Technology Blog

The technology behind GPS systems can be complicated. However, a little research into what the various systems are and how they work can make choosing the right GPS system an easier decision. If you have looked into purchasing a GPS or owned a GPS system before then you probably have seen the term WAAS either on packaging or in ads for GPS systems.

WAAS stands for Wide Area Augmentation System. WAAS is an intricate GPS technology, which was developed to provide locations that are more accurate. This is done through GPS signal corrections attained through a network of ground stations and satellites. The stations and the satellites work together to create plots on maps so GPS systems can easily make this information available to the consumers that use these products.

WAAS is still being developed through the joint efforts of the FAA (Federal Aviation Administration) and the DOT (Department of Transportation). The reason the DOT and the FAA are developing WAAS is actually to make flight locations more accurate. WAAS works together with GPS because GPS does not currently meet navigational requirements of the FAA on its own.

At this time, WAAS is five times more accurate than the average GPS system technology. In fact, a GPS receiver with WAAS capabilities can maintain an accuracy of three meters or less over 90% of the time. Of course, the best feature of WAAS is that it is built in to certain GPS systems. This means there are no additional fees and you do not have to order any additional receivers or other equipment for WAAS to work correctly. Additionally, depending on the type of GPS device you own, you may be able to upgrade your GPS system to start using WAAS capabilities if it does not do so already.

GPS alone faces problems such as ionospheric disturbances, precision timing, and orbit errors for the satellites used. However, when used together with WAAS, these three main problems, as well as smaller errors in the GPS system are corrected. WAAS is also capable of providing information on the GPS satellite itself so there is never a question of whether the satellite is working to its greatest potential or not.

There are around 25 different ground stations, which WAAS uses as reference in the United States alone. The GPS satellite data is communicated to these ground stations so the information can be monitored. Then the information is compiled and sent to two master stations (one on the east coast and one of the west coast), which correct any errors in the GPS satellite information.

Corrections are made based on the orbit of the satellite, clock drift, and delays in the signal caused by the ionosphere and atmosphere of the Earth. After the corrections are made, the master station transmits this information to a geostationary satellite (one of two), which are located in a stationary position over the equator. Since the information is GPS compatible (the signal structure is the same) a GPS receiver with WAAS is able to read the signal from the satellite.

At the present time, only people in North America can use WAAS technology. GPS can be used in South America. However, WAAS will not work to correct accuracy errors. This is because WAAS enabled GPS receivers cannot receive signals due to the fact that South America has no ground stations. WAAS technology is constantly being tweaked and improved though, so in time it could become available across the world.

For now, it is best to use WAAS enabled GPS systems in open land or at sea. Since the stationary satellites are at the equator, it can be hard to receive the transmission if you are not close to the equator or if the signal is being blocked by mountains, trees, or other natural and man made objects that get in the way.

While WAAS technology is not perfect, it is much better than what is currently available. As the system improves, the accuracy will improve, making WAAS one of the leading technology systems for GPS receivers. You can find out if a GPS system is WAAS compatible by looking on its package or searching online. Some examples of WAAS enabled GPS units include:

·Garmin GPS 18 PC Deluxe
·Garmin Nuvi 660 Auto GPS Unit
·Garmin etrex Legend Handheld GPS Unit
·Garmin StreetPilot C530

Posted by Aadi on 23 December 2006 at 2:08 PM | Permalink