Info

General Information

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, TGD, T01, and T02 formats as well as in the Receiver INdependent EXchange Formats (RINEX) versions 2.10, 2.11, and 3.02. Data for the CORS stations is collected at 1-second epoch intervals, and can be retrieved in various epoch intervals ranging from 1 to 60 seconds.

Reference Frame

As of February 15, 2013, the Vermont CORS are referenced to NAD 83(2011) epoch 2010.00. These coordinates are employed for all data products, both raw and real-time.

Note on File Formats and Satellite Observables

The Trimble DAT files do not contain GLONASS observations and are compatible with both older and newer Trimble software. The RINEX files written in RINEX version 2.10 and 2.11 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 data 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, tgd, t01, t02)

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):

Time 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
ID 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.