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A new hyperspectral imager (HSI) is designed for the next-generation HY-1E ocean color monitoring satellite. This instrument requires a reduced ground sampling distance (GSD) of 100 m and increased number of spectral bands (from 8 to 10). A GSD of 100 m corresponds with a frame rate of approximately 70 Hz. The sensor has an elongated format of 2176 * 320 pixels of 30 μm to increase the sensitivity. Multiple sensors will be used in a staggered configuration to guarantee a full earth coverage in 2-3 days The overall length of the sensor is 73 mm and is subdivided in 4 segments of 16.32 mm each. Each segment is read out via two SAR ADC blocks. Each conversion takes 48 clock cycles resulting in ADC clock speed of 120 MHz. The ADC can also be read with 12 bit accuracy with increased conversion speed; and by oversampling the LSB’s it is possible to reach 16 bit accuracy. The pixel is equipped with a 4-fold High Dynamic range readout mechanism. Under low-illumination conditions all acquired signal charges are remaining in the pixel. When the illumination is increased, the additional charges will be accumulated in an additional capacitor. For even larger photon fluxes a third and a fourth capacitor are activated. In this way all intensity level are treated by the same sensitive area and in exactly the same integration time, eliminating all motion artefacts. The 4 gain stages can contain respectively 24, 120, 600 and 2500 ke- . For each gain stage the dynamic range is 5000:1 resulting in an overall dynamic range of 114dB. The Image sensor is designed in a Rad-Hard by Design (RHbD) way to cope with the LEO space environment. The dark current increase under the influence of 75 krad(Si) is a factor 3500, but the effect is largely annealed with a high temperature anneal. The SEE is higher than 37 MeV/mg/cm2 due to the use of DICE based digital blocks. The Image sensor is packaged in a custom designed ceramic package, closed with a dedicated filter window. All environmental and life time tests were executed on the assemblies.
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