The aerospace industry is increasingly turning to fiber optics to bear data and communications in the avionics systems of next-generation aircraft. This is due to the technology’s clear size, weight and power (SWaP) advantages which are highly sought after in the industry, particularly as it moves toward electric power systems.
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Fiber optics are also well-suited for high-bandwidth applications, they are not affected by electromagnetic interference (EMI), and modern hardware is more reliable than copper wire. Combined with the technology’s SWaP advantages, these factors are leading manufacturers to design innovative cockpit systems and cabins for the newest air transportation technology.
Modern Avionics and the Need for SWaP
Avionics refers to all of the electronic systems used in aircraft, satellites, and spacecraft. They power most controls, as well as communications, navigation, display, and system management in the cockpit; they drive the hundreds of individual systems performing small but essential tasks to maintain flight; they also include additional systems fitted to aircraft to make them useful such as searchlights, winches, and in-flight entertainment.
As consumer and specialist electronics technologies have progressed exponentially in the last half-century or so, so has the potential for avionics technology. However, the demands of gravity mean that SWaP priorities have often outweighed avionics benefits, especially when more bandwidth means more heavy, bulky copper wire.
This demand and possibility for more data processing capacity (for example, streaming video) is concurrent with a move toward even smaller, lighter flying vehicles and devices in the next stage of our journey with aviation. Industry commentators have predicted that small, flying, battery-powered electric vehicles with vertical take-off capability could replace cars for personal transportation in the future. Meanwhile, companies are already utilizing drones for everything from delivering products to environmental monitoring.
As a result of these changes, manufacturers are moving toward fiber optic connections for avionics in next-generation aircraft, and leaving the bulky, heavy copper wires on the runway.
Advantages of Fiber Optics for Avionics
Fiber optics have numerous advantages over traditional copper wire for avionics systems. They offer higher bandwidth, meaning that they can carry more data at once and work with higher resolution files. They are also much lighter, more reliable with better signal integrity, impervious to EMI, and can carry out multiple signaling and information transmission tasks through the same connection.
In terms of bandwidth, fiber optics can reach up to 60 terabytes per second (Tbps), while copper wiring can only get up to around 10 gigabytes per second (Gbps) or 0.00124 Tbps.
SWaP advantages (smaller size and weight) over copper are also clear to see. Fiber cables typically weigh approximately 1.8 kg per 300 m of cables, while copper can weigh almost ten times this much for the same length.
In terms of signal integrity, fiber optics perform much better than copper wires. This is demonstrated by the less frequent use of repeaters in fiber optic-based avionics systems: a repeater is used once every 30 miles on average with fiber optics connections; this increases to once every three miles on average with copper wiring.
EMI immunity means that fiber optics-based avionics systems are not affected by electrical noise generated by other equipment, which means different sensitive instruments can be placed close together to save space without causing either machine to stop working. Solar flares and weaponized EMI are also less effective with fiber optics systems.
Optical communications are also not prone to signal leakage in the way that electronic communications (signals sent through copper wires) often are. This increases security in these systems, preventing hackers from breaking in.
More Data for Avionics to Deal With
As mentioned above, the introduction of fiber optics has also enabled aircraft and avionics systems inside them to deal with much larger data packets than ever before. Fiber optics is particularly suited to the high-speed computing and electronics operations demanded by modern aviation.
High-performance radars, for example, help aircraft accurately pinpoint objects in the sky and keep the plane’s occupants safe. But these devices work in 4K or even 8K high resolution, and need connections and computers capable of reliable high-speed processing in real-time.
Digital compression can only reduce these file sizes so much before the latency and delayed image display costs make the data unusable. Fiber-optic systems can present high-quality imagery to pilots to enable them to make split-second decisions effectively.
Advanced imaging systems such as LiDAR, which can create three-dimensional computer models of its physical surroundings in real-time, also rely on the latest high-speed electronic connectivity to be adapted for avionics.
Systems such as the automatic dependent surveillance-broadcast (ADS-B) and flight information services-broadcast (FIS-B) gather and deliver valuable information in and out of planes’ cockpits. Now, all of the data available to air traffic control (ATC) can also be transmitted to pilots, including live weather information and the location of other planes in three-dimensional space.
References and Further Reading
Koon, J. (2020) How Fiber Optics Will Propel Future Avionics. Aviationtoday.com. [Online] Available at: http://interactive.aviationtoday.com/how-fiber-optics-will-propel-future-avionics/.
Davidson, J. (2021) ADS-B UPDATE 2021 – WHERE ARE WE NOW? Universalweather.com. [Online] Available at: https://www.universalweather.com/blog/ads-b-update-2021/.