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• vtgs cors

The Geodetic Survey Section of the Vermont Agency of Transportation maintains a network of Continuously Operating GNSS (Global Navigation Satellite System) Reference Stations (CORS).  These stations are intended to operate 24 hours/day seven days/week.

There are two separate components to VECTOR: Downloadable Data for post-processing and Real-Time Corrections to support real-time applications

 Downloadable Data

The data from these stations are made freely available to users and are downloadable from this web site.
These receivers collect data from both the GPS satellites and GLONASS satellites.  Data files for these stations are available in Trimble's DAT format as well as in the Receiver INdependent EXchange Format (RINEX).  Data for the CORS stations are stored in one-hour files and are collected at 1-second and 15-second epoch intervals.

Reference Frame

As of February 15, 2013, the Vermont CORS are referenced to NAD 83(2011) epoch 2010.00.  These coordinates are employed both in the RINEX header and the RTCM data streams 

Note on File Formats and Satellite Observables

The Trimble DAT files do not contain GLONASS observations and are compatible with the both older and newer Trimble software.  The RINEX files are written in RINEX version 2.1, and do contain GLONASS observations.  User's software should recognize the GLONASS data and use it if GLONASS data was collected by the user.  Also, the users' software should ignore the GLONASS data in a RINEX file if the software is not compatible with GLONASS observations.

 File Naming

The dat file naming convention is as follows:

{ssss}{ddd}{h}{t}; where ssss is the four character site identifier, "ddd" is the day of year, "h" is a letter which corresponds to an hour long UTC time and "t" is the file type.  For hourly files, the format
would be {ssss}{ddd}{h}.dat.
 

The RINEX file naming convention is as follows:

{ssss}{ddd}{h}.{yy}{t}; where ssss is the four character site identifier, "ddd" is the day of year, "h" is a letter which corresponds to an hour long UTC time block, "yy" is the year and "t" is the file type.  For hourly files, the format
would be {ssss}{ddd}{h}.{yy}o.

    Hour long UTC time block identifier (h):

00  01  02  03  04  05  06  07  08  09  10  11  12  13  14  15  16  17  18  19  20  21  22  23
 a    b     c    d     e    f     g     h     i      j     k     l     m   n     o    p    q     r     s     t     u    v     w    x
 

 Data Storage Policy

Data files are currently available on line for at least 45 days, after which they will be deleted. Data is not archived prior to deletion and is therefore unrecoverable from this site. Users are encouraged to download data as soon as practicable.  However, all data collected from the Vermont CORS that are part of the National CORS Network are available from the NGS CORS Page.