Waas Receiver
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 NEW GNS 5870 MFI GPS AVIATION IPAD IPHONE RECEIVER WAAS $81.00 Time Remaining: 12d 19h 4m Buy It Now for only: $81.00 |
 Columbus V 800 USB GPS Receiver 66 ch MTK2 WAAS 5Hz $29.99 (1 Bid) Time Remaining: 22h 32m |
 Lowrance iFinder H2O C GPS+WAAS Compact handheld GPS Receiver $108.99 Time Remaining: 25d 11h 47m Buy It Now for only: $108.99 |
 Lowrance iFinder H2OC H2O C GPS+WAAS Compact handheld GPS color Receiver $109.99 Time Remaining: 9h 47m Buy It Now for only: $109.99 |
 NEW GNS 5870 MFI GPS FOREFLIGHT IPAD IPHONE RECEIVER WAAS WINGX PRO $81.00 Time Remaining: 12d 19h 16m Buy It Now for only: $81.00 |
 Lowrance iFINDER H20c GPS WAAS Receiver $129.95 Time Remaining: 23d 31m Buy It Now for only: $129.95 |
 Lowrance Airmap600C Upgraded Color Display GPS+WAAS Receiver $198.99 Time Remaining: 16d 9h 26m Buy It Now for only: $198.99 |
 Columbus V 800 USB GPS Receiver 66 ch MTK2 WAAS 5Hz $29.99 Time Remaining: 1d 22h 56m |
 GPS Receiver with Molex Interface Support WAAS EGNOS MSAS GAGAN NMEA Protocols $33.99 Time Remaining: 21d 9h 57m Buy It Now for only: $33.99 |
 Lowrance iFinder H2O C GPS+WAAS Compact handheld GPS Receiver $107.19 Time Remaining: 13d 11h 39m Buy It Now for only: $107.19 |
 Lowrance Waterproof iFINDER Hunt Handheld GPS+WAAS Receiver $109.99 Time Remaining: 15d 6h 17m Buy It Now for only: $109.99 |
 Lowrance LGC 4000 GPS WAAS High Sensitivity Receiver Antenna 0125 25 $199.99 Time Remaining: 20d 20h 21m Buy It Now for only: $199.99 |
 Garmin GPSMAP 4208 WAAS enabled Includes 12 parallel channel GPS ext receiver $1,720.00 Time Remaining: 20d 19h 14m Buy It Now for only: $1,720.00 |
 Lowrance Ifinder H2O C Plus H2OC Outdoor waterproof handheld GPS + WAAS receiver $125.98 Time Remaining: 20d 18h 40m Buy It Now for only: $125.98 |
 NEW Garmin eTrex 10 GPS Receiver WATERPROOF 20 HOUR USB WAAS ENABLED $124.99 Time Remaining: 3d 22h 17m Buy It Now for only: $137.99 |
 Lowrance Airmap600C Upgraded Color Display GPS+WAAS Receiver $199.99 Time Remaining: 25d 9h 18m Buy It Now for only: $199.99 |
 Furuno Bbw gps Waas Receiver F Navnet $347.72 Time Remaining: 12d 22h 25m Buy It Now for only: $347.72 |
 Garmin eTrex Legend GPS Handheld Personal Navigator Receiver WAAS Minty in Box $79.95 Time Remaining: 28d 1h 12m Buy It Now for only: $79.95 |
 USB GPS Receiver WAAS $37.00 Time Remaining: 15d 21h 6m Buy It Now for only: $37.00 |
 Furuno BBW GPS WAAS GPS Receiver $313.88 Time Remaining: 25d 17h 3m Buy It Now for only: $313.88 |
 Garmin Montana 600 Handheld GPS WAAS enabled GPS receiver $507.99 Time Remaining: 12d 15h 46m Buy It Now for only: $507.99 |
 Lowrance iFINDER H2O Plus GPS Receiver Waterproof Casing GPS+WAAS receiver $10.49 (2 Bids) Time Remaining: 5d 3h 57m |
 Furuno BBW GPS WAAS GPS Receiver $318.19 Time Remaining: 6d 1h 19m Buy It Now for only: $318.19 |
 Furuno GP32 WAAS GPS Navigator 12 Channel Parallel Tracking GPS Receiver $409.99 Time Remaining: 26d 20h 55m Buy It Now for only: $409.99 |
 IN BOX GARMIN ETREX VISTA W WAAS 12 CHANNEL GPS HANDHELD RECEIVER $125.00 Time Remaining: 22d 16h 37m Buy It Now for only: $125.00 |
 Humminbird 4063401 AS GR16 16 Channel WAAS GPS Receiver $114.09 Time Remaining: 2d 21h 46m Buy It Now for only: $114.09 |
 Furuno GP32 45Receiver GPS WAAS LCD Display $444.05 Time Remaining: 13d 6h 33m Buy It Now for only: $444.05 |
How GPS Receivers Work
GPS Units make sure you know where you are going no matter where you are. Gone are the days of getting lost easily. A GPS system can cost under $100 for a less-than-fancy model. However, what your GPS Unit looks like is not as important as what it actually does.
