Guy Norris Inmarsat, Boeing and Cobham trial end-to-end cockpit-to-ground internet protocol satellite communications for more efficient operation.
Guy Norris
Enhanced connectivity with Inmarsat’s Iris data link system is one of 20 technologies being tested on Boeing’s eighth ecoDemonstrator—a 737-9 owned by Alaskan Airlines. Credit: Joe Walker
Aside from improvements in airframes and engines, one of the biggest potential untapped areas for reducing aviation carbon emissions in the near term is smarter, more efficient use of airspace, including direct routing and optimized cruise altitudes.
A key enabler to achieving these efficiencies is underway through the modernization of air traffic management (ATM)—in particular, focusing on digitalization to enable secure global broadband communications between aircraft and controllers. In Europe, under the Single European Sky ATM Research (SESAR) program, satellite provider Inmarsat has partnered with the European Space Agency on Iris—a communication data link system to relieve pressure on ground-based VHF radio frequencies.
From its vantage place in space on Inmarsat’s coming Elera satellite network, Iris will be able to pinpoint an aircraft in four dimensions (latitude, longitude, altitude and time) using 4D trajectories, which enables more efficient tracking and routing of flights through Trajectory-Based Operations. This allows flights to take the shortest available routes, cruise at optimum altitudes and use continuous climb and descent paths.
The system, which is text-based and therefore less error-prone, has cybersecurity protection through a virtual private network barrier and, according to SESAR planners, has the potential to claw back much of the 5-10% of CO2 emissions it has estimated are generated by congestion of airways and needlessly long flight trajectories.
Now, as part of Boeing’s latest ecoDemonstrator program, an enhanced version of Iris is being tested with a recently introduced standard of the next-generation Aeronautical Telecommunication Network using Internet Protocol Suite (ATN/IPS) satellite communications (satcom) system. The tests mark a key step toward the future global rollout of Iris beyond its upcoming European debut later in the 2020s and provide valuable data on the levels of bandwidth and throughput for air navigation service providers (ANSP) and airspace users.
“Having the capability on the aircraft to be able to start sharing true trajectory-based operation is the big step on this version of the ecoDemonstrator,” says John Broughton, senior vice president of aircraft operations and safety services at Inmarsat. “The Iris program is about adding satcom in a multilink capability with VHF radio to support air traffic communications over continental airspace. That’s a bigger step than most people realize from what we’ve done over oceanic airspace because it drives issues over security, latency and network capacity.”
The current tests follow trials of a baseline internet protocol suite communications management unit on the 2019 ecoDemonstrator, a 777-200. Credit: Guy Norris/AW&ST
The 2021 ecoDemonstrator is a Boeing 737-9 and follows an earlier limited demonstration of the IPS system in late 2019 on a Boeing 777-200 test aircraft. “The IPS [Communications Management Unit (CMU)] was trialed on the 2019 ecoDemonstrator to test the operation of IPS in a flight environment,” Broughton says. “Furthermore, a ground IPS-OSI [open systems interconnection] gateway was prototyped by Boeing, which allowed the operation of B1/IPS messaging from the aircraft in the European B1 ATN/OSI environment,” he adds, referring to the use of controller-pilot data link communications.
“However, due to the configuration of the 2019 ecoDemonstrator, satcom was not included as part of the IPS demonstration on the aircraft,” Broughton notes. “In the 2021 ecoDemonstrator, we are building on that activity to test full [Internet Protocol version 6 (IPv6)] IPS connectivity from CMU and [flight management system] end systems through the satcom system to ground processors.” IPv6, with 128-bit addresses, is the next-generation IP designed to replace the 32-bit-long IPv4 addresses.
“This is a material step forward both in terms of proving the functionality [and providing] valuable input to the standardization activities at the [International Civil Aviation Organization], RTCA and Eurocae—the European Organization for Civil Aviation Equipment,” Broughton says.
As a result, the IPS capability for the 2021 ecoDemonstrator features several additions. These include two different CMUs: a red-label (for flight testing only) IPS CMU that runs on black-label (production-standard) hardware and a “soft CMU” based on production CMU code. “Both support capabilities more closely aligned with the current IPS specification, including IPv6, mobility, aspects of security and multilink capability,” Broughton explains.
In addition, an IPS satcom system has been provided by Inmarsat and Cobham, which is supporting IPS on an aircraft for the first time, utilizing both priority ethernet and standard ARINC avionics bus specifications. “There are also two VHF solutions to provide ground connectivity,” he adds. “The different configurations have been flown multiple times, collecting important performance and operational data to further validate IPS and the move toward its use in operations.”
“This time around with Boeing and Cobham, we have developed the full end-to-end chain using IPS functionality from the cockpit to our satcom unit [and] all the way to the ground system,” says Danny Bharj, director of aviation technology programs for Inmarsat. “What IPS really brings to the business arena is the pipe—the bandwidth that will allow those 4D applications to be used. And that really helps with the overall efficiency of air traffic management.” Bharj also serves as program manager for Iris and the company’s involvement with the ecoDemonstrator.
Beyond the ecoDemonstrator, work in Europe continues to focus primarily on plans for the commercial rollout of Iris. The effect of the COVID-19 panic has likely pushed back these plans by “about a year,” Broughton says. “But, in terms of the challenges and the [limitations of the] VHF network on the growth of air traffic, none of these have gone away. The pressure on green operations has increased, so the pressure on airlines to be able to demonstrate how they’re managing aircraft in conformance with carbon-reduction targets in Europe, if anything, is even more intense now.”
The delay has given Inmarsat and its partners additional time to develop the technology. “The Inmarsat infrastructure will be ready to be used in an operational environment by about the third quarter of this year,” Bharj says. “The next step is we need to get the airlines engaged. There hasn’t been any lack of commitment from the airlines and the ANSPs. It’s just that the current pandemic has pushed things to the right unfortunately.”
Broughton adds that the first element of Iris—Inmarsat’s SwiftBroadband-Safety system—is already in service. “It will go through what’s called a formal internal customer service introduction in the third quarter of this year,” he says. “So that infrastructure and hardware on the ground side, plus the avionics and the avionics type certification, [are] all in place right now with some aircraft manufacturers. The next big step on Iris, the familiar kind of chicken-and-egg state, is more institutional. The airlines will equip when they can see a real operational benefit, but to get the real operational benefit, you need a number of airlines equipped.”
The ability to upgrade to use Iris is dependent on aircraft age. “It ranges from being pretty straightforward in terms of software service bulletins to something which requires a more substantial hardware change,” Broughton says. He adds that one of the few silver linings of the pandemic has been the culling of older equipment from the global fleet.
“Across the board, we are finding that [the effects of the pandemic are] flushing out the older aircraft types of the fleet,” Broughton says. “So it is one of the factors which might unlock the ability to exploit some of these new capabilities. By and large, the fleets coming out of COVID are going to be a lot more modern than they were going in.”
