Development of detailed design concepts for the EarthCARE multi-spectral imager
conference paper
The EarthCARE mission is dedicated to the study of clouds by observations from a satellite in low Earth orbit. The payload will include major radar and LIDAR instruments, supported by a multi-spectral imager (MSI) and a broadband radiometer. The paper describes development of detailed design concepts for the MSI, and analysis of critical performance parameters. The MSI will form Earth images at 500m ground sample distance (GSD) over a swath width of 150km, from a nominal platform altitude of around 400 km. The task of the MSI is to provide spatial context for the single-point measurements made by the radar and LIDAR systems; it will image Earth in 7 spectral bands: one visible, one near-IR, two short-wave IR and three thermal IR. The MSI instrument will be formed in two parts: a visible-NIR-SWIR (VNS) system, radiometrically calibrated using a sunilluminated diffuser, and a thermal IR (TIR) system calibrated using cold space and an internal black-body. The VNS system will perform push-broom imaging, using linear array detectors (silicon and InGaAs) and 4 separate lenses. The TIR system will use a microbolometer array detector in a time delay and integration (TDI) mode. Critical issues discussed for the VNS system include detector selection and detailed optical design trade-offs. The latter are related to the desirability of dichroics to achieve a common aperture, which influences the calibration hardware and lens design. The TIR system’s most significant problems relate to control of random noise and bias errors, requiring optimisation of detector operation and calibration procedures.
Topics
Gallium alloysIndium alloysOptical designOrbitsRadar imagingRadar measurementSilicon detectorsSpace-based radarSpectroscopyThallium alloysCalibration procedureCritical performance parametersGround sample distancesLinear array detectorsMicrobolometer arraysMulti spectral imagerSingle-point measurementTime-delay and integrationsOptical radar
TNO Identifier
782885
ISSN
0277786X
ISBN
9781510616219
Publisher
SPIE
Article nr.
105660I
Source title
International Conference on Space Optics, ICSO 2008, 14-17 October 2008, Toulouse, France
Editor(s)
Costeraste, J.
Armandillo, E.
Karafolas, N.
Armandillo, E.
Karafolas, N.
Collation
8 p.
Files
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