RTK (Real-Time Kinematic) correction services provide centimeter-level positioning accuracy by using a network of fixed, ground-based reference stations. These corrections are delivered in real-time to the user’s mobile receiver (rover) via the Internet using the standard NTRIP protocol.

The global RTK landscape is divided into three main categories based on scale, quality assurance, and pricing model: commercial networks, government/public networks, and crowd-sourced (community) networks.

Paid Commercial RTK Networks (Global/Continental Focus)

These are professionally operated networks that aggregate thousands of Continuously Operating Reference Stations (CORS) across countries and continents to provide seamless, high-accuracy service via a single subscription. They offer guaranteed Service Level Agreements (SLAs) for reliability and are the standard for professional surveying, construction, and high-value agriculture.

• Examples: Swift Navigation’s Skylark Nx RTK, Hexagon’s HxGN SmartNet, Trimble’s VRS Now, Topcon’s Topnet Live.

• Technology: Utilize a dense grid of reference stations to generate Virtual Reference Station (VRS) corrections, minimizing the baseline error for the rover.

• Pros:

  • Centimeter-Level Accuracy: Consistently provides 1-3 cm accuracy.

  • High Reliability: Guaranteed uptime, professional monitoring, and customer support.

  • Broad Coverage: Offers multi-country or continental coverage, simplifying cross-border operations.

  • Universal Compatibility: Corrections are in the standard RTCM format, compatible with almost all RTK-capable receivers.

• Cons:

  • Subscription Required:Aannual or monthly fees which can be high depending on vendor.

  • Internet Dependence: Requires a stable mobile internet connection (NTRIP).

  • Fragmented RTK Coverage: While services are global, the density of the RTK network is still localized to specific continents or countries.

Free Public/Government RTK Networks (National Focus)

Many countries and regional government agencies (e.g., Departments of Transportation, national mapping agencies) operate public CORS/NTRIP networks, which they often provide for free or for a nominal, heavily-subsidized fee to local users.

• Examples: US state DOT networks (e.g., Oregon’s ORGN), various European national networks (e.g., Portugal’s ReNEP).

• Technology: Standard Network RTK (VRS or single-base).

• Pros:

  • Low/No Cost: Excellent, affordable option for local users within the national boundary.

  • Survey-Grade Quality: Often managed and maintained by high-standard government geodesy experts.

• Cons:

  • Geographic Restriction: Generally restricted to use within the host country/state.

  • Varied Access: User registration and access policies differ widely; public networks can be prioritized for government use.

Free Community/Crowd-Sourced RTK Networks (Global Availability)

These networks rely on individual users contributing their own GNSS base station data to a shared, global NTRIP Caster, making the corrections available to anyone with a receiver and internet connection.

• Examples: RTK2GO.

• Technology: Primarily single-base RTK correction streams distributed via a global NTRIP caster.

• Pros:

  • Completely Free: Excellent for hobbyists, educational use, and feasibility testing.

  • Global Availability: Patches coverage gaps in regions where commercial or public networks are unavailable.

• Cons:

  • No Quality Guarantee: Correction stream uptime, accuracy, and latency are entirely dependent on the quality and operation of the individual contributor’s base station.

  • Sporadic Coverage: Coverage is only available near a contributing base station (max 35-50 km range) and can disappear without warning.