Galileo OS SIS ICD.indd - GSA - Europa

SAR Data
Total
Start Bit
Short/Long RLM
Identifi er
SAR RLM Data (bits)
1 1 20 22
Table 56. SAR Field Bit Structure
The RLM identifi er bit is described in the following table.
SAR data in Nominal Mode
RLM Identifi er Value Description
0 Short RLM
1 Long RLM
Table 57. RLM Identifi er Description
In nominal mode, 22 bits are allocated to SAR data in one E1-B I/NAV page. The SAR
messages are formatted according to the values and structure stated in Table 58 and
Table 59 respectively for the short RLM and the long RLM. This structure allows the
downlink of a short RLM within 8 seconds and of a long RLM within 16 seconds. The
content of the SAR data is provided in paragraph 5.2.
● Short RLM
Start bit = 1
Part (1/4) Part (2/4) Part (3/4) Part (4/4)
Short RLM
SAR RLM
data
Beacon ID
(1/3)
Start bit = 0
42 © European Union 2010
Document subject to terms of use and disclaimers p. ii-iii
OD SIS ICD, Issue 1, February 2010
Short RLM
SAR RLM
data
Beacon ID
(2/3)
Start bit = 0
Short RLM
SAR RLM
data
Beacon ID
(3/3)
Start bit = 0
Short RLM
SAR RLM
data
Message
code
1 1 20 1 1 20 1 1 20 1 1 4 16
● Long RLM
Start bit = 1
22 22 22 22
Table 58. SAR Short RLM
Part (1/8) Part (2/8) Part (3/8) Part (4/8)
Long RLM
SAR RLM
data
Beacon ID
(1/3)
Start bit = 0
Long RLM
SAR RLM
data
Beacon ID
(2/3)
Start bit = 0
Long RLM
SAR RLM
data
Beacon ID
(3/3)
Start bit = 0
Long RLM
Parameters
SAR RLM
data
Message
code
1 1 20 1 1 20 1 1 20 1 1 4 16
22 22 22 22
Parameters
(1/5)