Finding Myself

Alone on the wilderness is not a great place to be. Even as a group, not knowing where you are is disquieting. As scouts we are told to always bring along a compass. This is nice, but a compass is only good at telling direction and then it is only as good as you knowledge of how to use one.

Orienteering

The sport of Orienteering has many options. Compass only (without a map) requires that you are using the compass at all times, counting your pace, and using reference points along the route as you go. The minute you lose track of your pace or a reference point you are lost. You find very quickly that mountains, trees, cliffs, etc all seem to look alike.

With a map, you can be a bit more casual. By orienting a map with the compass, you have a better chance of locating yourself. Once oriented, the map gives you a guide as to what to expect on your left right, in front and behind. From this you can probably and reasonably find where you are on the map. Then you can use the compass to regain your goal and restart. Pace becomes less important and you have a chance to recover.

GPS

By itself, a basic GPS unit that gives Latitude and Longitude will not really locate you. The numbers are meaningless without a map. If you have a second set of Longitude and Latitude coordinates, say your goal set (see GeoCache below), then you can use the GPS to get where you are going, but without this second set you are still lost. With a map that has latitude and longitude markings (like most trail maps) you can locate yourself precisely with a GPS unit. No guesswork, well maybe a little interpretation between the lines, but you can very closely find your spot on the map with GPS.

GeoCaching

Orienteering has been taken to a new level with the sport of GeoCache. This is where someone hides an item and publishes its latitude and longitude. People use their GPS units and maps to locate the items. You might think this very easy, but there can be many twists to the game. First, GPS accuracy in most Consumer units will only place you near the item, within about 25 to 50 ft. Many items will be well hidden and take some real looking around. The Cache boxes may look like ordinary debris or hidden under a rock. Others may hide the latitude and longitude numbers in riddles or formulas. Now there are currently 6570 active caches in 70 countries

A Brief History of Orienteering

I am here . . .

Before the invention of the compass, most people used “dead reckoning”, which basically means locating oneself by the physical references around them. A familiar mountain or stream or even using the stars. Early Arabs figured out how to use the Stars for navigation and used a crude measurement using their hands and arms.

The magnetic compass is an old Chinese invention, probably first made in China during the Qin dynasty (221-206 B.C.). This gave people a way of finding directions, but still couldn’t locate where we were.

Things improved with the invention of the sextant in 1730, which was based on the sun and stars, but still this required being able to see the sun or the stars. It used angles to put us on the right latitude. As long as there were no clouds in the skies and we used it properly all along the trip we were okay.

Now using the same basic concept we use satellites to give our position exactly, or at least within a few feet. The Global Positioning System (GPS) is a worldwide radio-navigation system formed from a constellation of 24 satellites and their ground stations. GPS uses these "man-made stars" as reference points to calculate positions accurate to a matter of meters. In fact, with advanced forms of GPS you can make measurements to better than a centimeter!

GPS

Know Where You Are and Where You Are Going

GPS is a Satellite Navigation System

  • GPS is funded by and controlled by the U. S. Department of Defense (DOD). While there are many thousands of civil users of GPS world-wide, the system was designed for and is operated by the U. S. military.
  • GPS provides specially coded satellite signals that can be processed in a GPS receiver, enabling the receiver to compute position, velocity and time.
  • Four GPS satellite signals are used to compute positions in three dimensions and the time offset in the receiver clock.

Space Segment

  • The Space Segment of the system consists of the GPS satellites. These space vehicles (SVs) send radio signals from space.
  • The nominal GPS Operational Constellation consists of 24 satellites that orbit the earth in 12 hours. There are often more than 24 operational satellites as new ones are launched to replace older satellites. The satellite orbits repeat almost the same ground track (as the earth turns beneath them) once each day. The orbit altitude is such that the satellites repeat the same track and configuration over any point approximately each 24 hours (4 minutes earlier each day). There are six orbital planes (with nominally four SVs in each), equally spaced (60 degrees apart), and inclined at about fifty-five degrees with respect to the equatorial plane. This constellation provides the user with between five and eight SVs visible from any point on the earth.

