David Krutz

DESIS (DLR Earth Sensing Imaging Spectrometer for the ISS-MUSES platform)

Over the past 20 years, the DLR Institute of Optical Sensor Systems has been responsible for a variety of multi and hyperspectral instruments. This responsibility has included the design, manufacturing, calibration, verification and in orbit validation. In some programs the institute also participates at the subcomponent level, such as the VNIR-FPA (Boremann, 2001) on EnMAP (Janesick, 2001). Heritage missions and instruments from the institute also include MKS on IK21, MOS on MIR, MOS on IRS, MeRTIS on Bepi Colombo and Sentinel 4/5. A forthcoming instrument from the institute will be DESIS - the DLR Earth Sensing Imaging Spectrometer. DESIS will be the first instrument to be installed on ISS attached to the MUSES platform, which provides power, data-flow, and inertial pointing stabilization for up to four instruments. DESIS is a hyperspectral instrument with additional steering capability. The spectral sensitivity of DESIS will be optimized for the range of 400 nm-1000 nm based on an Offner spectrograph design and 235 equi-distant spectral bands. The scientific goals of the mission are to develop standard hyperspectral applications and an operational Earth-sensing capability in the VNIR and to use the BRDF as additional information source to proof the current atmospheric correction calculations (ISO/DTS 19159-1, 2014). The GSD of the DESIS instrument will be 30 m when aboard ISS at a 400 km orbital altitude (Jahn and Reulke, 2012). The paper will give an overview over the MUSES platform and the DESIS design in detail and will show the advantage by using the BRDF.

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)

The hyperspectral sensor DESIS on MUSES: Processing and applications

The hyperspectral instrument DLR Earth Sensing Imaging Spectrometer (DESIS) will be developed and integrated in the Multi-User-System for Earth Sensing (MUSES) platform installed on the International Space Station (ISS). The DESIS instrument will be launched to the ISS mid of 2017 and installed in one of the four slots of the MUSES platform. The MUSES / DESIS system will be commanded and operated by the publically traded company Teledyne Brown Engineering (TBE), which initiated the program. TBE provides the MUSES platform and the German Aerospace Center (DLR) develops DESIS and establishes a Ground Segment for processing, archiving, delivering and calibrating the data used for scientific and humanitarian applications. Harmonized products will be generated by the Ground Segment established at Teledyne. This article describes the processing ground segment and the foreseen data validation activities. Finally comments regarding the data policy and foreseen scientific uses are given.

Design of an imaging spectrometer for earth observation using freeform mirrors

In 2017 the new hyperspectral DLR Earth Sensing Imaging Spectrometer (DESIS) will be integrated in the Multi-User-System for Earth Sensing (MUSES) platform [1] installed on the International Space Station (ISS).

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.

BTDI detector technology for reconnaissance application

The Institute of Optical Sensor 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 institute’s scientific results of the leading-edge detector design in a BTDI (Bidirectional Time Delay and Integration) architecture. This project demonstrates an approved technological design for high or multi-spectral resolution spaceborne instruments. DLR OS and BAE Systems were driving the technology of new detectors and the FPA design for future projects, new manufacturing accuracy in order to keep pace with ambitious scientific and user requirements. Resulting from customer requirements and available technologies the current generation of space borne sensor systems is 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 control applications and new focal plane concepts opens the door to new remote sensing and smart deep space instruments. The paper gives an overview of the detector development and verification program at DLR on detector module level and key parameters like SNR, linearity, spectral response, quantum efficiency, PRNU, DSNU and MTF.

Qualification and Calibration of DLR’s optical BiROS Payload

Direct optical communication links might offer a solution for the increasing demand of transmission capacity in satellite missions. Although direct space-to-ground links suffer from limited availability due to cloud coverage, the achievable data rates can be higher by orders of magnitude compared to traditional RF communication systems.

Reconfigurable architecture for real-time image compression on-board satellites

Abstract. A high-speed image compression architecture with region-of-interest (ROI) support and with flexible access to compressed data based on the Consultative Committee for Space Data Systems 122.0-B-1 image data compression standard is presented. Modifications of the standard permit a change of compression parameters and the reorganization of the bit stream after compression. An additional index of the compressed data is created, which renders it possible to locate individual parts of the bit stream. On request, stored images can be reassembled according to the application’s needs and as requested by the ground station. Interactive transmission of the compressed data is possible such that overview images can be transmitted first followed by detailed information for the ROI. The architecture was implemented for a Xilinx Virtex-5QV and a single instance is able to compress images at a rate of 200  Mpx/s at a clock frequency of 100 MHz. The design ensures that all parts of the system have a high utilization and parallelism. A Virtex-5QV allows compression of images with a width of up to 4096 px without external memory. The power consumption of the architecture is ∼4  W. This example is one of the fastest implementations yet reported and sufficient for future high-resolution imaging systems.