Auto GPS » Satellites

How GPS Receivers Work

admin — Sun, 21 Mar 2010 05:36:30 +0000

It seems that almost everyone has heard of GPS (Global Positioning System) in one form or another. The most well known GPS device is the car navigation system that shows and tells the driver through voice commands how to get to their desired pre-programmed destination. But if you’re wondering how these little technological wonders work then you’ve come to the right place.

A GPS receiver is an electronic device that uses the Global Positioning System to determine its exact location on earth with pin-point accuracy. This system is made up of the three parts; 27 satellites that send out continuous positioning signals, ground stations around the world that help synchronize the satellites, and various types of GPS receivers.

In this article we’re going to concentrate on how a GPS receiver works within this system since it’s the piece of the GPS puzzle that keeps you from getting lost. Its main function is to calculate its position on the earth using the signals that it receives from the satellite system.

To do this the receiver needs to lock onto the signals of at least 3 satellites. Once 3 or more satellites have been detected it then needs to determine the distance between the satellites and the distance between itself and each satellite. It then uses the basic math principles of triangulation or trilateration to compute its location on the earth’s surface.

The signals a GPS receiver uses to figure its location are radio signals transmitted by the satellites. These radio signals have three bits of information embedded in them; ephemeris data, almanac data, and a pseudorandom code. Using this information the GPS unit is able to triangulate its position and report that back to its user.

Accuracy is another question many first time users wonder about. The good news is GPS receivers are very accurate with the ability to pin-point your location to within a radius of 20 meters. There are ways to increase accuracy through the use of DGPS (Differential GPS) and WAAS (Wide Are Augmentation System) which can get within 3 meters of accuracy. Units with these two features normally cost more but the increase in accuracy can be well worth the cost.

There are many factors that can and do affect how accurately a GPS unit reports its position. These include:

1. The number of visible satellites
2. Signal delays caused as they pass through the earths atmosphere
3. Signals bouncing off of objects
4. Inaccurate clock in the GPS unit
5. Ephemeris errors
6. Satellites in poor positions
7. Satellite signals that are blocked because of terrain or manmade features

GPS is a great technology that has found its way into many everyday applications. Depending on your needs for keeping track of where you are there is sure to be a GPS receiver that fits the bill.

By: Andrew Bicknell

GPS Navigation

admin — Thu, 04 Mar 2010 12:09:21 +0000

I remember driving around not wanting to stop at the corner store and get directions. Ahh, the good ole days.

That is exactly what they are becoming thanks for GPS car navigation devices. Unless you just got of the boat from Antarctica then you are fully aware of just how cool these devices are.

GPS stands for Global Positioning System. This is a system developed by our friends at the Department of Defense. It uses a grid of many satellites to triangulate positions anywhere in the world.

Our tax dollars really did the trick this time too because these devices can put you within 10 feet of the exact location. Pretty amazing.

Now, GPS car navigation devices come in different sizes and have different features. Most commonly you have the systems that come built-in to your car when it was made. Those usually have a larger popup screen and cost a lot more money.

The other is the portable kind. These devices and have a decent size screen and can literally fit in the palm of your hand. The great advantage to this is that they for one are inexpensive, and two can plug into any car using the cigarette lighter.

Now a days $150 gets you precise GPS navigation… instantly!

The benefits to having a GPS car navigation device are plain to see.

It can save you a ton of gas. All those U-turns and miles going in the wrong direction are not exactly free. Last time I checked it cost me money for every mile I put on my car.

It can also save you a ton of time. This not only translates right back to saving you money, but also a lot of frustration. Having the route mapped out in front of you makes driving more pleasurable. Not to mention that shorter routes are often figured out for you.

Lastly, it can help you avoid traffic. These slick little units can spit out alternate routes in about 10 seconds. Dodging all that accident traffic has never felt better or been so easy.

For the cost they are today I would highly suggest picking one up. It is quickly becoming one of those items that we will all wonder how we lived without years from now. Remember life before the microwave?

By: Cathy Seiler

What Is GPS and How Can It Be Used?

admin — Mon, 08 Feb 2010 10:48:48 +0000

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

admin — Sun, 17 Jan 2010 22:22:09 +0000

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

Tips For Finding a Discount Handheld GPS

admin — Wed, 06 Jan 2010 11:37:13 +0000

Discovering the world around you with out getting lost is sometimes a challenge. But with the help of discounted handheld GPS receivers, the adventure gets a lot easier. Hiking, biking or just traveling along the open road can sometimes be a challenge if you are unsure of where you are going.

