Two new footwear advances could help soldiers use their own footsteps to charge devices in the field and enable commanders to track their location.

The US Army recently awarded a $16.5 million contract to Robotic Research LLC for a sensor unit that fits on a boot and can be used to track individual soldier locations, even in GPS-denied environments, according to a Robotic Research statement.

Soldiers are carrying more electronic gear than ever before, and those radios, tablets, sensors and other devices need to be charged. And it is hard to find a wall socket on the battlefield.

One novel way to get after the charging problem while still keeping soldiers on the move comes in the form of a recent patent out of the US Army’s C51SR Centre, which is developing a shoe insole that can generate electricity with each step. They are developing a device that creates an electric charge every time a soldier’s heel pushes down into the insole.

US Army researchers have also been experimenting with wearable, flexible solar panels that can charge devices when weather permits.