For whoever may be interested in the final results of the dual frequency sessions on the POST, here they are in all their glory, processed by OPUS with the precise ephemeris. As a recap, the original coordinates on POST were derived from a couple of airport PAC/HARN points and several local control points established in the area by Joey Stanger of Tyler, Tx. These “HARN” relative coordinates on POST have been used for most of our local area work for over a year. The next phase in the evolution of POST was three separate all night sessions, seperated by 6 to 8 days. This data was processed with data downloaded from 5 CORS stations, L1 only, that surrounded station POST. As the L1/CORS results from the three individual sessions seemed to agree closely with the HARN based coordinates, and even more so with themselves, further verification of the position was deemed necessary. At this point, Joey Stanger volunteered his time, a Trimble 4000si, and later submission of data to OPUS. First submission of data was for processing with rapid orbit ephemeris. Joey ran two all day sessions on the POST seperated by about a week. Both sessions were processed “rapid orbit” and both later processed “precise orbit” by OPUS. I’m going to list the coordinates for each session and method processed. Data is in NAD83, US Survey Feet, SPC Texas North Central Zone 4202, Orthometric El. The three L1 tests were done with three separate Locus units.

NORTHING EASTING ORTHO DATE DATUM

6835851.505 3100685.732 402.979 SEPT 00 HARN RELATED

6835851.427 3100685.739 402.873 01.325 ORGI/TEST1
6835851.422 3100685.757 402.956 01.333 ORGI/TEST2
6835851.415 3100685.742 402.728 01.340 ORGI/TEST3
6835851.421 3100685.746 402.852 AVERAGE


6835851.413 3100685.767 402.804 01.361 OPUS-R/O
6835851.416 3100685.774 402.791 02.003 OPUS-R/O
6835851.415 3100685.771 402.798 AVERAGE


6835851.420 3100685.770 402.804 01.361 OPUS-P/O
6835851.423 3100685.777 402.794 02.003 OPUS-P/O
6835851.422 3100685.774 402.799 AVERAGE



There’s just nothing else I can add to this. Next week the Interstate ORGI will take us to a new level. There’s gonna be plenty of L1 data to share for all kinds of processing experiments. Maybe someone can come up with a better method using AS 2.xx than my method of “throw ‘em all in and squish ‘em to the middle Stumpwater style data processing”. But, hey it worked. (see numbers above)

Sorry for re-posting all this again. I just felt like it all needed to be on the same page with the OPUS Precise Ephemeris processed data for easy comparison. Besides, I still kinda proud of the numbers.


J.D. Billings, former driver of the ORGI bus-now content to sip fresh ale and go along for the ride

J.D:

Those are indeed amazing results.

The only couple of millimeters difference between the OPUS-derived positions using Rapid and Final Orbits confirm that the Rapid Orbits are indeed pretty good. Did Joey Stanger indicate whether the different OPUS runs showed any differences in the precision of the position of POST using Rapid as opposed to Final?

Best regards,
Kent McMillan, RPLS Austin TX

SESS LATITUDE LONGITUDE EL HGT ORTHO HGT

R/O1 0.009M 0.010 M 0.019M 0.031M

R/O2 0.010M 0.012M 0.006M 0.026M

P/O1 0.009M 0.010M 0.019M 0.032M

P/O2 0.010M 0.012M 0.006M 0.026M

J.D.:

Yes, those look like the peak-to-peak differences in coordinates that OPUS reports.

If I've got it right, a peak-to-peak difference of 1cm in, say, longitude when all three CORS-to-POST vectors are compared implies that the the standard error of the longitude of POST using only one of the dual-frequency vectors would be about 0.010m/1.91 = +/- 5mm. That would give the results that OPUS reported as the mean of three vectors a standard error of about +/-5mm/sqrt 3 = +/-3mm

Your test results using two more CORS records actually have a precision that is so good that if systematic effects of the NAD83-ITRF97 and NAD83(xx) differences were known to have been eliminated, I would use both the Billings and NGS data to form a weighted mean for POST as the best estimate of its true postion.

Best regards,
Kent McMillan, RPLS Austin TX

JD...I think that this proves the axiom, that using NAD-83 fixed points (which we all did) still gets a good ground position, regardless of the ITRF/NAD-83 rotation..Since we fixed to ground monuments, then this will repeatable...That's my goal...I want to repeat and fit to my local control , no matter what the NGS does to actual reference system, ect.....
I went back and looked at my actual posted stuff and I missed the OPUS
N 0.09
E.0.16

Not bad considering the lengths of lines...You got better results than this, so I'd hate to draw conclusions, but it's there for all to see...

TM_ Still Yellow at this point!

I'm an looking forward to our science project next weekend...Don't know how the logistics will work out, but it sure should provide some entertainment for all participating....

I'd add, that this experiment has made me look a lot closer at the software side of the issue and I now have a much better awareness of what it is looking for...At this point, then more 'bad' data is better than 'less' good data...Totally changed my outlook on how I used to process..
I thank you my friend...

