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Proceedings Paper

Virtual instrument simulator for CERES
Author(s): John J. Chapman
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Paper Abstract

A benchtop virtual instrument simulator for CERES (clouds and the Earth's radiant energy system) has been built at NASA, Langley Research Center in Hampton, Virginia. The CERES instruments will fly on several earth orbiting platforms notably NASDA's tropical rainfall measurement mission (TRMM) and NASA's Earth observing system (EOS) satellites. CERES measures top of the atmosphere radiative fluxes using microprocessor controlled scanning radiometers. The CERES virtual instrument simulator consists of electronic circuitry identical to the flight unit's twin microprocessors and telemetry interface to the supporting spacecraft electronics and two personal computers (PC) connected to the I/O ports that control azimuth and elevation gimbals. Software consists of the unmodified TRW developed flight code and ground support software which serves as the instrument monitor and NASA/TRW developed engineering models of the scanners. The CERES instrument simulator will serve as a testbed for testing of custom instrument commands intended to solve in-flight anomalies of the instruments which could arise during the CERES mission. One of the supporting computers supports the telemetry display which monitors the simulator microprocessors during the development and testing of custom instrument commands. The CERES engineering development software models have been modified to provide a virtual instrument running on a second supporting computer linked in real time to the instrument flight microprocessor control ports. The CERES instrument simulator will be used to verify memory uploads by the CERES flight operations TEAM at NASA. Plots of the virtual scanner models match the actual instrument scan plots. A high speed logic analyzer has been used to track the performance of the flight microprocessor. The concept of using an identical but non-flight qualified microprocessor and electronics ensemble linked to a virtual instrument with identical system software affords a relatively inexpensive simulation system capable of high fidelity.

Paper Details

Date Published: 31 December 1997
PDF: 12 pages
Proc. SPIE 3221, Sensors, Systems, and Next-Generation Satellites, (31 December 1997); doi: 10.1117/12.298079
Show Author Affiliations
John J. Chapman, NASA Langley Research Ctr. (United States)


Published in SPIE Proceedings Vol. 3221:
Sensors, Systems, and Next-Generation Satellites
Hiroyuki Fujisada, Editor(s)

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