The Inmarsat/Cobham SB-Helo X-Stream system is to allow high data rate satcom service on helicopters, such as the Mi-8. Photo: United Nations

On Nov. 5, at the Vertical Flight Expo and Conference in Farnborough, United Kingdom, Inmarsat debuted its  SwiftBroadband Helo (SB-Helo) X-Stream, a new system to allow X-Stream high data rate services in rotorcraft.

The system, developed by Inmarsat and Cobham, is to enable streaming performance on intermediate and high-gain antennas through the elimination of signal interference by rotor blades.

Moving rotors can drastically disrupt satellite communication signals–a signal degradation known as “rotor shadow” that leads to up to 40 percent packet loss for satcom data–according to Cobham, which developed the waveform for SB-Helo X-Stream last year. There have been some workarounds in the past, yet they are expensive, and the SB-Helo X-Stream may prove to be just one-quarter the operational cost of those workarounds, according to Cobham.

The system aims to increase the throughput of high-quality 1.5 megabit-per-second streaming from 60 percent to nearly 100 percent for helicopters in the air, thus offsetting the effect of “rotor shadow” almost entirely.

“Without a way to confirm exactly how many of the world’s approximately 31,965 civil helicopters and over 25,000 military helicopters are equipped with some form of connectivity, it’s safe to say the number is relatively low,” Cobham said in a white paper last August.

An enhancement of Inmarsat’s X-Stream service, SB-Helo X-Stream demonstrated in testing this year “a 40 percent reduction in data packet loss compared to standard background IP service” and throughputs of up to 400 kilobits-per-second per channel, Inmarsat said on Nov. 5. The system also permits the aggregation of multiple channels to improve system performance, the company said.

A standard SB X-Stream connection “promises theoretical throughput of up to 432 Kbps – but rotor shadowing means real-world performance in larger aircraft is typically only in the range of 200-250 Kbps,” Cobham said in the white paper last August.

Todd McDonell, the president of Inmarsat’s global government business unit, said on Nov. 5 that SB-Helo X-Stream “will ensure government helicopter operators have reliable satellite connectivity, enhancing the capability of rotary wing platforms by providing simultaneous voice and data communications.”

Earlier this year, McDonell predicted that SB-Helo X-Stream “will be greatly sought after in the growing government helo market.”

After developing the new waveform from May to November last year, Cobham said it successfully tested the waveform on a Russian Mi-8 that belonged to a Hungarian skydiving company. The company wanted to test the waveform on a large, big-bladed helo like the Mi-8, as the rotors on such helicopters are known to disrupt SATCOM signals more than the blades on smaller helos.

SB-Helo X-Stream “is designed to achieve higher streaming performance on class 6 terminals,” according to Cobham. “During the field test conducted on a Mi-8 platform in Austria, a class 6 terminal performed extraordinarily and achieving a speed exceeding 430 kbps with minimal packet loss using a single channel of SwiftBroadband.”

SB-Helo X-Stream will be free for operators that already have Cobham AVIATOR SP systems. A significant majority of AVIATOR SP users are government clients, including the military, border patrol, disaster management agencies, Medevac, firefighting units, and humanitarian/international organizations like the United Nations.

SB-Helo X-Stream “ensures that applications requiring the consistent transmission of real-time data, such as video streaming, provide a high-quality delivery during operational use,” Inmarsat said on Nov. 5. “Traditionally, satellite data connections to rotary wing platforms have been constrained by the effect of the rotating blades. However, Inmarsat’s new solution will deliver additional power and effectively reduce packet loss and jitter, significantly improving the bandwidth, quality and reliability of service.”

SB-Helo X-Stream “will provide a variety of hardware options, allowing customers to select the most appropriate hardware for their platform, whatever the needs of the crew or passengers on board,” the company said. “To support the introduction of the new SB-Helo X-Stream, Inmarsat has created a dedicated commercial offer which is fully adapted to helicopter grade services.”