As a primary support component for surface weather observations at approximately one thousand locations, ASOS advises air traffic management of the current weather conditions in support of the national airspace, safety of the flying public and Navy, Marine Corps, and Army operational airfields. The surface weather observation is a crucial component of day to day operations at these locations. The absence of ASOS observations at a location can delay flight operations, prevent air traffic from landing or taking off and cause second and third order effects that prevent passengers and cargo from reaching their final destinations on schedule, precipitate economic consequences or worse in the case of contributing to an aircraft mishap.

As an operational system in the field for nearly 30 years, ASOS failure rates are increasing, system outages are lasting longer and replacement equipment is suffering from diminishing manufacturing sources and material shortages (DMS/MS) making it more difficult to procure and deliver parts to effect repairs. Original Equipment Manufacturer (OEM) vendors for the current sensor array have announced end of lifecycle support for some ASOS sensors with more coming. Numerous sensor obsolescence and end of life support from OEM vendors manifests itself in the form of increased operational sensor failure rates and ASOS component attrition. These sensor obsolescence issues are secondary to the deterioration of the data processing and dissemination technology ASOS uses that was developed in the 1980’s.

The ASOS Service Life Extension Program (ASOS SLEP) – led by the NWS; an initiative undertaken by the NWS, FAA and DoD to modernize the ASOS. Under the Program the initial project goal was to replace the Acquisition Control, Data Collection and Dissemination capabilities of the ASOS along with all the sensors on the sensor array. This was deemed to be unachievable and the program was de-scoped to include just the ACU/DCP upgrade project; sensors were unfunded in light of prioritizing data processing and dissemination systems where increasing ACU/DCP obsolescence brought on by DMS/MS issues were deemed more important.

The ACU/DCP Upgrade Project Scope: The Acquisition Control Unit (ACU), Data Collection Package (DCP) and the Single Cabinet Assembly (SCA) are being upgraded to ameliorate significant obsolescence problems within each subsystem. The project comprises an integrated system that includes new hardware and software that allows for an upgrade path to modern IP communications, sensor agnostic system integration and expanding the availability and periodicity of ASOS data to end users. These upgrades will solve the most immediate obsolescence problems with ASOS while allowing members of the ASOS Tri-Agency to implement upgraded communications.

The ACU/DCP Upgrade Project will allow for ASOS sensor instrumentation and communications modernization initiatives--with two sensor projects already underway for the Legacy ASOS. Implementation of the sensor sustainment project initiatives is dependent upon ACU/DCP upgrade deployment to the field with the exception of the Ice Free Wind Sensor (IFWS) and the Temperature Relative Humidity Sensor (TRHS). All other Sensor projects are subject to being installed onto ASOS 2.0 deployed systems.