Posts Tagged ‘Altitude’

GPS Buying Tips For Technophobes

February 23rd, 2010



Black glasses with masking tape holding them together and a pocket protector are no longer a required part of the uniform for GPS owners. GPS has gone mainstream. But if you’re still not up to date on what it is and how it works, and if you’d like some advice on what to buy, this article will bring you up to speed.

A GPS device is like a map on steroids. First of all, it always gives you that little “You Are Here” dot – you no longer need to figure that out for yourself. And all you need to do is tell it where you want to go and it will plot the course for you. It doesn’t end there, however. New GPS units will provide you with voice guided directions for the entire trip, tell you where the nearest gas station is, and will even put you back on course if you take a wrong turn.

GPS stands for Global Positioning System, a system of 28 satellites orbiting earth. It was originally developed for military use, but its uses have spread far beyond just military applications. Your GPS unit can receive signals from these satellites, and by using these signals, calculates your position (within 3-10 meters), direction, altitude, and velocity. Once your GPS unit knows where you are, it can help you get to where you’re going as long as it has mapping software installed. All but the most basic GPS devices currently have mapping software.

Now that you know a little bit about what a GPS device is and how it works, it’s time to educate yourself on the features available and decide which unit will best suit your needs. There is certainly no shortage of GPS devices available, so doing a little research can save you a lot of time and hassle.

Step 1 – Which type of GPS do you need?

There are four main types of GPS units; the car navigation system, the portable outdoors unit, the marine system, and the PDA/GPS hybrid.

If you’re mainly planning on using your GPS to get you from point A to B in your car and don’t think you’d use it for much else, your best bet is the in-car navigation system. These systems can be built in to your car or you can purchase a device that mounts onto your dashboard. Desirable features for the in-car systems are: voice guided directions; detailed built in maps; touch screens; rerouting in case you get off course; and a database with points of interest to help you find the nearest gas station, restaurant, and many more places along your route.

If you’re going to want a GPS device that isn’t limited to the car, then you may want to consider a handheld GPS (http://www.gpsmaestro.com/handheld). These devices are ideal for anyone who loves to hike or bike. Features to look for in a handheld unit are: lightweight, rugged, waterproofing, long battery life, color screens, and mapping features. The handheld GPS units are geared towards people who spend a significant amount of time outside. For example, if you’re out hiking you can easily track where you’ve been; mark your own points of interest; and even find out how far you’ve gone and at what speed. Many new handheld devices offer some navigation features while driving. You can even purchase handheld units that offer built in radios that will not only allow you to communicate with other members of your party, but will also display everyone’s location on your screen.

If being on the water and fishing is your thing then you should probably consider a marine GPS. These units are specifically designed to be on and around water. All of these units will feature waterproofing and should have screens that are easy to read even in bright sunlight. Some other good features to look for are: color chart plotters, onshore and offshore maps, fish hotspots, and sonar capability. You may also want to consider a unit that will function as your car navigator, eliminating the need for two devices.

The final category of GPS device is the PDA/GPS hybrid. This device offers a good combination of the car navigation systems and handheld devices. You’ll get the large screen that you’d find in the car system and the portability of a handheld unit. Also, you get a PDA to help you keep organized. One drawback is the limited selection of these units. Only a few companies have attempted to make an integrated unit, and all have some serious limitations.

If you are considering a PDA/GPS hybrid, I’d recommend you purchase the PDA separately from the GPS. Find a PDA that offers all the features you want in your PDA, then look for a GPS receiver that will attach to your PDA via Bluetooth. The features to watch for are the same as listed for the in car systems. All of the current PDA/GPS devices are better suited towards driving than hiking, although they do offer the portability for outdoor activities if needed. This category probably offers the most potential of the four, but it is also the newest, so watch for significant improvements in this category in the future.

Step 2 – Budget Considerations

If you’re on a budget, then it’s important to decide which features are most important to you. If you want a full featured car navigation system, it can easily run over $1000 (and over $2000 if you want one that’s built in). If, however, it would be more of a toy to play with, then a handheld device could be a better choice as they can be as low as $100 and are rarely more than $500. Marine GPS devices vary widely in prices, but a very good device can usually be purchased for no more than $1000. If the PDA/GPS devices interest you, they typically range from $400-$900.

Step 3 – Where to Buy

Finding the right store to purchase your GPS device can be difficult. Most stores only carry one or two kinds of GPS. For example, if you go to a sporting goods store you’re likely to find the handheld GPS units and marine GPS units but not the car navigation or the PDA/GPS hybrids. I actually prefer shopping online for GPS units as the prices will likely be lower, and you’ll be able to read user reviews of the items before you buy. Just make sure that if you have a problem with your GPS you are able to return it.

