ACR ResQLink 400 - SOS Personal Locator Beacon with GPS (Model: PLB-400) ACR 2921

How An EPIRB or PLB Rescue Works

The Anatomy of a Rescue - Stage 1

When activated, EPIRBs and PLBs send a unique distress signal on the 406 MHz frequency to the Search and Rescue Satellites.

Each beacon is programmed with and sends a unique digital code called a HEX ID or Unique ID. The HEX ID identifies the type of beacon and, Search and Rescue use the HEX ID to identify the beacon registration information provided by the beacon owner.

This information can include: who the beacon owner is, the type of vessel the beacon is associated with (for EPIRBs), emergency points of contact, float plans, trip plans, and much more.

The Anatomy of a Rescue - Stage 2

After the satellite receives a beacon signal, it relays the signal to ground stations referred to as local user terminals (LUTs).

The LUT processes the data, computes the location of the distress beacon, and transmits a decoded alert message to its associated national Mission Control Center (MCC). This happens almost instantaneously after the initial beacon signal is received.

The Anatomy of a Rescue - Stage 3

The Mission Control Center then geographically sorts the data, and transmits a distress message to the closest appropriate SAR authority and another MCC if the beacon is registered to another country.

The RCC (Rescue Coordination Center) investigates the beacon alert and launches rescue assets to find the parties in distress.