Ardusimple simpleRTK2B board with RFD-900x Radios for a RTK GPS setup?

GPS / RTK / GNSS
1

Let me start by saying this is my first post as I am at the very early stages of learning about setting up AgOpenGPS and RTK GPS so if my questions don’t make sense please let me know as this is the only way I will learn…

My Goal
I am looking to get sub 10cm accuracy GPS in my tractor to allow me to more accurately with a drill seeder, boom spray and spread fertilizer with a spreader.

Terrain Details for Context:

The Farm is located in NSW, Australia not big (only 100 Acres) so the furthest distance between the Base Station and Tractor/Rover would be ~700m but hilly with trees.

I have used the line of site elevation tool (Solwise - Surface Elevation Tool) below to give you an idea of the terrain to get an opinion if you think it would work using static base station located at the Shed located at the Blue Pin on the screenshot vs the rover located at the two locations shown below by the 2 Red Pins and their respective Line of Site Elevation Profiles. (see below)

Below are 2 furthest points the Rover/Tractor (Red Pin) could be from Base Station (Blue Pin)

Option 1: simpleRTK2B board and NTRIP via mobile internet

I bought a Ardusimple simpleRTK2B Starter Kit and started testing it using NTRIP GPS correction data from a public Geoscience Australia AUSCORS NTRIP Broadcaster which provides free and open access to real-time GNSS data stream from a base station located ~20km away from me. I used my 5G Mobile internet to connect to the broadcaster and worked well but when I tested it around the farm I found, as I suspected that my mobile network is unreliable in my area so only worked for about 70% of my property so was too unreliable.

Option 2: Setup Static Base Station to generate RTK corrections with LoRa Radio Connection

I bought a second Ardusimple simpleRTK2B board and GPS antenna as given my unreliable mobile internet I have realised I need my own Base Station with a radio to transmit the RTK corrections.

My research lead me to look at the SparkFun LoRaSerial Kit - 915MHz (Enclosed) and the Ardusimple Radio module Long Range (LR) to transmit RTK Correction Data between a static Base Station and a Rover in my Tractor… but from what I have read given my terrain it was suggested that LoRa radios would also be unreliable.

Option 3: Setup Static Base Station to generate RTK corrections with RFD-900x Radios

RFD-900x radios seem to be used widely for transmitting telemetry data and commands between drones and controller base stations and was suggested I use them.

Details of the RFD-900x I was looking at but there is tons of video’s setup guides for their use in drones but am struggling to find any online guides or examples of people using them with base stations and rovers for basic GPS and wondering if there is a reason for this…

Questions :

  • Basically does any have experience using the Ardusimple simpleRTK2B board with RFD-900x Radios for a RTK GPS setup??

  • Given the distance is quite short (less than 1km) does anyone have a view on if the RFD-900x Radios would work for my terrain given it is not perfect line of sight?

Thanks in advance… I am documenting my journey in the hope once I can get the my GPS accurate that my mistakes / stumbles can help others as I move onto working on using AgOpenGPS.

FarmingEvangelist

1 Like
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Option 1: Have you tried a Cel-Fi signal booster ?

Option 2: LoRa is very low power. A few sheets of tin will completey ruin any sort of range, trees also. If you can get line of sight then it may be acceptabe with decent antenas. The hardware is pretty cheap to test.

It’s been a while since I had my RFD900’s out; I used them for ArduPilot telemetry and they were excellent for line of sight links even with pretty average surface mount antennas on the airframe.

I’ve not done it personally but I’m pretty sure you can set them up to act as a radio bridge for serial data. Maybe reach out to RFDesign and ask directly, they probably have a FAQ document that details the process; I’ve always found them helpful when I’ve had questions.

If LoRa doen’t work out for you I can probably dig up a couple of RFD900 modules you could test with.

Jump onto the AgOpenGPS Australia Facebook group for local users.

3

Have you looked into ardusimple XLR radios as an option? Commonly referred to in this community as Xbee radios.

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gday we are using the rfdesign radios 900x with MP 3 firmware installed covers a 5000 acre farm with not perfect line of sight… have radios mounted on roof with rs232 adaptors tl save cable losses.the guys at rfdesign in QLD are very helpfull

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Nope, I have not and possibly should have but they look quite pricey (A$600-A$1200). I purchased the second Ardusimple simpleRTK2B board so going to give setting up my own base station, but thanks for the suggestion.

Thanks I will send them an email this evening.

I have joined the Facebook group and will bear your kind offer in mind if I get stuck but from what I have heard LoRa is not going to work given my terrain.

I looked at the ardusimple LR & XLR radios but was worried about 2 things :slight_smile:

  1. Range with my terrain… my distances are low max 1km but not great line of sight…
  2. Price, they are US185 (A$280) each without antenna and I need 2 so A$560++ vs A$378.50 for RFD900x-AU Modem Bundle which comes with 2 X RFD900xAU Radios and antenna + leads…

My little 100 acre farm should be a breeze and going to reach out to RFDesign to make sure the RFD900x can be used to transmit the RTK correction data between Ardusimple simpleRTK2B boards at Base & Tractor/Rover.

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I have reached out to Ardusimple about the RFD900x and this is what they replied… I will revert with the info I get from RFDesign.

We don’t know RFD radios, but if they are a transparent serial port over the air it should work. Check that they are TTL UART, as our boards are TTL UART. Our boards need an adapter to connect to RS232 radios. Lastly don’t forget to connect GND, you will also need GND.

Thanks again for the community support here… making me more confident I will get this sorted and move onto the fun stuff like actually setting up and using AgOPenGPS.

FarmingEvangelist

6

  1. Both the RFD900 and the Ardusimple XLR are 900 Mhz radios with a max of 1 watt of output power. The RFD900 supports two antenna connections. I’m not sure that there is going to be a drastic performance difference between the two?

  2. Good point, I didn’t realize the price difference was so great.

7

My understanding from Ardusimple - simpleRTK2B - already has radio communication circuit as part of the board, to send correction data from base to rover. This is what I see from their website. They also mention that it covers upto 2 km distance between base and rover. Is my assumption wrong?

8

Do you have a link to the specific product?

2B Basic has headers for xbee form factor addon boards but doesnt include an rf link on the base board.

9

Hi,
Just wondering how you went with everything, what setup have you found best ?

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I did not use with AGOPENGPS, but in a different module. I use one as BASE and one as ROVER. I get 1 cm accuracy with this kit. For configuration of BASE and ROVER I used U-Center application