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ForensicsVoice forensics to help Coast Guard nab hoax callers

Published 28 September 2017

The U.S. Coast Guard receives more than 200 false distress calls a year over its Very High Frequency (VHF) radio channel 16—the mariner’s “911”—and the number is growing. These false calls are not simply a nuisance: Every distress call the Coast Guard receives compels the federal agency to launch an expensive search-and-rescue effort. In December 2014, DHS S&T connected the Coast Guard with Dr. Rita Singh of Carnegie Mellon University to see whether a voice forensic technology could be developed which would glean information from the caller’s audio signal — because this was the only evidence the Coast Guard had in cases of false distress calls.

In 2014, when an anonymous caller cost the U.S. Coast Guard roughly $500,000 by sending first responders on unnecessary rescue missions twenty-eight times, the agency asked the Department of Homeland Security (DHS) Science and Technology Directorate (S&T) for help.

The U.S. Coast Guard receives more than 200 false distress calls a year over its Very High Frequency (VHF) radio channel 16 — the mariner’s “911” — and the number is growing.

These false calls are not simply a nuisance: Every distress call the Coast Guard receives compels the federal agency to launch an expensive search-and-rescue effort involving at a minimum a small rescue boat, a C-130 fixed-wing aircraft or rescue helicopter, and the several Coast Guardsmen to operate them. The cost of each outing can run from $10,000 to $250,000. Small boats cost typically $4,500 per hour to operate and helicopters - $16,000.

“I have seen responses run into the three figure numbers quite often,” said Marty Martinez, special agent in charge for the Chesapeake Region of the Coast Guard Investigative Service in Portsmouth, Virginia.

The penalty for transmitting a hoax distress call to the Coast Guard is up to six years in prison, a $250,000 fine, a $5,000 civil fine, and reimbursement to the Coast Guard for the cost of performing the search.

“The men and women of the Coast Guard put themselves at risk every time our surface and air assets respond to a call for assistance. Hoax callers place Coast Guardsmen at unnecessary risk,” said Martinez. “Also, hoax calls interfere with legitimate search and rescue cases, diverting assets from being available to help actual mariners in distress.”

Besides wasting taxpayers’ money in fruitless rescue operations, the pranksters also divert manpower and equipment from other critical missions such as drug interdiction and other law enforcement efforts.

S&T notes that in December 2014, S&T connected the Coast Guard with Dr. Rita Singh, who has collected a large repository of sound recordings of different voices and environments over the years. “They were looking for any information we could provide from the caller’s audio signal because that was the only evidence they had,” Singh said. She is a senior systems scientist at Carnegie Mellon University (CMU)’s Language Technologies Institute, which partners with the Center for Visualization and Data Analytics, an S&T Office of University Programs (OUP) Center of Excellence.