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  • A sign....

    A sign.... could anyone kindly explain to me what this sign means, located on the breakwater in Bodo....

    With best regards from Jan-Olav Storli

    Administrator and Owner of CaptainsVoyage.
    Main page: http://www.captainsvoyage.com
    Old forum: http://captainsvoyage.7.forumer.com/
    Join us: Save the "Kong Olav" on facebook

    Surround yourself with positive, ethical people who are committed to excellence.


  • #2
    I don't know why it's there, but I can READ it!!!! HOORAY!!!!!

    (ok, a 3-year old Norwegian CHILD could read it, but that's NOT the point.......)

    Comment


    • #3
      Well, I guess that "someone" would be me then.... (Mohahahahaha)

      I don't know precisely what it is, but as far as I know, it's one of Kystverkets many referencepoints along the coast for GPS navigation
      "IF GOD COULD MAKE ANGELS...., WHY IN HELL MAKE MAN?"

      Comment


      • #4
        Originally posted by Sterkoder View Post
        I don't know precisely what it is, but as far as I know, it's one of Kystverkets many referencepoints along the coast for GPS navigation
        That I kind of figured out, but a reference to what?

        As far as I know, GPS doesn't use signs to tell the position... unless, they track the movement of this sign from space?
        With best regards from Jan-Olav Storli

        Administrator and Owner of CaptainsVoyage.
        Main page: http://www.captainsvoyage.com
        Old forum: http://captainsvoyage.7.forumer.com/
        Join us: Save the "Kong Olav" on facebook

        Surround yourself with positive, ethical people who are committed to excellence.

        Comment


        • #5
          do the trolls come out in the middle of the night and move it around Norway??????

          Comment


          • #6
            Originally posted by pakarang View Post
            That I kind of figured out, but a reference to what?

            As far as I know, GPS doesn't use signs to tell the position... unless, they track the movement of this sign from space?
            On every Airport the position and altitude is printed on the wall in front of every parking bay for the pilot to check and calibrate his instruments. This sign serves the same purpose for ships I assume, although I have never seen such a sign in real life.

            It probably serves to check that your GPS receiver is giving the correct position and is set to the right Datum, in this case WGS-84, which is widely used on GPS Receivers for positions. If another Datum is used, either for the GPS position or as the datum for the chart, the difference can be quite substantial in today's terms. (Up to 100 m. in worst case)

            A warning about this fact is printed on every BA Chart and in every Manual for GPS Receivers, which is approved as "Aid to Navigation" on commercial vessels. A prudent navigator checks the datum of every chart he uses to ensure that it correspond to the GPS setting in use. Failing this is a frequent reason for grounding as some navigators trust their instrument more then their own eyes.

            One more point; When looking at AIS positions of ships in port you may have noticed that ships alongside are sometime shown as a bit away from the quay, or appears to be on dry land? This is because of difference between the datum used on the AIS presentation you receive and the GPS receiver from where the AIS transmitter gets it's data.

            If the ship appears to be on a different heading relative to the wharf, the Gyro is inaccurate, or not operating at all.
            You may even have seen vessels at sea moving 180 degr. to the gyro heading displayed on the AIS? Sorry, I don't know how that may come about, except if it is a "double ended" ferry.

            One thing for sure, all these Navigation Aids are only as good as the data and programme put into them, or the interpretation of the user. NOTHING beats good seamanship and alert watch keepers when it comes to safe navigation.

            Comment


            • #7
              Pakarang, I was starting to write something for you late last night about the World Geodetic System 1984 (WGS-84), the reference coordinate system used by GPS, when some computer issues here intervened. Probably a good thing, as it was far too late for clear thinking and ombugge has now explained the issues from a nautical point of view much better than I would have.

              On a different but related topic, I do remember reading somewhere about a number of receiving stations in Norway that are monitoring the satellites, and that corrections calculated from these observations are then broadcast and can be used to improve the accuracy of positions from GPS equipment. This updating service is called Differential GPS (DGPS) and it is using the WGS-84 datum.

              Comment


              • #8
                Originally posted by pakarang View Post
                That I kind of figured out, but a reference to what?

                As far as I know, GPS doesn't use signs to tell the position... unless, they track the movement of this sign from space?
                The reference is actually printed on the sign..., you know: latitude and longitude...
                The reference for this particular sign (the exact point where the pole stands) is 67° 17.020'N 014° 21.801'E
                "IF GOD COULD MAKE ANGELS...., WHY IN HELL MAKE MAN?"

