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At least 73 records · Page 4
All sourcesNASA NTRSDOE OSTI
NASA NTRS2020

Design and Performance of an Open-Source Star Tracker Algorithm on Commercial Off-the-Shelf Cameras and Computers

Recent frustration in finding low size, weight, power (SWaP), cost, and lead time star trackers has driven an internal research and development effort at Johnson Space Center (JSC) in partnership with Rensselaer Polytechnic Institute (RPI) to develop and demonstrate a commercial off-the-shelf (COTS) camera and COTS computer-based star tracker system. A set of open-source algorithms has been developed and their function demonstrated on multiple low-cost COTS single board computers (SBCs) across a variety of operating systems and COTS cameras. The goal of this effort is to release the software and setup guide to the community in order to reduce spacecraft development costs while increasing their capability (perhaps most of interest to low-cost missions like CubeSats). This material will show the high level architecture of the system, detail the algo-rithm, various tested configurations, and results. Forward work and applications will also be discussed.

Pedrotty, Samuel↗
NASA NTRS1976

A precision star tracker utilizing advanced techniques and materials

An image dissector star tracker has been developed which operates in the photon counting mode making it possible to utilize all digital electronics. A unique pulse processing circuit allows bright stars to be tracked as well as dim stars. Thermal mechanical stability has been greatly enhanced by fabricating a housing with graphite/epoxy composite material with a linear coefficient of thermal expansion near zero. Test results indicate the +10 Mv stars can be acquired and tracked, while position variation with star intensity is less than 2 arc seconds from 2.5 Mv to +10 Mv. The noise equivalent angle for a +8 Mv star is 3 arc seconds. Polynominal correction for remaining cross-coupling and nonlinearity reduced error over total 1 x 1 deg field to 1.5 arc seconds.

Gates, R. F.↗
NASA NTRS1992

A low-cost, CCD solid state star tracker

Applied Research Corporation (ARC) has developed an engineering model of a multi-star CCD-based tracker for space applications requiring radiation hardness, high reliability and low power consumption. The engineering unit compared favorably in functional performance tests to the standard NASA single-star tracker. Characteristics of the ARC star tracker are: field of view = 10 deg x 7.5 deg, sensitivity range of -1 to +5 star magnitude, NEA = 3 in x 3 in, linearity = 5 in x 5 in, and power consumption of 1-3 W (operating mode dependent). The software is upgradable through a remote link. The hardware-limited acquisition rate is 1-5 Hz for stars of +2 to +5 magnitude and 10-30 Hz for -1 to +2 magnitude stars. Mechanical and electrical interfaces are identical to the standard NASA star tracker.

Chmielowski, M.↗
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 NTRS1984

Optical analysis of the star-tracker telescope for Gravity Probe

A ray tracing modeling of the star tracker telescope for Gravity Probe was used to predict the character of the output signal and its sensitivity to fabrication errors. In particular, the impact of the optical subsystem on the requirement of 1 milliarc second signal linearity over a + or - 50 milliarc second range was examined. Photomultiplier and solid state detector options were considered. Recommendations are made.

Zissa, D. E.↗
NASA NTRS1993

Flight Performance of TOPEX/POSEIDON Star Tracker

The TOPEX/POSEIDON spacecraft was launched on August 10, 1992. This paper will present data on the measured performance of the ASTRA Star Trackers supplied by Hughes Danbury Optical Systems (HDOS) for this satellite.

Topex/Poseidon↗
NASA NTRS1997

Realization of a Faster, Cheaper, Better Star Tracker for the New Millennium

The first Danish satellite, إrsted, will be launched in August of 1997. The scientific objective of إrsted is to perform a precision mapping of the Earth's magnetic field. Attitude data for the payload and the satellite are provided by the Advanced Stellar Compass (ASC) star tracker. The ASC consists of a CCD star camera and a capable microprocessor which operates by comparing the star image frames taken by the camera to its internal star catalogs.

star↗
NASA NTRS1994

Color/magnitude calibration for National Aeronautics and Space Administration (NASA) standard Fixed-Head Star Trackers (FHST)

This paper characterizes and analyzes the spectral response of Ball Aerospace fixed-head star trackers, (FHST's) currently in use on some three-axis stabilized spacecraft. The FHST output is a function of the frequency and intensity of the incident light and the position of the star image in the field of view. The FHST's on board the Extreme Ultraviolet Explorer (EUVE) have had occasional problems identifying stars with a high B-V value. These problems are characterized by inaccurate intensity counts observed by the tracker. The inaccuracies are due to errors in the observed star magnitude values. These errors are unique to each individual FHST. For this reason, data were also collected and analyzed from the Upper Atmosphere Research Satellite (UARS). As a consequence of this work, the Goddard Space Flight Center (GSFC) Flight Dynamics Division (FDD) hopes to improve the attitude accuracy on these missions and to adopt better star selection procedures for catalogs.

Landis, J.↗
NASA NTRS1987

Star-Tracker Computer Program

Image-analyzing pointing systems aimed to high precision. Star-tracker program, STRACKER, developed to solve algorithm-design problems for area-array tracking and pointing systems operating at accuracies of 0.001 to 0.01 picture element. Includes auxiliary programs for reformatting point-spread data from commercial ACCOSV lens-design program. Other optical-analysis program data reformatted by use of utility routines included in package. Written in FORTRAN 77.

Glavich, Thomas↗