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Eisenman, A. R.

Publications and source records attributed to Eisenman, A. R..

8 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS2002

The Mars Exploration Rover suncam

One of the onboard cameras is to point the high gain antenna at Earth and to provide a reference for the inertial measurement unit that is used for rover navigation.

Mars rover sunsensing CCD centroiding↗
NASA NTRS1997

The New Generation of Autonomous Star Trackers

The most accurate instrument for spacecraft attitude determination is a star tracker. However, these first-genereation designs are limited to outputting positions of a few stars in sensor-referenced coordinates and require extensive external processing.

pointing↗
NASA NTRS1981

CCD sensors for interplanetary spacecraft navigation and pointing control

The applications of practical optical image sensing CCDs to interplanetary spacecraft precision science payload delivery are discussed. The increasing demand for precision and flexibility in spacecraft for proposed new missions is forcing a transition to autonomous onboard navigation and pointing control. Onboard processing of video data is a crucial element in this transition and is made possible by CCD imagers and microprocessors. The pending Halley's comet close flyby is used as an example to examine details of the sensor design and the data processing which will meet the requirements. Target body centerfinding for optical navigation, target body tracking signal processing, and CCD sensor heads are examined, and flow charts and block diagrams are given for each.

Eisenman, A. R.↗
NASA NTRS1979

CCD sensors for spacecraft optical navigation

The optical navigation process uses spaceborne measurements of the apparent direction vector from the spacecraft to a target body, (planet, satellite, star, etc.) to improve estimates of the spacecraft trajectory. Ground-based controllers assimilate the optical measurements, together with spacecraft radio-tracking data and target ephemeris data, to generate a best estimate of the trajectory relative to the target. The present paper deals with a development program supporting the use of (solid state) CCD (Charged Coupled Device) imagers for spacecraft navigation. It is shown that stars can be detected that are two to three magnitudes fainter than with an equivalent vidicon based instrument, that effects of global response nonuniformity and dark current spikes can be essentially eliminated from the data as a result of the reproducibility of both effects, and that charge trailing during readout of star image data can lead to position measurement errors.

Eisenman, A. R.↗
NASA NTRS1970

Why go to the outer planets

Scientific motivation for outer planets exploration covering solar system clues, atmosphere comparisons with earth, radiation and planetary radii measurement, etc

Eisenman, A. R.↗