As this diagram shows, very few satellites are needed to cover huge swathes of Earth if the satellite is far enough away from it, but satellites in Low Earth Orbit cover only a small portion of the Earth’s surface. Multiple LEO satellites are needed for global coverage, and the first – and to date only – globally accessible satellite network is Iridium. This is why Iridium is so often the choice for UAV manufacturers looking to add failover communication to their drones.
Iridium offers multiple airtime options for connecting to their satellites, from Certus 700 (700 Kbps, fast enough to support live video broadcasts) through to Short Burst Data (packet-based data which sends 270 / 340 bytes per message). Short Burst Data (SBD) is ideal as a failover connection; with SBD, operators can get position, altitude and speed, and can return basic commands such as ‘go to the nearest rally point’, ‘go home’ or ‘terminate flight’.
SBD is lightweight, low power consuming, and meets most SWaP requirements for UAVs. It offers a secure and reliable connection to the drone to make it less vulnerable to hacking, and safe to pilot within controlled operating areas.
Our team visiting Zipline in late 2023
Supported by satellite IoT connectivity, important work is already taking place. Our customer Zipline is using SBD as the failover communication method for its Zips: autonomous aircraft that are being used to deliver prescriptions, groceries, vaccines, livestock supplies and more.
Very recently, Zipline was cited in the peer-reviewed journal Vaccine, noting that its method of delivering vaccines aerially to more isolated parts of Ghana has improved clinical outcomes and prevented disease among children.
In fact, it’s estimated that Zipline delivery has saved an estimated 727 lives in the Western-North Region by enabling 15,000 children to access vaccines who would not previously have been able to.
Popular Youtuber Mark Rober filmed his experience at Zipline, and it’s well worth a watch to learn more about this incredible operation.
To deliver vital chemotherapy drugs to patients on the Isle of Wight, UK-based Skylift UAV built an autonomous eVTOL (electric, vertical take-off and landing) aircraft which can fly for 1.5 hours on a single charge, with a maximum speed of 100 Mph. In BVLOS configuration, it can travel up to 100 Km, depending on the payload.
The drones are autonomous, but monitored by Skylift’s safety pilots who can take control of the drone at any time. As the drone travels BVLOS, and across a body of water (the Solent), it’s essential that the pilots have two reliable means of communication with the drone at all times. The Skylift UAV team chose the RockBLOCK 9603 to deliver SBD connectivity in addition to aviation-grade L-Band radio to ensure that irrespective of the drone’s location, connectivity is guaranteed.
RockBLOCK allows them to send and receive data from the aircraft, and is part of the robust communications package with which all Skylift drones are equipped. It’s also the final line of defence for mission success.
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