GPS Repeater

I’m wondering if anyone is using GPS repeaters to achieve reception inside sheds etc?
I would like to be able to use recorded paths to send my (small) tractor through the storm water culverts in between my orchard blocks that have public roads between them. It would also be handy to have it park itself in the shed when done. :smiley:

Gps repeaters are usually used to test avionics to see if the electronics pick up anything at all, they do not allow positioning inside the building.

Some survey equipment like from JAVAD, uses other means of telemetry inside the structure. All referenced to an emitter outside, synced by the gps outside.

Gps needs to determine the position of the satellite overhead. With a repeater you will only see the position of the exterior repeater antenna regardless of your position in the building.

Yes I see, :man_facepalming:, is there a solution?

From my understanding you want tractor going alone cuting public road? That is dangerous.

There are many Indoor positioning system (IPS) non that work with AOG they have limited precision. As discussed in other posts if you know how to handle a tractor you will do better job then autosteer on complex operations like implements attachment, driving in roofed areas, parking etc.

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Yes, we’ve already discussed that.

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Sorry, I didn’t make myself clear. I want the (simulated) unattended tractor to go UNDER the public road in the concrete culvert. It is approx 1.8m height x 3m wide x 10m long. The tractor I want to use is Antonio Carraro 4400 HST with ROPS frame folded down which is only small thing. If something went wrong on approach the tractor would be unable to get onto the public road because the wing walls on the culverts are 2m high and vertical. I wonder if the easiest method is to use one unused machine control relay, use that relay to switch off the “Kill Autosteer” for a predetermined time, say 8-10 seconds so the tractor will continue driving straight under the road and hopefully re-acquires signal before “kill autosteer” stops the whole show? :thinking:

It depends so its not manual tractor and AOG can stop it if it doesn’t re-acquire signal, if you are close to it you can lock wheels strait by remote and when it comes out at other side release them or AOG will stop tractor if you dont.

You can do a test do AB line strait thru tunnel slow down before entering to be on line and dont need to steer, lock wheels at 0 (I think that it will provide better results then just turning off motor) and see where that takes you if you need to take control of wheels then this is not good method. Risks are that it will bump into walls and damage it self or implement and general unattended equipment risks, be safe.

You also could just sit on the tractor and drive it by yourself, without the risk of damaging equipment, animals, humans…

You would need to modify AOG to look for another source if no gps. AOG is designed to disable autosteer when it does not get signal. If running a straight line, you could default to zero steer angle if no signal. If not then you could perhaps use a lydar system to sense the walls and drive center.

I’ve seen some Bluetooth indoor guidance that measures between the four corners to triangulate a location.

Either way, you will have to tell AOG, “I have it right now, please wait and you can drive in a minute.” If not, the GPS will be wrong while under the bridge and AOG will fight you to try to correct the GPS errors.

Perhaps we’re all getting too hung up on the terminology here. Seems to me @Fruitfarmer is really just needing a way of steering over a short distance when GPS is unavailable. In other words, dead reckoning for short periods of time using other sources of information, including wheel speed, steering angle, and IMU acceleration. This is something that is very common in automobile navigation and of course autonomous driving. For example, if you’re using Google Maps and your car goes in a tunnel, it does quite well at predicting where you are.

AOG has no dead-reckoning abilities. But this is one of the primary reasons for the features of the ZED-F9R receiver with its built-in IMU. Unfortunately the F9R when doing full sensor fusion cannot get more accurate than RTK Float. It’s too bad, really, because it sounds like the F9R would about give @Fruitfarmer what he needs.

Some form of IMU only guidence or just basic keeping wheels strait should be enough to go 10m (this can be done as is or minimal code modification) with out gps but you need to set wheels 0 before lose of RTK because AOG can jump bad between FIX and Float or DGPS GPS and that is critical moment when you enter tunel and start to lose signal AOG will aggressively steer to get back to line and result in hitting wall.

Autonomous vehicle needs more hack, go wrong safety measures then human operated vehicle where if autosteer misbehaves human will hit breaks.

I dislike videos or IRL operators that will go outside of tractor to film/watch autosteering and then run back to tractor if you slip and fall strain ankle or something how long will your manual tractor keep on going until it hit someting. AOG is not made for “physical equipment” and it certainly isn’t for autonomous be really careful when implementing systems and I can’t recommend leaving tractor without operator which is probably illegal as well.

Thanks, I hadn’t thought of locking at 0 deg. Don’t worry about bumping into walls, will have ultrasonic sensors up front (cheap as chips) and a bump strip, which is like a rubber hose with contactors in it, around the forward half. The bump strip from a friend of mine who does factory automation, he uses it around machines in abattoirs, ip66 rated. :+1:

Sorry again, didn’t explain that this project is for autonomous tractor for slashing and undertree weed spraying. I have no need for AgOpenGPS for auto steer, I’m driving in orchards only. Staying between the tree rows is not that hard. :smiley:

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I totally agree about the safety measures, must have multiple redundant systems.
I don’t intend to jump on and off the tractor, I hope to be driving another tractor entirely, or possibly home in bed. The idea of using multiple small autonomous vehicles to replace larger tractors has interested me since seeing a video on Swarm Robotics. There are also a few companies in the retro-fitting of standard tractor game. GoTrack and Blue and White are a couple that will sell you a fully autonomous kit for your orchard/vineyard tractor right now. GoTrack in particular have a couple of great Youtube videos if your interested. :+1:


Thanks for the reply, I think that you have what will eventually be the solution, but I think I will have to wait for u-blox to release a more ruggedised version. When (if) that happens I expect there is a good chance it might be adopted by AgOpenGPS generally.

Thanks for the reply, I think adapting those bluetooth units is a big job to solve a small problem, same for lidar which I want to stay away from because I hear it gets a bit unreliable in fog or light rain. Granted, not a lot of rain falling under the bridge! I think locking at 0 deg steer angle for a few secs whilst driving through as suggested by Radmuffins may be an easy way. I should mention I will physically speed limit this thing to <5km/hr. :+1: