Engineering topics
Herman, M.
Publications and source records attributed to Herman, M..
Statistically Optimized Inversion Algorithm for Enhanced Retrieval of Aerosol Properties from Spectral Multi-Angle Polarimetric Satellite Observations
The proposed development is an attempt to enhance aerosol retrieval by emphasizing statistical optimization in inversion of advanced satellite observations. This optimization concept improves retrieval accuracy relying on the knowledge of measurement error distribution. Efficient application of such optimization requires pronounced data redundancy (excess of the measurements number over number of unknowns) that is not common in satellite observations. The POLDER imager on board the PARASOL microsatellite registers spectral polarimetric characteristics of the reflected atmospheric radiation at up to 16 viewing directions over each observed pixel. The completeness of such observations is notably higher than for most currently operating passive satellite aerosol sensors. This provides an opportunity for profound utilization of statistical optimization principles in satellite data inversion. The proposed retrieval scheme is designed as statistically optimized multi-variable fitting of all available angular observations obtained by the POLDER sensor in the window spectral channels where absorption by gas is minimal. The total number of such observations by PARASOL always exceeds a hundred over each pixel and the statistical optimization concept promises to be efficient even if the algorithm retrieves several tens of aerosol parameters. Based on this idea, the proposed algorithm uses a large number of unknowns and is aimed at retrieval of extended set of parameters affecting measured radiation.
Advanced RF front end technology
The ability to achieve low-mass low-cost micro/nano-spacecraft for deep space exploration requires extensive miniaturization of all subsystems.
DS1 Ka-band Solid State Power Amplifier
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DS1 Technology Validation Report for Small Deep Space Transponder
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In-Flight Validation of Small Deep Space Transpoder (SDST)
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DS1 Technology Validation Report for Small Deep Space Transponder
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Pluto Express - Out of the Darkness
Pluto, discovered in 1930, is the largest of a class of primordial bodies at the edge of our solar system that have comet-like properties and remain relatively unmodified by warming from the sun. It is the only planet in the solar system not explored via robotic spacecraft. This lecture discusses the status of the Pluto Express preproject (science objectives, etc.), and its telecommunication subsystem.
Transmission Lines for High Frequency and High Density Packaging
We report on resistivity and chemical stability of Cr/Au bilayers deposited by sputtering on three kinds of substrates: alumina, aluminum nitride and aluminum nitride coated alumina. The insertion loss of Cr/Au microstrip lines fabricated on these three substrates was low and stable after 100 cycles in the -65 degree C to 125 degree C temperature range.
High Frequency Electronic Packaging Technology
Commercial and government communication, radar, and information systems face the challenge of cost and mass reduction via the application of advanced packaging technology. A majority of both government and industry support has been focused on low frequency digital electronics.
A High Frequency Electronic Packaging Technology
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Pluto Mission Development Status
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Pluto Mission Development Status
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Pluto Fast Flyby: An Overview of the Mission and Spacecraft Design, Advanced Technology Insertion Efforts, and Student Involvement Opportunities
In an effort to complete the initial reconnanissance of our solar system, the Jet Propulsion Laboratory (JPL) is designing a mission to send two very small spacecraft to explore Pluto and its moon, Charon.
Observations in the solar spectrum interest for remote sensing purposes
The polarization of the sunlight scattered by atmospheric aerosols or cloud droplets and reflected from ground surfaces or plant canopies may convey much information when used for remote sensing purposes. The typical polarization features of aerosols, cloud droplets, and plant canopies, as observed by ground based and airborne sensors, are investigated, looking especially for those invariant properties amenable to description by simple models when possible. The question of polarization measurements from space is addressed. The interest of such measurements for remote sensing purposes is investigated, and their feasibility is tested by using results obtained during field campaigns of the airborne POLDER instrument, a radiometer designed to measure the directionality and polarization of the sunlight scattered by the ground atmosphere system.
Polarization properties of snow and clouds as observed by the airborne POLDER instrument
Aircraft photopolarimetric observation of cloud and snow fields made by the POLDER (Polarization and Directionality of the Earth Reflectance) instrument during the EUCREX (European Cloud Radiation Experiment) and RACER (Research Antarctica Coastal Ecosystem Rates) campaigns are presented. Over clouds, the polarized component of the reflectance at the wavelength of 450 nm and scattering angles of 90 to 100 deg is sensitive to the molecular optical thickness between the cloud top and aircraft altitudes and, therefore, may be used for cloud altimetry. Liquid water clouds and snow exhibit similar spectral and bidirectional characteristics, but distinct polarization signatures. In the rainbow region (scattering angles of about 140 deg), water droplets strongly polarize incident sunlight while snow crystals do not, making it possible to distinguish the two types targets by scanning the angular polarization.
Novel Techniques for Millimeter Wave Packages
A new millimeter-wave package architecture with supporting electrical, mechanical and material science experiment and analysis is presented.