What is the most accurate GPS device?

9-29-05 | delphinium

[meowmeow]

Running: I love my Garmin Forerunner 201!

[Delphinium]

You can tell I am pretty ignorant about these devices.

I'm not sure he will even use it for hunting.

[Delphinium]

Garmin, and Magellan are the compatible ones. Probably the simpler the better, I can't even get him to answer the cell phone.

[RightWhale]

Get one that comes with the computer cable and a CD with the software. The unit will have a couple of ports for different things, power, data, antenna. Also, go to the website and see if what they say there makes any clear sense. You can probably get away with a decent, capable unit for $300 although there are cheaper ones. The computer end can be covered with shareware, for starters anyway.

[JeffreyH]

Curious as to how many of you here are surveyors by trade?

Also remember - that the error's you get are in an ellipse. If you located your house, it could be 7' out to the northwest, and the other corner 10' to the east - adding 17' approximately to your measurement of the house.

Survey grade instruments we've used were able to obtain 5mm horizontal and 15mm vertical (vertical is usually 2-3 times worse). That was by long occupation and post-processing the cooridnates via least squares adjustments. Running real time kinematic to about 1-2 cm.

I've gotten handhelds down to 10' - not bad for hiking or even rudimentary mapping.

[Conspiracy Guy]

LOL

[Senator_Blutarski]

Caver,

Do you know if there is a way to covert positions on a plat map into GPS coordinates?

[CHICAGOFARMER]

HI

been following you posts.

What is your recommendation for street GPS quality and price concerns.

thanks

[kinsman redeemer]

As for me: cartographer

[Crusher138]

What other uses do FReepers have for GPS?

We are looking to relocate to the other side of the continent and are:

1. Intimidated by the large number of routes available and their conditions (post-Hurricane) and

2. Freaked out by a good sized city that names instead of numbers their streets.

We looked at maps but after a few "turn left on Mesa, then right on Riverside, then merge onto Academy Road" type instructions, it became obvious that a GPS would be very handy.

[caver]

"Do you know if there is a way to covert positions on a plat map into GPS coordinates?"

With plat map coordinates, I usually get a 7.5 minute topo and manually plot it according to the quarter-quarter description. Then I measure and convert into UTM. I don't know of any way to convert from quarter-quarter description to lat-long or UTM.

[JeffreyH]

I've got some programs to convert... do a search on Corpscon - also search on the National Geodetic Survey site - they have some free downloads.

Any help needed - let me know.


Jeffrey

[JackDanielsOldNo7]

We use AtRoads at our work. Works great.

[JackDanielsOldNo7]

GPS at our company means Golf Postponement System. LOL

[parcel_of_rogues]

I've used the program here
http://www.jdmcox.com/
to superimpose my Magellan Map330 tracks onto satellite images. If I'm on the road it usually matches the road perfectly on the image, whereas on a Delorme map it may be off.

You can also find free utilities to transfer the magellan tracks to Excel and play with the data to your heart's content.

[pointsal]

Go check out the product by ARKON
www.arkon.com
I have the 12-volt powered unit with uses my iPAQ 3950 as the PDA/COMPUTER. This unit is used solely in my vehicle and has been right on the money in the boondocks.

ARKON also has a blue-tooth model coming in mid-October that is supposed to be the latest stuff and does not need to see the sky. Tech support is pleasant and helpful.

Wanna buy my junk NAVMAN? I also has a Garmin gathering dust.
Have fun.

[Texas Songwriter]

That is really, really funny.

[M1911A1]

I've used the military PLGR and the commercial units, never a survey grade device.

In short, unless you need the extreme accuracy of the survey instruments, the commercial units today do a pretty good job for hunting, Geocaching, street navigation and the like. The main difference between them involve features other than accuracy. My Etrex Legend generally tells my that my accuracy is within 6 meters. Goes way down with poor satellite reception...the more your unit can see, the better, and you want at least one satellite overhead and a couple near the horizon for best results.

The accuracy of civvie units was improved a lot when Selective Availability was turned off. DoD controls the satellites, and they used to "spoof" the signals too keep you from getting an really accurate reading, and they can do it again, if they want to.

No GPS unit is designed to work indoors or under heavy tree cover without an external antenna.

Really, you have to define what you want a GPS receiver to do before you can decide what model you want and how much to spend. I use mine for Geocaching, navigating around in a car, keeping track of how far I've hiked, finding nearby parks for the kiddies, etc. I could not use it to survey, but I didn't spend thousands, either.

The main factors for me in choosing the model I purchased were price, hand portability, the ability of the unit to display electronic maps and the being able to plug it in to a computer. If the money wasn't a concern, I would have liked to get one with a color display.

It is truly one of the more useful gadgets I've owned, but if I were off in the back country (or back in Iraq) I would sure as heck bring along a paper map and compass.

[pointsal]

Go look at the ARKON gps units <>