We are looking for an RTK GNSS system (1 Base+ 1 Rover)

Other
1

We are looking for an RTK GNSS system (1 Base+ 1 Rover) with the following position accuracy and L-Band capability:

RTK Positioning Accuracy: H: ±8mm + 1 ppm RMS or better, V: ±15mm + 1 ppm

Please suggest the most suitable and low cost system from your side. For communication between the Base and Rover using telemetry, we are using SIYI HM30.

2

Hi @Jijinck ,

Please tell us more about your application. Are you looking for enclosed GNSS units with internal batteries, or are you looking for bare breakout boards?

The HM30 is capable of transmitting full HD video. Will your Rover be mounted on a UAV / drone?

Best wishes,
Paul

3

Rover will be Mounted on UAV. This is for bathymetry servey in lakes.

4

OK. Thank you.

The simplest solution is probably a pair of LG290P Breakout Boards with suitable antennas. But we still need more information.

For the Base:
Do you need an enclosed product with an internal battery?
Will you survey-in the Base location, or does the Base need its own RTK corrections to calculate its position?
Does the Base need built-in WiFi or Bluetooth so it can obtain corrections from a mobile phone?

For the Rover:
Can you provide 5V or 3.3V power for the GNSS from the UAV?
What is the consumer of the Rover position data? Is it the UAV Flight Controller? Or something else?

It would help a lot if you could upload a sketch diagram of the complete system. Think through: how power will be provided to each component; how the Base and Rover UARTs are to be connected. Is the HM30 only carrying RTCM corrections from the Base to the Rover. Or is it also carrying video and or flight controller data? Are you using a laptop computer to plan and control the flight plan?

Lots to think about…!

Best wishes,
Paul

5

For the Base:

  • Do you need an enclosed product with an internal battery?
    • If it is available so it would be a good fit, otherwise we need to add battery externally.
  • Will you survey-in the Base location, or does the Base need its own RTK corrections to calculate its position?
    • Base can provide the correction to Rover over HM30. The base also need a GPS, which not require L band. RTK will be sufficient.
  • Does the Base need built-in WiFi or Bluetooth so it can obtain corrections from a mobile phone?
    • Can be through UART input from PC and using wifi/Bluetooth

For the Rover:

  • Can you provide 5V or 3.3V power for the GNSS from the UAV?
    • Possible to take 5V from UAV but if battery is inbuilt that would be great
    • What is the consumer of the Rover position data?
      It will be transferred through HM30 to Base station. The data login will happen in the base station laptop with depth information from eccosounder fitted with UAV.
  • Is it the UAV Flight Controller?
    • yes, it has flight controller.
  • how the Base and Rover UARTs are to be connected?
    • The HM30 has telemetry port that we can use otherwise we can use Ethernet using serial to ETH converter.
  • Is the HM30 only carrying RTCM corrections from the Base to the Rover?.
    • Yes, please provide the wiring diagram how the correction can be provided rover GPS module.
    • The HM30 is also carrying video and or flight controller data
  • Are you using a laptop computer to plan and control the flight plan?
    • yes
6

Hi @Jijinck ,

OK. Thank you for the update.

For the Base, perhaps the Postcard plus Portability Shield would be a good solution? The ESP32 can connect to your phone or laptop using WiFi or Bluetooth. It would be possible to access NTRIP corrections that way if needed. You will also need a suitable battery and antenna.

For the Rover, perhaps the same Postcard+Shield+Battery+Antenna combination? Or perhaps just the LG290P Breakout on its own? Again, you need a suitable antenna.

On both boards, you can access one of the LG290P COM ports directly via a 4-way JST connector. The UART signals are 3.3V and should be compatible with the HM30.

I hope this helps,
Paul

7

Thank you for the information.

We noticed that the SparkFun Quadband GNSS RTK Breakout (LG290P) documentation mentions support for PPP correction services such as BDS PPP-B2b, QZSS CLAS/MADOCA, and Galileo HAS. However, the documentation also states that “the corrections for some of the PPP services may not be implemented yet” and that these features are still under development.

Our application is in India, and we specifically require a satellite-based correction service that can operate without an internet connection. We would therefore like to clarify whether the LG290P supports traditional commercial L-band correction services (for example, Trimble RTX, TerraStar, Fugro Marinestar, or similar services commonly delivered through Inmarsat L-band satellites).

If the LG290P does not support these traditional L-band correction services, could you please recommend a suitable receiver or module that does support commercial L-band corrections and is available for deployment in India?

Any guidance regarding supported correction services, firmware status, and recommended hardware for reliable high-accuracy positioning in India would be greatly appreciated.

8

Hi @Jijinck ,

Can you please clarify where you need the L-band corrections?

Do you need them to establish the Base position accurately?

Or are you thinking you also need them at the Rover?

It depends whether you need good relative or absolute accuracy in your application. Once the Base is generating RTCM corrections and these are being received and used by the Rover, the relative position of the Rover (relative to the Base) will be very good.

The question is whether you need good absolute accuracy for the position of the Base.

Perhaps Galileo HAS could be a good solution for you? The LG290P supports Galileo HAS (E6). It is designed as a European service, but users in North and South America are also reporting good results. I have not yet heard if Galileo HAS works well in India, but India is covered by the HAS Service. If it works, you may be able to achieve an absolute Base accuracy of perhaps 20cm.

If you decide you do need traditional L-band corrections, you will need a separate or different receiver for those. I am afraid SparkFun can not help you there.

I hope this helps,
Paul