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The results of a preliminary study to access the accuracy of global ionospheric maps are presented. Global ionospheric maps, produced using dual-frequency data from the global network of GPS receivers, are.
A globally distributed network of dual-frequency global positioning system (GPS) receivers is the primary source of data used to measure ionospheric total electron content (TEC) on global scales. Maps of TEC useful for calibrating propagation delays, or monitoring the solar-terrestrial environment, can be produced using this continuously operating network. The maps can also form the basis of a TEC calibration service for users around the world. Potential users may include single-frequency satellite altimetry missions, satellite tracking stations, and astronomical observatories.
This paper presents methods of analyzing the perturbation due to thermal radiation and determining its effects on the long term orbital behavior of GPS satellites.
This paper examines the dependence of the threat model upon the spatial distribution of GPS measurements.
This paper presents a method for characterizing in terms of a scalar metric the degree which a given spatial region is sampled densely and uniformly by a given set of GPS measurements.
This paper discusses the frequency transfer in space using GPS measurements.
The paper discusses orbit determination of VSOP-2 regarding GPS measurements.
The Global Positioning System (GPS) constellation of satellites is revolutionizing the science and technology of the Earth's ionosphere.
Data from terrestrial GPS receivers are being used in growing numbers of applications requiring precise tropospheric sensing. One emerging application is the calibration of water vapor measurements from spaceborne microwave radiometers.
During the 1998-1999 Antarctic field season, we installed three autonomous GPS stations in Marie Byrd Land, West Antarctica to measure glacio-isostatic rebound and rates of spreading across the West Antartic Rift System.
In this paper, we describe some recent advances in GPS-based precise orbit determination for low-Earth orbiting satellites.
Technology is currently available to support real-time on-board knowledge of the position of a low earth orbitor at the 5-15 meter level using the civilian broadcast GPS signal with sophisticated models and filtering techniques onboard the spacecraft.
Data from a worldwide Global Positioning System (GPS) tracking network spanning six days during the EPOCH '92 campaign are used to estimate variations of the Earth's pole position every 30 minutes. The resulting polar motion time series is compared with estimates derived from very long baseline interferometry (VLBI) observations.
As part of TOPEX altimeter verification, the Global Positioning System has been used to measure the baseline between the verification site at oil platform Harvest and a GPS antenna collocated with the satellite laser ranging site at Quincy, California.
Study of the September-October 1997 Umbria-Marche earthquakes that took place in Italy. Use joint inversion of GPS and SAR interferometry data.
This paper talks about how 2 spacecraft launches add two new instrumetns for climate monitoring and GPS radio occultations.
The IGS network today consists of 364 stations managed by about, 100 different agencies worldwide. The RINEX observations are contributed to the IGS Data Centers, which permanently archive the data and make it freely available to all users. The primary customer of the data set is the IGS Analysis Centers, which acquire the data for generation of precise GPS products such as ephemerides, clocks, earth orientation parameters, and station position and velocities.
GPS measurements collected between 1999 and 2002 in Marie Byrd Land, West Antarctica indicate no significant present motion between East and West Antarctica greater than 1-2 nm/yr.