Global CORS Networks

What Are CORS Networks?

CORS are permanent GNSS reference stations that continuously capture satellite observations. Networks process and broadcast corrections in real time (RTK/Network RTK) and publish RINEX files for post-processing (PPK). This delivers robust, traceable positions tied to modern geodetic frames.

What’s the difference between RTK and PPK (RINEX)?

RTK uses live corrections from CORS via NTRIP for real-time centimeter accuracy. PPK (post-processing) uses RINEX files from rovers and CORS stations to compute precise positions after data collection, often improving robustness in challenging environments.

Do I need my own base if I use CORS?

Typically no. CORS networks replace a local base, saving time and cost. For redundancy or remote gaps, some users still stage a backup base or log PPK.

Which datum/epoch should I use?

Match the network’s published reference frame (e.g., NAD83(2011), CSRS, ETRS89, or ITRF) and epoch. Confirm transformations if delivering to client-specified datums.

Are services free or paid?

Many public networks (state/provincial) are free once registered. Commercial RTNs (e.g., SmartNet, TopNETlive) are subscription-based with SLAs and additional support.