GPS slow speed accuracy

[Méchant Malade]

One thing that hear quite often is the fact that it’s kind of difficult to get a very precise slow trolling speed on the GPS; numbers seems to go up and down and not stable. The reason is the usage of Digital numbers instead of Analogic numbers.
Hoping you’re machine can do the changes that I will show you. I have on my computer the Emulator for the LCX 19C that I download from the Lowrance website. I know that many Lowrance model offer the same capabilities and surely other manufacturers, just a menu learning probably.
There is a way to get the Analogic gauge:
Once the emulator is open, choose the button: Page and then full map (just to make things easier). Then push Menu and choose: Overlay data and Enter:


In the window that just open, press Enter on: Press enter to add in the other window, click on GPS data and check the Ground speed box and push the button Exit, that brings you back in the previous window and you should have: Ground speed Small. Press Enter. That takes you in the window name: Data information ground speed

You click on Ground speed small, that brings you in the window name: Data information ground speed, bring the cursor on: Overlay Style and choose: Analog and on the right choose Analog Setup and pick: make transparent


Once done it should look like this:



Hope it can help you catch more fish

[karma]

I've encountered the same issues when travelling at less than 4kph. My GPS provider told me that digital scrambling is an issue at slow speeds, but this may be resolved this summer when the U.S. government reduces the range for GPS units. In the late 1990s, Bill Clinton signed legislation that would reduce the scrambling range from 30 metres to 10 metres for public use. The US is hesitant to move lower then this range to maintain their military advantage. Thus, if you’re within a 10-metre range during several refresh rates on your GPS unit, the information will be scrambled. At speeds over 4kmp, it's not a problem. If the US reduces this range as expected this summer, the speed and range issue will be further reduced giving greater accuracy at slower speeds.

[Méchant Malade]

But for now the analogic speedo is helping a lot; it's more accurate then a digital that goes from .7 to 1.3, then .9 etc...
If you go 1KPH it will stay right on it giving you a precise speed.

[Terry_F]

There is also an undocumeted feature on the Lowrance H2O.
From any screen, press EXIT 3 times in quick succession and a speedometer will appear. You lose the map feature but you can return later and it still keeps your trails.