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D Logs summary
MiLLennium Command Descriptions Manual 197
SBTA/B SATELLITE BROADCAST DATA: RAW SYMBOLS
This message contains the satellite broadcast data in raw symbols before FEC decoding or any other processing.
An individual message is sent for each PRN being tracked. For a given satellite, the message number increments
by one each time a new message is generated. This data matches the RBTA/B data if the message numbers are
equal. The data must be logged with the 'onnew' trigger activated to prevent loss of data.
SBTA
Structure:
SBTB
Format: Message ID = 53 Message byte count = 168
$SBTA week seconds prn cstatus message # # of symbols
raw symbols *xx [CR][LF]
Field # Field type Data Description Example
1 $SBTA Log header $SBTA
2 week GPS week number 883
3 seconds GPS seconds into the week 413908.000
4 prn PRN of satellite from which data originated 115
5 cstatus Channel Tracking Status 80812F14
6 message # Message sequence number 119300
7 # of symbols Number of symbols transmitted in the message. At present,
always equals 256 symbols.
256
8 raw symbols 256 symbols compressed into a 128 bytes, i.e. 4 bits/symbol.
Hence, 256 hex characters are output. If FEC decoding is
enabled, soft symbols are output with values ranging from E
to 3 where 3’s represent binary 1 and E’s represent binary 0
output.
EE33EEEE33333E33EE33EEEE33
333E33EE33EEEE33333E33EE33E
EEE33333EEEE3333EEE33E33E3
EE33EEE3EEEE33EE3E3EEEEEE
EEEEEEEE3333EEE33EEEEE33E
E3EEE3E3EE3EE33EEE33E333EE
3333E3E3333E33E3333EEEEE333
EE3E3333EE3EE3EE33EE3EE3EE
3E33E33E3EEE33333E3333E33E3
E333E3E33333E3EEE3E3E
9 *xx Checksum *4C
10 [CR][LF] Sentence terminator [CR][LF]
Field # Data Bytes Format Units Offset
1 Sync 3 char 0
(header) Checksum 1 char 3
Message ID 4 integer 4
Message byte count 4 integer bytes 8
2 Week number 4 integer weeks 12
3 Seconds of week 8 double seconds 16
4 PRN number 4 integer 1-999 24
5 Channel Status 4 integer n/a 28
6 Message # 4 integer n/a 32
7 # of Symbols 4 integer n/a 36
8 Raw Symbols 128 char n/a 40