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How NASA’s microwave radar – designed for space – saved lives after earthquake

With recent earthquakes in Japan and Ecuador, we were reminded of life-saving NASA technology that helped locate survivors in last year’s Nepal quake. We spoke with Jim Lux, Task Manager for the FINDER project, which was first used in Nepal.  The two companies that are producing FINDER units are both helping search and rescue teams at the most recent earthquake sites. SpecOps Group is currently in Japan with FINDER, and R4 is in Ecuador

One year ago today, a magnitude 7.8 earthquake struck Nepal. CNN reported that the death toll from the massive quake exceeded 8,000. An additional 17,800 people were injured. The search and rescue operation went on for days: Survivors were pulled from beneath the rubble as much as a week after the quake. Much of the damage occurred in remote villages, making search and rescue even more difficult to staff. The ability to quickly locate survivors in order to prioritize rescue operations was crucial.

FINDER is a portable radar device developed by NASA. It enables search and rescue teams to scan an area of debris for survivors without entering the debris field. FINDER looks for heartbeats and respiration. It was used to search multiple collapsed buildings in the Nepalese village of Chautara.  

“Emergency workers were able to identify four men who’d been trapped in Nepal’s rubble—and then save them—thanks to a novel technology: advanced heartbeat detection.”

Brian Clark Howard, National Geographic

Image credit:

What is FINDER?

Finding Individuals for Disaster and Emergency Response (FINDER) is a portable, multi-channel radar housed in airline carry-on style luggage. It was designed to detect a human heartbeat buried beneath 30 feet of rubble. FINDER was designed to save people, and that’s exactly what it did on its first field deployment.

As FINDER is again at the front lines of search and rescue operations, we discussed the engineering effort and technology that went into creating FINDER with Jim Lux:

Q: How did the FINDER project start?

A: FINDER started when FEMA was looking for a tool to help with mass disasters, such as the Haiti earthquake, where you have hundreds of collapsed structures. They wanted something that they could walk down the street and figure out which structures had victims in them, and which didn’t .

Q: How does FINDER work?

A: The radar illuminates the rubble pile and receives reflections back from a disaster site, including the victim(s). FINDER looks for changes in the reflection that indicate movement, and then checks to see if those movements can be attributed to human heartbeats (1 mm variations) and respiration (1 cm variations). It can distinguish human respiration from animals or mechanical movements.

Q: How long did it take to get to the FINDER version that was used in Nepal?

A: We started really working on the design in the fall of 2012, and began building the first portable prototype in January 2013. Our first prototype went through field tests at the Fairfax County, VA rubble site in April 2013.  After a few iterations, we had our final prototype ready in September 2013.

The units like the one that went to Nepal were a slightly updated version of that prototype, improved for easier production, but still basically the same design.

Q: What was the biggest technical challenge for this project?

A: I think the biggest challenge was putting together a team that could do this in the short time that we had to complete the project. The basic pieces of the technology all existed in different places. We needed to recast them to this specific application; that required a multidisciplinary approach. We had people who did the antennas, people who do radio frequency design, people who developed the software, people who developed the user interface, and then things like packaging. We had to make it all fit in a box that could go in an overhead compartment of an airplane.

Q: What are FINDER’s main hardware components?

A: There’s the Pelican case that holds the radar and a handheld Toughbook tablet. The Pelican case has 5 JPL-designed and built RF modules: 1 transmitter and 4 receivers. Each module has a microcontroller, RF components and a patch antenna. They’re connected to an embedded PC, which also has a GPS receiver and camera connected.  The radar is a Wi-Fi access point that the tablet computer connects to for communication.

Q: What software was used to design FINDER?

A: We used quite a lot of software to design FINDER, and of course, there’s an essential component of software in FINDER.  Our initial designs and modeling were done with purpose-specific programs written in MATLAB to do things like simulate the radar behavior and build finite element models for simulation. We wrote a MATLAB program that generates a simulated rubble pile by virtually dropping random shaped and sized pieces of rubble into a virtual box. The program generates a scene file full of constructive solid geometry primitives for later rendering, and fills in voxels for the finite element model. The actual finite element propagation model was done with FORTRAN. A MATLAB program reads the model output and generates graphs and analyses. We used POVray as a 3-d rendering engine to generate pictures of the simulated rubble.

Our post analysis of test data and adjustment of operating parameters used MATLAB to read the log files generated by the victim detection code, and to get statistics across multiple data sets.

Q: Can you tell us about the software running on FINDER when it is in the field?

A: The FINDER unit itself has a variety of software. The microcontroller in the RF modules is a Teensy 3.1 (an Arduino-like device from programmed in a combination of C/C++.  The actual victim detection is compiled MATLAB running on the tablet PC.

Q: What other applications is FINDER used for?

A:  In addition to search and rescue in rubble application, FINDER can locate victims of snow avalanches. In an avalanche, there’s a fairly large area to search, and the current search technology basically relies on sticking a long probe into the snow and seeing if you hit something that feels like a victim.  Avalanche beacons do help, but they get you into the general area, and then you go to the probes.  FINDER can help detect victims who weren’t carrying a beacon.

Q: Does FINDER have applications in space as well?

A: FINDER does have applications in space. There’s the original application of measuring an astronaut’s heart rate with a non-contact sensor. There’s a whole lot more, though: what we really have is a small, low power, non-contact distance sensor that has relatively low processing requirements to make a measurement.  So if you’re designing a spacecraft that can rendezvous with another spacecraft, small radar sensors like those in FINDER can be pretty useful: it has a wide field of view, and it can easily and accurately measure the range and velocity of something 100 meters or more away.

Q: The FINDER system has been released to two companies for commercial roll-out. Does that mean your team is finished with this project? If not, what’s next?

A: As you say, the Search and Rescue FINDER is in commercial production, but there’s a lot of other applications for the sensor. We’ve been looking at other medical device applications, not so much for measuring heart rate, but for more sophisticated measurements. We can measure small changes in the motion, and depending on the frequency, we can detect the motion of tissues under the skin. You might be able to have something like a non-contact microwave stethoscope, or perhaps we can directly measure the motion of the heart.  We’re also doing some work on extending the detection range and combining the FINDER sensor with other sensors.

At JPL, we’re always interested in reducing the size, weight, and power requirements, so I think we can expect to see smaller, lighter FINDER-type sensors in the future.


FINDER is another great example of how technology, originally designed for space applications, has found an extraordinary alternate use. The U.S. Chamber of Commerce added FINDER to its list of technologies having a momentous impact here on EarthFINDER joins an elite club of venerable technology from NASA, which includes memory foam, ear thermometers, and artificial limbs.  NASA has an online magazine dedicated to spinoff technology. Check it out here.



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