The optical alignment of the star trackers on the Global Precipitation Measurement (GPM) core spacecraft at NAS A Goddard Space Flight Center (GSFC) was challenging due to the layout and structural design of the GPM Lower B us Structure (LBS) in which the star trackers are mounted as well as the presence of the star tracker shades that blocke d line-of-sight to the primary star tracker optical ...

Star tracker is one of the most promising optical attitude measurement devices and it is widely used in spacecraft for its high accuracy. However, how to realize and verify such an accuracy remains a crucial but unsolved issue until now. The authenticity of the accuracy measurement method of a star tracker will eventually determine the satellite performance. A new and robust accuracy measuremen...

An alternative to the 3D motion marker-based optical camera capture is the Star Tracker 3D, a marker-less video-based tracking system. The aim of our study is to investigate the efficacy of the Star Tracker 3D. A series of gait analysis tests were carried out on ten subjects with a marker and marker-less tracking system simultaneously. The study suggests potential application in gait analysis i...

We discuss the characteristics of a Quadrant-CCD developed by Tektronix for pointing and tracking applications. The device is discussed in the context of its application to the Johns Hopkins University adaptive optics program, where it is being used for the correction of stellar image motion resulting from atmospheric turbulence. The transfer function of the device is discussed and results are ...

This paper addresses the problem of attitude estimation in fractionated spacecraft clusters. Each module in the cluster may have either a startracker, a relative attitude sensor, or both. Using results in nonlinear observability theory, we provide graph-theoretic sufficient conditions for the attitude of every module to be observable. In particular we show that the attitude of every module in t...

This paper describes a path toward the development of theory for using a low noise high frame rate camera as a star tracker for spacecraft attitude estimation. The benefit of using a low noise high frame rate camera is that star data can be sampled at a faster rate while allowing one to measure very dim stars, increasing the number of stars available for attitude estimation. The development of ...

The STAR experiment at the Relativistic Heavy Ion Collider RHIC studies the new state of matter produced in relativistic heavy ion collisions and the spin structure of the nucleon in collisions of polarized protons. In order to improve the capabilities for heavy flavor measurements and the reconstruction of charged vector bosons an upgrade of the tracking system both in the central and the forw...

NAVSYS Corporation has developed a design and prototype of a flexible, high performance, miniaturized, space-based Software GPS Receiver (SSGR) based on a Software Defined Radio (SDR) architecture that optimally combines GPS, INS, and star-tracker inputs to provide a flexible, integrated precision navigation and attitude determination solution for space applications including LEO, HEO and GEO m...