SoftBank Corp cited benefits for disaster recovery planning after partnering with US-based Altaeros Energies to deliver stable and wide-area network coverage using a base station attached to a high-altitude autonomous tethered balloon during a field trial at Hokkaido Spaceport in northern Japan.

In a statement, SoftBank noted the system was equipped with its multi-element phased array antenna, developed with its subsidiary HAPSMobile.

It claims its proprietary cylindrical antenna can enable “stable connectivity regardless of airborne motion”.

SoftBank explained the antenna with digital beamforming control enables its footprint fixation technology to secure the cell coverage on the ground by controlling the direction of radio beams as the airborne vehicle rotates.

Compared with previous versions, the field trial showed the newly developed system was able to operate at higher altitudes, carry heavier communication payloads and achieved wider area network coverage with greater stability, SoftBank stated.

Using airborne base stations, high-altitude platform stations provide mobile coverage from the stratosphere to the ground while flying in a circle.

SoftBank invested $7.5 million in Altaeros Energies in 2017.

HAPSMobile is developing high-altitude unmanned aircraft to deliver affordable connectivity services to remote areas and disaster sites.