The GPS receiver is a handheld, sometimes portable device that works with the Global Positioning System (GPS) network. The GPS network is comprised of 27 satellites that constantly orbit the earth. As the earth rotates, so do the satellites. Of these 27, 24 of the satellites actually work, while three are used as backups. As you can imagine, running the GPS is quite costly.
The GPS network was originally developed by the United States military. The military used it to increase navigational accuracy. However, it was not long before the GPS network was open for use by anyone.
How it works is simple. First, the satellites have multiple orbit routes around the earth. At any one moment in the day, at least four of the satellites are able to transmit information from the satellites to GPS receivers. Of course, it is imperative that the view between the satellite and the GPS unit is unobstructed. That is why GPS receivers sometimes do not work right in areas with high mountains, a lot of trees, or skyscrapers in the way.
GPS receivers work with the satellites. First, the GPS hunts down four of the satellites that can connect with and transmit information to the GPS unit. Once four satellites have been found, the distance to each of the satellites is recorded, and the GPS can pinpoint its location, by the distance it is from each satellite.
This mapping and estimating is based on a principle in mathematics, which is known as trilateration. How it works is by traveling through three-dimensional space. This is complex to understand, but the result is amazing, and it should be what you look for when purchasing a GPS unit of your own.
Trilaterion that works in 3-D is what is used to map your location. A series of spheres line the distance from one place to the next, based on the location of the satellites at the time of the transmission to the GPS receiver. The spheres intersect and meet and as the distances from different locations on different spheres are measured, your exact location is pinpointed. All of the four satellites' plots work together, to intersect in one place through the spheres.
GPS receivers generally try to use more than four satellites at one time. This provides a more accurate location and less room for error. The Earth is also used as a marker, which works with the GPS network to help pinpoint locations on the surface of the planet.
GPS receivers have to know how far a distance it is from the satellite to the unit. To do this, radio signals sent from the GPS satellites are analyzed. These signals are high in frequency though they are relatively low in power. The better your GPS unit is the better chance you have of using multiple satellites in order to pinpoint your exact location.
Since radio signals travel at the same speed light does, GPS receivers are able to determine how fast the waves travel and how far they have traveled. At random times, the satellites transmit pseudo-random code, which are digital patterns, to the GPS receivers. The GPS unit will then play the digital pattern, though there will be a lag. This lag is based on how fast the signal traveled, and is a major part of the GPS plotting process.
In order to track the signal's pattern, the satellite and the GPS receiver use clocks, which synchronize together. The Satellite uses an atomic clock, while the GPS receiver uses a regular clock. However, to accommodate synchronization, the clock in the GPS unit is able to constantly reset. This prevents any type of clock problems from occurring.
There are various types of GPS systems. These systems work to fix any inaccuracies and errors in the GPS receiver's location tracker. These systems include WAAS and DGPS.
About the Author
Catherine Tower of Gottronics, is in charge of the research department, where she gathers information and reviews different
portable GPS
units, whether it be good or bad and stays up to date with all of the latest developments of the products.