Download - CLSA

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STEP 2 - Get Coordinates for your stations of interest (SOI)
a. If you are in the map view, click on the station name in the list or the
pushpin on the map.
b. On the balloon that appears over the site click on “Get Site Info”.
c. On the left side of the Site Info page click on “Coordinates”. The coordinate
sheet will come up. You should use the Antenna Reference Point
(ARP) values. There are coordinates on the ITRF2000 datum and the
NAD_83_CORS96 datum. The EPOCH being used will be listed. You will
need to copy and paste these coordinates into your processing software
for site position control.
Note: Looking on the list on Figure1, you will see that you can also get
the Data Sheet (ARP Only) which will also have the coordinates in NAD83
(CORS) and State Plane Values. You may want to download this for project
information used in reporting, etc. The SiteLog will show you the receiver and
antenna for the site. The antenna information is usually embedded in the
RINEX file, but you should verify the antenna type.
STEP 3 Method A– Download RINEX using UFCORS
a. To access User Friendly CORS (UFCORS) do one of the following.
1. From the Site Info page from the Map, just click the “Custom Files
(UFCORS)” link on the left, - OR -
2. From the main NGS web page http://www.ngs.noaa.gov/ select
“UFCORS” on the left – OR -
3. From the CORS web page http://www.ngs.noaa.gov/CORS/
select “Data Products” and on that page under “Methods of obtaining
NGS CORS data, 1. Customized”, select “User Friendly CORS
(UFCORS)”. Once you are on the User Friendly CORSweb page,
b. Day Selection: Select the “Starting Day” for your survey. The number
to the right is the ordinal day. That number is usually embedded in
your data file names.
c. Time Selection: Enter the Start time in your time zone, which should
include a period of time prior to when you began collecting data.
d. Enter your time zone. Note that daylight saving time zone changes
are available, so you will have to know that.
e. Determine how many hours of data you need. This should cover the
full time span during which you collected data. These files are not huge
so make sure you get enough hours of data.
f. Click “Continue” to get to the second input page.
At the top of the next web page:
g. Select the site for which you want information.
h. Select the data time interval. This should match the time interval for
your data collection. The default “As is” should be fine, but you can set
it to match your sample rate.
i. You can also download the coordinate files, meteorological files, the
data sheet and if necessary the orbit information in SP3 format which
is an ASCII file with the orbit information.
j. Finally you can select the compression type.
k. Click on “SUBMIT”. A dialog box asking where you want to save the
zip file will come up.
l. Save the data to the appropriate folder. Once you have saved that
data file, you can select the next CORS you need from the
pull-down list, then click submit.
Note: The zip file you just saved contains the site
observation information file, a navigation information file,
and other files.
STEP 3 Method B – Directly copy from the NGS FTP site
a. Go to the main CORS page on the NGS Website
http://www.ngs.noaa.gov/CORS/
b. Select “Data Products” from the left side.
c. Under “Methods of Obtaining NGS CORS Date, 3. FTP”,
click on the “Silver Spring” Anonymous ftp site
ftp://www.ngs.noaa.gov/cors/ . (You can click on the
Alternate site if you just can’t help yourself.)
d. Click on the “rinex/” folder, then the folder for year of your
survey, then the folder for ordinal day.
e. First find the global broadcast orbit file (navigation file)
“brdc[ddd]0.[yy]n.gz”, Where dddde notes the ordinal day and yyde
notes the year.
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