GPS Watch Guide

It’s sometimes difficult to see the true value of certain technical innovations, especially with technology moving at such a mind boggling pace. That’s the case with GPS watches. These high-tech timepieces are ideal for a wide range of uses in today’s fast-paced society. Below are some key applications.
Health Improvement/Physical Training

GPS watches greatly assist runners and joggers who want to fine-tune a workout regimen, and those who need a physical training program

to recover from surgery or disease. These watches provide critical workout data, like average speed, maximum speed, total distance, and total time, necessary to a good workout. With this data runners and joggers target improvements in their workout programs and monitor performances toward meeting their exercise goals. And once they have this data in their watches, they can download it to a computer, using special software, and then analyze and trend it. This activity sets the stage for performance improvements. When linked to heart rate monitors, GPS watches also help people train at the right intensity level, a key to getting the most out of one’s workout. Heart rate is the most accurate measurement of intensity or exertion level.
Tracking/Location

GPS watches provide key benefits to avid hikers or outdoors people. These watches give these users the unique ability to map out their hikes or hunting routes and then have the watch suggest the best route for them. One GPS Watch (Suunto M9) features a Man Overboard function that activates with a push of a button. If you’re kayaking or canoeing and an accident occurs, this function notifies others who can track you down and provide help. GPS watches even track heart rate, distance, and other health monitoring checkpoints, as well as how far and fast one is running, rowing, biking, or skiing. They even can help determine your exact position or location if you’re running or hiking in a strange territory.

Safety/Health Checks

Since GPS systems communicate with satellites orbiting the earth to determine your exact coordinates each time you move, GPS watches can be used to notify the authorities or EMS if you are lost or injured on a remote trail. GPS watches can also be used to provide instant access to blood pressure and heart rate, which is essential to avoid over working one’s heart. And GPS watches can be used to safeguard others. Technology exists that will let a parent or a guardian monitor a child’s whereabouts. By linking GPS watches to a unique online interface, this technology adds a whole new level of child defense and monitoring. With instant access to digital maps, a parent or guardian can use a computer to locate a child if he or she has gone missing.

GPS uses a network of 24 satellites as reference points to determine position. By accurately measuring the distance from three satellites the GPS can “triangulate” a position anywhere on earth. But how do you measure the distance to something floating in space. Basically, by timing how long it takes for a signal sent from a satellite to arrive at a receiver here on earth using a Pseudo Random Code (PRC).

A fundamental part of the GPS process, the PRC is a complicated digital code, or in other words, a complex sequence of “on” and  “off” pulses. The code’s complexity helps makes sure that the receiver doesn’t accidentally “sync up” to some other signal. The complexity also makes it possible to use “information theory” to “amplify” the GPS signal, making GPS economical.

In addition, since each of the 24 satellites has its own unique PRC, the complexity guarantees the receiver won’t accidentally pick up another satellite’s signal. So all the satellites can use the same frequency without jamming each other, making it more difficult for a hostile force to jam the system. In fact, the PRC gives the DoD a way to control access to the system.

GPS comprises three segments. The Space Segment consists of satellites orbiting the earth once every 12 hours. More than 24 operational satellites are often in service as new ones are launched to replace older ones. The satellites repeat almost the same ground track (as the earth turns beneath them) once each day. They pass over any point on the earth once every 24 hours (4 minutes earlier each day). Four satellites are needed to compute the dimensions of X, Y, Z (position), and Time.

The Control Segment consists of tracking stations located around the world. The Master Control facility is headquartered at Schriever Air Force Base in Colorado. These stations measure signals from the SVs. The signals are then incorporated into orbital models for each satellite. The models compute precise orbital data (ephemeris) and SV clock corrections for each satellite. The Master Control Station then uploads ephemeris and clock data to the SVs, which send a subset of the orbital ephemeris data to GPS receivers using radio signals.

The User Segment consists of people employing GPS receivers. These receivers convert satellite vehicle signals into position, velocity, and time estimates. They make navigation the system’s primary function. Additional functions are mapping, tracking, locating, and timing. Receivers have been miniaturized to just a few integrated circuits and are becoming economical, making GPS technology more and more accessible to everyone.

