Engineering topics

Palmer, James M.

Publications and source records attributed to Palmer, James M..

8 records

NASA NTRS1992

Calibration of satellite sensors in the thermal infrared

The addition of a calibration capability in the 8-14 micron thermal infrared region to the current ground-based calibration of orbiting sensors is discussed. Radiance- and reflectance-based methods are compared. An infrared thermometer was selected as the favored instrument for the determination of ground truth. Three methods to determine the effect of sky background on the thermal emittance of the ground are presented, along with use of LOWTRAN 7 to determine atmospheric effects.

Palmer, James M.↗

NASA NTRS1992

Definitions in use by the visible and near-infrared, and thermal working groups

The Calibration Advisory Panel (CAP) is composed of calibration experts from each of the Earth Observing System (EOS) instruments, science investigation, and cross-calibration teams. These members come from a variety of institutions and backgrounds. In order to facilitate an exchange of ideas, and assure a common basis for communication, it was desirable to assemble this list of definitions. These definitions were developed for use by the visible and near-infrared working group, and the thermal infrared working group. Where necessary or appropriate, deviations from these for specific instruments or other sensor types are given in the individual calibration plans. The definitions contained in this document are derived, wherever possible, from definitions accepted by international and national metrological commissions including the United States National Institute of Standards and Technology (NIST), the International Bureau of Weights and Measures (BIPM), the International Electrotechnical Commission (IEC), the International Organization for Standardization (ISO), and the International Organization of Legal Metrology (OIML).

Bruegge, Carol J.↗

NASA NTRS1991

Solar-diffuser panel and ratioing radiometer approach to satellite sensor on-board calibration

The use of a solar-diffuser panel is a desirable approach to the on-board absolute radiometric calibration of satellite multispectral sensors used for earth observation in the solar reflective spectral range. It provides a full aperture, full field, end-to-end calibration near the top of the sensor's dynamic range and across its entire spectral response range. A serious drawback is that the panel's reflectance, and the response of any simple detector used to monitor its reflectance may change with time. This paper briefly reviews some preflight and on-board methods for absolute calibration and introduces the ratioing-radiometer concept in which the radiance of the panel is ratioed with respect to the solar irradiance at the time the multispectral sensor is viewing the panel in its calibration mode.

Slater, Philip N.↗

NASA NTRS1991

A ratioing radiometer for use with a solar diffuser

The use of an on-board solar diffuser has been proposed to monitor the in-flight calibration of satellite sensors. This paper presents the preliminary specifications and design for a ratioing radiometer, to be used to determine the change in radiance of the solar diffuser. The issues involved in spectral channel selection are discussed and the effects of stray light are presented. An error analysis showing the benefit of the ratioing radiometer is included.

Palmer, James M.↗

NASA NTRS1991

Requirements of a solar diffuser and measurements of some candidate materials

If the solar spectral irradiance and the orientation and directional reflectance of a solar diffuser are known, then the spectral radiance of the diffuser is readily calculated and it can be used for the accurate absolute calibration of a satellite sensor. However, the solar diffuser is exposed during in-flight satellite sensor calibration to high-energy ultraviolet irradiance, particle impacts and atomic oxygen effects. This paper describes desirable solar diffuser characteristics and the results of proton and UV irradiation on the directional-hemispheric spectral reflectance, the bidirectional spectral reflectance factor and the polarization properties of candidate diffuser materials.

Guzman, Carmen T.↗

NASA NTRS1991

Stray light effects on calibrations using a solar diffuser

The sun is the intended source of radiation for a solar diffuser for the calibration of spacecraft radiometric sensors. Two unwanted sources have also been identified: (1) solar radiation reflected from the earth and scattered by the atmosphere, and (2) solar radiation reflected from surrounding spacecraft structures. This paper describes the determination of the stray radiation incident on the diffuser for the High Resolution Imaging Spectrometer (HIRIS). Finally, the optimization of the calibration geometry is considered.

Palmer, James M.↗

NASA NTRS1989

Optical radiation measurements II; Proceedings of the Meeting, Orlando, FL, Mar. 27, 28, 1989

The present conference discusses topics in the characterization of imaging radiometers, laboratory instrumentation, field and spacecraft instrumentation, and quantum and thermal standard detectors. Attention is given to UV radiometric imaging, dual-color radiometer imagery, a novel diode-array radiometer, a novel reference spectrophotometer, radiance calibration of spherical integrators, instrumentation for measurement of spectral goniometric reflectance, and a real-time IR background discrimination radiometer. Also discussed are a multichannel radiometer for atmosphere optical property measurements, the UV spectroradiometric output of a turbojet, characterizations of the Earth Radiation Budget Experiment scanning radiometers, total-radiation thermometry, future directions in Si photodiode self-calibration, and radiometric quality Ge photodiodes.

Palmer, James M.↗

NASA NTRS1986

Spectroradiometric calibration of the thematic mapper and multispectral scanner system

A list of personnel who have contributed to the program is provided. Sixteen publications and presentations are also listed. A preprint summarizing five in-flight absolute radiometric calibrations of the solar reflective bands of the LANDSAT-5 Thematic Mapper is presented. The 23 band calibrations made on the five dates show a 2.5% RMS variation from the mean as a percentage of the mean. A preprint is also presented that discusses the reflectance-based results of the above preprint. It proceeds to analyze and present results of a second, independent calibration method based on radiance measurements from a helicopter. Radiative transfer through the atmosphere, model atmospheres, the calibration methodology used at White Sands and the results of a sensitivity analysis of the reflectance-based approach is also discussed.

Slater, Philip N.↗