5.3 Beacon Signal Processing
The processing of the 406 MHz beacon signals in the Ground Segment is performed by the LUTs which receive the data through their antennas on the ground. The maps in Figure 5‑4 show the locations of the LEOLUTs and GEOLUTs that are available to the Cospas-Sarsat System. The configuration of the MEOLUTs is still (in 2020) in the process of being established.
Each LUT has one or more antennas that track the appropriate satellites and receive the downlink signals that are transmitted by those satellites. The LUTs are normally capable of unmanned operation; the selection of a satellite to track and the tracking of the visible satellites is fully automated, as is the reception and processing of the data as it arrives from the satellite.
a. Typical LEOSAR Local Coverage Area
b. Typical GEOSAR Local Coverage Area
Figure 5‑4: Local Coverage Area Maps
These illustrations show the typical local coverage areas for the Cospas-Sarsat LEOSAR and GEOSAR satellite constellations. The locations of the various LEOLUTs and GEOLUTs are marked on the maps. The light-grey areas on the LEOSAR map show areas where LEOSAR satellites and operational LEOLUTs have mutual visibility. When a satellite is outside a light-grey area and detects beacons, data are stored, and then sent down to a LEOLUT as soon as the satellite is tracked again entering a light-grey area. The outlines on the GEOSAR map indicate where each system can reliably expect to detect and locate a beacon.