MHI Solutions Improving Supply Chain Performance
Low Earth Orbit Satellites Offer Global Asset Tracking
Companies desiring greater visibility into their supply chains now have another option for tracking their goods. By using IoT sensors that communicate with low earth orbit (LEO) satellites, they can gain new insights into where their products are and the conditions under which they are traveling.
IoT sensors attached to shipping containers, embedded into products or built into trucks can provide a great deal of information about the journey of goods from source to seller to end user. They can relay a shipment’s location, the temperature the shipping container has maintained throughout the journey and the condition of the truck that is transporting it. IoT sensors transfer the data they collect to the internet via wireless communications protocols like Wi-Fi, Bluetooth, Zigbee and, for longer distances, cellular networks.
But cellular services are not always available. According to Iridium Satellite Communications, cellular networks only cover about 15% of the world. There are no cell phone towers on the ocean, and many remote locations throughout the globe are without cellular signals. In some areas, topographical features like mountains and large lakes limit cellular coverage.
That leaves logistics managers unable to check on the status of shipments traveling on container ships across the Pacific Ocean or transported by trucks through wild, unpopulated areas. They have no way to tell if the goods are still on the transport, or if they are being maintained at the necessary temperatures or pressures.
LEO satellites can help bridge that gap and keep the IoT data coming.
The Basics of LEO Satellites
LEO satellites orbit the earth at altitudes of 1,200 miles or less. Their proximity to earth provides several benefits. One is low latency; they can send messages back to earth in much less time than either geostationary (GEO) satellites, which travel 22,236 miles above the earth’s. surface, or medium earth orbit (MEO) satellites, which are between 1,243 and 22,236 miles above earth.
Since it takes less energy to transmit messages across shorter distances, LEO satellites do not need much power. So, these satellites can be much smaller than GEO or MEO satellites; LEO nanosatellites may only be the size of a Rubik’s cube. Their small size makes them less expensive to build and less costly to launch, with 20 to 30 LEOs riding into space on a single rocket.
Their small size does have some drawbacks, however. They degrade faster than larger satellites and are more often damaged by space debris, so they must be replaced more frequently.
It takes three GEO satellites or six MEO satellites to cover the entire globe, but a LEO satellite can only cover areas with a diameter between 1,200 and 1,800 miles. To provide wider coverage, LEO satellites are commonly linked together in networks or constellations.
“You can place your satellites strategically so that you can cover the globe with fewer satellites,” said Fatima Vigil, head of marketing at Astrocast, a global nanosatellite IoT network operator. The number of satellites in a network and the path of those satellites will determine how often you can transmit a message from an IoT-sensor on earth to the satellite.
Iridium Satellite Communications has a large network of 66 satellites, which travel in six planes of 11 satellites each. With this wide coverage, the company’s customers can expect real-time visibility into where their assets are all the time, said Ian Itz, director of IoT.
For the most part, however, LEO satellites are not intended to provide IoT sensor data in real time. They receive and transmit data in regular but less-frequent intervals.
Astrocast, for example, has 18 LEO satellites in orbit, and they travel in a north-south global path. “So, if you have your device close to either the North or South pole, you will get more satellite passes, and therefore more chances to transmit your messages, maybe every one hour or every two hours. But if you are closer to the equator, the worst-case scenario is that you will be able to transmit just four to six messages per day,” said Vigil.
“Customers need to know what they actually need and what compromises they can make,” she continued. “People come to us and they want to implement satellite communication but they then realize that they won’t get their messages every hour.” In some cases, a company may need that data immediately, but other times it decides it can live with getting data less frequently, perhaps two or three times a day.
Cost is another factor, since transmitting IoT data via a LEO satellite is significantly more expensive than via a cellular network.
“It really depends on how important the data is for an organization. A lot of customers don’t need total visibility, they’re happy with what they get from a cellular perspective,” said Itz. “But for some more critical applications, and for applications where customers know that their devices are going to be outside of cellular coverage, they’ll spend the extra money to integrate Iridium services to ensure that they’ve got full visibility across the operation. Ultimately, it becomes a cost analysis, and a company has to make that determination about whether or not they want their data all the time.”
Supply Chain Potential
To transmit data to a LEO satellite, IoT devices must include a built-in or retrofitted satellite module (modem). The modules, which are small and require very little power, must use the same communications frequency band as the satellite to which it connects.
The IoT sensors gather data that has been collected by some device, then, depending on the system, send that data directly to the satellite or through a gateway. The satellite, in turn, transfers that information to a ground station where it is processed and put into a form that the end user can read and use.
To date, much of the IoT data transmitted to LEO satellites comes from monitoring activities and events in industries like agriculture, utilities and energy. But there are many potential ways these networks could be deployed for supply chain purposes.
“A lot of it is safety and security. There’s also continuity of service and making sure everything is running appropriately,” said Itz. For example, Iridium’s satellites may track the location of armored rail cars in Mozambique as they transport minerals to the coast for export. Small, well-hidden IoT sensors in shipping containers could help deter cargo loss on ships, because thieves might not want to risk having their location tracked.
Eric Hewitson, head of communications at Wyld Networks. sees an opportunity in field-to-fork traceability for food shipping. LEO satellites can receive and send information from IoT devices about the temperature and humidity that was maintained in a food-carrying container. “With something refrigerated, you might have to be tracking temperature the whole time. You may not need to know at a particular point [i.e., in real time] that the container is at this temperature. But you do need to know that over the last six hours it has maintained the temperature,” he said.
Vigil thinks that the use of IoT satellite technology offers a means of being proactive in preventing potential problems. Suppose a company is shipping a cargo of medicines or very expensive goods across the ocean. IoT devices had tracked the shipment via a cellular network when it was on land, but that capability disappeared when the ship moved out into the ocean.
“If you have those blind spots, and you get a pirate in the middle of the ocean who steals your goods, it can have a huge impact,” she said. While the cargo owner will not get an immediate notification about the container doors being opened during the theft, it will be able to use the data received by satellite to identify where the piracy occurred. It can then send future shipments via safer routes.
If cargos of vaccines or other medicines arrive spoiled because the container refrigeration failed at some point, the owners can access the IoT data from throughout the trip to determine when the temperatures started to rise. They can then try to figure out what happened so the spoilage could be prevented in the future.
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