Free NTRIP for RTK surveys using Emlid Caster

By on 1 April, 2022

With no need for recurring and expensive subscriptions, real-time corrections for RTK surveys via NTRIP are now possible for free!

To perform an accurate RTK survey, you use a rover and a correction broadcast in real-time from a nearby base. The most common RTK correction sources are local base stations broadcasting the correction via radio (eg. UHF), or from a remote base, using technology called NTRIP.

NTRIP (Networked Transport of RTCM via Internet Protocol) allows your survey rover to accept corrections over the internet, removing the need for a local base station and extending your range between base and rover beyond what you could achieve with radio communications.

NTRIP includes the following components: a base, server, caster, and rover. Typically the base is a stationary Continuously Operating Reference Station (CORS). The data is then sent to the NTRIP caster, where it is retransmitted to the client’s rover. This requires an internet data connection and most commonly, a subscription with a commercial CORS network provider. Whilst convenient, the cost for this option can soon add up.

NTRIP Caster: Work with your own Base and Rover

Using existing technologies, such as mobile internet and existing protocols, Emlid Caster makes establishing your own RTCM corrections service really simple for any GNSS receiver that supports NTRIP.

Just set up your own RTK base station over a known or post-processed point, and configure it to send corrections to the Emlid Caster service.

If your base station is an Emlid Reach receiver, select the option for NTRIP in the Emlid ReachView3 App to broadcast your corrections to the Caster service via the internet.

Sign up for free and get started

Connect up to 10 rovers simultaneously, anywhere within a reasonable baseline (distance to your base). This only depends on your acceptable level of positional uncertainty – as with any kinematic positioning, longer baselines increase uncertainty.

You won’t have any additional expenses, as there are no subscription costs — the Emlid Caster is free and works worldwide.

You can connect up to five base stations to Emlid Caster, to broadcast your own corrections. This comes in handy for small to medium organisations such as mining exploration sites, quarries and local government areas, where reliable, repeatable and accurate measurements are required on a regular basis with a minimum of budget impact.


Need more rovers and bases stations for larger projects? A pro version of Emlid Caster is available. For a monthly fee from US$199.00 you can operate up to 50 bases and 1000 rovers simultaneous on your own private NTRIP network. This should have you and enterprise prepared even for the largest project operations.

For more information and to access your free subscription, head to

Map Gear is the exclusive distributor of Emlid Reach RTK GNSS receivers in Australia.


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