Using a handheld GPS to fix an exact position?

[ffiill]

Has anyone tried to do this perhaps whilst trying to find an anchor you have lost but marked by GPS?
In my case I was given an exact position for a new mooring and whilst it was easy enough to plot it on my charting software and take some bearings when it came to fixing the postion and dropping a marker bouy not so easy at all.The problem was that despite it being a flat calm in Plockton harbour this morning once I had got to the aprox. position with "go to waypoint" the only way I finally fixed it was to orientate myself NSEW and row until reaching either the lat or long.then fixing the line with landmarks/compass and rowing at right angle until other pos. was arrived at.
The task would have been totally impossible in anything other than a flat calm.
A beautiful two hours in between snow showers and not too cold

 

[ukmctc]

exact position with GPS and hand held too. only accurate to 10 mtrs.
take the position 2 or 3 times and you might get closer.

 

[Ex-SolentBoy]

There are many apps on the iphone that will save you all that fussing about.

 

[richlear]

Noise in a typical GPS system is random in nature so to establish an accurate position fix you need to derive an average from a lot of observations. To accurately fix a position you will need at least EGNOS augmentation and preferably something more like a good differential or RTK signal - these are not normally available on consumer hand held systems. Best bet would be to log at least a couple of hours of position data and derive an average from that. I doubt whether you will get closer than a few metres.

 

[[70521]]

How exact do you need to be?

 

[LadyInBed]

If the GPS has an 'Averaging' facility in the setup, make sure it is OFF
you should then see the position lat/long jumping around.

The way you did it is the same, but not so accurate, as taking transits, lining up and rowing in on one transit till another, and possibly a third also line up.

 

[sailorman]

How exact do you need to be?

whoever gave the OP the info must have thought it 01/04/13

 

[mjcoon]

Has anyone tried to do this perhaps whilst trying to find an anchor you have lost but marked by GPS?
In my case I was given an exact position for a new mooring and whilst it was easy enough to plot it on my charting software and take some bearings when it came to fixing the postion and dropping a marker bouy not so easy at all.The problem was that despite it being a flat calm in Plockton harbour this morning once I had got to the aprox. position with "go to waypoint" the only way I finally fixed it was to orientate myself NSEW and row until reaching either the lat or long.then fixing the line with landmarks/compass and rowing at right angle until other pos. was arrived at.
The task would have been totally impossible in anything other than a flat calm.
A beautiful two hours in between snow showers and not too cold

My page http://www.mjcoon.plus.com/page37.htm links to a Google Earth track of our losing an anchor and then failing to find it the next day despite my handheld GPS...

Mike.