marchi ICSO Ajaccio, France 09/10/2012 TEC Slide 27

28 BACKUPS ESA Presentation Alessandro Zuccaro Marchi ICSO Ajaccio, France 09/10/2012 TEC Slide 28

29 Platform Design Subsystem overview Mixed Honeycomb structure Alu/CFRP Passive thermal control (except Battery) Three body mounted solar panels with triplejunction GaAs cells Single box miniature avionics (ADPMS): LEON-2 based Data handling system Unregulated power bus V 16 Gbits of mass memory needed 128 Gbits flash implemented 12 Ah Lithium-Ion battery S-band communication system (1 Mbit/s downlink, 64 kbit/s uplink) X-band communication system (35 Mbits/s downlink) 3-axis stabilised ACNS 4 reaction wheels 3 redundant magnetotorquers 2 three-axis magnetometers 2 Star Trackers with 2 optical heads 2 GPS receivers ESA Presentation Alessandro Zuccaro Marchi ICSO Ajaccio, France 09/10/2012 TEC Slide 29

30 Technology Demonstration Payloads Implemented Technology Demonstration Payloads a. Experimental X-band transmitter ESA Presentation Alessandro Zuccaro Marchi ICSO Ajaccio, France 09/10/2012 TEC Slide 30 Based on GaN technology Providing additional redundancy in science data downlink chain b. Energetic Particle Telescope (EPT) Innovative science class radiation spectrometer Demonstration of sensor technology and on-board treatment of data c. Automatic Dependent Surveillance Broadcast (ADS-B) Air traffic surveillance system Validation of space-based monitoring system d. SATRAM TIMEPIX based radiation monitor, complementing EPT