Global Positioning System Reference
In-Depth Information
nals before transmission of the message data onto their carriers so that the data sym-
bol rate on each signal in symbols per second (sps) is twice the data rate in bits per
second (bps). The data contained in the navigation message are summarized next.
•
Navigation and timing data are generated by the GALILEO Ground Mission
Segment (GMS) and uploaded to all satellites for dissemination through all
signals data channels.
Integrity data are also generated by the GALILEO GMS and uploaded to all
satellites for dissemination through the E5b and L1F signals data channels.
•
Commercial data will be provided by external service providers that will
interface with the GALILEO Control Center (GCC) before dissemination
through all GALILEO satellites. The service providers will give access to the
data directly to the CS users through the E5b, E6C, and L1F signals data
channels.
•
PRS data will be transmitted on the E6P and L1P signals.
•
Table 10.2 is a summary of the primary GALILEO navigation signal parame-
ters (see Section 4.2.3 for an overview of BPSK-R and BOC modulations).
10.3.2 Modulation Schemes
10.3.2.1 L1 Signal
The transmitted GALILEO L1 signal
st
L
t
x
1
()consists of the multiplexing of three
components as follows:
The L1F data channel (L1F-d):
The modulation on this channel results from
the modulo-two addition of three components—the L1F navigation data
stream
d
L
1
F
(
t
), the L1F-d channel PRN code sequence
c
L
1
F-d
(
t
), and the L1F-d
subcarrier
sc
L
1
F
-
d
(
t
). The BOC subcarrier has sine phasing. The signal corre-
sponds to BOC
s
(1,1) modulation by the d-channel code sequence and the
d-channel data signal.
•
Table 10.2
Primary GALILEO Navigation Signal Parameters
User Minimum Received
Power Above 10º
Elevation (dBW)
Frequency
Bands
Modulation
Type
Chip Rate
(Mchip/s)
Symbol
Rate (sps)
Channel
E5a data
50
E5
−
155
E5a pilot
N/A
AltBOC(15,10)
10.23
E5b data
250
−
155
E5b pilot
N/A
E6
E6P
BOC
c
(10,5)
5.115
To be decided
−
155
E6C data
1,000
BPSK-R(5)
5.115
−
155
E6C pilot
N/A
BOC
c
(15,2.5)
L1P
2.5575
To be decided
−
157
E2-L1-E1
L1F data
250
BOC
s
(1,1)
1.023
−
157
L1F pilot
N/A
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