Selective Availability (SA) was a feature intentionally introduced in the GPS navigation system to generate random errors for GPS receivers used by the general public. It was done to prevent enemy soldiers from using GPS to their advantage while allowing friendly troops to use the real signals if their GPS receivers were equipped with military-grade encryption.
The Gulf War compelled the U.S. military to supply a large number of consumer-grade GPS receivers to their troops, which forced them to disable SA temporarily. In 2000, the U.S Government permanently disabled SA due to advancement in ground-based augmentation systems, rendering SA unnecessary. These systems made up for consumer-grade GPS receivers’ lack of precision and provided more accuracy, further improving GPS navigation services’ reliability.
FAQs
What did Selective Availability do in GPS navigation?
Selective Availability was a feature introduced in GPS navigation that purposefully generated errors in GPS signals for civilian GPS receivers. This was done to prevent enemy soldiers from exploiting GPS, while allowing the friendly troops to use a more precise GPS system.
Why was Selective Availability disabled?
Selective Availability was permanently disabled in 2000 because of advancements in ground-based augmentation systems. These systems made up for consumer-grade GPS receivers’ lack of accuracy, making Selective Availability unnecessary.
How does GPS work without Selective Availability?
GPS works by using a network of satellites orbiting Earth to triangulate a receiver’s position. Once the receiver can receive signals from multiple GPS satellites, it can calculate the distance between each satellite and its location. By combining these distances, the receiver can determine its precise location on the Earth’s surface. Ground-based augmentation systems further improve GPS accuracy by correcting errors caused by atmospheric interference, giving users more precise location data.
Conclusion
Selective Availability (SA) was a feature introduced in GPS navigation that generated random errors in GPS signals for consumer-grade GPS receivers. It was done to prevent enemy forces from exploiting GPS data, while providing more accurate signals to friendly forces with military-grade encryption. Due to advancements in ground-based augmentation systems and the lack of need for SA, it was permanently disabled in 2000. As a result, GPS navigation became more reliable and accurate, serving as an essential tool in various sectors, including transportation, disaster management, and personal navigation.
