Two of the general criticisms of GPS are that the technology doesn't do very well in dense urban areas, and it doesn't get accurate enough for some uses. At least two separate organizations—the ...

At the heart of GPS is the ability to measure the distance from a receiver to several satellites. There are always 4 to 8 satellites visible at any given time. Each satellite sends out a signal, which ...

Editor's note: The following is Planet Analog's first in a series of Design Challenges. This one was sent to me by a reader/design team interested in using GPS in a particular application. We are ...

Since water blocks the radio frequency used for GPS triangulation, GPS is considered pretty useless for SCUBA divers. Apparenlty some of them are finding it useful to waterproof off the shelf units ...