Warranty after fix for GTA02 GPS rework for SD card interferenceissue

Brian Wilson brian at wildsong.biz
Thu Jul 31 21:00:44 CEST 2008

> Besides the point that a small pocket-IMU would be great. To GPS jumts
> that big exist? As fas as i understand GPS it should have little jitter.

Trimble had a few GPS models out with dead reckoning. Not pocket
sized.  I think they are all off the market now. I got one off Ebay a
few weeks ago but have not had time to set it up yet. To me it's more
interesting reading the manuals and learning how it works since I
don't use my car more than once a month. Trimble was addressing loss
of signal in urban canyons not (ahem) antenna placement issues.

See  http://www.trimble.com/tms/placer450.aspx?dtID=overview

They use a small gyroscope. There are much smaller gyros available now
but my intuition from reading their materials is that it will work in
a car if you are going fast enough (they want you to go 22 mph) to
generate steady predictable g forces but if you are going at a walking
pace it would never work.

If you are walking around and want a reasonable position the Kalman
filter would probably be easier to deal with.
Is there a mathematician in the house?


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