Spinoff is NASA’s annual publication featuring successfully commercialized NASA technology. This commercialization has contributed to the development of products and services in the fields of health and medicine, consumer goods, transportation, public safety, computer technology, and environmental resources.

For decades, airport operations have relied mainly on voice communications over unsecured radio frequencies, with landline phone calls as the only secure backup option. Now, the Aeronautical Mobile Aircraft Communication System (Aero-MACS) will allow Federal Aviation Administration (FAA) staff in control towers to send safety-critical information digitally and securely, leading to shorter wait times on the tarmac.

AeroMACS will phase out the use of voice communication as the primary method of information sharing for airport ground operations. The new, encrypted, high-speed digital data networks will streamline communications among ground crews and air traffic controllers. Messages sent to a pilot after the plane is on the ground can include diagrams and GPS-style maps as well as text instructions for runway navigation, gate assignment details, and surface navigation directions.

Aviation authorities from more than 150 countries chose and agreed to adopt the WiMAX standard. Formally adopted in 2007, WiMAX uses cellular network infrastructure that’s customizable for the new frequency — the spectrum of 5091 to 5150 megahertz is reserved for safety-critical aviation communications only.

NASA engineers have been part of this process from the start. The agency’s Glenn Research Center in Cleveland took the lead on AeroMACS testing. The center had worked on these issues previously and had extensive expertise, which made it a natural partner for the FAA.

To run the first aviation tests, NASA worked with the Broadband Wireless Access division of Alvarion Technologies Ltd. to modify existing WiMAX hardware. Acquired by Telrad Networks, the company was able to leverage its work with the agency to become one of the first to receive AeroMACS Wave 1 Certification, an independent validation of performance from an industry observer.

The Telrad BreezeCOMPACT 1000 4G broadband base station — a modem and radio all in one — is used to set up an AeroMACS-based wireless network. (Telrad Networks)

In this family of hardware, any sensors — called subscriber stations — will collect, transmit, and receive data. Telrad builds the base station that performs the same function as in a cellular network, routing transmissions with GPS providing timing for the network. The company also assists with identifying the best antenna type; placement depends on the airport configuration and signal coverage needed around the surface.

A proxy client server executes security protocols and enables user authentication to verify the sender and receiver, blocking outside intrusions. The Access Service Network gateway enables connectivity throughout the network. This complete system customized by Telrad is all that’s needed to set up an AeroMACS-based wireless network. Telrad has also created Star Suite, a software network management program that can support any application an airport might require.

AeroMACS is cheaper to operate and maintain than existing voice-based infrastructure but it will take time to transition all airports to the new technology. Each aviation authority may choose to implement it in smaller stages. So far, some U.S. airports are using the system to collect information from surveillance sensors, which will help improve aircraft tracking on runways and taxiways.

In 2016, for the first time, NASA successfully transmitted aviation data, including route options and weather information, to a taxiing airplane over a wireless communication system. Successfully eliminating the risk of signal interference while maintaining throughput capacity was what made this accomplishment so significant. NASA engineers also proved that mobile assets such as emergency vehicles and laptop computers could be included in the wireless network.

To date, more than 50 airports in about 15 different countries are using AeroMACS to replace voice with data transmission. It’s estimated that it will take 20 years to transition more than 40,000 airports worldwide.

Read this article, and other NASA Spin-Off articles, at spinoff.nasa.gov .


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This article first appeared in the March, 2021 issue of Tech Briefs Magazine.

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