GPS app ?

Discussion in 'Precision Farming & GPS' started by bobk, Sep 16, 2014.

  1. Rob Graham

    Rob Graham Member

    Location:
    Co.Armagh N.I
    I've tried it in 3 fields on 3 blocks of ground (specifically) and found where it indicates 200-300mm accuracy it's been 200mm...but when 50mm it's been 100mm, and that's measured using a fibreglass tape, so I alter the working width to overlap 100mm.
    This is in NI in an area where my Trimble R10 RTK has quite poor signal, so I'm very surprised. Also used effectively in West Sussex to map tramlines @24m for carting grain/compost and no issues. Does my job, and for the money I'd hope it does many Others. I could package it.and send to you for a demo?
     
  2. jg123

    jg123 Member

    So you just bought a Garmin glo for £80ish and it was that accurate with the free software from field navigator? On the Garmin website it says accuracy 2-3m o have a teejet GPS but would be handy to have a second occasioally to mark out a field headland for drilling while someone is also spreading fert
     
  3. I kind of doubt that you could achieve 0.1m accuracy with Garmin GLO. Our best results was like 0.5 meter horizontal dilution.
    It's not the same as overall accuracy because it excludes vertical dilution, which almost doesn't matter for ground operations.
     
    Northern farmer likes this.
  4. jg123

    jg123 Member

    @MindaugasFieldNavigator I'm guessing your something to do with the app, is there any way of putting in a non-straight A-B line ie following a slightly curved hedge for the first run when spreading fert or does it have to be dead straight between the 2 points A and B?
     
  5. Currently we support only dead straight lines. We didn't decided how A-B curve should work with all edge cases and course correction, so it is on hold.
     
  6. jg123

    jg123 Member

    Seems to be a good app, with ab curve and ability to mark out headlands in the future it could do most things on a small/mixed farm. If you discover which antenna works best for mobile phones let us know
     
  7. nuffield1060

    nuffield1060 Member

    Location:
    Edinburgh
    Given that phone gps accuracy is about the same as the apparent accuracy of the Garmin reciever and light bars are a good guide but pretty difficult to follow without wiggling all over the field, is there any point buying a Garmin? Apart from colouring in where you've been with the fert spreader and marking out the odd line for example to start the drill off in a field, phone gps apps aren't much use so i can't see the point in buying the Garmin?
     
  8. Northern farmer

    Location:
    North
    Garmin GLO specs seem confusing. Some websites say it supports WAAS/EGNOS but the manufacturer site did not say anything.

    In any case, any receiver with an antenna mounted properly outside the tractor cabin performs much better than a smartphone internal GNSS receiver. Still I would ignore all receivers without EGNOS or higher correction signal support.
     
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  9. jg123

    jg123 Member

    I
    If the Garmin was accurate enough for marking out drilling and spreading fert nothing else on the market comes close to only costing £80, a lower budget agri GPS system is about £800. I find our teejet lightbar good, once used to it can follow it within 20cm ish all day long as long as your doing straight runs and never have a problem with misses when burning off fields etc. Wouldnt use it for drilling.
     
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  10. Charles Quick

    Charles Quick Member

    Location:
    Somerset
    Surprised nobody has mentioned AgOpenGPS yet..
    Free open source software capable of section control, autosteer, and rate control. Of course you can use it as a simple lightbar too!
    A cheap GPS receiver such as this one from eBay would do the trick for Egnos accuracy. I personally use the uBlox C94-M8P receiver boards which are capable of RTK and cost £300 for a pair (Base station and rover)
     
  11. nuffield1060

    nuffield1060 Member

    Location:
    Edinburgh
    So do you have to be really smart to make it talk to a tractor for autosteer or is it something your average ag student could do?
     
    jg123 likes this.
  12. Stevethemeat

    Stevethemeat Member

    I have been trying to get the ublox to send correction data to the rover but there seamed to be no messages received curently blowing my mind as I know it could just be a tiny setting I have missed be great if you could share your u blox rtk settings
     
  13. Charles Quick

    Charles Quick Member

    Location:
    Somerset
    @Stevethemeat Not to hand as I'm up at uni, but in U-center, I think you need to go to UBX-CFG-MSG and enable the messages to be sent to the correct output, e.g. 1004 should be sent to UART1. Are you using the radios or NTRIP? If radio, the messages should go to the UART; if NTRIP, you'll most likely want them sent over USB to the host PC. On the rover, in UBX-CFG-PRT, select the data type (rtcm3) and the input port (usb or UART). Ublox have a comprehensive quick start guide on their website for the c94-m8p which I found very useful.


    @nuffield1060 I would say anyone with a basic working knowledge of computers, electronics and hydraulics could get this system set up in a week. We don't actually need to get it talking to the tractor's steering system at all; instead, we tee in our own hydraulic valve. Much simpler.
     
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  14. Stevethemeat

    Stevethemeat Member

    Charles quick many thanks for that explanation it sounded far simpler than what I could find after 4 weeks reading and trying
    I am trying to send data via ntrip from base station to rover which is 3G 4g data and been using lefrenbru ntrip on the rover
    Think I might have just ran out of wet days to discover more but will try your suggestions and see what we get many thanks
     
  15. Northern farmer

    Location:
    North
    You have Lefebure NTRIP client on the rover or Lefebure NTRIP caster at the base (sorry, not familiar with uBlox)? Does your caster receive the NTRIP stream? How does the base get internet access? Can you reach the caster from a laptop on a different network (done port forwarding)? Explain more details and you don't need to read these stupid questions.
     
  16. Stevethemeat

    Stevethemeat Member

    The lefrenbru is on the rover the ublox is on the server/caster conected to WiFi as a home base
    I can connect to the server and find mount point on the list but once conected it times out eventually as no data is received I tried with another mount point in Oxford and the USA and that received data but no use as too far away for accuracy I don’t mind the stupid questions as each one teaches me a little extra and I’m not a computer boffin so unable to point the right questions in a sensible order apologies For that
     
  17. Charles Quick

    Charles Quick Member

    Location:
    Somerset
    Ok so it sounds like the caster is not receiving data.
    In U-center, can you go to the serial monitor and check that the RTCM messages are being sent? And also that the fix mode is 'TIME'. Did you set it to survey in or provide a location?

    I have attached the document I followed to make it all work over radios. For ntrip, In steps 2 and 3, where it says UART1 change it to USB.
     

    Attached Files:

  18. Soil67

    Soil67 New Member

    I have the Field Navigator app on my Samsung available in The Play Store
     
  19. Well comparing apples to apples, your smartphone isn't going to control the tractor either. So if you are just using it for a lightbar and want to make AB Lines like the other programs, just attach a GPS source that outputs a GGA VTG or an RMC sentence - like the GLO garmin and you're good to go. Best part is, its free, and extremely powerful.

    You can also do Contour, Curved AB, AB, full auto headland, boundaries, headlands, machine control, Google earth geofencing, full autosteer...... But yes, then you have to be a bit smarter, but all the info is there.
     
    Northern farmer and nuffield1060 like this.
  20. Rob Graham

    Rob Graham Member

    Location:
    Co.Armagh N.I
    I have to say that any form of relatively accurate guidance really showed it's benefit this week. As the decent weather kicked in last week the contractor dribble barred the remainder of the silage ground, which left me to sow the fert and spray the docks on it. Now I'm not the worst at driving parallel but it's very difficult when the dribble bar tracks throw your eyes. Screenshot_20180423-105805.jpg
     

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