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What is SBAS?
A satellite based augmentation system, or SBAS, is an augmentation system that uses additional messages from satellite broadcasts to support regional and wide area augmentation. A satellite based augmentation system is usually made up of several ground stations that can be located at exact surveyed points. The ground stations measure satellite signals and other environmental factors that can impact the satellite signal that is being received by users. These measurements make it possible for navigation data to be created and sent for broadcast via multiple satellites.
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There are several satellite based augmentation system implementations and designs. SBAS implementations include the Wide Area Augmentation System from (WAAS) from US, the European Geostationary Navigation Overlay Service, or EGNOS from Europe, and the Multi-functional Satellite Augmentation System, or MSAS from Japan. These systems and the other augmentation systems in the world follow a specific frequency and message format set by the International Civil Aviation Organization.
The WAAS is a very accurate navigation system that was developed to provide civil aviation services to each and every class of aircraft in every phase of flight including airport departures, en route navigation and airport arrivals. The EGNOS improves the reliability and accuracy of navigation signals that originate from GPS systems. These systems, including the other satellite based augmentation system implementations, have different configurations and execution processes, but they all adhere to the same specifications so they can communicate with each other effectively if the situation demands it.
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How does it work?
Satellite based augmentation system implementations make use of the emerging technology of global positioning system satellites and it is gaining prominence in the field of global navigation. Geostationary satellites work with ground stations to improve the performance of global navigation systems by making additional satellites and signal corrections available to end users. The additional satellites have constant and known positions, making them more reliable and easily accessible to other satellites and ground stations.
The design of satellite based augmentation systems make it possible for them to receive navigation signals from satellites that they can broadcast to end users. Their signal is similar to GPS signals such that it has augmentation data with integrity and differential correction for wide areas. SBAS improves the integrity, accuracy, availability and continuity of existing global navigation systems by implementing its kind of infrastructure.
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Why are Satellite Based Augmentation Systems important?
The infrastructure of satellite based augmentation systems rely on observation and relay ground stations scattered all around the world and global navigation system satellites with fixed positions high above the Earth. This infrastructure provides reliable and stable distance information, the very information used to correct satellite global navigation signals that are used for atmospheric delays, poor geometry and incorrect satellite positioning. In effect, satellite based augmentation systems increase global positioning accuracy in certain regions. SBAS is basically an extremely vital provider of precision and reliability for the entire aviation industry, as well as other applications that require precision and stability.