Dissemination of Aviation Weather Information

BACKGROUND

Development of the Next Generation Air Transportation System (NextGen), a national program designed to meet the expanding air transportation needs of the US in the 21st century, is well underway, with member agencies overseeing R&D and implementation acquisitions.  Defining the weather information needs of NextGen and providing common weather-related decision information to all stakeholders within the system is an important element of the overarching program. Since weather conditions can seriously restrict aircraft operations and levels of service available to system users, the manner by which weather is observed, forecast, disseminated, and used in decision–making is of critical importance.

RAL's activity in dissemination of aviation weather information is focused in two areas:

  1. Common Support Services – Weather (CSS-Wx), developing next generation technology and infrastructure for dissemination of weather data to US Government and other users; and
  2. Weather Technology in the Cockpit (WTIC), developing methods for making the best weather information available to pilots for decision-making in the cockpit.

COMMON SUPPORT SERVICES – WEATHER (CSS-WX) PROGRAM

Figure 1. Diagram of FAA NextGen Weather Architecture with CSS-Wx in a central role
Figure 1. Diagram of FAA NextGen Weather Architecture with CSS-Wx in a central role

RAL has been one of the key contributors in developing standards and technology for the FAA research and acquisition programs focused on weather in the NextGen.  This work, part of the FAA’s Common Support Services Weather (CSS-Wx) Program, is aimed at developing next generation technology and infrastructure for dissemination of weather data to FAA and other aviation users. It focuses on enabling ubiquitous access to aviation weather data anywhere an appropriate network connection is available.

CSS-Wx achieves its goal by using a service-oriented architecture (SOA) approach in which existing Internet technology is leveraged to build weather data delivery services that conform to international standards. CSS-Wx has defined a network of data servers based on the Open Geospatial Consortium (OGC) Web Feature Service (WFS), Web Coverage Service (WCS), and Web Map Service (WMS) standards, operating over the FAA’s System Wide Information Management (SWIM) messaging broker. The services provide weather data encoded with standards from the World Meteorological Organization (WMO), International Civil Aviation Organization (ICAO), and UCAR’s Unidata. Using these technologies, it is possible to build complex, dynamic weather systems in which data sources and clients can be developed and modified independently but remain compatible while optimizing data latency and network bandwidth. RAL's participation in this program is sponsored by the FAA CSS-Wx Program Office and work is conducted collaboratively with the FAA's William J. Hughes Technical Center, MIT/Lincoln Laboratories, and NOAA.

FY2019 Accomplishments

In FY2019, the FAA CSS-Wx program has been proceeding with acquisition of the system through a contract to a commercial vendor for implementation and operational deployment of the CSS-Wx system in the FAA National Airspace System. The contractor has been heavily engaged in developing and testing the software for CSS-Wx this year. Based on years of experience during the development of CSS-Wx program concepts and proof of concept prototypes, NCAR/RAL acts as a subject matter expert to the FAA advising the agency about technical issues related to the contractor’s implementation of the system.

NCAR/RAL has also been a key contributor to the coordination between NOAA and FAA subsystems of NextGen. Forecast model output generated at the National Centers for Environmental Prediction (NCEP) and weather observations from various existing subsystems are reformatted for dissemination through the CSS-Wx network and generation of supplementary forecast products in the NextGen Weather Processor (NWP). NCAR/RAL has been the leader in developing and maintaining software for bridging from Gridded Binary (GRIB2) datasets to netCDF and for converting Traditional Alphanumeric Code (TAC) en-route advisory streams into the ICAO Meteorological Information Exchange Model version 3 (IWXXM-3).

In addition, RAL continues to work with experts from US and international agencies to validate and refine rules of practice for operational use of the data service standards and weather data format standards. RAL hosts an official validator for IWXXM schemas for public access online.

FY2020 Plans

The focus for FY2020 is to continue supporting the FAA's acquisition process for CSS-Wx, including providing technical guidance to the FAA and the CSS-Wx commercial vendor. RAL expects to troubleshoot and propose solutions to technical issues in the operational system as they are uncovered.  RAL will maintain a limited-scale testing system to verify solutions and anticipate issues that may be faced during the operational implementation. RAL will also continue its work on data services and weather data formats in concert with the new standards from the OGC, ICAO, and WMO. The new versions of the standards will improve interoperability of weather systems, but will require additional evaluation and integration with legacy systems.

WEATHER TECHNOLOGY IN THE COCKPIT (WTIC) PROGRAM

One of the programs led by the FAA's Aviation Weather Office (AWO) is Weather Technology in the Cockpit (WTIC). RAL is engaged in an effort for WTIC to study the requirements and technologies that would enable pilots to gain the advantages inherent in the rapidly emerging world of mobile technologies, including both tablets and phones. In this project, referred to as MobileMet, RAL provided a comprehensive technology assessment of mobile devices for use in delivery of weather information to the cockpit. RAL conducted a broad survey of the needs and expectations of users in relation to mobile devices for aviation weather delivery, developed several prototype applications based on the user needs survey, evaluated pilot responses to various weather presentations, and crafted an initial set of Minimum Weather Service Recommendations (MWSR) for mobile device use in general aviation aircraft.

FY2019 Accomplishments

Radar Latency

Figure 2. NVN simulation for the Radar Latency pilot evaluation
Figure 2. NVN simulation for the Radar Latency pilot evaluation

RAL examined the potential benefits of presenting pilots with a radar depiction on a mobile device, forecasted to the current time. The goal is to reduce pilot error due to the latency involved in sending observed weather data in the cockpit. As part of this study, RAL researchers developed and validated a novel, “virtual volume,” approach to reducing radar processing time as well as forecasting cell growth and decay. The resulting nowcast was named NEXRAD Valid Now (NVN). NVN forecast lead times from 0-15 minutes were verified to assess their potential errors. RAL prepared software for a pilot evaluation to compare these errors with the errors in pilot judgement from latent radar information. The results of that evaluation may be combined with other studies conducted at the FAA, and incorporated into the Minimum Weather Service Recommendations report.

Tactical Turbulence

Figure 3. Determination of the turbulence notification and demonstration display
Figure 3. Determination of the turbulence notification and demonstration display

RAL performed pilot evaluations and simulator evaluations to assess the feasibility, identify capabilities, and prototype implementations for tactical turbulence notification in the cockpit.  From these evaluations RAL has developed a real-time notification system, FlightAlert, that projects aircraft positions forward in time and calculates a categorical severity for a turbulence along the aircraft's path.  The system is capable of creating XML output messages which are sent to each target aircraft via Aircraft Access to SWIM (AAtS) and present to the aircraft's pilots. This notification can provide advanced warning and avoidance capabilities to mitigate turbulence injuries. The project focused on the tactical use of the notification messages to mitigate turbulence injuries, rather than forecast use for route planning.

In FY2019, RAL refined the FlightAlert system to generalize the algorithm to work with any gridded categorical hazard type and, additionally, to run on all available commercial aircraft.  RAL also analyzed the timeliness of available input aircraft data and the accuracy of aircraft projections utilizing the real-time system.  The results from the analysis showed that the projected aircraft hazard box locations were sufficiently accurate to forecast turbulence and that the system as a whole was suitable to support direct aircraft notifications.

FY2020 Plans

RAL expects to participate in a Radar Latency pilot evaluation in FY2020, providing software and technical support to the FAA-designated executor of the evaluation, assisting with processing of the results, and communicating findings through a Minimum Weather Service Recommendations report.

Although the Tactical Turbulence project completed in FY2019, RAL is currently discussing with the WTIC office the potential for follow-on work to apply the same technique to other aviation hazards.