Jumping out of an airplane at 28,000 feet in the middle of the night, wearing an oxygen mask and descending into a hostile environment, is no easy task even if you are parachuting alone and are relatively light.

But it’s a lot harder when you’re doing the same mission carrying not only pounds of gear, but jumping in tandem, strapped to another person who isn’t a trained parachutist. This setup makes it almost impossible to look down and gauge how far off the ground you are, so you can not only warn your passenger in time to raise their legs horizontally, but also correctly time your landing maneuver. .

This is the problem addressed by the French special forces of the 13^e Parachute Dragon Regiment, known as 13^e RDP, an army regiment entirely dedicated to collecting human intelligence in any theater in peacetime, wartime or other crises.

Until recently, the 13^e The RDP paratroopers used a ground detection system developed over 30 years ago which they found insufficient. So, inspired by the reversing sensors that power some cars – they’re ultrasonic and electromagnetic, with the distance to anything behind your vehicle calculated by the time it takes for the waves emitted by the sensors to bounce back to your vehicle – one of the soldiers with hundreds of tandem jumps under their belt came up with the idea of ​​developing a similar system that would beep at increasingly shorter intervals during his jump as he came closer to the ground.

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With a few colleagues, he presented the concept to the French Defense Innovation Agency (AID), a specific branch of the French Ministry of the Armed Forces created to discover and develop disruptive technologies. AID provided him with approximately $ 51,000 in funding to work with the small French electronics design firm Bordelaise Electronique to develop a better system.

The result is DAPCO (Operational Falling Positional Assistance Device), a device that looks like a small box (it is only 4 × 4 inches) to aid operational paratroopers in landing. DAPCO uses lidar technology (acronym for Light Detection and Ranging), which emits a pulsed laser. Since the speed of light is a known quantity, the time it takes for the light to touch the ground and return to its source will indicate the exact distance from the source (in this case the DAPCO on the parachutist’s chest. ) on the ground. This information is also provided by a backlit altimeter on the wrist, but the audible signal is no longer immediately available.

The director of Bordelaise Electronique, Nicolas Tauzin, explains that they had initially studied two different technologies: radar and lidar. But radar was quickly eliminated because it was too easy to detect: a radar beam is wider than a laser beam and radar detection instruments are relatively more widespread than those with laser detection. “Lidar is much more discreet, especially since the light beam is extremely thin,” explains Tauzin. “Overall, given the criteria of precision, weight and size that we had to meet, lidar was the way to go. ”

The operator calibrates DAPCO before each jump to take into account the total weight under the parachute for that particular jump. Its beeps become a continuous sound about 25 feet above the ground, as this is the altitude at which the parachutist begins their landing maneuver. The system is connected to the parachutist’s radio, so only he can hear the beeps in his headphones.

In addition, the paratroopers “have a compass and a satellite positioning system to guide us along the designated route because with our parachutes operational, we can travel approximately 45 miles after a HAHO jump.” By the way, HAHO stands for ‘High Altitude, High Aperture’.

A HAHO jump, known to military paratroopers around the world, occurs when they exit the aircraft at high altitude wearing an oxygen mask and open the parachute 10 to 15 seconds later. These types of jumps are particularly used in covert operations to prevent missions from being compromised by the loud click emitted by a parachute when it deploys. In the United States, they are undertaken not only by the Green Berets, but also by the SEALs, the Delta Force, the Pararescuemen, the Combat Controllers and the Special Operations Weathermen of the United States Air Force and the 75^e Ranger Regiment, among others.

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“We land at speeds between 50 and 40 feet per second,” explains the sergeant major who came up with the idea for DAPCO. They also use what’s called a shock bag, which inflates under the rear of the passenger. Given its lower position in front of the pilot parachutist, the passenger will land on their buttocks, so the shock bag makes the experience more comfortable as long as they have their legs horizontally in front of them, otherwise they risk breaking some bones, d ‘where the importance of knowing where the ground is. “Skydiving is not an end in itself. It’s just a way to get us into the mission area, so it’s important that everyone is in good shape when we hit the ground, ”adds this person.

DAPCO was used in approximately 70 experimental jumps and was cleared for operational use by special forces. Thirty of them are ready for delivery to army special forces and another 30 to air force special forces. The French army’s test center, STAT, is currently working to authorize it also for conventional paratroopers.