GPS positioning

Gday All,

I have a quick query - prob a stupid one and easy to fix, but being very new to boating i am still relying on GPS for positioning.

The other day i was out in the middle of the river, yet the GPS was showing me going over the bank, any suggestions of how to fix?

My GPS system is a Humminbird 97 Matrix series.

 

Thanks


Posts: 111

Date Joined: 03/02/10

 Press the escape botton on

Tue, 2013-03-26 16:59

 Press the escape botton on lowrance, might be the same on hummingbird.

Posts: 354

Date Joined: 25/03/09

Might be in the wrong format

Tue, 2013-03-26 17:35

Might be in the wrong format . Ignore the gps and use the navigation markers.

dant's picture

Posts: 504

Date Joined: 13/03/13

 ok il have more of  play

Tue, 2013-03-26 18:04

 ok il have more of  play around with it, wanted to rule out that it was malfunctioning

Jeff Hugo's picture

Posts: 48

Date Joined: 14/09/09

zoom

Tue, 2013-03-26 18:23

 Maybe a case of you being zoomed in close and near the bank?

 

Rec GPS accuracy can be many meters out. It can appear worse if you are not on the move as most units have no way of telling what your heading is due to the fact it is using a single antenna.

I had a Navman that has poor update rates, it was painfull to use in chart mode for getting back on a waypoint.

Cheers,

 

Jeff

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Jeff

sunshine's picture

Posts: 2629

Date Joined: 03/03/09

Overhanging trees / large structures

Tue, 2013-03-26 19:26

 Can throw it out - dont know why - most GPS can be calibrated to specific known locations - did that ages ago with my 8120 and it is amazingly accurate allowing me to drop anchor within 5 metres when diving (not that I have done that for a while)   

Jeff Hugo's picture

Posts: 48

Date Joined: 14/09/09

Tree canopy and structures

Tue, 2013-03-26 19:42

 Basically reduce the number sats the receiver can veiw and calculate your current position.

The more it has a veiw of the better the accuracy will be. Height of any external GPS antenna will also help as the horizon is not lost so soon.

Hope you get it sussed.

cheers

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Jeff

dant's picture

Posts: 504

Date Joined: 13/03/13

its usually spot on, but

Tue, 2013-03-26 19:55

its usually spot on, but something muat have put it out the other day, hoping its a once off

 

cheers guys, appreciate the responses

 

Posts: 70

Date Joined: 05/12/12

GPS

Tue, 2013-03-26 20:00

Depends on which datum you have selected, try WGS84, normally the most accurate for X Y co-ords but not for elevation

 

pricey10's picture

Posts: 486

Date Joined: 07/01/12

 I genially use my GPS as a

Tue, 2013-03-26 21:05

 I genially use my GPS as a guide. It seems to vary from day to day but it always get you pretty close to where you need to be. Then common sence takes over from there. How ever I had a hummingbird 1198 unit with a cmap and it done the same, if I was up a creek the GPS was saying I was driving around on land it was miles off

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Karratha. WA