The global positioning system is a satellite navigation system that provides location information to GPS units anywhere on Earth in any type of weather. The global positioning system allows individuals to pinpoint their precise location within a few metres anywhere they have a direct line of sight to the four or more satellites in the sky. GPS has revolutionised the manner in which people and governments utilise technology to navigate the globe. GPS units give the user a living map of the world that can provide precise destination information and detailed instructions on how to get there.
One can find many excellent GPS units in the marketplace, but Garmin is considered a leader in the industry. Individuals interested in purchasing Garmin GPS units need to get an understanding of GPS technology as well as the features available in the different types of GPS units.
About GPS Technology
The global positioning system is a series of satellites based in medium Earth orbit that can trilaterate the position of a GPS receiver on Earth. To accomplish this, GPS satellites continually transmit information that gives their location and exact time, and these signals are synchronised to repeat at the exact same time by all GPS satellites. The GPS receiver on the ground records these signals at slightly different times because some satellites are farther away than others. The GPS unit calculates the variations in the signal times of at least four satellites, which allows it to determine the distance to each satellite. Once the GPS unit can calculate these distances, it can determine its exact position on Earth within three dimensions.
There are a minimum of 24 GPS satellites in operation at any given time orbiting around the earth. Each of these satellites complete two rotations of the earth each day in a pattern in which at least six of the satellites can be observed from any point on the earth at any given time. Because timing is so critical to the proper operation of GPS, each GPS satellite is fitted with an atomic clock to keep exact time and is synchronised with the United States Naval Observatory, which also utilises atomic clocks.
Types of Garmin GPS Units
Garmin specialises in producing consumer-, aviation-, and marine-based technologies for the global positioning system. Garmin produces a large variety of GPS units that range from commercial aviation applications to personal units similar in size to a watch.
Automotive GPS units hit the market in the late 1980s. Automotive GPS units may be installed in vehicles at the factory during the manufacturing process, or they may be installed by the vehicle owner after purchase. Automotive navigation systems acquire the vehicle's position and utilise a map in the Garmin GPS units database to place the vehicle on the corresponding road. The unit must be updated periodically to include new roads that have been constructed since the previous update. The navigation system gives turn-by-turn directions to the destination by either voice prompts or a two- or three-dimensional map displayed on the screen, depending on the driver's preference.
Marine GPS units operate in the same manner as automotive GPS units, except the receivers are loaded with nautical charts rather than road maps. Marine GPS units are referred to as chartplotters, and they are capable of displaying depth contours, tidal stations, and currents, along with the position and direction of the boat within the chart. Marine units can feature coastal charts for offshore boating as well as inland waterway maps for lake and river excursions. Some of the Marine GPS units come equipped with both sets of charts. These units allow the boater to create waypoints that mark a certain position on the chart and allow the boater to return to that exact position at a later time.
Sonar Fishfinders are GPS-based units that also include a sonar transducer. The transducer is capable of mapping the underwater terrain below the boat and identifying targets that are in the water column. Fishfinders detect fish when the sonar beam is transmitted to the bottom and bounces off a fish. That signal is returned to the transducer before the signal from the bottom is, and the result is the fish can be seen on the screen and targeted by the angler. Fishfinders also make use of charts to help fishermen set waypoints on the chart to return to their favourite fishing spots.
Handheld GPS units are small portable devices not much larger than a cell phone. A handheld unit allows the user to take a GPS receiver to any location regardless of how remote it is and still have the capability to determine his position and navigate from it. These units are excellent for adventurers and hikers who sometimes venture deep off the grid and can become lost. Handheld units are downloaded with topographical maps that can help a hiker find the best route back to civilisation. Handheld units can also be used as portable GPS units onboard boats and automobiles, giving the user a great deal of versatility.
One can find a variety of Garmin GPS units for personal use such as golfing, running, hiking, and swimming. These units are typically very small and can be worn on the wrist or kept in a pocket until needed. Personal GPS units for running and swimming allow athletes to monitor how far they have run and the various times associated with their runs. The units can also monitor the runner or swimmer's body state by measuring weight and body fat and relaying it to a computer programme for tracking. Golfers can benefit from a GPS unit that downloads the various courses they play, gives their precise position on that course, and tells them the yardage remaining to the hole. The unit also keeps tabs on the golfer's score as well as various statistics such as fairways and greens hit in regulation and putts per round.
How to Buy Garmin GPS Units on eBay
If you are in the market for a new Garmin GPS unit for use in your next outdoor activity or road trip, eBay is a great source where you can find and purchase a GPS unit at a great price. You can start shopping on the website by navigating to the eBay home page and entering an applicable keyword such as "Garmin GPS" into the search box. If you want to find a specific type of Garmin GPS unit, such as a "Garmin handheld GPS", then type that information directly into the search box to only see the items specifically related to that keyword. You can also choose from filters, such as price and condition, to further narrow the search results to be more specific to what you are looking for. Do look within the eBay Deals section, where you may find Garmin GPS units listed with promotional pricing.
Global positioning technology has changed the way people navigate the world around them. GPS has made travel and navigation much safer across different modes of transportation. The technology has simplified the way that drivers get from one place to the next in their cars, and it has made it possible for boaters to find their way back to port in the thickest of fogs. Regardless of the user's outdoor needs, there is a Garmin GPS unit available that can handle the task. When purchasing a Garmin GPS unit, it is necessary to consider the purpose for which one needs the product. Once the purpose is determined, it is easy to find that ideal GPS unit by utilising the powerful shopping tools on eBay, where one can save money and shop safely.
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