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DGPS were do you get it from and with what?

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Whose receiving DGPS signals and what kit are you using?
IALA and Inmarast or can you get VHF signals where you are?

5 Replies

  • I don't think many recreational boats are using DGPS, mainly because regular GPS, especially with WAAS corrections, is good enough. One unit I do see sometimes on yachts is the Furuno GP37 GPS/DGPS.

  • DGPS predates SBAS (WAAS/EGNOS/MSAS) and requires a separate antenna & receiver, whilst SBAS (WAAS/EGNOS/MSAS) can use the same antenna as the GPS itself. DGPS only works in the vicinity of a DGPS ground station, WAAS has US coverage whilst EGNOS covers Europe and MSAS covers Japan.

    I'd say its clear from the above why most new recreational GPS receivers use SBAS.

  • I have a Magellan DBR-IV (OEM: CSI Wireless SBA-1) that receives differential corrections from the land-based network and feeds the correction data to a Garmin GPS 36. Sailing on the Chesapeake, we have a land-based station well within receiving range. I can't remember that last time I saw another differential receiver in use on a boat.

    I have never compared it against a set using WAAS to see if there is a measurable difference. I am quite interested in this now because, thanks to Ben's articles, I am interested in the Vesper XB-8000.

  • As the name suggests, WAAS is a wide-area augmentation system.

    Differential GPS signals tend to come from local ground stations, and they cover local areas. This allows for greater accuracy than in a wide-area augmentation.

    With real-time differential signals, the position accuracy can be measured in centimeters, while with WAAS the accuracy is still measured in meters.

    In most instances of navigating a boat, an accuracy of a meter or two is quite sufficient, so WAAS is able to satisfy the maritime navigators need for precision.

  • I have a North star 952 which has both WAAS and DGPS. They both seem to have the same accuracy.