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elbridge / yard_bot

GPS-RTK based autonomous lawn mower
GNU General Public License v3.0
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Discussion of GPS options #4

Open elbridge opened 5 years ago

elbridge commented 5 years ago

Let's just track conversation here. If we link your github account to this as a collaborator responsible for this topic, you'll get updates when I post something new. So I think we need a better understanding of the GPS landscape. It would be awesome if we could use the NOAA system. They've got enough stations to probably meet our needs, but I don't know enough to know if the data they provide is sufficient/compatible with the uBLOX module.
The other one looks like it would probably be more effort to implement. See http://mr337.com/blog/unmaned-robotic-mower-navigation-part-2/ for a quick pass at implementing that module.

elbridge commented 5 years ago

The existing stations might not be the best solution. There is a subscription required for accessing the Virginia stations for RTK data. The one out by me is operated by Smartnet North America. Just getting initial access runs more than the cost of a second RTK unit to use as a base station. And then there is monthly fee as well.

frivas12 commented 5 years ago

I agree, after more research we are going to need a base. Here is a link to live map of GPS satellites. We would need an exist strategy if we lose too much resolution because we have lost too many satellites while mowing out in the middle of the yard, maybe just stop and wait.

The link you have above was written in 20016. The current NS-HP-GL tracks all GPS and all GLONASS in view satellites but still requires 7 satellites, the NEO-M8P's needs 4 GNSS satellites after first fix. . I think we should go with the GPS-RTK2 Board. For $20 more we get more features, satellites and can also act as the base.

elbridge commented 5 years ago

Very good point. I'm on board with using a ZED-F9P based board.

elbridge commented 5 years ago

Also, antennas matter. https://www.u-blox.com/sites/default/files/products/documents/GPS-Antenna_AppNote_(GPS-X-08014).pdf https://www.use-snip.com/kb/knowledge-base/question-what-antenna-should-i-use/

elbridge commented 5 years ago

Maybe something like this https://www.alibaba.com/product-detail/Roadmarker-IP67-GPS-L1-L2-GLONASS_60790565221.html?spm=a2700.7724857.normalList.22.2463106dNjr8RB

elbridge commented 5 years ago

This from ublox might be a good compromise for cost vs quality: https://www.u-blox.com/en/product/ann-mb-series