User's Manual

84066_UM_ L-3 FFSVR_B 11
ground station. The ground station or LUT has a 2500 km
satellite reception radius centered at the LUT. In areas without
LUT coverage (mostly less populated areas in the southern
hemisphere), signals from the 121.5MHz transmitter will not be
detected by the satellites, only by passing aircraft’s. From the
year 2006,no new satellites will be launched including
121.5MHz receiver, and from the year 2009,satellitedetection of
the 121.5MHz EPIRB is terminated. This is not the case with
the 406MHz transmitter, because the satellites have a memory
unit, which stores the signals for relay to the next available LUT
giving it a truly global coverage. Once the signal is received by
the LUT, it is processed for location and sent to a Mission
Control Center (MCC).The MCC sorts the alert data according
to geographic search and rescue regions and distributes the
information to the appropriate Rescue Co-ordination Center
(RCC), or if outside the national search and rescue area, to the
appropriate MCC that covers the area that the distress signal
was detected. The RCC in turn takes the necessary action to
initiate search and rescue activities.
1.1.3 Distress location determination
The location of the distress signal is determined by taking
measurements of the doppler shift of the EPIRB frequency
when the satellite first approach and then pass the EPIRB. The
actual frequency is heard at the time of closest approach (TCA).
Knowing the position of the satellite and using the received
doppler signal information, it is possible to determine the
location of the Capsule from the satellite at the TCA. At the
LUT, actually two positions are calculated. One is the actual
position (A) and the other is the mirror image (B) position
[FIG.1.1.3]. A second satellite pass confirms the correct
location (A).With the 406MHzsystem the real solution can be