Imaging devices in space

Transcription

1 Imaging devices in space Roland Meynart Earth Observation Projects European Space Agency Noordwijk, The Netherlands

2 Foreword Imaging devices in space a very wide subject This presentation gives the perspective of somewhat exotic high-end users of imaging devices Space is one sub-segment of a small business segment (security, defense, industrial, space) Selfie of Rosetta with comet 67P/Churyumov Gerasimenko Meynart SEMICON 2014 Slide 2

3 Contents a. Introduction what do we look at? b. Looking at stars, from the simple star trackers to the large observatories c. Earth Observation, some examples of single-channel, multispectral and hyperspectral requirements d. Some comments Meynart SEMICON 2014 Slide 3

4 Imaging Sensors in Space Detection in the range γ-rays to λ= µm Let s focus on range µm (from UV to Thermal Infra-Red ) Main applications: a. Spacecraft/Attitude sensors (monitoring cameras, sun sensors, star trackers) b. Science/operational observations Astronomy, astrophysics (long-range, low-flux) Earth Observation, planetary missions (high-flux) Meynart SEMICON 2014 Slide 4

5 Atmosphere transmission VNIR: Visible-Near-IR (0.4-1 µm) SWIR: Short-Wave-IR (1-2.5 µm) called NIR in astronomy MWIR-LWIR: µm VLWIR: µm multi and hyperspectral sensing Atmospheric sensing, Temperature sensing Meynart SEMICON 2014 Slide 5

6 InfraRed detectors Bolometers One workhorse technology HgCdTe ( MCT ) Two speciality technologies InGaAs Uncooled bolometers (Si, Vanadium oxides) VIS/NIR SWIR MWIR LWIR VLWIR Many exotic technologies for after L.Becker, SPIE 5881 (2005) specific applications Meynart SEMICON 2014 Slide 6

7 Visible range: the domain of Silicium CCD vs CMOS 1. Very happy with CCDs, but some limitations a. High dynamic range (100 db), high linearity, TDI easy b. BSI readily available c. Delicate operation, complex electronics, system cost d. Low speed, smear due to transfer time e. Stable technology (advantage!), limited number of providers, processes to be maintained f. Industry migration to CMOS 2. CMOS detectors a. CIS processes not always optimum for exotic and demanding space requirements (e.g. large pixels, high QE) b. industry/technology fast evolutions ( volatility of processes and supply chains) c. European preference (for ESA!) Meynart SEMICON 2014 Slide 7

8 Star trackers Basic attitude and orbit control system (AOCS) device: correlates images of sky with star maps, accuracy: a few arcsec Trends: use of CMOS arrays (simpler, compact: 2-3 kg) World market dominated by European companies (SODERN) (Selex ES) (JenaOptronik) Meynart SEMICON 2014 Slide 8

9 Attitude sensors, star trackers HAS2, ON Semi 1024 x 1024, 18 µm, 3T, on-chip 10-bit ADC DR: 65 db Designed as Rad-hard devices = does the job (e.g. identifies selected stars ) up to high level of radiation (e.g. 100 krad), not totally radiation insensitive In development: HAS x 1280, 11 µm on-chip bit ADC DR: 70 db (BOL) D.Van Aken et al. Proc. SPIE 7474 Meynart SEMICON 2014 Slide 9

10 The ultimate star tracker: GAIA Astrometry mission 14 orders of magnitude Resolution 20 µarcsec at V=15 (courtesy ASD-F) Meynart SEMICON 2014 Slide 10

11 High-end image sensors: GAIA (courtesy of ASD-F and e2v) The billion-pixel camera 106 x e2v CCDs, T= -110 C by 4500 pixels, 30 μm x 10 μm, 1.0 x 0.5 m 2, 1Bpixel, 0.28 m 2 CCD real estate Back-Side-Illuminated Time-Domain-Integration, shift time: 0.98 ms DR = db Meynart SEMICON 2014 Slide 11

12 Radiation effect: distortion of star image Monte-Carlo simulation of LSF deformation due to radiation induced CTI See R.Kohley et al, Proc. SPIE 8442 (2012) Trade-off: temperature - operation conditions + charge injection Meynart SEMICON 2014 Slide 12

13 The next generation: EUCLID 1. The dark energy mission 2. extra-galactic sky survey of: a. ~ 37% of sky (15,000 deg 2 ) b. 1.5 billion galaxies to m AB 24.5 c. z= 0 to 2 (10 billion years) δ. λ= 550 nm to 2 µm 3. two measurement techniques: a. Weak Gravitational Lensing (VISible instrument) b. Baryonic Acoustic Oscillations (Near Infrared Spectroscopy and Photometry instrument) Meynart SEMICON 2014 Slide 13

14 Visible Focal Plane spectral range: nm plate scale: 0.1arcsec/pix field of view: 0.787x0.709 deg 2 Step-and-stare operation Data-rate: 520 Gbits/day 6x6 CCDs Meynart SEMICON 2014 Slide 14

15 The EUCLID CCD E2v CCD273 Pixel format: 4096 x 4132 Active area: x mm Pixels: 12x12 µm (FWC=175,000e-) FPA > 30x30 cm 2 Read-out noise: khz QE > 0.83 [ nm] High resistivity (1500Ωcm) epitaxial Si (courtesy e2v) Back-thinned to 40μm Red-enhanced AR coating T=152 K After proton irradiation Meynart SEMICON 2014 Slide 15

16 And also in infrared 4 x 4 Hybrid HgCdTe detectors Teledyne H2RG 2048x2048, pitch18 µm Plate scale: 0.3 arsec/pix λ c = 2.3 µm Development model FPA NISP Euclid 2 detectors + 2 ROICs + 12 dummy (courtesy LAM) Meynart SEMICON 2014 Slide 16

