Printer-friendlyNYEC CORS File Downloads and Instructions
NGS Cooperative
CORS Site
The New York State Department of Environmental Conservation's Bureau of Wildlife has maintained a Global Positioning System (GPS) continuously operating reference station (CORS) since 1996. This station became part of the National Geodetic Survey's Cooperative CORS network on 24 July 2000. Code and carrier phase GPS data are generated and provided free of charge, in Receiver INdependent Exchange (RINEX) format.
The GPS data is currently available in two RINEX formats, 15 second dual frequency and 5 second single frequency. The dual frequency files are generally larger because they contain all L1 and L2 observables. These are stored at a 15 second epoch interval and are usually used by the surveying community who require highly accurate measurements. The single frequency files are stored in 5 second epoch intervals which are preferred by GIS/mapping project users. Since these files record L1 observations only, they are normally smaller than the dual frequency files.
Download Data
Dual Frequency Data, NYEC RINEX 2.0 - Receiver INdependent EXchange formatted data from this station at 15 second epochs.
Single Frequency Data, NYEC RINEX 2.0 - Receiver INdependent EXchange formatted data from this station at 5 second epochs.
NYEC Station Coordinates (PDF, 3kb) - download the coordinates in a PDF formatted document.
Helpful Hints
Which files are right for your application?
Highly accurate surveying applications usually require dual frequency data. Always choose the dual frequency data for these applications. Most hand held or backpack mounted resource grade GPS receivers are single frequency and do not use data from the L2 observables. The single frequency files would probably be the best choice for these applications.
FTP Protocol
File Transfer Protocol (FTP) is used to transfer files from our server to your computer. When you click on either the dual frequency link or the single frequency link from our reference station page, you will automatically be directed to the appropriate section using FTP mode.
Selecting Files to Download
Files are arranged in folders by year, month, day and time of day. The subdirectory naming conventions are of the form mmmYY/DAYdd, where mmm is the 3-character month of year, YY is the last two digits of the year; and dd is the day of the current month. For example, files from 5 April 2000 would be stored in the folder: Apr00/DAY05.
File Names
Files are named by the date and time when they are closed. RINEX file sessions contain data from a one hour time period. There are two components to each RINEX session, a navigation file and an observation file. Each of these components use the following naming conventions: nnnnddds.yyt, where nnnn is the 4-character station name, ddd is the Julian day of the year, s is the RINEX session code, yy is the last two digits of the year, and t is the file type (n for navigation or o for observation). For example, a file named 'NYEC1234.00O' is a RINEX Observation file from receiver 'NYEC' on Julian day '123' (2 May) during session '4' of the year 2000. Additionally, because we record both dual frequency and single frequency data, we need to modify the single frequency file naming convention to avoid duplicate file names. For these data we alter the decade digit of the year to an 'X'. Following the example above, the single frequency file name would be: 'NYEC1234.X0O'.
File Times
File time stamps are calculated at or near the closing time of the session. File creation times are recorded in Universal Coordinated Time (UTC). UTC is ahead of Eastern Standard Time (EST) by 5 hours and ahead of Eastern Daylight Time (EDT) by 4 hours. Therefore, a file time stamped 12:00 PM would contain data from 11:00:00 to 11:59:59 hours UTC, or 07:00:00 to 07:59:59 hours EST (08:00:00 to 08:59:59 hours EDT). RINEX navigation files are normally time stamped just before the close of the hour (e.g. 11:58 PM), so be sure to use the RINEX session code when selecting the correct navigation and observation file pair to download. Files times from the most recent sessions of the current day are displayed as 12:00:00 AM or 00:00:00, depending upon your browser's settings. This is because, from the server's standpoint, these files were last modified at a future time (UTC is ahead of local time). The server treats this as invalid information and does not display the proper file closure time. Once the server's time reaches the time that each file was last modified, the file closure UTC is correctly displayed. This affects only the 4 or 5 most recent sessions of the current day. During EST 5 sessions are affected, and during EDT 4 sessions are affected.
Downloading
Select an appropriate file to download using a single right mouse click. If you are using Microsoft's Internet Explorer browser, select Copy to Folder to begin the download. If you are using a Netscape browser, select Save Link As... to begin downloading. If you accidentally click on a file using the left mouse button the RINEX data file (an ASCII formatted text file) will open in your browser. Use your browser's back button to return to the directory listing.
If you need download assistance or have any questions or problems, please send e-mail to the link in the right column. In your message, include your name and a daytime telephone number where you can be reached. We will get back to you as quickly as possible.
