Hans Driescher

Compact blackbody calibration sources for in-flight calibration of spaceborne infrared instruments

High-emissivity blackbodies are mandatory as calibration sources in infrared radiometers. Besides the requirements on the high spectral emissivity and low reflectance, constraints regarding energy consumption, installation space and mass must be considered during instrument design. Cavity radiators provide an outstanding spectral emissivity to the price of installation space and mass of the calibration source. Surface radiation sources are mainly limited by the spectral emissivity of the functional coating and the homogeneity of the temperature distribution. The effective emissivity of a “black” surface can be optimized, by structuring the substrate with the aim to enlarge the ratio of the surface to its projection. Based on the experiences of the Mercury Radiometer and Thermal Infrared Spectrometer (MERTIS) calibration source MBB3, the results of the surface structuring on the effective emissivity are described analytically and compared to the experimental performance. Different geometries are analyzed and the production methods are discussed. The high-emissivity temperature calibration source features values of 0.99 for wavelength from 5 μm to 10 μm and emissivity larger than 0.95 for the spectral range from 10 μm to 40 μm.

High-accuracy focal plate alignment for the first commercial digital airborne camera ADS40

The Airborne Digital Sensor (ADS) a development to fulfil photogrammetric and remote sensing requirements. The new digital sensor is not only a camera for pretty nice pictures. It will be the next - full digital - generation as a measurement device for airborne photogrammetry and remote sensing. The high accuracy design of the focal plane system under flight and environmental conditions (pressure and temperature) will be presented. The ADS project will be introduced as a design of a modular customized CCD line scanner concept. It will be discussed on the ADS version with 4 multispectral CCD lines and 3 panchromatic CCD lines. The presentation will gives an overview of all dependencies and design constrains on the ADS Focal Pate Module (FPM). The ADS optical system has to support both photogrammetric accuracy and the requirement on the SNR for remote sensing applications. The principle to achieve good color pixel matching is described in relation to the customized CCD- and FPM- design. After a short description of the technical design and performances, some application examples are shown to demonstrate the main features of digital sensor: high accuracy, wide angle, high radiometric dynamics, high signal-to-noise-ratio, in-track stereo capability, multispectral capability.