Hi, has anyone tried Galileo HAS? I recently tested it on a GNSS board, and the accuracy appears promising. However, I’m uncertain about its applicability for use on a tractor. I would appreciate any insights or assistance on this matter. Btw, I was pleasantly surprised to discover that one notable advantage of this service is that it doesn’t require RTK correction data, and it also operates without the need for a radio or internet connection. Here is my testing result on RTKlib.
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For those of us who don’t know what HAS is, it’s basically a Precise Point Positioning system. This article is actually quite good at explaining how it works. Precise Point Positioning - Wikipedia
Given that time to resolve precise fixes with this method is on the order of 10 minutes or more, I’m not sure how useful that is for auto steer. How long does the system you played with take to get decent fixes?
PPP definitely requires more computing power but things are progressing pretty fast so that’s unlikely to be a problem.
Seems like for the near term it’s hard to beat RTK with a local base station.
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Thank you so much!!!
I’m totally on board with your point of view. Based on my testing, PPP doesn’t offer the same accuracy and stability as RTK. It also takes time to converge. However, the reason I’m interested in trying it is because this service doesn’t require any base station, making it completely free. If it can be successfully applied in practice, it would be incredibly convenient for farmers.
I previously used NovAtel’s AG Star, and that smart antenna provided a 20cm pass-to-pass accuracy without needing a base station. However, that level of accuracy only worked as a guidance system. Later, NovAtel introduced the TerraStar service (L-Band) with improved accuracy, even approaching RTK levels. While it didn’t require setting up a base station, the subscription cost was quite high.
Galileo HAS (PPP) gives me hope, but I haven’t integrated it into a complete system yet. I’ve conducted some tests based on a GNSS board. I’m trying to find if someone made such test before and can provide insights.
Thanks again! 
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To be honest, I have doubts about whether this accuracy can be used for a auto-steering system~ 
By the way, is this the result of static or dynamic testing? Do you have a trajectory?
Static. Until now, I haven’t made any test on tractor. I just received this board a few weeks ago.)))
Steering works okay with just WAAS or EGNOS DGPS, and that’s a pass-to-pass accuracy of about 25-30 cm. Repeatability is not so good obviously. WAAS and EGNOS accuracy is about 100-150 cm.
But if HAS can get continuous, real-time 20cm accuracy (after finally converging), that’s 5 times better than WAAS, and would be good enough for a lot of farmers’ needs, honestly. I haven’t looked closely at the claims of HAS accuracy, but if it can do 20cm, then pass-to-pass accuracy will be a lot better than that. Maybe down to 5-10cm under ideal conditions. Plus it’s available everywhere in the world.
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