> For the complete documentation index, see [llms.txt](https://docs.premium-positioning.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.premium-positioning.com/learn/what-is-network-rtk-and-vrs.md). # What is network RTK and VRS? Network RTK, or NRTK, is RTK that draws its corrections from a network of permanent reference stations rather than a single base. The network models the errors across a whole region, so a rover anywhere inside it receives a correction tailored to its position, and you carry only the rover. No local base to set up, and the same 1 to 2 cm accuracy as single-base RTK over a far larger area. A virtual reference station, or VRS, is the most common way those network corrections are packaged. The network synthesises the observations a base would have recorded right next to your rover, so the receiver computes a short baseline to a station that is not physically there. If you have not read it yet, [What is RTK](https://claude.ai/chat/b419af49-7d48-49a1-832b-42d52fe66419#) covers the base-and-rover technique that NRTK builds on. ### Why network RTK exists Single-base RTK leans on the rover and the base being close enough to see almost the same errors, so they cancel. That assumption weakens with distance: beyond a few kilometres from the base, the atmosphere over the rover is no longer the atmosphere over the base, and accuracy falls away. A network removes that limit. Permanent stations spread across a region feed their observations to a network engine. The engine interpolates the spatially correlated errors, the orbit and tropospheric (geometric) errors and the ionospheric (dispersive) errors, from the stations surrounding the rover, and streams back a correction matched to where the rover actually is. The result is a continuous service across the whole coverage area, not a bubble around one base. ### How VRS works With a virtual reference station, the rover sends its approximate position up to the network. The network uses that position to build a synthetic set of observations, as though a base were standing a few metres away, and sends them down. From the rover's point of view this looks exactly like an ordinary short-baseline RTK connection, which is why VRS works with standard NTRIP receivers without anything special. This is also why the GGA heartbeat matters. The position the rover sends is what the network builds the VRS around, and it has to keep sending it so the correction follows the rover as it moves. See [Mountpoint selection and the GGA heartbeat](/guides/mountpoint-selection-and-the-gga-heartbeat.md). ### Other ways network corrections are delivered VRS is the most widely used, but it is not the only method. * FKP delivers area correction parameters that describe how the errors vary across the region as a surface, which the rover then applies to its own position. * MAC, the master-auxiliary concept, sends one master station's observations plus the differences measured at the auxiliary stations, and lets the rover compute its own correction with full control over the process. For most users the method is transparent: you connect to a mountpoint and receive corrections. Which method is in use is a network and receiver detail rather than something you choose point by point. ### How we provide network RTK Premium Positioning runs a network of more than 2,000 base stations across over 25 European countries, delivering NRTK corrections as RTCM 3.x in ETRS89 at 1 to 2 cm accuracy. Any NTRIP-capable receiver can connect as a client to the COMMON mountpoint to receive them. See [Connect a receiver to our NTRIP caster](/set-up-and-connect/connect-a-receiver.md). ### FAQ What is the difference between RTK and network RTK? RTK uses a single base near the rover. Network RTK uses a network of permanent stations and delivers a correction tailored to the rover's location, so it works over a much wider area with only a rover. What is a VRS? A virtual reference station: synthetic base observations the network generates right next to your rover, so the receiver sees a normal short-baseline connection. Do I need my own base station for network RTK? No. The network is the reference, so you carry only the rover and a connection to the caster. Why does my rover send its position to the network? So the network can build the correction, or the VRS, around where you are, and keep it matched to you as you move. Is network RTK as accurate as single-base RTK? Yes, the same 1 to 2 cm class, and it holds that across the whole network rather than only near one base. --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter: ``` GET https://docs.premium-positioning.com/learn/what-is-network-rtk-and-vrs.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. 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