4.1 Cospas-Sarsat Data Flow
The data flow paths through the Cospas-Sarsat System are illustrated in the diagram in Figure 4-1, and are summarized in the following paragraphs. In this summary description of the data flow, the numbers in parentheses refer to the circled numbers in this diagram.
Figure 4‑1: Flow of Data Through the Cospas-Sarsat System
The path of data that flows through the Cospas-Sarsat System is
illustrated
in this diagram, and is explained in the accompanying text.
A more detailed explanation of each step in the operation of the Cospas-Sarsat System is provided in section 5.
The System is called upon when a 406 MHz distress beacon (1) is activated. The flow of information is as follows:
· The distress beacon (1) transmits a digital radio signal in the 406 MHz frequency band, which is received by the equipment on the spacecraft (2) that are a part of the Cospas-Sarsat Space Segment.
· The signal is re-transmitted (in the 1,544.5 MHz band) to one or more ground stations (3): the Local User Terminals (LUTs) of the Cospas-Sarsat Ground Segment.
· The LUT extracts the beacon message, measures the time and frequency of the signal received, and produces an independent determination of the location of the beacon.
· The LUT sends this incident alert data to its associated Mission Control Centre (MCC) (4).
· The MCC sends this incident alert data, either directly or through another MCC of the Cospas-Sarsat data distribution network, to the appropriate Search and Rescue (SAR) authority (5).
· The responsible authority that has been notified then takes action (6), according to its responsibilities and its authority, to respond to the incident alert message and to find and to rescue the person(s) in distress.
The appropriate authority to whom the Cospas-Sarsat distress alert is sent may be determined as any one or more of:
· The RCC that is responsible for the Search and Rescue Region (SRR) where the beacon is located.
· The SPOC that has been identified by the national authorities responsible for the 406 MHz beacons coded with their country code(s).
· The competent authority identified by the nation where a Ship Security Alert System (SSAS) beacon is registered, to address the security issue that caused the beacon to be activated
· The Return Link Service Provider (RLSP) associated with the Global Navigation Satellite System (GNSS) that provides support for an activated beacon with a Return Link Service (RLS) capability. In this case, the RLSP sends an acknowledgement through the satellite navigation links (7) and back to the beacon.
· The Location of an Aircraft in Distress Repository (LADR) maintained by ICAO for the storage of information received from ELT(DT) distress tracking beacons, and for further notification to the airline that operates the aircraft on which a distress tracking ELT has been activated.