NavyRecognition reports award of a $125.6 million follow-on contract to General Dynamics Mission Systems to support Rescue 21, a system that uses VHF radio direction finders to determine the origin of distress calls. The post also provides a quick overview of the system except it doesn’t seem to include Alaska and the Western Rivers (Mississippi, Missouri, and Ohio river valleys) which are also now included in the system.
This is how the Acquisitions Directorate describes the system:
“Rescue 21 replaces the National Distress and Response System, which has been in use since the 1970s. Rescue 21 can more accurately identify the location of callers in distress via towers that generate lines of bearing to the source of VHF radio transmissions, thereby significantly reducing search time. Rescue 21 extends coverage out to a minimum of 20 nautical miles from the coastline. It improves information sharing and coordination with the Department of Homeland Security and other federal, state and local first responders, and can also identify suspected hoax calls, conserving valuable response resources.”
You can trace the history of the system in a series of news releases here.