Re: Getting Accuracy Within a few inches?
From: Stichting ST (atarist_at_xs4all.nl)
Date: 12/06/04
- Next message: Andreas van Hooijdonk: "PDA mount with incorporated SiRF GPS receiver for in-car navigation."
- Previous message: David Lee: "Re: Questions about EGNOS."
- In reply to: Dave Baker: "Re: Getting Accuracy Within a few inches?"
- Next in thread: Marc Brett: "Re: Getting Accuracy Within a few inches?"
- Messages sorted by: [ date ] [ thread ]
Date: Mon, 06 Dec 2004 10:56:44 +0100
On Mon, 06 Dec 2004 10:09:24 +0800, Dave Baker <newsgroup_poster@jodael.com>
wrote:
>On Sun, 05 Dec 2004 18:53:00 -0700, matt weber <mattheww50@cox.net> wrote:
>
>>On 5 Dec 2004 12:20:30 -0800, geomanks@yahoo.com (George) wrote:
>>
>>>This is a just for fun question from my 12 year old son. I know the
>>>accuracy doesn't really matter. We are just curious!
>>>
>>>I know horizontal accuracy A (USGS) is like 1 in 10,000. If I wanted
>>>to establish a point in my yard with this accuracy with a handheld
>>>Garmin Vista how would I do it? Would an average of a day, week, month
>>>do it? Would I need to post process the data to do it? Can I post
>>>process the data fronm my handheld to do this? My son justs wants out
>>>own home benchmark and wanted to know how close we could get to having
>>>it be HORZ A accutate. Any help would be appreciated. Thanks!!!
>>
>>The only way to establish that kind of accuracy is using differential
>>GPS with carrier phase measurement. That can get you down to inches
>>fairly easily as long as the location of the dif beacon is known to
>>similar accuracy.
>>
>> That all tends to be a bit out of the league of a consumer hand held
>>gps. Magellan had a post processing option using doppler ship and
>>differential that could get you down to about 10 inches with a 20
>>minute observation with Pro 5000's (hand helds).
>>
>>In general 5 meter accuracy with WAAS isn't very hard,anything beyond
>>that gets messy quite quickly. There are commercial units that do it
>>all the time, but they cost a whole lot more than $100 each...
>
>How about this one?
>
>http://www.delorme.com/professional/postpro/default.asp
>
>"For less than $100, GPS PostPro 2.0 with an Earthmate GPS receiver is
>available to all XMap users! ". This is a little confusing to me - I'm not
>sure what an XMap user is - looks like you might have to have already bought
>some other software? However, when I bought by Blue Logger I noted that I
>could have bought it with the post processing software as well as the
>bluetooth GPS hardware for US$249 (I think - can't find the link now - I
>bought with a different software package).
>
>"Static baselines can be processed to sub-meter accuracies". Not sure how
>"sub" that is though. :-)
>
>Dave
>
>
>The email address used for sending these postings is not valid.
>All replies to the group please.
That stuff seem very usable for Americans having CORS stations and State
Planes.
The price is nice. They use a Sirf starIIe chipset and talk about NMEA. But
NMEA cannot transport raw data for RINEX conversion. So SirF protocol needs to
be used, I think. Anybody knows if this chipset gives indeed a good carrier
faze?
The postprocessing looks OK to me.
I have experimented with a Garmin GPS12 and postprocessing.
Results were very nice. See:
http://www.xs4all.nl/~atarist/geo/gps_accuracy.htm
Piet
- Next message: Andreas van Hooijdonk: "PDA mount with incorporated SiRF GPS receiver for in-car navigation."
- Previous message: David Lee: "Re: Questions about EGNOS."
- In reply to: Dave Baker: "Re: Getting Accuracy Within a few inches?"
- Next in thread: Marc Brett: "Re: Getting Accuracy Within a few inches?"
- Messages sorted by: [ date ] [ thread ]
Relevant Pages
|