Maps are okay, but they can be cumbersome and you normally have to pull off the road to get a real good look at them. The next best thing to a map would be a GPS navigational unit which tells you how to get to where you want to go, usually turn-by-turn by a calm, woman’s voice.

There are many advantages to having a GPS navigational receiver in your car or pocket when you set out on a road trip or hiking adventure. One is that the global positioning system (GPS) will help you from getting lost because the 24 satellites orbiting the earth twice a day are there to triangulate your position. Two, there are settings on the GPS which allow you to leave a ‘bread crumb’ trail for you to find your way back to where you started from, both from walking and in your car.

To find a discount handheld GPS receiver unit you need to do a little research and find the best quality for the lowest money. Not all low priced GPS units are cheap and not all high priced GPS units are good quality, you just have to shop around, do some comparison shopping. Read the reviews in consumer magazines that do the comparison shopping for you or on the Internet websites where writers and actual customers have used the discounted GPS units and are willing to put the truth out there about the GPS products and their experiences with them.

Once you have done your homework and figured out which handheld GPS receiver you are going to purchase, you need to find out where the discounted ones are. The Internet is the ideal place to begin shopping for discount handheld GPS receivers; it seems everyone is selling them now and at very low prices. However, make sure you are getting the ‘real McCoy’ because sometimes people are selling refurbished GPS units as original units, not that there is anything wrong with a refurbished GPS unit, it’s just that you need to know what you are getting. You can also try the manufacturer’s website; they often run specials or sales during the slower times of the year to move their products along and this means saving for you.

Another way to find discount handheld GPS receivers is to go to the auction websites and see if you can bid on a good used one. there are some sites that run like a regular auction where you place a bid and wait to see if you are the highest bidder, but others have recently implemented a ‘buy it now’ policy were there is a predetermined price and you can buy the handheld GPS navigation system for a reasonable price or a discounted price right now and not have to wait.

By: Charlie Lee

Handheld GPS Hunting – Never Lose Your Trophy Kill Again

admin — Sun, 03 Jan 2010 09:46:03 +0000

There are handheld GPS receivers for just about any sport out there today, hiking, biking and now fishing and hunting. Several manufacturers of GPS units are making handheld receivers for hunters complete with camouflage and compasses. Many of these personal GPS receivers have up to 12 satellites calculating your position. Some have a built in calendar helping you to chart the best time to go hunting. Most weigh between six and 10 ounces and won’t weigh you down, but have so many capabilities. Features include being able to store 500 to 2,000 waypoints – which are location you can navigate to later – both with graphics and names and the track log stores up to 10 to 50 retraceable paths. The trip computer indicates such things as sunrise and sunset times, speeds, distance and much more.

Some hunters think the handheld GPS receiver units are great when out wondering in the woods. One reason is because they don’t have to pay close attention to where they are going and can pretty much wonder freely and still be able to find their way back to their vehicle or campsite with the GPS trackers. Since you have marked your waypoints, you can easily find you way back to camp or your vehicle by turning around and placing the GPS on directional or compass screen and when the arrow points left, go left and when the arrow point right, go right and you will soon be where you want to be.

One of the most popular handheld GPS hunting receivers is one that has multiple receivers for hunting dogs as well as the hunter. You attach a GPS tracking unit to each of your dogs and then you can track there whereabouts with your GPS handheld unit. There are two screens in which to do this. One is a compass and if you have more than one dog, will show you which direction each dog is going, if they are running or on point (pointing to a bird or other wildlife) and do it in different colors so you can tell the dogs apart on the screen. The other way to track the dogs is on the dog info screen which give you individual dog information, such as where they are located, if they are running or on point, how much battery life their GPS unit has left and average distance and speed they have traveled over a predetermined amount of time. There is a dog screen for each dog you have, it even shows if one or more are back at the camp in their crates, not just out in the field.

There is additional software available for the handheld GPS hunting units to upload topographical maps and public hunting area maps. These are very useful to hunters who do not own or know someone with private property to hunt on. This upgraded system also comes with a memory card and personalizable software so you can create your own maps to use year after year.

