GALILEO - Understanding GPS: Principles and Applications - page 563

10.2.5 Support to Search and Rescue (SAR) Service
The GALILEO constellation of satellites will be equipped with transponders that
will allow the relay of alarms from distress beacons to SAR organizations. An inter-
face with those centers will also be implemented so that the system will be capable
of relaying back to the users an acknowledgment that the rescue operation is
engaged. This acknowledgment will be provided through the GALILEO navigation
signals themselves. This GALILEO SAR service will be integrated into the interna-
tional COSPAS/SARSAT cooperative effort on SAR activities.

10.3 GALILEO Frequency Plan and Signal Design

This section presents a summary description of the GALILEO frequency plan and
signal structure. The main considerations in the selection of the GALILEO signal
characteristics were [2-5]:

• Transmission of wide bandwidth signals in the L-band spectrum, enabling
precise and robust tracking performance and multipath mitigation capability;

Minimization of interference from and to existing satellite navigation systems
(e.g., GPS, GLONASS) for the purpose of radio frequency compatibility;

•

Selection of frequencies with good performance and small tracking errors in
the upper L-band frequencies for the purpose of ionospheric compensation in
dual-frequency receivers;

•

Interoperability with GPS;

•

Security aspects with respect to the military GPS M code and the GALILEO
PRS (i.e., the separation of military and specially protected services from civil
services).

•

The EU and the United States concluded an agreement on GALILEO and GPS at
the EU-U.S. Summit held in Ireland on June 26, 2004. The agreement on the promo-
tion, provision, and use of the two satellite-based navigation systems and related
applications was signed by EC Vice President Loyola de Palacio and U.S. Secretary
of State Colin Powell. The provisions of this agreement will allow each system to
work alongside the other without interfering with its counterpart's signals, thus
providing interoperability between GPS and GALILEO.

10.3.1 Frequencies and Signals
GALILEO will provide six navigation signals with RHCP in the frequency ranges
1,164-1,215 MHz (E5 band), 1,260-1,300 MHz (E6 band), and 1,559-1,592
MHz (E2-L1-E1 band), which are each internationally allocated for radionaviga-
tion satellite services (RNSS). The GALILEO frequency plan is shown in Figure 10.1
(the frequency band E2-L1-E1 is sometimes denoted as L1 for convenience). All sat-
ellites will make use of the same carrier frequencies with different ranging codes
through CDMA transmission.