07-09 Nov. 2005 Walberberg Workshop MET image 1 This document - - PDF document

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07-09 Nov. 2005 Walberberg Workshop MET image 1 This document - - PDF document

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Dr. B. Vo MET image 07-09 Nov. 2005 Walberberg Workshop MET image 1 This document contains information proprietary to Jena-Optronik GmbH. Any disclosure, use or duplication of this document is expressly prohibited. MET image General need

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METimage

  • Dr. B. Voß

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This document contains information proprietary to Jena-Optronik GmbH. Any disclosure, use or duplication of this document is expressly prohibited.

METimage Walberberg Workshop 07-09 Nov. 2005

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SLIDE 2

METimage

  • Dr. B. Voß

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This document contains information proprietary to Jena-Optronik GmbH. Any disclosure, use or duplication of this document is expressly prohibited.

METimage

  • General need for AVHRR successor

Jena-Optronik proposed instrument concept METimage for future operational weather satellites (Polar platforms). Various instrument concepts were established in a METimage study co- financed by DLR.

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METimage

  • Dr. B. Voß

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This document contains information proprietary to Jena-Optronik GmbH. Any disclosure, use or duplication of this document is expressly prohibited.

Instrument requirements

Spectral coverage between VIS (400 nm) and Thermal IR (14 µm)

Only reflecting optical system can cover the complete bandwidth

Wide swath width (> 2300 km) to allow global coverage Spatial resolution between 250 m and 1 km High absolute radiometric accuracy

Carefully devised calibration strategy High accuracy calibration sources

Low polarisation sensitivity

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METimage

  • Dr. B. Voß

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This document contains information proprietary to Jena-Optronik GmbH. Any disclosure, use or duplication of this document is expressly prohibited.

Development approach

  • Requirements are developing
  • Trade-off between user requirements and available

budget Flexibility is the most important design driver

Flexible number of channels Flexible SNR/NEdT Flexible instrument configuration

METimage instrument family (A, B1, B2, C)

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METimage

  • Dr. B. Voß

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This document contains information proprietary to Jena-Optronik GmbH. Any disclosure, use or duplication of this document is expressly prohibited.

Spectral separation

Dichroic beam splitters

Parallel beam required: afocal telescope + relay optics Single detector for each channel Limited to ≤ 10 channels because of accommodation constraints

In-plane

Many channels in a small volume Requires focal plane design with multiple detectors Larger aperture required, but confocal telescope can be utilized Image rotation to be compensated

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METimage

  • Dr. B. Voß

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This document contains information proprietary to Jena-Optronik GmbH. Any disclosure, use or duplication of this document is expressly prohibited.

FPA design approach

Matrix detector based FPA

Fast random access ROICs Telescope design independent from number of channels TDI flexible SNR

Baseplate Detector matrix Spectral filter

possible SNR

50 100 150 200 250 300 350 400 450 5 10 15 20 25 30 Number of detector elements in scan-direction SNR

possible SNR

50 100 150 200 250 300 350 400 450 5 10 15 20 25 30 Number of detector elements in scan-direction SNR

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METimage

  • Dr. B. Voß

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This document contains information proprietary to Jena-Optronik GmbH. Any disclosure, use or duplication of this document is expressly prohibited.

Time Delay Integration (TDI)

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METimage

  • Dr. B. Voß

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This document contains information proprietary to Jena-Optronik GmbH. Any disclosure, use or duplication of this document is expressly prohibited.

Pixel used for one earth pixel Imaged earth region

Pixel size over Scan region

0,5 1 1,5 2 2,5 3 3,5 4 4,5 3 6 9 12 15 18 21 24 27 30 33 36 39 42 45 48 51 54

Scan angle [deg] Pixel size [km]

0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9 1

normalized SNR

GSD (ACT) GSD (ALT) GSD (ACT) with steps Normalized SNR

Scan geometry

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METimage

  • Dr. B. Voß

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This document contains information proprietary to Jena-Optronik GmbH. Any disclosure, use or duplication of this document is expressly prohibited.

