The Advanced Automation System (AAS) refers to a comprehensive modernization effort undertaken by the Federal Aviation Administration (FAA) in the United States, aimed at upgrading the nation's air traffic control (ATC) system. The primary goal of AAS is to improve the efficiency, safety, and capacity of air traffic management by leveraging advanced automation technologies.

Implemented in the 1990s, AAS introduced significant enhancements to the air traffic control infrastructure, including:

1. Automation of routine tasks: AAS automated many routine tasks, such as data entry, tracking, and conflict detection, allowing controllers to focus on higher-level decision-making.
2. Advanced radar and surveillance systems: AAS integrated advanced radar and surveillance systems, including Mode S radar and Automatic Dependent Surveillance-Broadcast (ADS-B), to provide more accurate and reliable aircraft tracking.
3. Computer-based decision support tools: AAS introduced computer-based decision support tools to assist controllers in making optimal decisions about aircraft routing, spacing, and sequencing.
4. Enhanced user interfaces: AAS provided modernized user interfaces, including graphical displays and intuitive controls, to improve controller productivity and situational awareness.
5. Network-centric architecture: AAS adopted a network-centric architecture, enabling the integration of disparate systems and facilitating the sharing of data and information across the air traffic control network.

The Advanced Automation System has played a crucial role in modernizing the US air traffic control system, enabling it to handle increasing air traffic demand while maintaining safety and efficiency. Although the AAS program has undergone significant updates and upgrades over the years, its legacy continues to shape the development of air traffic management systems worldwide.

In the context of aerospace, AAS is also relevant to the development of autonomous systems, such as unmanned aerial vehicles (UAVs) and autonomous aircraft, which rely on advanced automation and sensing technologies to operate safely and efficiently.

I hope this provides a clear overview of the Advanced Automation System in aviation and aerospace!