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RTK GPS is such a cool technology. Maybe it’s because my undergrad was filled with inaccurate data but turning on a unit and having 1cm accuracy still feels lik

RTK GPS is such a cool technology. Maybe it’s because my undergrad was filled with inaccurate data but turning on a unit and having 1cm accuracy still feels like magic.

the__alchemist 2y ago
Yes it's nuts! You need a more expensive GPS chip (eg Ublox 9 series), and a base station, but is great for certain applications.
- Waterluvian 2y ago
  Years ago I experimented with this really cheap GPS. Pixi or something like that. It had poor ergonomics and as difficult to establish a connection. But once it worked it was accurate. Was like 1/10th the cost. Also there’s VRS RTK without a base station (but you need internet and a subscription) for some reasons. Works just as well. It’s basically turn key.
  - foobarbecue 2y ago
    Yeah, I remember the Pixi (sp?) kickstarter, back in the heyday of ArduCopter. There was a brief period there where open-source, open-hardware, DIY got you the best results for multicopters.
  - twobitshifter 2y ago
    You can also use RTK2Go for free or contribute to it with your own base station. http://rtk2go.com/ http://rtk2go.com/
thelastparadise 2y ago
Just deployed a Segway Navimow which uses RTK + vision for navigation. Going from Landroid (wired, fails frequently) to Husqvarna Automower (wired, fairly reliable) to now a GPS RTK solution is quite the leap in technology. Husqvarna does have an RTK unit but it is quite pricey ($6K). The Navimow is surprisingly inexpensive ($999 for entry level unit). The Mammotion Luba 2 is sort of in-between. The RTK units are only becoming widely available in the last year or so. I just so happened to set it up on solar flare day so it's hard for me to say how much that impacted it. It does seem to have a much more consistent signal today, though. It's quite something to see it precisely drive from one end of the garden to the other, especially after years of managing wires. I would say the RTK is quite good and accessible at this point. It does require placing the base unit in a place with both a good view of as much sky as possible, as well as being able to communicate on 900mhz to the bot. The bot itself receives GPS signals as well as the 900mhz. The tower and the bot have to see ~5+ of the same satellites at the same time. This is why it's key for the base station to have a good sky view --the bot will constantly be seeing a different subset of satellites, so you want the base station to see "all of them" if possible. My dream outdoor bot would use a combo of RTK, lidar, vision, as well as WiFi positioning techniques. I wonder how accurate that could get? Maybe overkill (RTK alone seems "good enough," but there's still a gap between precision of these outdoor bots and, say, lidar-based indoor vacuum robots. Oh yeah, the dream bot would also use photogrammetry plus all the other data to reconstruct a full detailed mesh of the outside.
- hagbard_c 2y ago
  I deployed a fully autonomous automower a few years ago which navigates by sight, sound and terrain-following sensors. It is guided by visual cues which tell it within which area it is supposed to keep the vegetation short. It does not need to be guided any further since it senses where the vegetation is in need of clipping. One of the best things about this system is that it does not require charging since it actually runs on the clippings it harvests. The remarkable thing about this solution is that it is not new, the current incarnation is 33 years old. It has self-reproduced twice. It is a small to medium sized Welsh mountain pony, keeper of grounds here at our farm.
  - 20after4 2y ago
    Pro: also fertilizes the lawn. Con: you have to avoid stepping in the fertilizer.
    - hagbard_c 2y ago
      This model has the design quirk that it concentrates its waste in a specific spot which negates the problem of stepping in fertiliser but which does mean it is up to us to spread it. We tried other models which did not show this behaviour but which ended up being too heavy for our type of landscape - a hilly, silt/clay mixture which does not provide enough support for heavier models when wet - so we'll use this one until it expires.
- Mtinie 2y ago
  Simply out of curiosity, how large of a space are you maintaining?
  - thelastparadise 2y ago
    About 2 acres. Right now there is a Husqvarna 315 and 415x doing the big open spaces. I have the i110n doing all the small/random/scattered areas that are hard or impossible to do with a wire. That said I think the whole job could be done with one single RTK mower that is rated for a bigger space, but that wasn't availa available at the time and I've been evolving the setup over the years.