Half angle mirror ω ω/2

Scan principle – rotating telescope

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METimage

  • Dr. B. Voß

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This document contains information proprietary to Jena-Optronik GmbH. Any disclosure, use or duplication of this document is expressly prohibited.

FoV BB1 BB2 Sun Diffusor Deep space Entrance PM SM HAM

Principle derotation mechanism

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METimage

  • Dr. B. Voß

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This document contains information proprietary to Jena-Optronik GmbH. Any disclosure, use or duplication of this document is expressly prohibited.

METimage C

  • Based on ESA future imager study

requirements

  • Up to 30 channels
  • Low polarisation < 1% due to polarisation

scrambler

  • METimage exceeds chosen SNR requirements

for 800m GSD

  • Ground sampling distance down to 250m

possible with reduction of radiometric performance.

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SLIDE 12

METimage

  • Dr. B. Voß

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This document contains information proprietary to Jena-Optronik GmbH. Any disclosure, use or duplication of this document is expressly prohibited.

METimage C Optics

Polarisation scrambler focal plane IR entrance pupil

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SLIDE 13

METimage

  • Dr. B. Voß

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This document contains information proprietary to Jena-Optronik GmbH. Any disclosure, use or duplication of this document is expressly prohibited.

Radiometric performance – solar channels

Wave length λ

[µm]

Spectr. band width Δλ

[nm]

Minimal radiance Lmin

[W/(m² sr µm)]

typical radiance Ltyp

[W/(m² sr µm)]

Maximal radiance Lmax

[W/(m² sr µm)]

Req. SNR @ Ltyp @ 800m GSD Possib. SNR @ Ltyp @ 800m GSD Possib. SNR @ Ltyp @ 400m GSD

2176 515 396 342 348 209 210 179 160 196 72 1627 1508 1493 951 963 794 627 742 314 1100 800 700 585 350 406 297 200 200 71

Possib. SNR @ Ltyp @ 250m GSD

0,443 20 8 42 585 179 0,490 20 11 31 582,7 197 0,554 20 8 18,5 528 117 0,670 20 2,7 9 1010 120 0,708 20 2 7 425,1 72 0,750 14 2 5 377 71 0,877 35 1,5 3,2 631 61 1,375 30 6 6 109 58 1,610 60 0,4 3,8 104 71 2,25 60 0,1 3,2 31,7 25

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METimage

  • Dr. B. Voß

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This document contains information proprietary to Jena-Optronik GmbH. Any disclosure, use or duplication of this document is expressly prohibited.

Radiometric performance – thermal channels

Wave length λ

[µm]

Spectral band width Δλ

[nm]

Minimal temp. Tmin

[K]

Typical temp. Ttyp

[K]

Maximal temp. Tmax

[K]

Req. NEdT @ Ttyp

[K] @ 800m GSD

Poss. NEdT @ Ttyp

[K] @ 400m GSD

0.08 0.08 0.26 0.28 0.1 0.08 0.07 0.29 0.3 0.3 0.1 0.08 0.08 0.3

Poss. NEdT @ Ttyp

[K] @ 250m GSD

3.70 380 190 270 335 0.21 6.30 1000 190 240 300 0.83 7.30 1000 190 240 300 0.92 8.55 1000 190 300 335 0.3 10.85 950 190 270 340 0.2 12 1000 190 270 340 0.2 13.40 600 190 270 270 0.77

  • METimage exceeds chosen SNR requirements for 800m GSD
  • Reduction of GSD down to 250m possible with reduction of

radiometric performance.

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METimage

  • Dr. B. Voß

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This document contains information proprietary to Jena-Optronik GmbH. Any disclosure, use or duplication of this document is expressly prohibited.

