Holger Venus

sCMOS detector for imaging VNIR spectrometry

The facility Optical Information Systems (OS) at the Robotics and Mechatronics Center of the German Aerospace Center (DLR) has more than 30 years of experience with high-resolution imaging technology. This paper shows the scientific results of the institute of leading edge instruments and focal plane designs for EnMAP VIS/NIR spectrograph. EnMAP (Environmental Mapping and Analysis Program) is one of the selected proposals for the national German Space Program. The EnMAP project includes the technological design of the hyper spectral space borne instrument and the algorithms development of the classification. The EnMAP project is a joint response of German Earth observation research institutions, value-added resellers and the German space industry like Kayser-Threde GmbH (KT) and others to the increasing demand on information about the status of our environment. The Geo Forschungs Zentrum (GFZ) Potsdam is the Principal Investigator of EnMAP. DLR OS and KT were driving the technology of new detectors and the FPA design for this project, new manufacturing accuracy and on-chip processing capability in order to keep pace with the ambitious scientific and user requirements. In combination with the engineering research, the current generations of space borne sensor systems are focusing on VIS/NIR high spectral resolution to meet the requirements on earth and planetary observation systems. The combination of large swath and high spectral resolution with intelligent synchronization control, fast-readout ADC chains and new focal-plane concepts open the door to new remote-sensing and smart deep space instruments. The paper gives an overview over the detector verification program at DLR on FPA level, new control possibilities for sCMOS detectors in global shutter mode and key parameters like PRNU, DSNU, MTF, SNR, Linearity, Spectral Response, Quantum Efficiency, Flatness and Radiation Tolerance will be discussed in detail.

A system on a chip concept for the Mercury Thermal Imaging Spectrometer MERTIS

A very advanced Mercury Thermal Infrared Spectrometer (MERTIS) was proposed by the German Aerospace Center (DLR) fulfilling the extreme resource restrictions of the ESA deep space mission BepiColombo to the inner planet Mercury. The design drivers for the MERTIS instruments are the limited mass and the harsh radiation environment. Derived from these main constrains are power-, volume- and thermal restrictions. This paper presents some key technologies applied to keep the BepiColombo mission limits. It will touch the extreme light weight and compact optic design but focuses on the system on a chip application of the MERTIS instrument digital electronics and its influence to the system structure and reliability concept. It will further show some techniques making the operation of the MERTIS instrument more robust in this radiation exposed environment. One example is the integration of a digital thermal controller for a thermo electrical cooler with less than 10 mK accuracy. It is synthesized into the MERTIS system on a chip instrument controller based on a field programmable gate array (FPGA)

MERTIS - a highly integrated IR imaging spectrometer

With a background of several instrument developments in the past the German Aerospace Center in Berlin proposed for ESAs deep space mission BepiColombo an imaging spectrometer which meets the challenges of limited technical resources and a very special operational environment. An 80-channel push broom-type spectrometer has been drafted and it s development has been started under the name MERTIS (MErcury Radiometer and Thermal Infrared Spectrometer). The instrument is dedicated to the mineralogy surface science and thermal characteristics studies of the innermost planet. It is based on modern un-cooled micro-bolometer technology and all-reflective optics design. The operation concept principle is characterised by intermediate scanning of the planet, deep space and black bodies as calibration targets. A miniaturised radiometer is included for low level temperature measurements. Altogether the system shall fit into a CD-package sized cube and weigh less than 3 kg. The paper will present the instrument architecture of MERTIS, its design status and will show the results of first components being built.

Thematic data processing on board the satellite BIRD

The general trend in remote sensing is on one hand to increase the number of spectral bands and the geometric resolution of the imaging sensors which leads to higher data rates and data volumes. On the other hand the user is often only interested in special information of the received sensor data and not in the whole data mass. Concerning these two tendencies a main part of the signal pre-processing can already be done for special users and tasks on-board a satellite. For the BIRD (Bispectral InfraRed Detection) mission a new approach of an on-board data processing is made. The main goal of the BIRD mission is the fire recognition and the detection of hot spots. This paper describes the technical solution, of an on-board image data processing system based on the sensor system on two new IR-Sensors and the stereo line scanner WAOSS (Wide-Angle-Optoelectronic-Scanner). The aim of this data processing system is to reduce the data stream from the satellite due to generations of geo-coded thematic maps. This reduction will be made by a multispectral classification. For this classification a special hardware based on the neutral network processor NI1000 was designed. This hardware is integrated in the payload data handling system of the satellite.

DESIS - DLR earth sensing imaging spectrometer for the International Space Station ISS

The DLR Earth Sensing Imaging Spectrometer (DESIS) is a new space-based hyperspectral sensor developed and operated by a collaboration between the German Aerospace Center (DLR) and Teledyne Brown Engineering (TBE). DESIS will provide hyperspectral data in the visible to near-infrared range with high resolution and near-global coverage. TBE provides the platform and infrastructure for the operation on the International Space Station (ISS), DLR has developed the instrument. This paper gives an overview of the design of the DESIS instrument together with results from the optical on-ground calibration. In-flight calibration, stability of dark signal and rolling vs. global shutter analysis will be presented.

Verification and calibration of the DESIS detector

This paper focuses on the calibration and verification of the DESIS (DLR Earth Sensing Imaging Spectrometer) detector for the VIS/NIR (VNIR) spectral range. DESIS is a hyperspectral Instrument for the international space station, developed from the German Aerospace Center (DLR) and operate by Teledyne Brown Engineering (TBE). TBE provides the MUSES platform, on which the DESIS instrument will be mounted. The primary goal of DESIS is to measure and analyse quantitative diagnostic parameters describing key processes on the Earth surface. The main components of the sensor, the detector and the focal plane, were examined and verified. This allows predictions about the future data quality. The verification and validation of components and the entire system is an important and challenging task. The verification of the detectors is necessary to describe the characteristics of the detector according to predetermined specifications. The quantities to be examined are e.g. the quantum efficiency, the linearity of the detector, the pixel response non-uniformity (PRNU) and the dark current noise. For this purpose, specially calibrated integrated spheres are used that allow traceability of the measured data. With these information, the future performance of the sensor can be estimated using simulations.

DESIS - DLR Earth Sensing Imaging Spectrometer

The DLR Earth Sensing Imaging Spectrometer (DESIS) is a new space-based hyperspectral sensor developed and operated by a collaboration between the German Aerospace Center (DLR) and Teledyne Brown Engineering (TBE). DESIS will provide hyperspectral data in the visible to near-infrared range with high resolution and near-global coverage. TBE provides the platform and infrastructure for the operation on the International Space Station (ISS), DLR is developing the instrument. This paper gives an overview of the design of the DESIS instrument together with first results from the optical calibration.