Geocaching article from AF News
GPS satellites help outdoor hobbyists link up
by Senior Airman John Parie
341st Space Wing Public Affairs
MALMSTROM AIR FORCE BASE, Mont. (AFPN) -- The coordinates N 47 degrees 12.595 W 110 degrees 55.990 mean very little to most people, but to a group of hunters know as "geocachers," it is the beginning of an adventure that starts on a nearby mountainside and ends with a hidden treasure in the belly of a state park.
Geocaching is a sport where people, using a handheld Global Positioning System unit, comb the countryside in search of "caches," which are containers, ranging in size from 35 mm film cases to standard military ammo boxes, that usually hold a log book, pen and various small trinkets. Once they find a cache, hunters sign the logbook, exchange a trinket and return the cache to its hiding place.
The only requirements for this outdoor hunt are a GPS receiver and a sense of adventure. A base-line receiver can be bought at most sports or electronics stores for about $100.
There are 25 caches within 30 miles of here and more than 750 scattered throughout Montana.
The sport began in May of 2000, following an announcement from former President Bill Clinton's administration that the intentional degradation of signals to consumer GPS units was being removed, making the consumer devices 10 times more accurate.
The first cache was hidden May 3, 2000, outside of Portland, Ore. Within three days, the cache had been visited twice, and a global phenomenon was born. Today, there are 146,137 active caches in 213 countries, according to the official Web site of the sport.
The backbone of this sport rests in the hands of Air Force Space Command operators and maintainers, whose mission includes the Navstar Global Positioning System that makes it all possible.
The Navstar Global Positioning System is a constellation of orbiting satellites that provides navigation data to military and civilian users all over the world. It is controlled by Airmen of the 50th Space Wing, at Schriever Air Force Base, Colo., according to the Schriever Web page. Delta II expendable launch vehicles launch GPS satellites from Cape Canaveral Air Station, Fla., into nearly 11,000-mile circular orbits.
"We're the satellite fliers here at the 50th Space Wing," said Ed Parsons, the wing's public affairs chief. "We fly the GPS satellites and keep them operating so that GPS users, both military and civilian, are able to take full advantage of this state-of-the-art satellite navigation system in their own backyards."
Airmen of the system's master control station, operated by the 50th Space Wing's 2nd Space Operations Squadron at Schriever, are responsible for monitoring and controlling the GPS satellite constellation. The GPS-dedicated ground system consists of five monitoring stations and four ground antennas located around the world. The monitor stations use GPS receivers to passively track the navigation signals on all satellites.
"From being able to direct munitions to an exact target to guiding outdoor enthusiasts along a sophisticated scavenger hunt, there isn't a more exact timing and navigation system anywhere," said Col. Gregg Billman, 45th Operations Group commander at Patrick AFB, Fla. "That's the utility and versatility of GPS, and it's only launched from Cape Canaveral."
"The sport provides a great way for families to get out and enjoy the beauty of Montana," said Airman 1st Class Chris Callihan, of the 341st Security Forces Squadron. "A lot of times, the caches lead you to parks and playgrounds you've driven past a dozen times but never seen."
After purchasing a GPS receiver, the next step is visiting the official geocaching Web site, to get a list of caches. Once a cache is selected, the Web site lists the latitude and longitude coordinates and provides links to maps of the area.
These maps are not only helpful for finding the cache, they also provide a general idea of the driving directions.
The last step before heading out and crossing another cache off the list is safety. People should let someone know where they are going and a time they expect to be back in case an accident occurs, officials said.
With a GPS receiver leading them and a lunch in their packs, "cachers" around the world search long into the day, yearning for another shot of adrenaline when they discover their next "geocache."