Performance METimage Polarisation

0,00% 0,50% 1,00% 1,50% 2,00% 2,50% 3,00% 3,50% 4,00% 4,50% 5,00% 400 500 600 700 800 900 1000

wavelength [nm] polarisation sensitivity

Polarisation sensitivity of one reflective surface

With polarisation scrambler Without polarisation scrambler 442nm: 1% 670nm: 0.5% 855nm: 0.5% 442nm: 11% 670nm: 3% 855nm: 2.7%

Except for blue channel, 5% polarisation requirement can be met without scrambler

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METimage

  • Dr. B. Voß

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This document contains information proprietary to Jena-Optronik GmbH. Any disclosure, use or duplication of this document is expressly prohibited.

METimage B2

Volume: 65 x 83 x 70 cm³ Mass: 85 kg

Calibration Sources MIR/TIR FPA VNIR/SWIR FPA Half Angle Mirror

65 x 68 x 70 cm³

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METimage

  • Dr. B. Voß

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This document contains information proprietary to Jena-Optronik GmbH. Any disclosure, use or duplication of this document is expressly prohibited.

Reduced SNR requirements METimage B1

  • Entrance pupil and with that complete
  • ptical instrument can be scaled.
  • Based on ESA VIRI-M requirements
  • METimage B1 exceeds the VIRI-M

requirements:

– Solar channels can be operated at 400m GSD by reducing the detector pixel size. – Thermal IR channels meet requirements with 800m GSD

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METimage

  • Dr. B. Voß

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This document contains information proprietary to Jena-Optronik GmbH. Any disclosure, use or duplication of this document is expressly prohibited.

METimage B1 Budget for VIRI-M requirements

  • Volume:

– Instrument: 26 x 33 x 28 cm³ – ICU: 30 x 24 x 25 cm³

  • Mass: 40kg

330 mm 260 mm 2 8 m m Half angle mirror FPAs

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METimage

  • Dr. B. Voß

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This document contains information proprietary to Jena-Optronik GmbH. Any disclosure, use or duplication of this document is expressly prohibited.

VIRI-M requirements

  • METimage B1 exceeds the VIRI-M requirements:

– Solar channels can be operated at 400m GSD by reducing the detector pixel size. – Thermal IR channels meet requirements with 800m GSD

Channel Centre wavelength [µm] Spectral Width [µm] Required SNR possible SNR/NedT @ 800m GSD possible SNR/NedT @ 400m GSD ME443 0.443 0.02 20 109 226 165 180 215 0.07K 0.24K 0.10K 0.08K 0.09K 0.19K 23 AH1 0.670 0.02 20 51 AH2 0.865 0.02 20 36 VI1.38 1.375 0.03 40 40 AH3A 1.61 0.03 40 46 AH3B 3.74 0.38 0.1K 0.28K MO6.7 6.7 0.36 0.3K 1.35K SE8.7 8.7 0.3 0.1K 0.45K AH4 10.8 1.0 0.1K 0.34K AH5 12.0 1.0 0.1K 0.40K SE13.4 13.4 0.3 0.2K 0.83K

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METimage

  • Dr. B. Voß

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This document contains information proprietary to Jena-Optronik GmbH. Any disclosure, use or duplication of this document is expressly prohibited.

Summary

Minimum Advanced Maximum METimage

requirements VIRI-M ESA future imager study GSD 1 km 500 m (VIS) – 1 km (IR) 250 m

  • pol. scrambler

no yes entrance pupil 150 mm 50 mm 120 mm dichroic beam splitters in-plane spectral separation rotating telescope half angle mirror characteristics 1 detector / channel matrix based detector

  • pol. sensitivity

5 % < 1 % 8 11 Up to 30

A B1 B2 C

channels volume 74 x 25 x 56 cm³ 56 x 33 x 28 cm³ 65 x 83 x 70 cm³ 40 kg mass 36 kg 100 W (+ 50 W active cooling) 90 x 83 x 70 cm³ 150 kg 115 W (11 channels) 165 W (17 channels) + 60W for active cooling 85 kg power consumption 45 W 105 W (11 channels) 155 W (17 channels) + 60W for active cooling