GPS in the Snow
Recall that one of the errors in GPS is called “mulitipath error” - that’s when the signal from the GPS satellite bounces off something before it gets to the receiver, making its path artificially “longer.” Its noise for most applications, but in fact is valuable in ... wait for it… measuring snow depth. Researchers at the University of Colorado, Boulder, looking to learn about the impact of soil moisture on the echoes found their experiment in the middle of a snow storm. That lead to a startling realization: “The snow slowed the reflected GPS signals, and the delay corresponded to the snow’s depth…” That in turn led to a method to accurately measure snow fall in real time. The team’s paper, in Geophysical Research Letters appeared this month.
