Simrad MDS datagram format
Simrad MDS is a proprietary datagram format created by Kongsberg Maritime. It contains the location, bearing and depth of a tracked target. All information is presented relative to your own vessel. All data are related to the tracked target.
Format
$PSIMMDS,hh:mm:ss,dd:mm:yy,aaaa,A,llll.lll,a,
yyyyy.yyy,a,xxx(+),M,ppp,P,zzz(+),M,vvv.v,N,
ttt,D,www(+),A,ddd(+),A*hh<CR><LF>
Description
1 $PSIMTalker identifier
2 MDSDatagram identifier
3 hh:mm:ssCoordinated Universal Time (UTC)
4 dd:mm:yyDate (Day, month and year)
5 aaaaTarget identification
These four characters contain the target identifier on the format AT X, where X is an integer defining the target number. The sonar system will export information from maximum three tracked targets simultaneously.
•  If one target is tracked, one datagram is exported.
•  If two targets are tracked, two consecutive datagrams are exported.
•  If three targets are tracked, three consecutive datagrams are exported.
•  If a fourth target is selected, the information about the first (oldest) target is disabled.
6 AStatus
•  VThe information is valid.
•  NThe information is not valid.
7 llll.lll,aLatitude (Degrees, minutes and hundredths)
•  NNorth
•  SSouth
8 yyyyy.yyy,aLongitude (Degrees, minutes and hundredths)
•  WWest
•  EEast
9 xxx(+),MHorizontal range (Metres)
An empty denomination field indicates an invalid value. This field has a variable length that must contain minimum three digits.
10 ppp,PDirection to target in degrees, relative to north
An empty denomination field indicates an invalid value.
11 zzz(+),MDepth (Metres)
An empty denomination field indicates an invalid value. This field has a variable length that must contain minimum three digits.
12 vv.v,NSpeed (knots)
An empty denomination field indicates an invalid value.
13 ttt,DCourse (degrees)
An empty denomination field indicates an invalid value.
14 www(+),AArea in square metres
An empty denomination field indicates an invalid value. This field has a variable length that must contain minimum three digits.
15 ddd(+),AVolume in tonnes
An empty denomination field indicates an invalid value. This field has a variable length that must contain minimum three digits.
16 *hhChecksum