Introduction
This article explains how to use Skylark, Swift Navigation's cloud-based GNSS corrections, with Quectel LG69T receivers, to improve computed position accuracy. This article applies to the AM (no-IMU) and AP (includes IMU) variants of LG69T.
The LG69T is compatible with the following Skylark variants:
Preparation and Tips
To use Skylark corrections with LG69T, the following are required:
- Quectel LG69T-AM with firmware version LG69TAMNR11A02_RTK_PO(Refer to Appendix A to check Firmware version and Appendix B to update Firmware version)
- L1/L5 or L1/L2/L5 GNSS antenna in open sky location (refer to GNSS Antenna Placement Guidelines)
- Windows, macOS, or Linux computer with Internet access connected to LG69T over USB
- QGNSS V2.1 software available for download on Quectel's Website
- Skylark account (if you do not have an account, go to Skylark Sign Up)
The procedure outlined below has been tested using LG69T-AM with firmware version LG69TAMNR11A02_RTK_PO and QGNSS V2.1
Receiver Connections
The Skylark corrections are distributed over the Internet using NTRIP protocol. Quectel's QGNSS tool features a built-in NTRIP client that operates over an Internet connection (preferably via Ethernet). A reliable Internet connection is required for good navigation performance.
The receiver must be connected to an L1/L5 or triple-band GNSS Antenna. A USB cable is used to connect the receiver to the Control Computer.
Connection Diagram
Connection Setup example
(1) L1/L5 Antenna on ground plane with Open Sky view
(2) LG69T-AM Evaluation Kit connected to Antenna and Computer
(3) Internet Access using Cell Modem
(4) Windows computer with QGNSS2 software
Setting up Quectel LG69T
- Connect the receiver to the computer and note the COM port. Ensure there is internet access.
- Start the QGNSS2 software. On the toolbar, click the gear icon, 'Set Device Information'.
- Select the correct COM port
- Select the receiver model as LG69T(AM) from the drop down
- Set the baud rate as 460800
- Click OK
- Click on the 'Connect or Disconnect' Icon.
- There should be at least 10 satellites in view, strong GNSS signals should reach a level of around 45 dB-Hz, and the receiver should have a valid GPS SPS Mode Quality Indicator.
- Check the if the firmware version is LG69TAMNR11A02_RTK_PO or newer (Appendix A) otherwise, perform firmware update (Appendix B)
Using Skylark Corrections
- On the toolbar, go to Tools -> NTRIP -> Client
- In the NTRIP Client window, under the Client tab, enter one of the following addresses based on your region
Region URL Europe eu.l1l5.skylark.swiftnav.com North America na.l1l5.skylark.swiftnav.com Asia / Pacific ap.l1l5.skylark.swiftnav.com - Enter the Port as 2101 and your NTRIP credentials
- Click 'Update NTRIP source table' button to get the mount points populated.
- From the NTRIP mount point drop-down menu, select NXRTK-MSM5 for RTK corrections
- Toggle the 'Connect To Host' button to receive corrections.
- Refer to NTRIP Client Configuration for Skylark Corrections for a full list of available mountpoints (corrections data streams), including regional reference frames (datums).
Verifying Corrections Usage
To verify that the receiver is using corrections, check the Data View window and look at the Quality Indicator field. You should see Fixed RTK if you are using NXRTK-MSM5 mount point.
Appendix A - Checking Firmware Version
To check the Firmware Version on the receiver,
- On the toolbar, go to Tools -> Console
- Enter the command $PQTMVERNO*58
- Click Send
- Check the Message Statistics Window for the response.
Appendix B - Firmware Update
To update the firmware to the latest version,
- On the Toolbar, go to Tools -> Firmware Update
- In the Firmware Update window, next to Firmware Path, click 'Open' icon and select the latest firmware.bin file.
- Click Start
- Press Reset Button on the receiver to complete the Download.
- Power cycle the receiver and Firmware download is complete.