RTK GPS is such a cool technology. Maybe it’s because my undergrad was filled with inaccurate data but turning on a unit and having 1cm accuracy still feels like magic.

the__alchemist 2y ago

Yes it's nuts! You need a more expensive GPS chip (eg Ublox 9 series), and a base station, but is great for certain applications.

Waterluvian 2y ago
Years ago I experimented with this really cheap GPS. Pixi or something like that. It had poor ergonomics and as difficult to establish a connection. But once it worked it was accurate. Was like 1/10th the cost. Also there’s VRS RTK without a base station (but you need internet and a subscription) for some reasons. Works just as well. It’s basically turn key.
- foobarbecue 2y ago
  Yeah, I remember the Pixi (sp?) kickstarter, back in the heyday of ArduCopter. There was a brief period there where open-source, open-hardware, DIY got you the best results for multicopters.
- twobitshifter 2y ago
  You can also use RTK2Go for free or contribute to it with your own base station. http://rtk2go.com/ http://rtk2go.com/

thelastparadise 2y ago

Just deployed a Segway Navimow which uses RTK + vision for navigation. Going from Landroid (wired, fails frequently) to Husqvarna Automower (wired, fairly reliable) to now a GPS RTK solution is quite the leap in technology. Husqvarna does have an RTK unit but it is quite pricey ($6K). The Navimow is surprisingly inexpensive ($999 for entry level unit). The Mammotion Luba 2 is sort of in-between. The RTK units are only becoming widely available in the last year or so. I just so happened to set it up on solar flare day so it's hard for me to say how much that impacted it. It does seem to have a much more consistent signal today, though. It's quite something to see it precisely drive from one end of the garden to the other, especially after years of managing wires. I would say the RTK is quite good and accessible at this point. It does require placing the base unit in a place with both a good view of as much sky as possible, as well as being able to communicate on 900mhz to the bot. The bot itself receives GPS signals as well as the 900mhz. The tower and the bot have to see ~5+ of the same satellites at the same time. This is why it's key for the base station to have a good sky view --the bot will constantly be seeing a different subset of satellites, so you want the base station to see "all of them" if possible. My dream outdoor bot would use a combo of RTK, lidar, vision, as well as WiFi positioning techniques. I wonder how accurate that could get? Maybe overkill (RTK alone seems "good enough," but there's still a gap between precision of these outdoor bots and, say, lidar-based indoor vacuum robots. Oh yeah, the dream bot would also use photogrammetry plus all the other data to reconstruct a full detailed mesh of the outside.

hagbard_c 2y ago
I deployed a fully autonomous automower a few years ago which navigates by sight, sound and terrain-following sensors. It is guided by visual cues which tell it within which area it is supposed to keep the vegetation short. It does not need to be guided any further since it senses where the vegetation is in need of clipping. One of the best things about this system is that it does not require charging since it actually runs on the clippings it harvests. The remarkable thing about this solution is that it is not new, the current incarnation is 33 years old. It has self-reproduced twice. It is a small to medium sized Welsh mountain pony, keeper of grounds here at our farm.
- 20after4 2y ago
  Pro: also fertilizes the lawn. Con: you have to avoid stepping in the fertilizer.
  - hagbard_c 2y ago
    This model has the design quirk that it concentrates its waste in a specific spot which negates the problem of stepping in fertiliser but which does mean it is up to us to spread it. We tried other models which did not show this behaviour but which ended up being too heavy for our type of landscape - a hilly, silt/clay mixture which does not provide enough support for heavier models when wet - so we'll use this one until it expires.
Mtinie 2y ago
Simply out of curiosity, how large of a space are you maintaining?
- thelastparadise 2y ago
  About 2 acres. Right now there is a Husqvarna 315 and 415x doing the big open spaces. I have the i110n doing all the small/random/scattered areas that are hard or impossible to do with a wire. That said I think the whole job could be done with one single RTK mower that is rated for a bigger space, but that wasn't availa available at the time and I've been evolving the setup over the years.