According to the American Hiking Society, there are well over 40,000 miles of hiking trails in the United States. When a hiker goes missing in rugged and remote terrain, search and rescue operations unfortunately often become recovery operations. Among risks presented by extreme temperatures, inclement weather, lack of food, water or shelter, fall injuries and other factors, chances of survival dwindle by the hours a hiker is lost.
Search and rescue operations are most successful in the first 24 hours, especially when aided by cell phone pings that can narrow the search area. Unfortunately, phones and other devices have limited battery lives so when the pings go silent, so do the clues. Time is of the essence, so having a device on hand that can detect signals before batteries go dead can literally mean the difference between a rescue and a recovery.
Drone-mounted advanced signal detection technology, specifically BlueFly, can significantly improve the chances that lost individual can be located more quickly with a successful outcome.
BlueFly detects low-power Bluetooth and Wi-Fi signals from a wide range of devices, identifies the devices emitting these signals and determines their location based on signal strength relative to a drone’s position. Data collected by the BlueFly is transmitted in real time to Team Awareness Kit (TAK)-capable Android devices, allowing teams on the ground to receive immediate updates and respond accordingly, enhancing their efficiency and effectiveness in the field.
Inspiration born in tragedy
The inspiration for BlueFly began with the case of a hiker who went missing in Montana in 2020. A volunteer with the search and rescue team was familiar with technology from QRC, a Parsons company, that conducted radio frequency spectrum surveys for the defense industry. Knowing the hiker was equipped with a Bluetooth wallet tracker card, the volunteer reached out to QRC for help locating him with QRC’s Bluetooth/Wi-Fi survey tool.
After a helicopter and foot search of the area, the S&R rescue team found the Bluetooth card – and the hiker’s remains – buried under dense foliage and two feet of snow. Finding the device and human remains in such conditions would have been unlikely without the survey tool.
The survey device was “overkill for what they needed to do and what they used it for” said Kate Jones, general manager for QRC, but the successful recovery sparked an idea. “Then we said, ‘OK, what if we get rid of everything they didn’t need, shrink it as small as we can and put it on a drone?’”
From concept to creation
Turning the survey tool into a smaller, affordable, drone-mounted version began as a summer intern project to test feasibility.
“We hired five interns, put them together and said, ‘OK. We kind of already know it’s possible, but see what you can do with it,” said Jones. The first two prototypes were functional but oversized; one was the size of a pizza box and the other the size of a shoe box. “Really capable, but, again, overkill,” said Jones.
She challenged the interns with new requirements. The device had to:
- Be smaller than a cell phone.
- Be drone-mountable.
- Use TAK mapping tools.
“The interns in 11 weeks were able to pull together a really quick and dirty variant of this product. So, we knew it was possible,” said Jones. “It was the size and did everything we wanted. It was a really successful team. The interns were great.”
Making the prototype a product
The next goal was to make the prototype a product, which is a much more complicated and time-consuming process.
“Once the internship was over, we then stood up an engineering team and said, ‘OK, here it is – productize it,” said Jones. To make the price point work for search and rescue teams, they needed to produce it in mass quantities and make it drone-agnostic to work with any model or manufacturer. Less than 18 months later, the engineers were finished and production began.
How BlueFly works
BlueFly is a drone-mounted payload that detects the presence of low-energy and Wi-Fi signals at a distance up to 200 meters line of sight. It does not communicate directly with devices but reads a device’s Bluetooth low-energy (BLE) advertising packet – essentially a “hello, I’m here” broadcast from the device that announces its presence and transmits a limited amount of data, such as the device’s name and manufacturer-specific data.
BlueFly then uses the BLE data from the individual devices to create a real-time heat map of Bluetooth device type information to users on the ground using TAK.
Not only does BlueFly detect signals from items people carry or wear every day like cell phones, smart watches, fitness trackers, ear buds, AirTags, wallet trackers and Oura rings, it also can pick up medical devices like glucose monitors, heart rate monitors, hearing aids and pacemakers. It also detects other types of smart devices like body cameras, dash cameras, smart water bottles and headlamps.
Sailor Hasting, director of products for QRC and a retired Marine Corps signals intelligence officer, explains that if there is cellular coverage and a working cell phone, then rescuers should of course use that method to get a precise location. But different devices have different signal strengths, and when one goes dim, signals from the other devices grow stronger. BlueFly plots relative signal strength from classic Bluetooth, BLE and Wi-Fi emissions on a TAK heat map so devices can be located within reasonable proximity. Using the TAK plug-in, operators can filter the data, isolating the device type it’s looking for while ignoring what isn’t relevant.
“Phones die in about a day and a half,” said Hasting. “Once the phone dies, the devices attached to it start screaming to connect to the phone. They’re looking for it, so it gets louder. On day two, you’re not going to find a phone. You’re not going to be able to manipulate a phone. And then everything we’re looking for becomes relatively easier to find than it was when the phone was on.”
Hasting gives an analogy. “If you turn on a flashlight, you can see 65 feet, but I can stand on a hill and see you from a mile away,” he said. “We’re just detecting. We’re sniffing it out. We don’t need big throughput to get all the media that’s being passed through the device. We just need to see that it’s there.”
Time is of the essence
BlueFly is intentionally versatile by design. Not only is its light, small frame mountable to any drone, it can also be mounted in a helicopter, as an early deployment in Wyoming showed. Due to the altitude, BlueFly was mounted in a helicopter flying in a drone pattern. After the search, when the helicopter regained speed and height to return to base, BlueFly continued to detect signals from robot vacuums, smart TVs, thermostats and other Bluetooth- and Wi-Fi-enabled devices in homes 2,000 feet below.
BlueFly was brought in about a week after the hiker went missing. “At that point, I can tell you it’s not good,” said Hasting. Although the search operation did not result in a live rescue, the mission validated the technology’s performance and potential. It also underscored the importance of agencies involved in search and rescue having BlueFly on hand to cover large search areas quickly within the likely window of survival, increasing the chances of a successful rescue.
Beyond search and rescue
From a lost hiker or child to an elder who may have wandered off, equipping search and rescue teams with BlueFly increases their speed, efficiency and effectiveness in their field and increases chances of a successful rescue operation. But other use cases add up to a smart investment.
After natural disasters like earthquakes or floods, drones can quickly scan for clusters of Bluetooth devices, helping search teams target areas and assist survivors faster.
In vulnerable border areas, remote areas or high-risk zones, drones equipped with BlueFly can provide continuous surveillance, ensuring no suspicious activity goes unnoticed.
“We’re not the end-all be-all,” said Hasting. “We’re a tool in the toolbox.” But when time can make the difference between life and death, having BlueFly in your arsenal can increase your chances of success.
For more information, visit BlueFly.