Owning a GPS can be extremely helpful, especially if you tend to get lost a lot or if your glove compartment is overflowing with outdated maps. They can also make planning a long trip to an unfamiliar area a breeze. Deciding which GPS to purchase can be difficult, but as long as you make a list of the features you absolutely must have then all you have to do is find the units that match your budget. Read reviews from other owners and you should have no trouble at all. Once you purchase your own GPS unit, you’ll wonder how you ever lived without one.

By: Gary Ruplinger

What Is GPS and How Can It Be Used?

February 8th, 2010



GPS stands for Global Positioning System and was initially designed to be used by the U.S. military and is operated by the U.S. Defense Department. This system consists of 24 satellites, these satellites are 12,000 miles above us, are constantly moving in a precise orbit, have an atomic clock, and are solar powered. They do have a battery backup so they will continue to run in the event of a solar eclipse, and each satellites has a small rocket booster to maintain their orbit. The first satellite was launched in 1978 and it wasn’t until 1994 when there were a total of 24 satellites. Each satellite has a life expectancy of about 10 years, so new satellites are constantly being built and launched. Each satellite weighs about 2,000 pounds and is approximately 17 feet in width when the solar panels are extended. In the 1980s the GPS became available to the public, and although it is still maintain by the U.S. Defense Department there is no charge for its usage by the public.

These 24 satellites orbit the earth twice a day and continuously sends the location of the satellite. A GPS system can tell how far a satellite is away by comparing the time difference between the time a signal was transmitted and the time it was received, the longer it takes the signal to be received by a receiver, the farther away the satellite is. If a GPS is receiving signals from three satellites it can calculate latitude and longitude. Altitude can be determined if the GPS is receiving signals from four satellites.

GPS can be used for navigating your car through traffic day-to-day or tracking a fleet of vehicles. Not only can a driver use a GPS for directions the main office knows where that vehicle is and the speed of the vehicle. GPS can be used while on vacation for activities such as hiking, camping, or hunting. Is your passion fishing but get frustrated trying to find the fish? With a fish finder which uses both GPS technology and sonar you’ll know exactly where to go to find those fish. GPS technology is also being used as a way to track your pet if he wanders off or to safeguard a pet from being stolen.

Another use for GPS is as a child finder with a receiver in a child’s cell phone or wristwatch to ensure a child’s safety. It can be used in a teenager’s car in order to both know where they and how fast they are driving. This could also be used to keep track of someone who tends to ‘roam’ but is not capable enough to find there way back; i.e. someone with Alzheimer’s disease.

As GPS technology improves, it uses will increase. Who knows where it will take us next?

Copyright 2006 Angela Carter

By: Angie Carter

GPS And How It Works

January 17th, 2010



GPS stands for Global Positioning System, a satellite navigation system with twenty-four satellites in orbit. These satellites were put in place by the United States Department of Defense for military uses, and were called NAVSTAR. The first satellite was launched in 1978 and the twenty-fourth and last satellite was finally in place in 1994. In 1980 NAVSTAR was made available to the general public for commercial use.

GPS works 24 hours a day in any weather. The satellites orbit the earth twice a day in a specific orbit that is about 12,000 miles above us. In orbit, the satellites travel as fast as 7,000 miles an hour. As they are orbiting, they transmit information to receivers on earth. The receivers use this information to calculate the user’s location. This calculation is made by determining the difference between the time a transmission was made and when the receiver received it. This is then used to calculate the distance and the position is displayed on the receiver.

For a receiver to calculate a latitude and longitude position is to receive information from three satellites. To calculate latitude, longitude and altitude a receiver must be able to receive information from four or more satellites. After position is known the GPS can then tell the user information about speed, trip distance, the distance to a desired destination, sunrise and sunset times, bearing and other information.

While in orbit, the satellites are powered by solar energy. They also have backup batteries that are used in the event of no solar power such as an eclipse. The energy is used to power small rockets on the satellites that keep them in the proper orbit. At any one time only about 50 watts of power or less is used to transmit information. The satellites are designed to last about ten years, and the U.S. Department of Defense is constantly making and launching replacement satellites. Each satellite is about 2,000 pounds and seventeen feet across when the solar panels are out.

GPS receivers are generally accurate within 15 meters. Other than investing in a receiver there are no fees or other equipment required to access the GPS signal. If very accurate readings are needed, Differential Global Position Systems (DGPS) will provide accuracy within three to five meters. The United States Coast Guard operates the most popular DGPS.

Two power signals are transmitted and are referred to as L1 and L2. The L1 frequency is used for civilian purposes. These signals are relatively low power signals and travel by line of sight, so they can go through clouds, glass, and plastic, but not solid objects like buildings or mountains. In every transmission the satellite sends three types of information, its pseudorandom code, ephemeris data and almanac data. The pseudorandom code is an I.S. code that identifies which satellite the information is being sent from. Ephemeris data tells the receiver where the satellite should be at any time of the day, and almanac data sends information about the status of the satellite, the current date and the time. The almanac data is the part that is essential for determining the user’s position.

By: Chris Simons