Results 41 to 50 of about 134,911 (241)

Transits and secondary eclipses of HD 189733 with Spitzer [PDF]

, 2008
We present limits on transit timing variations and secondary eclipse depth variations at 8 microns with the Spitzer Space Telescope IRAC camera. Due to the weak limb darkening in the infrared and uninterrupted observing, Spitzer provides the highest ...
David Charbonneau, Drake Deming, Eric Agol, Heather Knutson, Holman M, James Bushong, Jason H. Steffen, Nicolas B. Cowan, Queloz D, Sasselov D, Torres M   +10 more
core   +2 more sources

A rapid stability assessment of China's IGS sites after the Ms7. 0 Lushan earthquake

Geodesy and Geodynamics, 2013
A rapid and accurate assessment of the stability of surveying and mapping reference points is important for post – disaster rescue, disaster relief and reconstruction activities. Using Precise Point Positioning (PPP) technology, a rapid assessment of the
Meng Jie, Chen Yongxiang, Wan Xin, Zhang Yingli   +3 more
doaj   +1 more source

ALMA Solar Ephemeris Generator [PDF]

, 2019
An online software tool for the easy preparation of ephemerides of the solar surface features is presented. It was developed as a helper tool for the preparation of observations of the Sun with the Atacama Large Millimeter/submillimeter Array (ALMA), but
Brajša, R., Skokić, I.
core   +3 more sources

Real-Time Precise Orbit Determination of Low Earth Orbit Satellites Based on GPS and BDS-3 PPP B2b Service

Remote Sensing
This study investigates and verifies the feasibility of the precise point positioning (PPP)-B2b enhanced real-time (RT) precise orbit determination (POD) of low Earth orbit (LEO) satellites.
Yali Shi, Tianhe Xu, Min Li, Kai Wei, Shuai Wang, Dixing Wang   +5 more
doaj   +1 more source

Precision rectification of high resolution satellite imagery without ephemeris data

International Journal of Applied Earth Observation and Geoinformation, 2001
Abstract The huge capability of high resolution satellite imageries (HRSI), that includes spatial, spectral, temporal and radiometric resolutions as well as stereoscopic vision introduces them as a powerful new source for the Photogrammetry, Remote Sensing and GIS communities.
Mahmoud Reza Delavar, Ahmad Abootalebi, Mohammad Javad Valadan Zoej, Saeid Sadeghian   +3 more
openaire   +2 more sources

Assuring the Legacy of the CoRoT Planets

EPJ Web of Conferences, 2015
For the long-lasting impact of CoRoT’s planet findings, precise knowledge of the times of their transits is of vital importance for any future observing campaigns.
Deeg H.J., Klagyivik P., Alonso R., Hoyer S.   +3 more
doaj   +1 more source

Precise Orbit Determination of LEO Satellite Using Dual-Frequency GPS Data [PDF]

Journal of Astronomy and Space Sciences, 2009
KOrea Multi-purpose SATellite (KOMPSAT)-5 will be launched at 550km altitude in 2010. Accurate satellite position (20 cm) and velocity (0.03 cm/s) are required to treat highly precise Synthetic Aperture Radar (SAR) image processing.
Yoola Hwang, Byoung-Sun Lee, Jaehoon Kim, Jae-Cheol Yoon   +3 more
doaj   +1 more source

Analysis and Assessment of BDS-2 and BDS-3 Broadcast Ephemeris: Accuracy, the Datum of Broadcast Clocks and Its Impact on Single Point Positioning

Remote Sensing, 2020
For the global ordinary users, the broadcast ephemeris plays important roles in positioning, navigation and timing (PNT) services. With the construction of a new generation of the BeiDou navigation satellite system (BDS), the development of BDS has ...
Guoqiang Jiao, Shuli Song, Yangyang Liu, Ke Su, Na Cheng, Shengli Wang   +5 more
doaj   +1 more source

ASSIST: An Ephemeris-Quality Test Particle Integrator [PDF]

arXiv, 2023
We introduce ASSIST, a software package for ephemeris-quality integrations of test particles. ASSIST is an extension of the REBOUND framework and makes use of its IAS15 integrator to integrate test particle trajectories in the field of the Sun, Moon, planets, and 16 massive asteroids, with the positions of the masses coming from the JPL DE441 ephemeris
arxiv  

Performance Assessment of Non-Integer-Hour Data Blocks in BDS Broadcast Ephemeris

IEEE Access
Due to system anomalies, BeiDou navigation satellite system (BDS) sometimes updates the broadcast ephemeris at non-integral hours. The gross errors contained in the non-integer-hour data blocks of broadcast ephemeris will lead to the signal-in-space (SIS)
Jingjing Wang, Chao Zhou
doaj   +1 more source