The satellite company has adapted the popular IoT technology for use in its constellation. There are plenty of reasons to deploy an Internet of Things (IoT) network in a rural area. But connecting dozens or hundreds of sensors to a network can also be a nightmare. Wind turbines or oil wells benefit from sensors measuring their respective environments and performance, but their operators should count themselves lucky if such energy harvesting facilities happen to be in range of robust cellular networks so they can stay connected to the Internet.
Traditionally, there hasn’t been a good option for connecting low-power, low-data devices to the Internet en masse when they’re in an area without good coverage. Satellite services tend to be expensive: Most cost on the order of US $1 to send the amount of data roughly equivalent to that in a text message. Hundreds of IoT devices sending equivalent amounts of data as status updates, multiple times per day or even multiple times per hour, would break the bank.
Swarm, a satellite start-up that uses CubeSats about the size of a grilled cheese sandwich to provide IoT coverage, has instead developed a satellite network specifically for IoT networks that would otherwise struggle to connect to the Internet. To do so, the company has adapted the popular IoT wireless technology LoRa, turning it into a high-flying—and even longer-ranging—solution.
LoRa, if you’re not familiar, is a wireless communication method owned by California-based semiconductor and chip manufacturer Semtech. The name is short for, very simply, “Long Range.” The wireless standard sends data in small bursts, similar in size to a text message, which makes it perfect for devices that need to send plenty of status updates or a regular stream of measurements. The technology is also designed to require very little power, so that it does not drain the batteries of IoT devices too quickly. But LoRa was still very much designed for terrestrial networks, where devices and gateways would be relatively stationary with respect to one another.
The distance was also a challenge. LoRa, as its name implies, is designed for the long distances covered by a wide IoT deployment. But even the most expansive deployments come nowhere close to the distances that satellite signals need to cover. Swarm’s satellites zip past the Earth at an altitude of 550 kilometers. And that’s the distance when a satellite is directly overhead.
The company also fine-tuned several radio components to make it possible to send and receive LoRa signals over such long distances. The CubeSats, for example, carry extremely sensitive low-noise amplifiers and preamplifiers to boost the weak signals upon arrival, making them easier to decode before the satellite retransmits them to a ground station elsewhere on the planet.