In the realm of RTK architecture, the precision positioning calculations depend on RTCM correction data stream. Within this framework, transmitting correction data to the RTK rover is an indispensable aspect. Presently, there are two predominant methods for correction data transmission. They are: radio-based and internet-based (NTRIP) solutions.
Establishing a radio connection requires radio module hardware for both the base and rover. However, radio connections can be complex to configure. Moreover, regulatory restrict on radio frequencies in most countries, often mandating permits. Some frequencies might even be banned in certain regions. Additionally, radio transmission distances are constrained.
In contrast, transmitting correction data over the internet(NTRIP) has gained widespread popularity. Internet-connected devices exist everywhere, such as smartphones, tablets, computers, Raspberry Pi, Arduino, and various internet-enabled modules. The internet connectivity, via cable, fiber, cellular, and satellite are widely accessible. Internet transmission holds a distinct advantage over radio-based methods. It transcends distance limitations, proving more dependable and user-friendly.
This article delves into the NTRIP caster services available at the moment in 2023:
Free NTRIP Caster Services
GPSWebShop, Emlid and rtk2go are 3 famous free NTRIP caster services. If you possess an RTK base and require an NTRIP caster mount point for streaming correction data over the internet, these platforms offer a convenient solution. You can utilize them effortlessly, foregoing the need to establish your own NTRIP caster. Below are step-by-step instructions for your reference:
The Free NTRIP Caster from GPSWebShop
The Free NTRIP Caster from Emlid
The Free NTRIP Caster from rtk2go.com
Setting Up and Operating Your Own NTRIP Caster
SNIP Software:
I would like to mention SNIP software.
SNIP is Windows-based NTRIP caster software available in Lite, Basic, and Pro editions. While Lite is free, it lacks NTRIP caster functionality. Should you opt to run your NTRIP caster, acquiring a Basic or Pro edition license is necessary. Further details can be found on their website.
Personally, I do not particularly like the concept of utilizing a Windows console application to operate the NTRIP service. If SNIP could function as a Windows or Linux service, it could potentially enhance the reliability. However, the options for NTRIP caster software are somewhat limited in the current market landscape of 2023. Consequently, choices are relatively constrained for those seeking to operate their NTRIP service.
Other options:
An official NTRIP Caster by BKG is available at https://igs.bkg.bund.de/ntrip/bkgcaster. This software is priced at 1000€, inclusive of the source code. It serves as a valuable resource for reference if you contemplate developing or running your NTRIP Caster service. While I haven’t personally tested it, your experiences and insights with this tool are welcome.
Additionally, I found several NTRIP caster projects on GitHub that had shared source code. I conducted tests on them, but unfortunately, none of them have demonstrated functionality at this point. Should any of you come across a functional NTRIP solution with source code, please don’t hesitate to share your findings below. This collaborative approach ensures that a wider audience can reap the benefits of your knowledge and information.
I will try to keep the NTRIP caster information on this article current. Stay tuned for updates.
Thank you and best regards,
Jack Wu
Director,
GPSWebShop