By: Charlie Lee

Types Of GPS Devices

admin — Tue, 29 Dec 2009 22:28:36 +0000

The Global Positioning System – or GPS – has transformed how the world finds its way. It’s no secret that the popularity of GPS has made it a standard feature in many a car. But in truth there are quite a number of GPS devices that are used in today’s modern society. What began as a government experiment and then a standard device used by the military, is now more popular than ever in civilian society.

When Russia launched Sputnik in the late 1950’s we had our first glimpse into the role that satellites would play in our future. Those who were monitoring Sputnik found that they were able to pinpoint its location based on the radio waves it provided. The seeds of GPS were born.

In the 1960s the U.S. Navy began experimenting with the technology, using the positioning of six satellites to help missile-carrying Navy submarines pinpoint their location. But the Global Positioning System that we know today was designed and implemented by the United States Department of Defense; the first operational satellite was launched in 1978 and by the mid 1990s there were 24 satellites – all of which are still in operation today.

The byproduct of this new technology has been GPS devices, designed to harness the power of satellite navigation to offer the highest level of convenience. It seems as though every year more GPS devices hit the shelves and in so doing they become part of what’s expected in society. The types of GPS devices are varied and your choice to use them depends largely on your frequency of need.

One of the more popular GPS devices is GPS mapping that allows you to visit any number of websites and enter any address in the world. If satellites have access to this area, you are immediately given a satellite picture showing the precise location you requested. For mapping trips, these GPS devices can take information downloaded from your computer and put it to use in your car, giving you detailed directions for the most expedient trip.

Another one of the more popular GPS devices is a GPS navigational unit. These units can either be mounted in your car or come in a portable system that you can transfer from vehicle to vehicle. Once a destination is entered into the GPS navigational system, it can literally walk you through your trip telling you where to turn and the time and distance relative to each portion of the drive. Some navigational units offer a feature whereby you can find restaurants, shopping, hospitals, and accommodations regardless of where you are; this can be incredibly useful when hunting services in a town with which you are unfamiliar.

GPS tracking, another of the GPS devices, allows you to track another person or thing. Many parents use GPS tracking in the cars of their teenage drivers. Others use this system to help protect precious items that are in danger of being stolen.

No matter which of the GPS devices you choose, you will no doubt find GPS to be an essential part of your life before long.

By: Michelle Bery

Using A GPS Receiver

admin — Wed, 23 Dec 2009 20:52:05 +0000

As the Global Positioning System – or GPS – continues to rise in popularity, a host of GPS-related products continue to hit the shelves. The GPS receiver is an interactive map that can show you exactly where you are at all times; this can be enormously helpful when finding your way around unfamiliar surroundings.

GPS was initially launched by the United States Department of Defense in the late 70’s when the first operational satellite was sent into space. By the mid-90’s, 24 satellites circled the earth and continue to be in operation today. What was originally designed for use exclusively for the military, now functions as a navigational system for military and civilians alike. More and more consumers, eager to take advantage of the timely and accurate information supplied by this network of satellites, choose to have GPS navigational systems included as standard equipment in their new vehicles.

But portable GPS has become just as popular. The GPS receiver is a compact navigational system that literally fits in the palm of your hand. The GPS receiver interfaces with the government’s network of satellites and can instantly perform a series of latitudinal and longitudinal calculations that can precisely target the user’s location. The screen of the GPS receiver displays a map of the area – including roads, landmarks, and other points of reference – and the user’s location in relation to it.

For outdoor hobbyists the GPS receiver has been enormously beneficial, allowing them to navigate possibly unfamiliar terrain without ever losing their bearings. Travelers who may not be using one particular car can still access satellite navigational information through the use of the GPS receiver.

The GPS receiver comes in a variety of styles and is manufactured by numerous companies. The models can be differentiated largely by price and included features. For anyone interested in a GPS receiver, certain things must be considered prior to purchase including manner and frequency of use. Those who plan to use their GPS receiver may be interested in those models that have a greater range of features. While this particular GPS receiver will likely come at a greater price, it could be well worth the investment to ensure safe and enjoyable travel. It’s wise to research each GPS receiver before you make a purchasing decision. But no matter which model you choose, you will likely find a GPS receiver to be a convenience you become used to very quickly.

