Galileo OS SIS ICD.indd - GSA - Europa

Even/odd=0
Page Type
E5b-I E1-B
Dummy data (1/2) Tail
Total (bits)
Even/odd=1
Page Type
Dummy
data
(2/2)
1 1 112 6 120 1 1 80 24 8 6 120
Even/odd=1
Page Type
Dummy
data
(2/2)
CRC
Spare
Tail
Total (bits)
Even/odd=0
Page Type
© European Union 2010
Document subject to terms of use and disclaimers p. ii-iii
OD SIS ICD, Issue 1, February 2010
CRC
Spare
Tail
Dummy data (1/2) Tail
1 1 112 24 8 6 120 1 1 112 6 120
Table 54. I/NAV Dummy Page with Bits Allocation
The parameters for the dummy page have the following meaning and related values:
● Even/Odd (1 bit) to indicate the part of the page (0=even/1=odd) that is broadcast
● Page Type (1 bit) equal to 0 to indicate the nominal page type
● Dummy Data (192 bits = 80 bits + 112 bits)
● CRC (24 bits): computed on the Even/odd fi elds, Type fi elds and Dummy data fi elds
(1/2 and 2/2) for the Even/Odd page of the same frequency (“vertical CRC”), and
the CRC is always broadcast on the second part of the “vertical page”
● Spare (8 bits). This fi eld is not protected by the CRC
● Tail bits (2*6 bits) as defi ned in 4.3.2.2. These fi elds are not protected by the CRC
The dummy data word is formatted according to Table 55, with
Type = 63
Dummy Sequence
Total (bits)
Total (bits)
Total
(bits)
6 186 192
Dummy Data (1/2)
(112 bits)
Dummy Data (2/2)
(80 bits)
Table 55. Dummy Word with Bits Allocation
● Word Type (6 bits) to indicate the word type dummy message, which is defi ned as
type 63
● The dummy sequence (186 bits) is an arbitrary sequence
4.3.7. SAR Field Structure
In the nominal mode the SAR RLM is transmitted only in the E1-B component. The SAR
fi eld structure for the E1-B component in nominal mode is formatted according to the
values stated in Table 56. When an alert is present, the SAR data will not be transmitted
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