Control Segment

  • The Control Segment consists of a system of tracking stations located around the world.
  • The Master Control facility is located at Schriever Air Force Base (formerly Falcon AFB) in Colorado. These monitor stations measure signals from the SVs which are incorporated into orbital models for each satellites. The models compute precise orbital data (ephemeris) and SV clock corrections for each satellite. The Master Control station uploads ephemeris and clock data to the SVs. The SVs then send subsets of the orbital ephemeris data to GPS receivers over radio signals.

User Segment

  • The GPS User Segment consists of the GPS receivers and the user community. GPS receivers convert SV signals into position, velocity, and time estimates. Four satellites are required to compute the four dimensions of X, Y, Z (position) and Time. GPS receivers are used for navigation, positioning, time dissemination, and other research.
  • Navigation in three dimensions is the primary function of GPS. Navigation receivers are made for aircraft, ships, ground vehicles, and for hand carrying by individuals.
  • Precise positioning is possible using GPS receivers at reference locations providing corrections and relative positioning data for remote receivers. Surveying, geodetic control, and plate tectonic studies are examples.
  • Time and frequency dissemination, based on the precise clocks on board the SVs and controlled by the monitor stations, is another use for GPS. Astronomical observatories, telecommunications facilities, and laboratory standards can be set to precise time signals or controlled to accurate frequencies by special purpose GPS receivers.
  • Research projects have used GPS signals to measure atmospheric parameters.

How to use GPS Receiver in Game

Several models of GPS (Global Positioning Systems) receivers are available at boating and outdoor stores. Here is some basic information to get your started.

How GPS works:

The GPS is a network of satellites that circle the earth and continuously transmit coded information by low-powered radio signals. These signals make it possible for a GPS receiver to calculate exact locations on Earth by measuring the distance from several satellites.

How to get started:

  • Choose a cache on For example, let's choose Water Ranch Roundup in Gilbert.
  • Enter the waypoint into your GPS receiver: 33 degrees 21.772 minutes north latitude and 111 degrees 44.111 minutes west longitude.
  • Set your GPS receiver to "go to." It will calculate which direction to head and how far away you are from the cache. In this case, we needed to go southwest for eight miles. The receiver continually updated information as we traveled. The closest we could get by car to our destination was Greenfield and Guadalupe roads. Next, park the car and store your current location as an additional waypoint. This is like leaving a trail of breadcrumbs -- your receiver marks your path so you can find your way back to the car.
  • Set your receiver to "go to" the waypoint you entered for the cache and let it lead you to it. We stayed on the walking trails to get as close to the cache as possible.
  • Start looking on your own when the receiver tells you that you are with a few feet of the cache. Look for places you would hide a cache.

For more information on GPS receivers, visit REI in Tempe also offer classes on using GPS receivers. For information, call Paul Reinshagen REI at (480) 967-5494.

Geocaching Uses GPS to Create Technological Version of Hide-and-Seek

Staff photo by Michael Jewart

Kevin and Jacqueline Mart spend their weekends hunting and hiding treasure, sometimes as close as South Mountain, and sometimes as far away as Cost Rica. The Ahwatukee Foothills couple, along with their sons, Brandon, 16, and Travis, 14, participate in high-tech treasure hunts with the help of a Global Positioning System (GPS) receiver and an Internet Web site. It’s all part of a new sport called Geocaching. "The thing that I like most about Geocaching," Jacqueline Mart said, "is that it introduces me to places that I’d normally never go. You discover the most gorgeous places, sometimes in your own backyard." Here’s how it works: Players search for treasures, or caches, that other geocache enthusiasts have hidden in interesting outdoor spots. The longitude and latitude coordinates of the caches are posted on an Internet site, along with directions to the trailhead and a couple of general clues. Cache seekers search the Web page for a list of nearby caches. They enter the coordinates of a chosen cache into a hand-held GPS receiver, print out the clues, and hit the trail.

Jacqueline said she became interested in the high-tech, hide-and-seek game after visiting Iowa last summer where her brother was already a veteran geocaching player. Kevin and Jacqueline like the sport because it adds an interesting dimension to hiking that encourages their teen-agers to take part.

"For the kids, there’s a technical element, a gadget, and there’s a treasure," Kevin said. "For us, there’s the benefit of the hike plus having our kids with us." For Travis, a freshman at Mountain Pointe High School, the treasure is the best part. "The prizes are cool," he said. "I’m starting a key chain collection."