*now just bring a cask of the stump brew for my session and I'll be very happy*

TM

At 10:00 p.m. cst I'm cranking up two ProMark 2 units. One on POST and one on BRIK (a nail driven between bricks in the yard) about 30-40 feet away from POST. We've done the vector between POST and BRIK several times the last year, I just don't remember the distance between. I'm not gonna look either. I'll process the data from these two units Monday to ARL5, DQUA, WNFL and HOUS (PATT is down so I'm definately limited to the looonnnngggg base lines now). The results here may help next weekend's processing. I promise not to look at the old data for BRIK until I've processed the data. When doing the original POST L1/CORS sessions, I knew what my trarget was. For BRIK, I'm going without looking at previous "knowns".

Hope I remember to go out at 10:00 p.m. and start the units.......


J.D.

Modified By J.D. Billings on 1/26/2002 at 7:55 PM

My sessions for OGIE next weekend are also to prove Point to Point...You may beat me to the punch...
I thinking that our Point to Point will agree very well, but maybe not perfect to the NSRS (so what!)
Guess you intend to process the data to both points, but not your point to point at first pass and see what the CORS inverse is, then as a check, use the point to point session, then use a simple chain/plumb bob distance to check both of these...
Kinda my thinking....

TM

If anybody has FTP software try
getting on:

jimbo1.d2g.com
user = orgi
password = orgi

I figure if a few of us all post results to one place then everybody that wants them can get them easily.

I would like to see whoever posts files to make a unique subdirectory....either board handle....TM...JD... or city/state such as lawton-ok.

For some reason I keep getting switched to an old URL by my Win IE 6.x and can't verify that the directory will be and is available.

if you use Ie i think the correct url is

ftp://orgi

JImbo

Found the website (jimbo1.d2g.com), but couldn't access the FTP site...
Where would I find a good reliable FTP program?
Are we going to be able to use this FTP as our 'go between' to transfer data instead of e-mail...?
Sounds like a good idea, then anyone can grab the data that they want..
TM

I know a coupla FTP prog. let me go find the URL and then I'll post them.

I'm just gonna get one or 2 really basic FTP programs.

And yeah, the idea is to be a central depository for the data, instaed of e-mailing to who knows how many.

Jimbo

EDIT

EZFTP

FreeFTP


Both of these are freeware.

Let me test the links......


links ok.

I hadn't looked at the message before that gave the url.....it got screwed up cuz it looks like html.

try this in your browser address bar

ftp://orgi<orgi@jimbo1.d2g.com

Jimbo


whomever is trying orgi site...try without the <orgi in the url and see if it asks for the password.might getin like that.


Modified By James Webb on 1/26/2002 at 10:15 PM

Got the message Jimbo..Using the last link you posted...Password worked, but still need software to upload?

TM

Should be able to drag and drop, I think.

Right click copy from your hard drive and paste to FTP window.

right click copy from FTP and paste to your hard drive to download.

I saw it tried to connect a coupla times before you got in....it was giving a password error from what I could see. That is why I suggested the alternate.

Jimbo

Win32 O/S's have an ftp utility (but it's butt-ugly command line stuff). For a Win ftp client, I like Max FTP (freeware). Do a search for it on winfiles.com.

I just got through stumbling blindly under a near full moon trying to get to ProMark2's up and running and now Jimbo is forcing a crash course on ftp's????? O.K., I'll get another beer and try this thanggg

J.D.

By the way TM, what's "OGIE"???

Whomever is logging in....

set the server type to auto instead of Unix.

Jimbo

Check out this web site for FTP Software. http://download.cnet.com/downloads/0-10064-100-1572132.html

With my FTP software the proper address is ftp.jimbo1.d2g.com

I am using the WS_FTP software from the address in my previous post.

Steve Corley
Little Rock, Arkansas

must use a username....orgi
and password........orgi

jimbo

I just "ftp'd". I'm not sure. I downloaded and installed the Brandyware freeftp s/w. Not sure if I did that right. I let it install in it's own folder. I get online, minimize aol, bring up ftp s/w, minimize it, get aol back up and ftp....gets confusing already and not even midnight.

Anyhow, I think i finally got into jimbo's secret hideout. I say 4 or 5 files listed, last of which was jimbo.doc. I tried to copy that but didn't succeed.

Am I gettin close yet?

are you on dialup connection ???

if so then yeah, you are doing it "the only way". If cable or aDSL then you shouldn't need to connect to aol first.

On my end it looks like you are downloading the file steve corley sent....jimbo.doc.

try and send, upload, one of yours,

wordpad or something that just says hello.

Jimbo

GOT it.....geek science, not redneck !!
Modified By James Webb on 1/27/2002 at 1:02 AM

!

Mr. G's and Kent M.'s are way to hard on this po' ol coonass brain. They must think some of my brain cells aren't dead r sum'in.

Jimbo

I lernt that ftd thing fastrn' i spected.

How often do you clean out the "junk". As in the junk file(s) I just put in. (one of which isn't junk...kinda a warning)

JD

Yeah !

This is a sub-folder (subdirectory for all us old dos users).

I'll probably make a message dir. so these can be archived there and still available.

my idea is for each to put their own files in independent sub-folders...I'll make a few so ya'll can see it.

Jimbo

Ps: What is the abbr. for arkansas ???

AS ??
Modified By James Webb on 1/27/2002 at 2:01 AM