OPUS computes coordinates using which network?

• A. European EGNOS
• B. US Army satellite network
• C. NOAA CORS Network (NCN)
• D. Global Satellite Positioning Service network

Answer: (C)

OPUS uses the NOAA CORS Network, the National CORS Network of permanent reference stations, to compute precise coordinates. It works by taking your GPS observations and applying differential corrections derived from this network of reference stations, producing accurate coordinates in a consistent reference frame (like NAD83/ITRF). This network-based approach provides centimeter-level accuracy by mitigating common GNSS errors such as satellite biases and atmospheric delays. Other options refer to augmentation systems or the GPS constellation itself, not the network of reference stations OPUS relies on.