Sealed Tupperware containers or metal ammunition boxes are used to protect the contents of the cache. They are usually filled with inexpensive items like stuffed animals, key chains or other trinkets. The geocacher takes one item, replaces it with a new one, and signs the logbook. Some caches include cameras inside to take your picture as proof of a find. "People are so clever with their caches," Jacqueline said. "My brother in Iowa did one called ‘Gotta Get a Date’ that took you to a cemetery where you had to get the numbers off of a tombstone. We also have a friend who created the ‘Green Tortilla,’ where everything in the cache is green."

The Mart family has placed five of their own caches, including one aptly named "Rattler’s Art Gallery."

"I was placing the cache into this perfect little hole we found," said Kevin. "There was a stick in the way, so I reached in to grab the stick and heard a rattle. My fingers were just inches away from the snake!"

Kevin did not receive a snakebite, but he’s a bit more cautious now.

The Marts just recently placed their newest Arizona cache, named Coyote Cave. The coordinates will be released soon on the Web site. They also have a cache on a beach in Costa Rica, which has yet to be found. According to the geocaching Web site, 179 caches are currently hidden in Arizona. The sport began in May 2000, when the Clinton Administration lifted the security restrictions on GPS, a government-owned network of 24 Earth-orbiting satellites and their ground stations. This meant civilian GPS receivers could be used with more precision. Two days after the restrictions were lifted, the first cache was placed and the sport has taken off from there. Paul Reinshagen, special events specialist at the REI store in Tempe, said that the sport has become very popular with local families. "I had one avid outdoorsman who was looking for something to do with his 9-year-old daughter," Reinshagen said. "He found this, she loves it, and she’s on the Web site constantly looking for new caches." But the sport isn’t limited to families. For many adults, geocaching is the perfect excuse to get away from the computer and explore beautiful outdoor location,. including Jeremy Irish, who runs the geocaching Web site in his spare time from his Seattle office. "As a Web site developer, I’m chained to my desk all day." Irish said. "I love the sport because it gets you outside and gives you the chance to apply technology to the real world." When Irish took over the Web site in September 2000, there were 75 caches worldwide. Now there are currently 6570 active caches in 70 countries. "People have such fun with it," Irish said. "One guy even proposed marriage to his girlfriend by placing a note in a cache." Irish said that the recent terrorist attacks have made people more suspicious and geocachers need to be cautious when placing caches. They should be sure the containers are clearly marked as geocaching treasures so they won’t be mistaken for something dangerous. As for the Mart family, plans are underway to organize a get-together for geocachers at an undisclosed location near their home. Participants will need to use their GPS receivers to find it.

By Sally Mesarosh AFN Correspondent --Published in Ahwatukee Foothills News, October 31, 2001

Which is Better – Compass or GPS?

The compass is a simple but effective navigational tool that has been in use for centuries. Countless explorers and adventurers have relied on the compass for directions. Now it seems that new technology in the form of the GPS device is replacing this humble tool. Millions of portable GPS units have been sold for car and boat navigation and many cell phones now include a GPS capability. GPS devices are quickly becoming the new universal tool for navigation.

Is a GPS device a good replacement for a map and compass when hiking and backpacking? It pays to do a head-to-head comparison before abandoning your compass.

Compass Pros and Cons

A compass is a light, portable tool that accomplishes one function – it indicates the direction of magnetic north. It’s inexpensive (a compass in a sturdy case can be purchased for less than $20) and doesn’t require a power source. A compass is not difficult to use, though some training and practice are required. With a map and a little skill, a compass is perfect for back country orientation.

How can a compass help you if you’re lost? If you’re completely disoriented and without a map, a compass can’t do much more than tell you which way is north. A compass is useful only when you’re prepared to use it correctly. It’s most useful when used with a topographical map.

It doesn’t take long to learn how to use a compass. There are good websites that walk you through it, including Kjetil Kjernsmo’s Illustrated Guide on How to use a Compass and several Boy Scouts of America guides such as this one on How to Use a Compass.

GPS Pros and Cons

A GPS device is a receiver for the Global Positioning System, a network of two dozen satellites that orbit the earth. The system was originally developed for use by the U.S. military but is now available to everyone. A GPS receiver use signals from this satellite network to compute its own location. In addition to telling you where you are in terms of longitude, latitude and altitude, a GPS device can track your movement. A GPS device can store a large number of maps and show you your position in real time on a map.