                Comment


                • #9
                  Originally posted by Seagull View Post
                  On a different but related topic, I do remember reading somewhere about a number of receiving stations in Norway that are monitoring the satellites, and that corrections calculated from these observations are then broadcast and can be used to improve the accuracy of positions from GPS equipment. This updating service is called Differential GPS (DGPS) and it is using the WGS-84 datum.
                  Previously (<2003 or so) the US Military put in an inaccuracy in the signals which could be received by civilians. Differencial signals were then received via local terrestrial means and was only available to licensed users, such as Seismic and Survey Companies etc. and had to be paid for.

                  Since this restriction was lifted and Differencial signals became freely available via Inmarsat, DGPS is widly used on vessels with DP system and for anything where VERY accurate positioning is required, like positioning drilling rigs etc. (Position accuracy in /100 of seconds)
                  For ordinary navigation GPS as it is has more than adequate accuracy (+/-5m. in good conditions)
                  Even small hand held GPS receivers, or those used in cars has this kind of accuracy today.

                  When the restrictions were first lifted we did a comparison during a rig move, running a plot using DGPS and another with "stand alone" GPS. The difference was never more than 5 m. and the difference for final positioning less 1.0 m. (Stationary, running 300 fixes with min. 5 satellites above 15 degr. inclination and calculating average position)

                  For those who wonder how GPS actually work, it is "atomic clocks" sending very accurat time (in millisecond) from 28 satellites orbiting the earth in different plans to give full earth coverage, pole to pole. By receiving the signals and comparing the times received the GPS receiver can calculate position and altitude where ever it is. The more satellites available above the horizon the better position can be obtained. But GPS signals are influenced by disturbances like any other radio signals in the Ghz band. (Weather, Sun spot activity etc) It is therefore NOT a 100% guaranteed system and should always be checked against terrestrial observations, like looking out the bridge windows, not just relying on a picture on the screen in front of you. (My pet subject these days as most collisions and groundings are caused by over reliance on electronics and not enough on your eyes and ears)

                  Comment


                  • #10
                    Originally posted by ombugge View Post

                    It probably serves to check that your GPS receiver is giving the correct position and is set to the right Datum, in this case WGS-84, which is widely used on GPS Receivers for positions. If another Datum is used, either for the GPS position or as the datum for the chart, the difference can be quite substantial in today's terms. (Up to 100 m. in worst case)
                    I think you're spot on

                    Look here, the sign's already been in the news:
                    http://www.nrk.no/nyheter/distrikt/n...d/2299714.html

                    Comment


                    • #11
                      Thank you all for the valuable inputs... Naturally, I knew the general idea of what it was, but really wanted to see if I could learn something new from all you guys and girls... drawing on your experiences!

                      And I think I did learn a few more things... this is educational for all of us!
                      With best regards from Jan-Olav Storli

                      Administrator and Owner of CaptainsVoyage.
                      Main page: http://www.captainsvoyage.com
                      Old forum: http://captainsvoyage.7.forumer.com/
                      Join us: Save the "Kong Olav" on facebook

                      Surround yourself with positive, ethical people who are committed to excellence.

                      Comment


                      • #12


                        I walked to the end of here (to get yet another view of a certain ferry!) when in Molde recently, and found another of these to photograph!:



                        So now we have numbers 1 and 4 in this thread!! Something else to keep an eye open for!!

                        Comment


                        • #13
                          Are you hinting that we may see #2 and #3 in the future?

                          Comment


                          • #14
                            No, no particular hint, (nor have I looked up where they are!) – it was just such a pleasure to walk up to that light, wondering curiously what a notice pointing away from the pier might say (something to do with where you could or couldn’t moor a boat I had supposed), and then to discover it was a reference point!
                            “Ah, a pakarang thing to be photographed for his thread” I thought to myself excitedly!
                            Even more fun than “collecting” Starbucks in Singapore for him!

                            Comment


                            • #15
                              How cool is that.. we now have two of them: wonder how many we may manage to find around Norway in the long run?
                              With best regards from Jan-Olav Storli

                              Administrator and Owner of CaptainsVoyage.
                              Main page: http://www.captainsvoyage.com
                              Old forum: http://captainsvoyage.7.forumer.com/
                              Join us: Save the "Kong Olav" on facebook

                              Surround yourself with positive, ethical people who are committed to excellence.

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