Modernization of Automated Surface Observing System (ASOS) Hardware and Software

The National Weather Service (NWS) Automated Surface Observing System (ASOS), which serves as the primary data source for more than 900 airports nationwide and is utilized for climate data archiving was deployed in the early 1990’s.  The ASOS system is equipped with Versa Module Europa (VME) technology computing elements that include a central processing unit (CPU) which uses the PSOS operating system. The CPU and operating system have now become obsolete and are now reaching end of life from a supportability standpoint.  The legacy OS is virtually unsupportable and the ASOS application that runs on the OS have become harder and harder to maintain and update. It is not cost effective to port the legacy code to modern computer hardware.

ASOS, a Tri-Agency Program comprised of DOC, DOT and DOD, is the primary source of surface meteorological data for these agencies and their mission. The NWS, the Federal Aviation Administration (FAA), and the U.S. Navy are in agreement that a more modern OS and modern computer hardware are required to extend the life of the ASOS.  As a result, the agencies entered into an ASOS Control Unit/Data Collection Package (ACU/DCP) upgrade focusing on replacement of the legacy hardware and software.  The NWS is in the process of finalizing the hardware design that will support the new software.  The FAA is in the process of developing the next generation ASOS software to replace the legacy OS.

A modern ruggedized computer will replace the CPU cards in the VME rack of the old system and serial servers will take the place of the Serial Input Output (SIO) cards.  The new ASOS will utilize a Local Area Network (LAN) architecture, with a large portion of the new components having Ethernet communications capability.  Additionally, all of the legacy DC power supplies, AC power control and the Uninterruptable Power Supplies (UPS) are also being replaced.

The new software will run on a Linux OS as a separate software application written in the C++ language.  The new ASOS software will feature additional storage space along with a completely updated maintenance interface, and the original text storage back end of the system is being replaced with a modern SQLite database.  The external communications interface is remaining in its legacy form; however an upgrade is planned for a later date.