Traditional GPS satellite signals can be used to measure snow depth and even soil and vegetation moisture, according to a research team led by the University of Colorado at Boulder.
The finding, to be presented in mid-December at the American Geophysical Union meeting in San Francisco, is expected to assist farmers, meteorologists and water resource managers.
The researchers developed a technique that uses interference patterns that are created when GPS signals reflect off the ground — called “multi path” signals — and are combined with signals that arrive directly from the satellite.
A field in Marshall just south of Boulder was the site of a recent demonstration. The area had been hit by two large snowstorms over three weeks in March and April, and GPS tracked snow-depth changes.
Another effort analyzed how GPS signals traveling through alfalfa, corn and grass correlate with water in the vegetation, revealing the moisture content.
Done in collaboration with Munson Farms of Boulder, the GPS study showed how the signals analyze an entire field, “unlike individual moisture sensors that are sometimes set up to measure only small, specific areas,” said Bob Munson, owner of Munson Farms and a former antenna engineer at Ball Aerospace & Technologies of Boulder.
If a farmer relied on only a single soil-moisture sensor that happened to be in an isolated dry area of the field, it could adversely affect the timing and quality of the harvest, Munson said.
Ann Schrader: 303-954-1967 or aschrader@denverpost.com
