Automated Surface Observing Systems (ASOS) by Coastal are the most advanced in the world.

ASOS Description

An Automated Surface Observing System, or ASOS, as defined by the Federal Aviation Administration (FAA) and the National Weather Service (NWS), is a suite of weather sensors which measure, collect and disseminate weather data to help meteorologists, pilots and flight dispatchers prepare and monitor weather forecasts, plan flight routes, and provide necessary information for correct takeoffs and landings. ASOS systems are a joint program between the FAA, NWS, and Department of Defense (DOD) to provide a primary network of surface observing weather stations.

NWS manages the infrastructure necessary to support all ASOS systems during the life cycle of the program. The
NWS-FAA Interagency Agreement describes NWS life support services, which include:

  • Identification of ASOS malfunctions and communication network failure.
  • Preventative and corrective maintenance.
  • Spare parts management, hardware, and software management.
  • Configuration and upgrade management.
  • Performance reporting.

ASOS systems have an internal processor on its platform, which provides an initial validation of the data. Data from ASOS systems are disseminated to airport towers, FAA systems, and NWS systems every minute, 24 hours a day.

The name ASOS specifically refers to approximately 1000 automated surface observing systems in the U.S. and some international locations that were installed in the late 1980's and 1990's. The name ASOS has become synonymous with AWOS. As there are many ASOS automated surface observing systems still in use today they are constantly being overhauled and upgraded. In some cases they all receive an upgrade, in other cases only select sites receive certain upgrades.

As time progresses this results in many different configurations of ASOS and different abilities.

Automated Surface Observing System Upgrades

Coastal can upgrade any ASOS completely or we can upgrade the field electronics and the PC/Server (i.e. the Data Collection Package and the Acquisition Control Unit in ASOS jargon), allowing you to continue using the same meteorological sensors you have (the original set, the upgraded set – or anything in between). With the upgraded DCP and ACU you can also add Runway Visual Range (RVR) and/or lightning detection as well as other features not available with ASOS currently.

Our Automated Weather Observing Systems (AWOS) can have up to 5 remote automated surface observing stations (full or partial sets of all the above meteorological sensors) on one or several runways. The data is all collected and processed in the weather room at either a PC or a server (depending on the scale of data distribution). The data is then sent to one or several display devices, other PCs, a LAN/WAN, and a voice output for broadcast to pilots.

ASOS Downloads

For complete information on Coastal's aviation weather stations and weather sensors, please contact us.

Coastal's Weather Algorithms comply with the U.S. National Weather Service ASOS Statement of Work contract 50-SANW-1-00050, Appendix 1, ASOS Weather Algorithms, the Office of Federal Coordinator for Meteorological Services (OFCM), Federal Meteorological Handbook Number One (FMH-1), Surface Weather Observations and Reports, and with ICAO Annex 3, Fourteenth Edition.

Who Depends on Coastal's AWOS Systems

Where Coastal's AWOS are Found

Automated Surface Observing System (ASOS) Image

ASOS Standard Sensors:

  • Wind Sensor
  • Redundant Altimeter
  • Relative Humidity (Dew Point)
  • Air Temperature
  • Visibility
  • Freezing Rain
  • Cloud Height and Cover
  • Precipitation Type
  • Precipitation Amount
  • Lightning
  • Runway Visual Range (RVR)
  • Optionally, the system can measure Soil Moisture and monitor the area with video.

Please contact us for a complete listing, or to discuss the best sensor options for your ASOS specifications.
(Sensor Specifications)


110/120 VAC, optionally 220/240 VAC.


Vacuum Fluorescent Display (VFD), Liquid Crystal Display (LCD) with back light, Flat Panel TFT, or PC Full Screen display and archival.


10 meter is standard, all other heights are available.

ASOS User Interface/Display Software:

Coastal's Aviation INTERCEPT® (AI) software for fully automated and/or operator-assisted aviation meteorological reporting. It is a complete program for processing, display, analysis, reporting, storage, and long-term management of meteorological data from your ASOS.