GPS World - February 2008 - (Page 55) System Design & Test | INNOVATION p FIGURE 6 The signature of the Sumatra tsunami in total electron content (TEC) at 03:18 UT (right) compared with the unperturbed TEC (left). The TEC images have been computed by vertical integration of the perturbed and unperturbed electron density fields. The broken lines represent the Topex/Poseidon (left) and Jason-1 (right) trajectories. The blue contours represent the geomagnetic field inclination. also explains this second perturbation as induced by the role of the magnetic field in the neutral-plasma coupling. GPS Data Processing To validate our model, we use groundbased GPS receivers to look for the ionospheric signal induced by tsunamis. Prior research has shown post-processed results detecting a tsunami-generated TEC signal using regional GPS networks such as GEONET in Japan (about 1,000 stations) or the Southern California Integrated GPS Network (about 200 stations). Those studies benefited from the very high density of GPS receivers in the regional networks, so that, for example, no forward modeling was needed to help initially identify the characteristics of the tsunami-generated signal. High-Precision Processing. More than 1,300 globally-distributed dual-frequency GPS receivers are available using publicly accessible networks, including those of the International GNSS Service and the Continuously Operating GPS Stations coordinated by the U.S. National Geodetic Survey. Most researchers estimate vertical ionospheric structure and, simultaneously, treat hardware-related biases as nuisance parameters. In our approach for calibrating GPS receiver and satellite inter-frequency biases, we take advantage of all available GPS receivers using a new processing technique based on the Global Ionospheric Mapping software developed at the Jet Propulsion Laboratory (JPL). FIGURE 7 shows a JPL TEC map using 1,000 GPS stations. This new capability is designed to estimate receiver biases for www.gpsworld.com February 2008 | GPS World 55 http://www.gps-wireless.com http://www.gps-wireless.com http://www.gpsworld.com
Table of Contents Feed for the Digital Edition of GPS World - February 2008 GPS World - February 2008 Contents Out in Front Expert Advice Galileo's Second Coming Soon UPS First to Use ADS-B European Industry Group Galileo Validation 2008 Antenna Survey Tsumani Detection by GPS Classifieds Advertisers Index Seen + Heard GPS World - February 2008 GPS World - February 2008 - GPS World - February 2008 (Page 1) GPS World - February 2008 - GPS World - February 2008 (Page 2) GPS World - February 2008 - GPS World - February 2008 (Page 3) GPS World - February 2008 - Contents (Page 4) GPS World - February 2008 - Contents (Page 5) GPS World - February 2008 - Out in Front (Page 6) GPS World - February 2008 - Out in Front (Page 7) GPS World - February 2008 - Expert Advice (Page 8) GPS World - February 2008 - Expert Advice (Page 9) GPS World - February 2008 - Expert Advice (Page 10) GPS World - February 2008 - Expert Advice (Page 11) GPS World - February 2008 - Galileo's Second Coming Soon (Page 12) GPS World - February 2008 - Galileo's Second Coming Soon (Page 13) GPS World - February 2008 - Galileo's Second Coming Soon (Page 14) GPS World - February 2008 - UPS First to Use ADS-B (Page 15) GPS World - February 2008 - UPS First to Use ADS-B (Page 16) GPS World - February 2008 - UPS First to Use ADS-B (Page 17) GPS World - February 2008 - UPS First to Use ADS-B (Page 18) GPS World - February 2008 - UPS First to Use ADS-B (Page 19) GPS World - February 2008 - UPS First to Use ADS-B (Page 22) GPS World - February 2008 - UPS First to Use ADS-B (Page 23) GPS World - February 2008 - UPS First to Use ADS-B (Page 26) GPS World - February 2008 - UPS First to Use ADS-B (Page 27) GPS World - February 2008 - European Industry Group (Page 28) GPS World - February 2008 - European Industry Group (Page 29) GPS World - February 2008 - Galileo Validation (Page 30) GPS World - February 2008 - Galileo Validation (Page 31) GPS World - February 2008 - Galileo Validation (Page 32) GPS World - February 2008 - Galileo Validation (Page 33) GPS World - February 2008 - Galileo Validation (Page 34) GPS World - February 2008 - Galileo Validation (Page 35) GPS World - February 2008 - Galileo Validation (Page 36) GPS World - February 2008 - Galileo Validation (Page 37) GPS World - February 2008 - 2008 Antenna Survey (Page 38) GPS World - February 2008 - 2008 Antenna Survey (Page 39) GPS World - February 2008 - 2008 Antenna Survey (Page 40) GPS World - February 2008 - 2008 Antenna Survey (Page 41) GPS World - February 2008 - 2008 Antenna Survey (Page 42) GPS World - February 2008 - 2008 Antenna Survey (Page 43) GPS World - February 2008 - 2008 Antenna Survey (Page 44) GPS World - February 2008 - 2008 Antenna Survey (Page 45) GPS World - February 2008 - 2008 Antenna Survey (Page 46) GPS World - February 2008 - 2008 Antenna Survey (Page 47) GPS World - February 2008 - 2008 Antenna Survey (Page 48) GPS World - February 2008 - 2008 Antenna Survey (Page 49) GPS World - February 2008 - Tsumani Detection by GPS (Page 50) GPS World - February 2008 - Tsumani Detection by GPS (Page 51) GPS World - February 2008 - Tsumani Detection by GPS (Page 52) GPS World - February 2008 - Tsumani Detection by GPS (Page 53) GPS World - February 2008 - Tsumani Detection by GPS (Page 54) GPS World - February 2008 - Tsumani Detection by GPS (Page 55) GPS World - February 2008 - Tsumani Detection by GPS (Page 56) GPS World - February 2008 - Classifieds (Page 57) GPS World - February 2008 - Seen + Heard (Page 58) GPS World - February 2008 - Seen + Heard (Page 59) GPS World - February 2008 - Seen + Heard (Page 60)
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