17 Back to Earth: principle of operation A few picture elements (pixels) for simple scanning imagers Long 1-D arrays for pushbroom imagers 2-D Detector Large 2-D arrays for dispersive spectrometers or staring imagers/spectrometers (e.g Fourier Transform) Telescope Imager Dispersing element Collimator Spectral radiance λ λ 2D detector x Slit Telescope Mirror 2-D Detector array Mirror 1-D Detector Telescope Telescope Meynart SEMICON 2014 Slide 17

18 An example of pushbroom imager: Sentinel-2 Land cover, land use and landuse change detection maps 12 spectral bands between 443 and 2190 nm Spatial resolution 10, 20, 60 m Meynart SEMICON 2014 Slide 18

19 Sentinel-2 detectors (ASD-F) (Sofradir) VNIR CMOS linear arrays, 1928 pixels Pitch: µm Hybrid HgCdTe arrays, 1928 pixels 2 cut-off wavelengths Pitch:15 µm T=190 K Some bands with off-chip TDI Meynart SEMICON 2014 Slide 19

20 Assembled Focal planes (ASD-F) VNIR focal plane SWIR focal plane Meynart SEMICON 2014 Slide 20

21 Multi spectral, high-resolution, instruments 1. Classical high-resolution spacecraft generally feature one high-res (e.g. 1m) PAN band and 4 VIS-NIR, lower-res (e.g. 4m), VIS-NIR bands 2. Evolution from large SPOT satellites to more capable, agile, new generation (e.g. Pleiades) or to smaller, commercial, spacecraft Spot-5 Pleiades Dubaisat-2 3. Detection with long detector arrays, using TDI 4. CMOS might replace CCDs, but on-chip TDI difficult Meynart SEMICON 2014 Slide 21

22 MeteoSat 3 rd generation (MTG) Meteosat Third Generation will carry two hyperspectral instruments: InfraRed Sounder (interferometer µm) Sentinel-4 UVNS (spectrometer (300 nm nm) one superspectral instrument Flexible Combined Imager (400 nm 14 µm) and one single-wavelength Lightning Imager (777 nm) Meynart SEMICON 2014 Slide 22

23 FCI and IRS detectors 1. FCI and IRS require multi-element detector arrays up to λ= 15 µm FCI: linear arrays in staggered configuration (VIS and IR) IRS: 2-D array with selectable sub-pixels FCI channels Meynart SEMICON 2014 Slide 23

24 FCI VIS detectors Pushbroom operation with E-W scanning mirror 5 channels of rhombus-shaped pixels with optical filters: Each channel (4x): 4 columns of 224 pixels 100μm x 100μm. One nominal, selectable, 3 redundant One channel has 4 columns of 448 pixels of 40μm x 50 μm in size for higher resolution imaging Meynart SEMICON 2014 Slide 24

25 FCI VIS detectors Prototype devices in handling jigs (no filter, no black coating). 4T pixel, 0.18 µm CIS FSI, global shutter (courtesy e2v) Detail of the pixels, with black coating. Meynart SEMICON 2014 Slide 25

26 FCI IR detectors 4 detectors to cover 11 channels between 1.3 and 13.6 µm HgCdTe hybridized on 2 different ROIC types Columns of 112/224 / 448 lines (rhombus pixels) Pitch grid: 12.5 / 25 µm Redundancy of up to 4 pixels per line (best detector per line selected) Operating Temperature: 60 K Challenge: low Idark, high-qe up to λ c 15 µm. Early prototype 13.6 µm (Sofradir) ROIC hybrid detector Meynart SEMICON 2014 Slide 26

27 High-accuracy spectroscopy on MTG: air quality (Sentinel-4) Water vapour Cloud Cloud Glyoxal Nitrogen dioxide Rayleigh scattering Bromine monoxide Formaldehyde Aerosol Aerosol Aerosol Aerosol Total ozone Sulphur dioxide Ozone vertical profile Wavelength [nm] Tropospheric NO 2 Dec 2004-Nov 2005 Large dynamic range in signals (100:1) Shallow spectroscopic signatures (<10-2 ) Meynart SEMICON 2014 Slide 27

28 CCD UV-VIS Pushbroom Hyperspectral imager with E-W scanning mirror nm BSI, non-inverted, four-phase, split frame-transfer (400 khz transfer) Integration time ms T=215 K RON: 15e- (BW: 4.3 MHz) FWC > 1.4 Me- (1% linearity limit) e2v CCD274 Meynart SEMICON 2014 Slide 28

29 RTS after proton irradiation Astrium - Open University Meynart SEMICON 2014 Slide 29

30 Back to event tracking: Lightning Imager Lightning seen from ISS (NASA) Smart detection of lightning Frame-to-frame subtraction and thresholding Signal to be read out also in pixels where events are detected Format: 1k 2 pxl, rate: 1000 frame/s, BSI for QE >70% Option1: In-pixel processing (60 µm, 42T) Option 2: Off-chip processing, pixel: 24 µm, 4T Internal 12-bit ADC, 60 LVDS outputs 0.18 µm CIS FSI demo S. Rolando et al., Appl. Opt. 52, C16-C23 (2013) (CMOSIS) Meynart SEMICON 2014 Slide 30

31 Some comments 1. Space requirements very diverse and generally demanding 2. Low volume/revenue 3. Visible detection High-end applications: custom devices, CCDs are not yet fully displaced, users expect CCD performance when better Commercial spacecraft more amenable to using existing CIS devices or building blocks Packaging, qualification, space environment are design and cost drivers Long development cycles: low risk, stability and predictability required 4. Infra-Red instruments are more likely to use existing devices Meynart SEMICON 2014 Slide 31

32 Thank you for your attention Selfie of Sentinel 1A Meynart SEMICON 2014 Slide 32