VDL Signal Information (VDI) messages

[schwehr]

Add support for VSI NMEA messages:

grep VSI uscg-nais-dl1-2015-06-08 | cut -d\\ -f3 | head
$ARVSI,r08XSTL1,,235959.84331689,2244,-066,0*0F
$SAVSI,D13MN-CR-ELKBS1,6,000059.632020,2236,-95,22*5D
$SAVSI,D13MN-CR-ELKBS1,7,000059.658396,2237,-71,46*57
$SAVSI,D05MN-NC-BUXBS1,6,235959.392559,2227,-99,28*44
$SAVSI,D05MN-NC-BUXBS1,7,000059.658979,2237,-81,46*45
$SAVSI,D08MN-HG-BAYBS1,4,000059.658854,2237,-101,14*6C
$SAVSI,D05MN-HR-CHIBS1,6,000059.658687,2237,-95,21*54
$SAVSI,D05MN-BL-NESBS1,1,000059.418351,2228,-95,23*59
$SAVSI,D05MN-BL-NESBS1,2,000059.658646,2237,-98,20*5F
$SAVSI,D05MN-BL-NESBS1,3,000059.659104,2237,-99,24*5B

[Hikarinoko]

Hi,

I'm looking for content regarding NMEA VSI messages, however, i have lot of difficulties finding something revelant...

I'm having trouble understanding the content of this message, i know it's a message supposed to indicate radio Tx/Rx related info (good power transmission,...etc) and has to be associated with a VDO Message, but i'm unsure how.

I think there is a identifier in the content of this VSI message, but the only one i see seem to be a 0-9 digit.

Which makes me wonder, how am i supposed to associate these messages when i build an LSS software that is receiving AIS message from multiple base stations...

Any idea where i can find information on this matter ?

Best Regards,

[schwehr]

VSI is documented in the NMEA spec from 4.0 on. But you have to buy the spec.

If the message's are grouped with TAG BLOCK, that is one way to see how they are connected.

Otherwise you can use the hhmmss.ss time field and maybe connect things up that way if you have consistent timestamps with fractional seconds, but that timestamp is likely when the last slot arrived