GPS VERY accurate ??
Ole Man Earl
Posts: 262
10:34PM MST
Will someone else check their GPS units.
All mine have suddenly stayed within 1 FOOT radius and +- 1 inch altitude over a 10 min period...No the unit is on. I see data flowing.
Did someone turn on high precision ???
Post Edited (Ole Man Earl) : 6/4/2009 4:55:33 AM GMT
Will someone else check their GPS units.
All mine have suddenly stayed within 1 FOOT radius and +- 1 inch altitude over a 10 min period...No the unit is on. I see data flowing.
Did someone turn on high precision ???
Post Edited (Ole Man Earl) : 6/4/2009 4:55:33 AM GMT
Comments
Selective Availability has been turned off for some time now. What you may be seeing is just the effect of data from the same subset of satellites over a ten-minute period. Give it more time; once new satellites orbit into view, I'll bet you start to move — without even lifting a foot!
-Phil
Europe is desparately trying to get their independant system up and running so I don't know if the US system is getting clawed back towards its original usage or even a licence, with payments, (probably on both)·will have to be obtained. Over here we get taxed on the tax.
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Links to other interesting threads:
· Home of the MultiBladeProps: TriBladeProp, SixBladeProp, website (Multiple propeller pcbs)
· Single Board Computer:·3 Propeller ICs·and a·TriBladeProp board (ZiCog Z80 Emulator)
· Prop Tools under Development or Completed (Index)
· Emulators: Micros eg Altair, and Terminals eg VT100 (Index)
· Search the Propeller forums (via Google)
My cruising website is: ·www.bluemagic.biz·· MultiBladeProp is: www.bluemagic.biz/cluso.htm
By the way, in the past the users that lived the short times of GPS error removal said it was a dream..
@Cluso: GPS altitude is on the WGS85 ellipsoid, while sea level is 0 on the geoid it can differ up to +-100meters with respect to the ellipsoid. Italy for instance shows a 40m difference. There are math models to calculate this value, and the most used is EGM96, while there is a new EGM2008 model available.
check http://commons.wikimedia.org/wiki/File:Geoid_height_red_blue.png
Massimo
-Phil
In fact I have a sort of added latency which made today's work useless..
How many satellites does $GPGGA report?
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Airspace V - international hangar flying!
www.airspace-v.com/ggadgets for tools & toys
On May 29, I had logged a 5 mile bike ride:
http://www.everytrail.com/view_trip.php?trip_id=224095
So last night I did the same ride, identical to probably within two feet over the entire trip as on May 29th, and it's shown here:
http://www.everytrail.com/view_trip.php?trip_id=231356
If you pull up two separate browsers, you can zoom in and compare paths between the two.
I don't see much of a difference.
The altitude summary shows a large difference, but altitude is always more error-prone, and this could be due to poor satellite geometry over the ride.
Scary stuff up there^^
There must be better things to use than GPS in most instances. You can easily set up some radio beacons and do some trig to find an object's location at half the price or less of GPS.
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Not the fish.
sites.google.com/site/bitwinproject/
Seriously, it's sobering to think how much depends on keeping the plates spinning and the balls in the air.
-Phil
I'm going to put my Prop-GPS-DataLogger back together this weekend and make a couple of runs and report back. I just cleaned up my protoboard and it didn't work also. I found the bugs. The cleaner it gets, the more bugs get introduced! That said, if you commit it to a PCB, it may not work at all
And it looks like Loran-C will go away soon:
http://www.navcen.uscg.gov/Loran/default.htm
I have a free Loran receiver available. The gentleman that·bought my sailboat said "I don't want that antique" so I pulled it....I forgot the pull my antenna·
Jim
Post Edited (hover1) : 6/5/2009 11:31:13 PM GMT