By: Michelle Bery

What is GPS Used For Today and How Does a GPS Receiver Work?

admin — Wed, 02 Dec 2009 05:24:21 +0000

When you hear about General Positioning System (GPS) system, you should first consider the GPS receiver. It is the part of the device responsible of processing the signal sent by the satellite in the space to find out your actual location. The receiver is usually placed on the dashboard of your car or underneath it. It renders on a dedicated output device your screen your destination.

The entire GPS is a constellation of about 27 satellites rolling around the center of the Earth at a steady speed. Amongst these satellites, 24 of them are responsible of processing signals emitted by the receiver and the remaining satellites are used for storage purposes on case of an unplanned event. The GPS receiver is responsible of hooking up with satellites used for storage purposes and working out its position from that satellite by computing their distance. The mathematical tenet used for this purpose is named trilateration.

Trilateration can be achieved in two dimensions and also in three dimensions. The rationale of this mathematical principle is to work out a triangle where you are located at the center of it. As soon as the GPS receiver emits its position and makes a connection with other satellites, it immediately works out three nearest points and computes your position.

Three types of GPS receivers can be noticed: those which can be installed in a car, lightweight and mobile GPS receivers and tracking GPS receivers. It is obvious that portable receivers are a huge boon for outdoor activities.

Finally, it is good to know that the actual process of GPS receivers is a little bit more intricate than what was described in previous sections. However, throughout this article, although the main objective was to give a broad overview how they work in theory the next paragraph will delve into advanced details about GPS computations.

From previous sections, we learned that the GPS receiver computes its distance to the nearest available satellites in space by noticing the time spent by the emission of a given signal from the receiver to the satellite. There are another category of GPS receivers that you have not mentioned throughout this article. In order to overcome the lack of precision of the traditional GPS receiver, differential GPS receivers were born. Their rationale is to estimate the level of GPS errors at a stationary receiver station with a location that was already computed before. Since the Differential GPS hardware at the station is already aware of its own location, it can work out its receiver’s level of errors in a straightforward way. The station then broadcasts a radio signal to all Differential GPS-equipped receivers in the nearby area, providing signal correction information for that area. In general, accessing this correction information makes Differential GPS receivers much more correct and precise than traditional GPS receivers.

The most essential function of a GPS receiver is to pick up the transmissions of at least four available satellites and combine the information in those transmissions with information in an electronic almanac, all in order to figure out the receiver’s position on Earth.

By: John B Mayall

What is an Car and Truck GPS?

admin — Mon, 23 Nov 2009 18:07:33 +0000

Do you travel a lot? Have you found yourself wishing you had a better way of finding your end point instead of using old fashion paper maps? If so, then you need an Car and Truck GPS. If you don’t know a lot about these devices, then you should know that they are the most modern way to find your way away. They can tell you exactly how to reach your end point by giving you precise directions. These directions are so advanced that it can even tell you when you need to make a turn and in which direction you are traveling. Choosing an Car and Truck GPS that is right for you will depend on how you plan on using the system.

These navigational systems work by using satellites to find your location and then mapping out a route to your end point. Without pinpointing your current location a new end point cannot be found. The system uses latitude and longitude to determine where you are and then to find the location you programmed as your end point. These systems can give you several routes to the location that you are searching for and it is your choice which one you decide to use. There are several different types of Car and Truck GPSs that you can choose for your vehicle.

There are both cheap and expensive Car and Truck GPSs available. Some of the cheaper models plug into the cigarette lighter of your vehicle and is great for the occasional use. However, these are a little harder to use than some of the other types. If you plan on using your system often, then you may want a bigger one with more features. There are several styles and sizes of these to choose from, so make sure you pick one that is suited for your vehicle. You wouldn’t want to choose a system that makes it uncomfortable when passengers are riding.

Some of these systems feature several different ways for you to find your end point. In other words, you can find a end point by using things like the address of the place you are searching for, a street name or choose a location from the map. These systems can use voice commands to help you find your end point. Many of them will also tell you the location of the nearest airport, bus station, train stations, ATM’s and banks. The Car and Truck GPS is a great asset to any vehicle that can ensure you never get lost or miss a turn again.

By: James Kronefield