Natural Resources

On the Edge: Southwest Shakes

March 1, 2012By
Researchers used data from 25 continuous GPS stations installed as part of the EarthScope Rio Grande Rift GPS experiment, supplemented by data from other GPS monuments in the southwestern U.S., resulting in a data set of daily position estimates of 284 GPS monuments for the years 2006 through 2010.

Using a large network of GPS stations, a team of researchers has found that the Rio Valley Rift in the Southwest United States — previously suspected to be dead — is slowly expanding, at a rate of about 0.1 millimeter per year. The Rio Grande Rift extends from Colorado’s central Rocky Mountains to Mexico. read more

On the Edge: Tracking Slips and Creeps: Earthquake Monitoring Gets Substantial Boost from GPS

July 1, 2011By
Arrow on a Velocity Field Map of Oregon and Washington represent ground motion as measured by GPS at each particular location. The grey circles are 2 sigma error ellipses (click to enlarge.)

The Earth’s surface is constantly shifting, being deformed as earthquake faults accumulate strain, and slip or slowly creep over time. Not long ago, scientists relied solely on seismometers to monitor the earth’s movements. Today, GPS has taken prominence as an indispensible tool. PANGA, the monitoring network covering the Pacific Northwest, uses GPS to monitor this movement by measuring the precise position (within 5 millimeters or less) of stations near active faults relative to each other. By determining how the stations have moved, ground deformation can be determined. read more

Out in Front: Welling Up

July 1, 2010By

One of the first industrial uses of GPS came in survey and seismic exploration for offshore oil, as evidenced by the cover story of this magazine’s September 1992 issue. A salient passage from that 18-year-old “Quality Control For Differential GPS in Offshore Oil and Gas Exploration” article: “Users are in danger of being mesmerized by the apparent simplicty of the technology and abandoning quality-control principles . . . . The key to routine operations is rigorous real-time quality control.” Eerily, among the companies acknowledged for support of that article was BP Exploration. read more

This article is tagged with and posted in From the Editor, Natural Resources

Innovation: Better Weather Prediction Using GPS

July 1, 2010By
Figure 3. The 21 GPS stations in the project area in the mountainous canton of Valais (see also Figure 2) used during the measurement campaign in July 2005. The stations’ altitudes vary between 527 meters (SION) and 3119 meters (ZER2).

Water Vapor Tomography in the Swiss Alps
A team of Swiss researchers is using data from a network of GPS receivers and the technique of tomography to obtain profiles of how moisture is distributed with height, which might lead to better weather forecasts. read more

This article is tagged with , and posted in From the Magazine, Innovation, Natural Resources, Remote Sensing

Sensor Fusion in Forestry

July 1, 2010By
Robotic wood harvester.

Modern machines such as wood harvesters can automatically cut trees and remove branches, but an expert is still needed to plan a thinning and to mark the trees to be felled. The process can be accelerated if the forest ranger can virtually mark trees to be cut, using geographic coordinates instead of colored crosses sprayed on the stems. This requires the robotic wood harvester to be able to locate itself accurately to enable automatic navigation to the next tree for cutting. Absorption of the GPS signal in the forest canopy leads to poor results, however, with errors up to 50 meters and more. read more

This article is tagged with and posted in Machine Control/Ag, Natural Resources, Sensor Fusion

On the Edge: Sharing GNSS Wealth

March 1, 2010By

Last year I helped coordinate a three-week workshop for 50 scientists from 15 African countries, introducing the basics of GPS for applications with socioeconomic benefits and scientific exploration. Held in Trieste, Italy, the workshop was quite successful, producing new initiatives on the African continent. We repeat the workshop next month, 
April 6–24, again in Trieste. read more

The System: Glitches and Vulnerabilities

October 1, 2009By

A range of unrelated events in September show that GPS, the world’s preeminent GNSS, remains a work in progress. The first in a series of deviations from normal GPS signal broadcasts during September was noted by researches at the University of New Brunswick, among others around the globe, who found that normal signals from the L1 and L2 transmitters on... read more