Rtk base station range question

Hi complete newbie to gps here
Base stations are quoted for a range say 20 kilometers
For arguments sake i set up a base and rover on my place,ok everything works fine as all my ground is within a mile
If I travel off out contracting under 20 kilometers
In theory a internet based corrections should be fine
What happens to the corrections if I’m 30k from base? Or 40k?
Is it because of the distance that the corrections will still correct but losing accuracy the further i go from base due to angles of satellites, curve of earth etc?
Obviously an internet based correction signal can be obtained anywhere theres 4g etc

Thanks

Dave

I think the consensus is you loose 1mm accuracy per Km. I have seen a Topcon system hold an RTK fix with a baseline distance of 167Km!! Reduced accuracy yes, but still a hell of a lot better than SBAS. I’ve used 30 to 40Km baseline distances for maize drilling with no real noticeable degradation.

1 Like

And the main reason is that the correction stops being valid further your are from the base as it’s correcting for athmospheric deviations in the signal, so it’s also dependent on conditions afaik

1 Like

This explains things quite well.

https://www.trimble.com/OEM_ReceiverHelp/V4.44/en/PositionModes_CriticalFactorsRTK.html

Base location accuracy is not a problem as zeroing in over a good length of time gets it very close indeed. Mine is within about 40mm with 31 hours of zeroing in I think. Sending recorded data away to be processed can get it a chunk more accurate too.

2 Likes

Thanks guys, that’s kind if what I thought re the distance

Thanks

Dave

1 Like

There may be bases already near your work areas on rtk2go ? Roughly where are you? I’ve a feeling I’ve seen your name on BFF or somewhere?

Yes on tff
I looked on rtk2go but couldn’t find a covering map
I’m in west wales

http://monitor.use-snip.com/?hostUrl=rtk2go.com&port=2101

Click “View All” at the top right then zoom in to your location.

There isn’t any in Wales.

Is that the only list of providers?
I think I looked at rtk4u and there was 1 in west wales

Ah, that’s the service set up by @Aortner . Not sure if he has a coverage map. Maybe he will advise?

For about £230 and a bit of fabrication you can have your own anyway.

1 Like

That was to be future questions as to how/where to get components and fit together

Many options, a very simple example approach is simpleRTK2B starter kit plus the WiFi NTRIP Master like this:

2 Likes

There are some very good topics here on this subject. If you’ve got half decent wifi near your proposed location and you dont need loads of fancy logging or access features on your base I would go with what @NorthernFarmer is suggesting or the only slightly more complex and even cheaper ardusimple board with ESP32 connected to it as I have.

I also have a laptop running snip caster but that is definitely more troublesome as it involves an operating system and all the associated potential restart pitfalls.

1 Like

When you say wifi for the rtk base does that assume I have wifi over my whole farm?
I only have wifi in my house
There is very good 4g coverage over mine tho

No, just where the base is going to be. So it can send correction messages over the internet.

1 Like

Doh yes ok🤦‍♂️how would you have wifi over a few thousand acres🤦‍♂️
Basically my house is on the edge of the farm

House…yard…all the land in 1 block

Where I thought to mount a base station on 1 of the higher sheds with electric in theres no line of sight without cutting down 3 trees and its approximately 80meters away from my house

I could move to closer shed but then theres more trees nearer

Option to put it on the side of my house?
There are trees about 30meters away🤷‍♂️

Basically I’m starting from scratch
Ive looked into this a few times over the years and every time I’ve been swamped with information, my head starts hurting then I forget about it for a while🤦‍♂️
I’m not the most computer minded person by a long way so some of my questions will sound like they come from a 10 year old (be honest perhaps I should ask my 13yo son to help🤦‍♂️)

I do have a mate who’s a computer programmer of sorts and is willing to help me out👍

My ultimate goal is to start off with agopen rtk and a base. Using a motor on the wheel to control the tractor.
I’m leaning to the motor so as I could move the system on different tractors for different jobs if I make a common motor mount
Personally I dont like messing with the tractors steering hydraulics for a safety point of view

Sorry if this long winded post is in the wrong section.

Dave

1 Like

That would be very good. We only want satellites above 10 degrees, some would say 20 degrees above horizon. My first base (still temporary) is on a 3m post 4 m east of my 6 m high house, which means most of the satellites to the west are shadowed away. And still I get rtk fix in tractor (via mobile phone hot spot)

2 Likes

Definitely your safest option. Especially if you’re not overly confident messing about with safety critical stuff. My first system in my 716 is exactly as you are proposing.

This topic shows how I did my base. Using the ardusimple xbee adapter is even easier. Just costs a bit more.

and this is how I did my motor. Has just one 17mm bolt to hold it on.

2 Likes

Base station range with GNSS is cut off basically when you cannot see three of the same satellites at the same time reliably at base and rover. But when you are that extremely far out it is like WAAS anyway

You can also get an Emlid RS2, or build a portable ant take the base with you and set up on the side of the field.

If you want to do year to year tramlines use a permanent base, or permanent monuments, for an extra challenge Precise Point Position the base location to get the minimum stated accuracy dilution.

1 Like