Side Scan and GPS

[apersohn17]

So I remember reading something that said you need your gps as close to the side scan transducer as possible. If not you could mark items out to the side of the boat and the coordinates would be off because the gps isn't directly on the transducer. Does anybody know more info about this? How far is it off? Are you having this issue with a console unit with internal gps?

Thanks for the help, I am looking into my first side scan unit and would like to know more about this topic.

[rnvinc]

It's always recommended to have the GPS antenna as close to the xducer as possible for more accurate marking and returning to waypoints ...

This is especially so in marking waypoints on the SI image to alleviate the inaccuracy incurred by the distance difference of the xducer and the GPS antenna ...

Rickie

[MonteSS]

It will be off the distance from the head unit (or external antenna) to the transducer.

[apersohn17]

So if my unit with internal gps is 6 ft from my xducer, just mark the spots on my side scan 6 ft forward and it should be good? That's an easy fix. Thanks guys!

[BobB]

Well, you might have to do the opposite if the tansducer is forward of the transducer.......When you mark a waypoint, it is marked at the position of the GPS antenna at the time you press the mark button........So, if you are exactly over an object with your 2D at the transom, and you mark a waypoint....it will be marked where the GPS antenna is.....not where the transducer is......If that GPS antenna is at the console, then you would have to move the cursor that distance behind the object to get closer to accurate.

[Zippy]

That seems more confusing than just marking it and understanding there will be some small distance off and either searching with sonar or down imaging to get right over it. It would be hard to estimate that distance accurately on side imaging looking out 45 feet or more.