From the NGS CORS Newsletter

Friday January 17 2014




After a significant false start the NGS CORS Team is ready to

transition from GPS-only to GNSS online storage of CORS data


Starting on 3 February 2014, NGS’s Continuously Operating Reference

Station (CORS) Network will start distributing additional Global

Navigation Satellite System (GNSS) signals beyond the current GPS L1 and

L2. The extra signals include GPS’s L2C and L5 and Russia’s GLONASS

satellites L1 and L2. Over 40% of CORS sites will distribute these

additional signals. The switch to GNSS will help users obtain quicker

three-dimensional positions in areas of limited sky visibility by

allowing users to process their own data with the additional signals.

CORS data will continue to be distributed in RINEX 2.11 format that

fully supports these signals. Although these extra signals will

be available through NGS, NGS’s Online Positioning User Software (OPUS)

will continue to process only GPS L1 and L2 for the foreseeable future.

However, many third party processing software are able to utilize these

additional signals.


This transition will involve a number of steps:


Currently: Updated CORS map to show which stations supply

GPS versus GNSS data (~800 out of ~1950).


Currently: Until the transition date, GNSS RINEX data are available at:{yyyy}/{ddd}/{ssss}

yyyy-4 digit year, ddd-3 digit day-of-year, ssss-4 alphanumeric site id

GPS-only data remain available, as usual, at:{yyyy}/{ddd}/{ssss}


Currently: UFCORS (User Friendly CORS) has a new beta version 4.0

that supports GNSS.

This beta version will remain available until the transition date, at

which point UFCORS3x will be terminated and replaced by UFCORS4.0. For

Pathfinder users this transition should be seamless.  The biggest change

is that UFCORS3x provided GPS data that excluded L2C and L5 data, and

now will include GPS L2C, L5 and GLONASS, if available. Users will be

able to exclude GLONASS data but not specific GPS signals.


For questions about UFCORS please email ngs.ufcors @


2014-feb-03:  Start distributing GNSS data to

We have GLONASS and/or L2C/L5 data from selected sites all the way back

to 2007 that will replace previous GPS-only data files. The replacement

of the older data will take a few weeks to complete.


If you have any questions please do not hesitate to contact the CORS team:

ngs.cors @


giovanni.sella @