The Global Positioning System (GPS) is the most accurate radio-navigation network in the world. Funded and controlled by the U.S Department of Defense, GPS employs a constellation of satellites placed in orbit by the United States. The satellites emit specially coded signals that can be processed by a GPS receiver, enabling it to compute position, velocity, and time. GPS works in any weather conditions, anywhere in the world, 24 hours a day.

The Department of Defense built GPS at a cost of about $12 billion. The system provides the U.S. military with a highly precise form of measuring position worldwide. The first satellite was launched in 1978, and a full constellation of 24 satellites was achieved in1994. The DoD made the technology available to civilians in the ‘80s. Growing in use, GPS is now employed by thousands of civilians worldwide.

Many critical activities depend on navigation and positioning. Yet the process has always been cumbersome. The global positioning system simplifies the process. GPS operates in five logical steps:

The basis of GPS is “triangulation” from satellites.

* To “triangulate” a GPS receiver measures distance using the travel time of radio  signals.
* To measure travel time, GPS needs very accurate timing, which it achieves with the help of some tricks.

* In addition to distance, the exact position of the satellites must be known.

* High orbits and careful monitoring are the secret.

* Also necessary correction for any delays the signal experiences as it travels through the atmosphere is needed.

GPS technology is finding its way into a wide variety of applications. It’s used in cars, boats, planes, construction equipment, farm machinery, computer networks, television stations, and buses. GPS technology also has helped fire fighters fight blazes in Modesto, California. And recently the city of Chicago developed a tracking system to monitor emergency vehicles through its streets, saving precious time responding to 911 calls.

While GPS is also used to disseminate precise time, time intervals, and frequency. Time is a powerful commodity and exact time is more powerful still. One investment banking firm uses GPS to guarantee that its transactions are recorded simultaneously at its offices worldwide, And a Major Pacific Northwest utility company makes sure its power is distributed at just the right time along its 14,797 miles of transmission lines using this global positioning system. Soon, GPS will be as basic as the telephone.

The global positioning system has been around for a while now and is being used in more and more areas of life: in cars for navigation, in traffic control systems, by field scientists and more. Lately, hobbyists such as golfers and joggers have also noticed the benefits of GPS. Watch manufacturers have responded to this need with new models, that merge watch and GPS sensor.

On these pages we would like to give you information on GPS watches. We will show you, that these devices are not just high-tech toys, but indeed very useable and useful in many situations.

To start viewing the contents, please select a link from the navigation bar.

When people talk about “a GPS,” they usually mean a GPS receiver. Its job is to locate four or more of the system’s 24 satellites, figure out the distance to each, and use the information to deduce its location. This operation is based on a simple mathematical formula called trilateration. Trilateration is a method of determining the relative positions of objects using the geometry of triangles in a similar fashion as triangulation. As long as you have a GPS receiver and a clear view of the sky, you will never be lost again.

GPS satellites send out radio signals that a GPS receiver can detect. But how does the signal let the receiver know how far away the satellite is? The simple answer is: A GPS receiver measures how long it takes a signal to travel from the satellite to the receiver. Since we know how fast radio signals travel — they are electromagnetic waves and so (in a vacuum) travel at the speed of light, about 186,000 miles per second — we can figure out how far they’ve traveled by figuring out how long it took for them to arrive.

GPS receivers come in one of two main types- non-mapping and mapping. Non-mapping GPS receivers show a numeric display of a location and route according to latitude and longitude, but the display does not overlay a map or other geographical information. Non-mapping GPS receivers are generally less expensive and less user-friendly than mapping GPS receivers. Mapping GPS receivers are by far the most common type because they show location and route graphically over some sort of map (geographical and/or road). This makes the mapping GPS receiver much easier to read, understand and navigate with.

GPS receivers are available in a wide range of sizes and types including handheld units, marine units, aviation units, and automotive units. They are sometimes incorporated into other electronic products such as cell phones, laptops, and more. And like many electronic devices, GPS receivers are growing more and more popular as the price and size has decreased while memory and functionality (and user-friendliness) has increased. GPS receivers are used across the country and on a daily basis for hiking, geocaching (finding and hiding ‘treasures’ for others to find with a series of clues placed by other ‘geocachers’), driving, flying, boating, and countless other activities that involve any sort of navigation, mapping, position, or timing.