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GPS
Finding your place in the world...

TheUS Global Positioning System (GPS) consists of a constellation of 24 satellites that emit radio signals for reception by specially designed devices.

If signals from 4 or more of these satellites are picked up by a GPS device, it can determine its location with high, reliable accuracy.


The orbits are arranged such that there are, in fact, always at least 4 satellites visible from any point on the surface of the earth.

See tutorials below for GPS details.

President Clinton announced at the beginning of May 2000 that the GPS signals would no longer be degraded for civilian receivers. Now these civilian devices can obtain location accuracy of 15m (~50ft) horizontally (100m previously) and 100m (328ft) vertically.

GPS devices are now available at prices as low as $100. The low end devices provide basic features such as current position, distance and direction to a set point, current speed, trip distances, track logs, etc.

..
Here's a video about the treasure hunting game of GEOCaching.

More expensive devices provide map features such as showing your current location on a map display. Also, they can guide you to a given address. They also have bigger, more sensitive antennas for faster response. Some portable units can also be connected to cigaretter lighters for power.


Comment: I did not include GPS as a HobbySpace topic initially because, like Direct-to-Home TV, I thought the space aspect of GPS was too hidden and irrelevant to the user. However, after using and enjoying my own handheld GPS navigator, I changed my mind.

When I first turn on my navigator, for example, the display shows the expected positions of GPS satellites in range and then gradually indicates which ones have been detected. Until a minimum number are found, it cannot find its position. As I move around I must avoid obstructing the view of the sky if the device is to keep the position updated. I continually return to the display to see how many satellites are currently detected.

So my GPS navigator makes me quite aware of the satellites above me. This is squarely in the HobbySpace spirit - promoting those activites that involve us, i.e. the general public, with the space infrastructure and make us aware of its benefits.


An introductory overview of GPS from the Air Force.
News

See the archive for previous articles...

See also

Applications

GPS locators provide many practical and recreational applications for the public such as the following:

  • GEOCaching
    • "..treasure hunting game. Armed with a Global Positioning System (GPS) device and coordinates, you can locate treasures that others have hidden in unusual places."
  • Hiking
    • Don't get lost. Mark waypoints along your way through unfamiliar territory.
    • Or, with the right maps, plan out your hike by downloading a route of waypoints to guide your trip.
    • Mark that beautiful, but isolated, vista in the mountains so that you can find your way back to it next time.
    • Avoid getting lost in snow "whiteouts".
  • Boating
    • Boaters, especially, sea-going ones, have long used GPS for navigation.
    • Kayaker & canoers can save their strength by going the straightest route on a big lake. They can also find their way when out of sight of land or along unfamiliar shorelines and can locate the spots reported best for portage.
  • Car Travel
    • Several commercial units for cars display your position on a map, which is very helpful for travel in unfamiliar cities, on back roads, and at night.
    • If you have a breakdown in a remote area, you can report your exact location by cell phone.
  • Fishing
    • Find your way back to that rich but secluded fishing hole you stumbled upon.
  • Hang Gliding
    • While vertical precision is not sufficient (~100m) for altitude determination, GPS will provide your horizontal position during your flight and at your landing point

 

Recreational Activities

Peer-to-Peer Communication & Positioning
New walkie-talkie systems include a GPS locator built in. This will allow people not only to talk with but easily to follow the current position of the other person. A display will show the position of the person relative to that device.

These systems will be useful for both serious and recreational activities. For example, search and rescue teams in a wilderness area could keep track of each other.

Or a family camping in the mountains can both talk to and keep track of the kids if they go off exploring.

Applications
These sites provide more information on practical GPS applications:

Resources

GPS: A New Constellation
This National Air & Space Museum site provides lots of information on the history, technical workings and applications of the GPS system.

GPS World
Online site of the magazine devoted to GPS and Glosnass.
Link lists include:

GPS Information.net
This site provides a long list of of links for GPS receivers, software, and hardware.

Tutorials
GPS Hardware
More sites
GPS Maps & Software

A waypoint, sometimes called landmark, provides the coordinates, e.g. lattitude and longitude, of a geographic location and is given a name. The location could be a road crossing, a mountain peak, etc.

With a many of the mapping programs you can access up to waypoints throughout the world. A table of waypoints would show each waypoint in a line entry with columns for a description, type (i.e. school, church, stream, etc.), longitude/lattitude, elevation and more.

With a program you can build a route by choosing the waypoints from the table for a hike or drive and then download the route into compatible GPS navigators.

Conversely, waypoints that you have entered into your navigator during a trip can be uploaded into a program and saved to disk.

General GPS Software

Maps
Most mapping software now includes the capability for downloading waypoints and routes to GPS devices.

Online Utilities
GPS - Commercial Activity

The creation of a commercial GPS industry has been slow but steady. The total GPS industry has revenues of about $12 billion per year according to the Economist magazine (March 14, 2002).

Handheld consumer GPS receivers are now available for as little $100. Boats and aircraft have long used GPS postioning and now there are systems also available for cars.

New applications are also appearing such as for cell phone location.

Stores

Manufacturers
These companies are the top manufacturers of consumer and professional GPS devices:

Tracking
Combining GPS with a communication device of some sort provides for tracking of virtually anything.

Micro-GPS 
A new GPS business involves locating cell phone from someone making an emergency call. Minature GPS receivers can now be placed in the phones to provide the position information:

Also, GPS recievers are becoming small enough for wrist-watches and other micro-applications.

Other Applications
New applications of GPS capabilities continue to appear:

Other GPS Companies & Organizations

 

Photo To Space
The Art of C. Sergent Lindsey
New Space Watch

Nasa Toys and Gifts

 

 

 

 

HobbySpace Store:
GPS
More GPS devices, books, maps, etc...

 

 

 
 
 
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