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Diffstat (limited to 'www/AIVDM.txt')
| -rw-r--r-- | www/AIVDM.txt | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/www/AIVDM.txt b/www/AIVDM.txt index f140a770..d5de08db 100644 --- a/www/AIVDM.txt +++ b/www/AIVDM.txt @@ -4601,7 +4601,7 @@ The 20 radio status bits are always present after end-of-data in the last slot and are in the format specified by <<IALA>>. The radio status is 20 bits rather than 19 because an extra first bit selects whether it should be interpretred as a SOTDMA or ITDMA state. - +i Note: Type 26 is extremely rare. As of April 2011 it has not been observed even in long-duration samples from AISHub. @@ -4613,6 +4613,10 @@ satellite). This message has a similar content to Messages 1, 2 and 3, but the total number of bits has been compressed to allow for increased propagation delays associated with long-range detection +Length according to ITU-1374 is 96 bits. However, in the wild these +are sometimes transmitted with 168 bits (a full slot). Robust decoders +should warn when this occurs but decode the first 96 bits. + //: Type 27 [frame="topbot",options="header"] |============================================================================== |