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Yunck, T.

Publications and source records attributed to Yunck, T..

18 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1999

A History of GPS Sounding

The roots of GPS sounding go back to the first days of interplanetary flight. Today we have the almost concurrent emergence of the very element vital to a new global enterprise in GPS sounding: copious high beacons at ideal frequencies bathing the globe; a profusion of low obiters carrying GPS receivers and designed for real-time global data transfer; low-cost microelectronics of unprecedented power; and the occultation techniques itself the most precise and arguably the simplest atmospheric probe yet devised.

occultation↗
NASA NTRS1995

Incorporation of Orbital Dynamics to Improve Wide-Area Differential GPS

A powerful technique to compute precise GPS satellite orbits for the FAA Wide-Area Augmentation System (WAAS) has been evaluated. This dynamical technique estimates GPS satellite states from a long history of measurements not only yields accurate orbit solutions, but it enables separation of orbit and satellite clock errors and yields orbit accuracies of better than one meter within the service volume, as compared to the JPL precise ephemerides.

Orbital↗
NASA NTRS1994

GPS Data, Acquisition, Environmental Effects

Precise geodesy with the Global Positioning System (GPS) emerged in the early 1990s from a decade-long incubation to find vigorous application worldwide.

Global Positioning System (GPS) geodetic receivers↗
NASA NTRS1993

Orbit Determination

An Earth satellite collecting GPS data with an onboard receiver can compute its state in a diversity of ways, the choice depending in part on the type of orbit and mission requirements.

GPS data tracking and navigation real time state k↗
NASA NTRS1983

Autonomous navigation using lunar beacons

The concept of using lunar beacon signal transmission for on-board navigation for earth satellites and near-earth spacecraft is described. The system would require powerful transmitters on the earth-side of the moon's surface and black box receivers with antennae and microprocessors placed on board spacecraft for autonomous navigation. Spacecraft navigation requires three position and three velocity elements to establish location coordinates. Two beacons could be soft-landed on the lunar surface at the limits of allowable separation and each would transmit a wide-beam signal with cones reaching GEO heights and be strong enough to be received by small antennae in near-earth orbit. The black box processor would perform on-board computation with one-way Doppler/range data and dynamical models. Alternatively, GEO satellites such as the GPS or TDRSS spacecraft can be used with interferometric techniques to provide decimeter-level accuracy for aircraft navigation.

Khatib, A. R.↗