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Ostrow, H.

Publications and source records attributed to Ostrow, H..

10 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1990

Sensor performance analysis

The theory is described and the equations required to design are developed and the performance of electro-optical sensor systems that operate from the visible through the thermal infrared spectral regions are analyzed. Methods to compute essential optical and detector parameters, signal-to-noise ratio, MTF, and figures of merit such as NE delta rho and NE delta T are developed. A set of atmospheric tables are provided to determine scene radiance in the visible spectral region. The Planck function is used to determine radiance in the infrared. The equations developed were incorporated in a spreadsheet so that a wide variety of sensor studies can be rapidly and efficiently conducted.

Montgomery, H. E.↗
NASA NTRS1989

Moderate Resolution Imaging Spectrometer - A progress report (April 1989)

The Moderate Resolution Imaging Spectrometer (MODIS) is a facility instrument to be flown on the first Earth Observing System (scheduled launch in the late 1990s). The MODIS has two components. One component is a 110-deg-scan-angle instrument called MODIS-N (nadir). This instrument has 40 selected bands supporting observations of the land surface, the oceans, and atmosphere in the visible, NIR, short-wave IR (1.0-3.0 microns), and thermal IR (3.0-15.0 microns). The other component is a 90-deg-scan-angle scanning instrument that can tilt fore and aft along the satellite track, called MODIS-T (tilt). Both MODIS-N and MODIS-T are nearing the end of detailed design studies. The driving scientific requirements include absolute calibration accuracy 2 percent, instrument-induced polarization less than 2 percent, SNR reaching 800:1 for observing ocean color at large solar zenith angles, and dynamic range allowing observations of cloud characteristics and snow-covered areas.

Salomonson, V. V.↗
NASA NTRS1988

Moderate resolution imaging spectrometer-nadir (MODIS-N) - Progress 1988

The paper describes progress made through 1987 in refining the required characteristics of the MODIS-N, which is one of two MODIS sensors being planned as a facility for the earth observing system. The MODIS-N will make it possible to observe new characteristics of the land and ocean surfaces and the troposphere at least once every three days over the entire globe for a decade following launch. Spatial resolutions of 1000 m or better are expected.

Salomonson, V. V.↗
NASA NTRS1987

MODIS - Advanced facility instrument for studies of the earth as a system

The Moderate Resolution Imaging Spectrometer (MODIS), a key part of the Earth Observing System planned for the 1990's, is described. The complementary MODIS-T (64 channels) and MODIS-N (40 channels) instruments provide a multispectral observing capability that has application to land, ocean, and atmospheric research. The modules have a 500-1000 meter spatial resolution to accompany a swath width sufficient to provide two-day repeat coverage from a polar-orbiting, sun-synchronous, space-station serviceable platform. High signal-to-noise capability (500/1 or better) and 10-12 bit quantization over the dynamic ranges of the various spectral bands will be provided by the two modules.

Salomonson, V. V.↗
NASA NTRS1986

Preliminary system concepts for MODIS - A moderate resolution imaging spectrometer for EOS

Plans are underway at NASA Goddard to develop a moderate-resolution (0.5-1.0-km) imaging spectrometer with 104 spectral bands in the range from 0.4 to 14.2 microns for use as a NASA facility aboard the Space Station Earth Observation System. Science requirements call for the system to image the earth's surface every 2 d for a period of 10 yr, using two electrooptic sensors. MODIS-T (tilt) has 64 10-nm-wide channels in the 400-1000-nm range. The system has 5-cm-diameter optics, scans + or - 45 deg, and can be pointed + or - 60 deg along track. Calculated S/N is in excess of 800:1 near 400 nm. MODIS-N (nadir) scans + or - 45 deg about nadir with 12 500-m- and 28 1000-m-resolution channels, including two polarization channels and 14 thermal-IR channels. With 20-cm-diameter optics the calculated S/N of the majority of the reflected solar bands is over 1000:1. NETD values for the thermal bands are on the order of 0.1-0.2 K at 300 K. Combined MODIS-T and MODIS-N data rates are 8.3 Mb/s in daylight and 1.5 Mb/s at night, resulting in a total of 360 Gb/d.

Barnes, W. L.↗
NASA NTRS1980

Thermal IR imaging system using a self-scanned HgCdTe/CCD detector array

It is likely that future high resolution earth observation imaging systems will utilize self-scanned IR detectors. In an initial step toward this goal, an IR imaging system operating in the 10 to 12 micron spectral region has been developed. This system uses a 9-element HgCdTe/CCD linear array operating in the photoconductive mode, nine pre-amplifiers and a silicon CCD multiplexer integrated into a focal plane assembly. Opto-mechanical techniques are used to scan the scene and images are produced in real time. The imaging performance of this system is described and measurements of noise, responsivity, specific detectivity, and detector sensitivity profiles are presented. The requirements for more advanced detector arrays for use in future NASA remote sensing missions are also discussed.

Husain-Abidi, A. S.↗
NASA NTRS1973

Control of contaminants on sensors. Report 1: Interdirectorate working group on earth observation sensors

Examples of contamination of sensors from various sources during space missions are presented. Design precautions to provide access to optical surfaces and venting of outgassing products are recommended as methods for coping with contamination. The effects of the sensor materials on sensor contamination are analyzed. Actions to be taken during transportation, storage, and testing of sensors to avoid contamination are discussed.

Hovis, W.↗