Design considerations, modeling, and analysis for the multispectral thermal imager
Infrared Imaging Systems: Design, Analysis, Modeling, and Testing X
a u s p l c e s o f t h e U . S . P e p a r t m e n t o f~. . C d s W a m a s N a b ' o n a l C a b a r a t o r l (~s u p p o r t s a c a d e m i c h e e d a m~a~~~t o publish; as an institution, however, the Laboratory does not endorse lhe viewpoint of a publication or guarantee its technical corredness. Form 836 (10/96) ABSTRACT The design of remote sensing systems is driven by the need to provide cost-effective, substantive answers to questions posed by our customers. This is especially
... tant for space-based systems, which tend to be expensive, and which generally cannot be changed after they are launched. We report here on the approach we employed in developing the desired attributes of a satellite mission, namely the Multispectral Thermal Imager. After an initial scoping study, we applied a procedure which we call: "End-to-end modeling and analysis GEM)." We began with target attributes, translated to observable signatures and then propagated the signatures through the atmosphere to the sensor location. We modeled the sensor attributes to yield a simulated data stream, which was then analyzed to retrieve information about the original target. The retrieved signature was then compared to the original to obtain a figure of merit: hence the term "end-to-end modeling and analysis." We base the EEM in physics to ensure high fidelity and to permit scaling. As the actual design of the payload evolves, and as real hardware is tested, we can update the EEM to facilitate trade studies, and to judge, for example, whether components that deviate from specifications are acceptable. As of the date of this writing, the MTI payload (Ref: Kay et al) is in calibration at Los Alamos National Laboratory for several months. The payload will be integrated with the satellite bus thisspring, with launch scheduled at the end of 1999. The ultimate test of our efforts will, obviously, come with on-orbit operations, in which we will quantitatively compare results from satellite measurements to known ground-truth. At that time the end-to-end model will contain all known as-built attributes of the MTI, and will be used as a tool to validate our understanding. The back-end of the EEM is transitioning into the analysis software that will be used at the Data Processing and Analysis Center. When the EEM is validated by actual measurements, it will be an even stronger tool, and, being based in physics, it can be applied to a number of other possible missions.