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Re: hey , i need help with "Rate of Turn"

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  • bdebbasch
    Look at: http://www.navcen.uscg.gov/?pageName=AISMessagesA It says that: ROTAIS = 4.733 SQRT(ROTsensor) That would mean that ROTsensor = (ROTAIS/4.733) ^ 2 If
    Message 1 of 3 , Oct 17 10:02 AM
      Look at: http://www.navcen.uscg.gov/?pageName=AISMessagesA

      It says that:

      ROTAIS = 4.733 SQRT(ROTsensor)

      That would mean that ROTsensor = (ROTAIS/4.733) ^ 2

      If you plug 126 in the formula you get 708.7 (degrees / minutes) so the formula looks right... Yo need to take care of the negative values and exceptions (127 and 128) before applying the formula.

      Bernard



      --- In aismon@yahoogroups.com, "said" <elgourbi@...> wrote:
      >
      > Hey everyone
      > im making a small program to decode ais sentence
      > i successfully decoded ( MMSI , Repeat indicator ...)
      > but i can't decode Rate of turn
      > its from bit (42 to 49) and its signed
      > i don't get the right value of rate of turn
      > plzz help
      >
    • Kurt Schwehr
      While not fun reading, you really really should take a look at the definition... get a copy of ITU 1371-4. It s free.
      Message 2 of 3 , Oct 17 10:44 AM
        While not "fun" reading, you really really should take a look at the definition...  get a copy of ITU 1371-4.  It's free.

        http://www.itu.int/rec/R-REC-M.1371/en
        Table 45.  3.1 Messages 1, 2, 3: Position reports
         
        Or take a look at the code in libais:


        -kurt


        On Oct 17, 2011, at 1:02 PM, bdebbasch wrote:

         

        Look at: http://www.navcen.uscg.gov/?pageName=AISMessagesA

        It says that:

        ROTAIS = 4.733 SQRT(ROTsensor)

        That would mean that ROTsensor = (ROTAIS/4.733) ^ 2

        If you plug 126 in the formula you get 708.7 (degrees / minutes) so the formula looks right... Yo need to take care of the negative values and exceptions (127 and 128) before applying the formula.

        Bernard

        --- In aismon@yahoogroups.com, "said" <elgourbi@...> wrote:
        >
        > Hey everyone
        > im making a small program to decode ais sentence
        > i successfully decoded ( MMSI , Repeat indicator ...)
        > but i can't decode Rate of turn
        > its from bit (42 to 49) and its signed
        > i don't get the right value of rate of turn
        > plzz help
        >


      • said
        Ty so much :) it works :)
        Message 3 of 3 , Oct 17 12:52 PM
          Ty so much :)
          it works :)
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