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Preventing Inaccurate Readings


Guest ighorsey

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Guest ighorsey

Yesterday, I went for a walk around the village where my parents live, and took my Garmin Venture with me. I kept a hold of my unit in my hand, as I was showing people what information I could get from it.

 

Now, when I walk, I swing my arms (almost Monty Pythonesque really) and this had the affect of reducing my speed. When I was walking and swinging my arms, it registered 1.9MPH, but when I walked with the unit held in front of me, it registered 2.9MPH.

 

It also gave me a maximum speed at one point of 16MPH, and I never even broke into a jog!

 

I reckon that my arms moving cause the inaccuracies, as it is either moving forwards faster than my body, or moving in the opposite direction to the way I am walking.

 

I figure that you would get the same problem if it was mounted on a ski pole or a walking stick.

 

Anybody care to back me up on my theory or propose another?

 

Cheers

 

Ian

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Guest JAMCC47

Mount it on your shoulder, keeps a better view of the sky. If you shake it those little internal mice (GPSINS) have trouble reading the gyroscope so they dont know really where they are! Thus they give you the wrong data.

 

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JoseCanUSea

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I suspect the problem is caused by the fact as you swing you arms and therefore the GPS, your body blocks different satellites. I think most GPS caculate their position every second. For example this could have happened. As you were walking the GPS used one set of satellites to calculates a position which happened to have a 12 foot error ahead of you. Then you swing your arm which causes the GPS to use different satellites, it calculates a position with the 12 foot error but this time behind you. So the GPS thinks you have covered 24 foot in one second. That is the same as a little over 16 MPH. You can get some of this effect by trees and such blocking satellites, I carry my GPS in my pocket as I hike, and once I had it indicate a max speed of 25 MPH.

 

[This message has been edited by ALacy (edited 23 January 2002).]

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