Global Positioning System (Gps); Section 7 - Authorizations - ACR Electronics ResQFix 406 Product Support Manual

COSPAS and SARSAT satellites receive distress signals from PLBs transmitting on the frequency of 406 MHz. The
COSPAS-SARSAT 406 MHz beacon signal consists of a transmission of non-modulated carriers followed by a
digital message format that provides identification data. The 406 MHz system uses Satellite-borne equipment to
measure and store the Doppler-shifted frequency along with the beacons digital data message and time of
measurement. This information is transmitted in real time to an earth station called the Local User Terminal (LUT),
which may be within the view of the satellite, as well as being stored for later transmission to other LUTs.
The LUT processes the Doppler-shifted signal from the LEOSAR and determines the location of the beacon; then
the LUT relays the position of the distress to a Mission Control Center (MCC) where the distress alert and location
information is immediately forwarded to an appropriate Rescue Coordination Center (RCC). The RCC dispatches
Search and Rescue (SAR) forces.
The addition of the GEOSAR Satellite system greatly improves the reaction time for a SAR event. This satellite
system has no Doppler capabilities at 406 MHz, but will relay the distress alert to any of the LUT stations. When
there is GPS data included in the distress message, SAR authorities instantly know your location to within 110
yards. This speeds up the reaction time by not having to wait for one of the LEOSAR satellite to pass overhead.
Because most of the search and rescue forces presently are not equipped to home in on the 406 MHz Satellite PLB
signal, homing must be accomplished at 121.5 MHz.
6.3

Global Positioning System (GPS)

The GPS system is a satellite group that enables a GPS receiver to determine its exact position to within 30m
anywhere on Earth. With a minimum of 24 GPS satellites orbiting the Earth at an altitude of approximately 11,000
miles they provide users with accurate information on position, velocity, and time anywhere in the world and in all
weather conditions. The ResQFix™ PLB stores this data into its distress transmission allowing search and rescue
forces to narrow the search into a very small area and thus minimize the resources required and dramatically
increases the effectiveness of the overall operation.
Figure 6- Satellite coverage
SECTION 7 – AUTHORIZATIONS
The ResQFix™ 406 GPS PLB meets the requirements of Federal Communications Commission (FCC) Part 95
Subpart K, European R&TTE Directive.
Figure 8- GPS satellite orbits
8
Figure 7- GEOSAR satellite orbits
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