BlockHeader
This is a ROS message definition.
Source
# Blockheader including time header for all ROS messages that publish SBF blocks
uint8 sync_1 36 # 0x24
uint8 sync_2 64 # 0x40
uint16 crc
uint16 id
uint8 revision
uint16 length
uint32 tow 4294967295 # ms since week start
uint16 wnc 65535 # weeks since Jan 06, 1980 at 00:00:00 UTC