A federal court has sentenced a Chinese citizen to more than five years in prison for taking thousands of files about a secret military project to China, Peter Finn of The Washington Post reports.

The project involves an advanced version of a tiny device that is "designed to allow drones, missiles and rockets to hit targets without satellite guidance."

The device, called a disk resonator gyroscope, was being secretly developed for the U.S. military by a small company and L-3 Communications. It "can navigate, control and position missiles, aircraft, drones, bombs, lasers and targets very accurately,” David Smukowski, president of Sensors in Motion, the small company in Bellvue, Wash., told the Post.

On Monday a court sentenced Sixing Liu, who worked at L-3’s space and navigation division, to five years and 10 months for exporting defense data without permission plus separate counts of possessing stolen trade secrets and lying to authorities.

Prosecutors said Liu, 50, twice told his supervisor he was going on vacation to Chicago when he actually went to China to speak at a technology conference organized by the Chinese government and Chinese universities.

“We believe Sixing Liu was a serial thief,” Assistant U.S. Attorney L. Judson Welle said, noting that Liu also took information on other defense systems.

Finn notes that military data theft by China is a huge problem as unsealed court documents indicate that "nearly 100 individual or corporate defendants have been charged by the Justice Department with stealing trade secrets or classified information for Chinese entities or exporting military or dual-use technology to China" in the past four years.

“These schemes represent a threat to our national security," John Carlin, acting assistant attorney general for national security, told the Post. "The intelligence community has assessed China to be among the most aggressive collectors of sensitive U.S. information and technologies and our criminal prosecutions across the country reflect that assessment.”

Last week a U.S. defense contractor in Hawaii was charged with passing classified information about nuclear weapons and ballistic missile systems to his Chinese girlfriend.