gps

[GARYGERNARD]

just wondering if my coordinates for my gps will do for my dgps or do i need different coordinates

 

[Norman]

Hi Gary, gps positions are the same as dgps positions ......
however I'm rather confused as to the need for a Dgps?
Dgps was an add on unit (or possibly built in) prior to year 2000 when the gps signals were deliberatly randomly "distorted" (known as selective availability SA) and the dgps unit detected the distortion (calculated from a land based known point) and added it back into the gps signal to end up as a corrected, undistorted, position. The SA part (or "distortion to fool enemies!") of the gps signal was dropped in 2000 (becuse it was so easily corrected) so all units are now simply gps and accurate to about 10mtrs or better .....
If you in fact have a dgps unit it will either fail to pick up the dgps bit or simply pick it up as zero distortion so will (or should) still perform the same....... hope this helps

norm

 

[GARYGERNARD]

cheers norman didnt no much about the units i had gps then somebody said to get dgps as they put you right on the wreck i used to get on the wrecks no bother with gps but cant seem to find some i have been on with dgps

 

[Norman]

Aye gary that was the case a few years ago but not now since SA has been turned off. If your having trouble pinpointing wrecks that you have definately found in the past maybe its just an offset in your set (or the older one) that needs correcting or setting, once you find a wreck, check how far it differs from the original then put that difference in the adjustable offset which should then correct everything.

cheers

norm

 

[GARYGERNARD]

thanks for your help norman

 

[Kev1n]

Just be sure that both plotters are using the same chart datum. Most of them use WGS84 but can be set to many others too.

 

[GARYGERNARD]

cheers mate