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At least 163 records · Page 9

Characterizing the scientific potential of satellite sensors

Analytical and programming support is to be provided to characterize the potential of the LANDSAT thematic mapper (TM) digital imagery for scientific investigations in the Earth sciences and in terrestrial physics. In addition, technical support to define lower atmospheric and terrestrial surface experiments for the space station and technical support to the Research Optical Sensor (ROS) study scientist for advanced studies in remote sensing are to be provided. Eleven radiometric calibration and correction programs are described. Coherent noise and bright target saturation correction are discussed along with image processing on the LAS/VAX and Hp-300/IDIMS. An image of San Francisco, California from TM band 2 is presented.

Source record↗

Characterizing the scientific potential of satellite sensors

Eleven thematic mapper (TM) radiometric calibration programs were tested and evaluated in support of the task to characterize the potential of LANDSAT TM digital imagery for scientific investigations in the Earth sciences and terrestrial physics. Three software errors related to integer overflow, divide by zero, and nonexist file group were found and solved. Raw, calibrated, and corrected image groups that were created and stored on the Barker2 disk are enumerated. Black and white pixel print files were created for various subscenes of a San Francisco scene (ID 40392-18152). The development of linear regression software is discussed. The output of the software and its function are described. Future work in TM radiometric calibration, image processing, and software development is outlined.

Source record↗

The Upper Atmosphere Research Satellite

The scientific aims of the Upper Atmosphere Research Satellite are discussed. Individual experiments studying energy input to the atmosphere, temperature and important trace chemical species, winds, the global morphology of ozone and of major trace species families, and the thermal structure of the middle atmosphere are described. The data processing and analysis on the ground are addressed along with correlative measurements and prelaunch theoretical studies.

Reber, Carl A.↗

Characterizing the scientific potential of satellite sensors

Algorithms and software were developed for the correction of coherent noise, scan correlated shift, and the bright target saturation effect in Thematic Mapper imagery. In addition, a package of LANDSAT Assessment System programs was developed to demonstrate the results from TM radiometric characterization and calibration work.

Lee, Y.↗

Scientific analysis of satellite ranging data

A network of satellite laser ranging (SLR) tracking systems with continuously improving accuracies is challenging the modelling capabilities of analysts worldwide. Various data analysis techniques have yielded many advances in the development of orbit, instrument and Earth models. The direct measurement of the distance to the satellite provided by the laser ranges has given us a simple metric which links the results obtained by diverse approaches. Different groups have used SLR data, often in combination with observations from other space geodetic techniques, to improve models of the static geopotential, the solid Earth, ocean tides, and atmospheric drag models for low Earth satellites. Radiation pressure models and other non-conservative forces for satellite orbits above the atmosphere have been developed to exploit the full accuracy of the latest SLR instruments. SLR is the baseline tracking system for the altimeter missions TOPEX/Poseidon, and ERS-1 and will play an important role in providing the reference frame for locating the geocentric position of the ocean surface, in providing an unchanging range standard for altimeter calibration, and for improving the geoid models to separate gravitational from ocean circulation signals seen in the sea surface. However, even with the many improvements in the models used to support the orbital analysis of laser observations, there remain systematic effects which limit the full exploitation of SLR accuracy today.

Smith, David E.↗

Coronal observations from the SMM satellite

The scientific purpose, coronal observations, and the instrument design and control of the Coronagraph/Polarimeter aboard the Solar Maximum Mission (SMM) satellite are discussed. The instruments were made with an optical design using an achromatic objective lens providing a 10 arcsec resolution in imaging and an SEC vidicon detector allowing integration on the low light levels of the corona. The computer control assures flexibility in the observing program to optimize observations of changing solar phenomena and allows rapid response to SMM or ground-commanded solar flare alerts.

Csoeke-Poeckh, A.↗

Algorithm Science to Operations for the National Polar-orbiting Operational Environmental Satellite System (NPOESS) Visible/Infrared Imager/Radiometer Suite (VIIRS)

The VIIRS sensor provides measurements for 22 Environmental Data Records (EDRs) addressing the atmosphere, ocean surface temperature, ocean color, land parameters, aerosols, imaging for clouds and ice, and more. That is, the VIIRS collects visible and infrared radiometric data of the Earth's atmosphere, ocean, and land surfaces. Data types include atmospheric, clouds, Earth radiation budget, land/water and sea surface temperature, ocean color, and low light imagery. This wide scope of measurements calls for the preparation of a multiplicity of Algorithm Theoretical Basis Documents (ATBDs), and, additionally, for intermediate products such as cloud mask, et al. Furthermore, the VIIRS interacts with three or more other sensors. This paper addresses selected and crucial elements of the process being used to convert and test an immense volume of a maturing and changing science code to the initial operational source code in preparation for launch of NPP. The integrity of the original science code is maintained and enhanced via baseline comparisons when re-hosted, in addition to multiple planned code performance reviews.

NPOESS (NATIONAL POLAR-ORBITING OPERATIONAL ENVIRO↗

Status of the MODIS Level 1B Algorithms and Calibration Tables

The Moderate Resolution Imaging Spectroradiometer (MODIS) makes observations using 36 spectral bands with wavelengths from 0.41 to 14.4 m and nadir spatial resolutions of 0.25km, 0.5km, and 1km. It is currently operating onboard the NASA Earth Observing System (EOS) Terra and Aqua satellites, launched in December 1999 and May 2002, respectively. The MODIS Level 1B (L1B) program converts the sensor's on-orbit responses in digital numbers to radiometrically calibrated and geo-located data products for the duration of each mission. Its primary data products are top of the atmosphere (TOA) reflectance factors for the sensor's reflective solar bands (RSB) and TOA spectral radiances for the thermal emissive bands (TEB). The L1B algorithms perform the TEB calibration on a scan-by-scan basis using the sensor's response to the on-board blackbody (BB) and other parameters which are stored in Lookup Tables (LUTs). The RSB calibration coefficients are processed offline and regularly updated through LUTs. In this paper we provide a brief description of the MODIS L1B calibration algorithms and associated LUTs with emphasis on their recent improvements and updates developed for the MODIS collection 5 processing. We will also discuss sensor on-orbit calibration and performance issues that are critical to maintaining L1B data product quality, such as changes in the sensor's response versus scan-angle.

MODIS LEVEL 1B ALGORITHMS↗

Smart Data Node in the Sky

A document discusses the physical and engineering principles affecting the design of the Smart Data Node in the Sky (SDNITS) -- a proposed Earth-orbiting satellite for relaying scientific data from other Earth-orbiting satellites to one or more ground station(s). The document characterizes the problem of designing the telecommunication architecture of the SDNITS as consisting of two main parts: (1) finding the most advantageous orbit for the SDNITS to gather data from the scientific satellites and relay the data to the ground, taking account of such factors as visibility and range; and (2) choosing a telecommunication architecture appropriate for the intended relay function.

Lansing, Faiza↗

Optimal orbits for space constellations of Mars navigation satellites

Recent scientific discoveries at Mars have heralded an unprecedented commitment and focus by NASA and its international partners toward further exploration of Mars. As part of this effort NASA has an on-going project, called the Mars Network, to examine communication and navigation infrastructure requirements needed to support Mars exploration.

satellite constellations navigation optimal design↗