What is the most accurate GPS device?

9-29-05 | delphinium

[Delphinium]

I know this is a personal matter but I am waiting for Garmin tech support to answer. I am wanting to buy a GPS device that is accurate atleast to 2 meters.

I know there are many high tech and high intellectual folks of Freerepublic, so I decided to ask.

[Solson]

I hear the new Blackberry 8700, due to be released later this year, will have GPS on board.

[El Gato]

The more satellites it receives at once, the more accurate, up to a point. AFAIK, the best you get with GPS is about 15 ft (5 meters) accuracy

There are differences in accuracy, and differences in applications. A set designed for a fighter has to track more channels because things change rather quickly in a fighter aircraft. There are also differences in the algorithms implemented in various devices. The way they "track" the signal from the satellites varies. That mainly affects how well they maintain "lock" under low signal conditions, but it also affect accuracy. For the most precise uses, you have to go to differential. That takes an additional set located at a known point. There are also ways to get more accurate positions relative to some nearby point, without the extra set. Thus the position might be off by a meter or two, but relative to a post on the corner of your field or block, you might be good to centimeters.

[Realism]

NavCom GPS

[Brad from Tennessee]

I don't know much about current civilian GPS products but I do know that nowadays high-tech electronics from pc's to televisions and their accessories can become obsolete within a year and replaced on the market by more advanced, cheaper products. I would check out Wal-Mart unless you are a surveyor or a cartographer.

[john316]

The one that flashes "You are here"

[Rebelbase]

Ha ha, can't get away from her can you?

[SuperSonic]

Roughly speaking:

Recreational grade:

10 meter accuracy $200

Mapping grade:

1 meter accuracy $5000
Sub-meter accuracy $10,000

Survey grade:

0.1 meter accuracy $20,000

[durasell]

Don't laugh. But check out Radio Shack.

[Publius6961]

If you buy a modern GPS receiver, the accuracy will have nothing at all to do with which one you use.

That will come as a surprise to us surveyors who have been using GPS for over 20 years with X/Y/Z accuracies of 1/4 inch.

[Red Badger]

19"?..........heh heh heh.............Hey, sailor........

[Senator_Blutarski]

Related to this topic: Has anyone used a GPS to get a close estimate of the location of a tract of land? I own a remote 40 acre tract where I can identify one corner (survey marker) but due to steep hills the other 3 corners are difficult to identify.

[Red Badger]

Ex-Wife Grade:

Priceless!.......

[aShepard]

A land surveyor I did some work for, swore by his Trimble unit, but it cost him about $15 grand, four years ago. Accurate to within an inch, when the government took off the dithering circuit it employs during heightened security.

[TChris]

For the most precise uses, you have to go to differential. That takes an additional set located at a known point.

OK, but that's not just GPS any more, is it?

[reagan_fanatic]

Don't laugh. But check out Radio Shack.

I almost laughed. Almost.

[Conspiracy Guy]

I use a map and a compass. No batteries needed.

[EagleUSA]

This is a 12 channel WAAS mounted unit on a 42 ft sailboat.
-----
The most accurate GPS service (code) available to the non-military user, will utilize a WAAS satellite for error correction information. If you need the ultimate, buy a good 12-channel system with WAAS capability.

[KC_for_Freedom]

If you buy a modern GPS receiver, the accuracy will have nothing at all to do with which one you use. GPS accuracy is a function of the physics involved with satellite positioning and the number of those satellites being tracked by your receiver. The more satellites it receives at once, the more accurate, up to a point. AFAIK, the best you get with GPS is about 15 ft (5 meters) accuracy.

Good point, you may be able to get a little better if one of the "satellites" is actually a GPS transmitter on the ground near you with a location known preciscely. But maybe you can't provide that, so the above is about as good as it gets.

[Rebelbase]

Speaking as one who has used maps my whole life and have yet to use GPS, I can find a couple uses that I would consider getting one.

Boating navagation and tagging fishing holes and good hunting spots to return to.

I have heard that adjusters in Mississippi/La are using them to locate addresses as most of the street signs are gone.

What other uses do FReepers have for GPS?