TABLE OF CONTENTS


Introduction

This document explains how to use corrections from Skylark CRS with a u-blox receiver.

The procedure outlined in this document has been tested using a u-blox C099-F9P application board.


For more information about Skylark, please visit the Skylark FAQ.

For more information about the u-blox ZED-F9P and the C099-F9P, please visit the related product pages:


The procedure outlined in this document is also compatible with:


Requirements

  • u-blox receiver
  • Skylark account
  • Windows PC with u-blox u-center installed
  • NTRIP client


Preliminary Setup

Check the firmware version installed on u-blox receiver

  1. Start u-center
  2. Connect to the appropriate COM port
  3. Navigate to View → Messages View → UBX → MON → VER
  4. Confirm that FWVER HPG 1.13

Disable CFG-NAVHPG-DGNSSMODE

Skylark CRS does not support Integer Ambiguity Fixing (RTK Fixed). However, the default DGNSS mode setting (CFG-NAVHPG-DGNSSMODE = 3) will allow the u-blox receiver to compute RTK Fixed solutions which can occasionally result in false fixes. In order to prevent this, the u-blox receiver should be configured to compute RTK Float solutions only.


  1. Start u-center
  2. Connect to the appropriate COM port
  3. Navigate to View → Configuration View → DGNSS
  4. Change Differential Mode to 2 = RTK float (No attempts are made to fix ambiguities)
  5. Press Send
  6. Receiver → Action → Save Config


Connect to Skylark

Option 1: Use u-center NTRIP client

  1. Start u-center
  2. Connect to the appropriate COM port
  3. Navigate to Receiver → NTRIP Client
  4. Configure the NTRIP caster settings section
    • Address: na.skylark.swiftnav.com (North America) or eu.skylark.swiftnav.com (Europe)
    • Port: 2101
    • Username & Password
  5. Click Update source table
  6. Select CRS for NTRIP mount point
  7. Press OK



  8. Wait for Fix Mode to change to 3D/DGNSS/FLOAT


Option 2: Provide Skylark correction data via USB, using an external NTRIP client

  1. Identify the USB serial port of your receiver


  2. Start your NTRIP client and configure NTRIP parameters
    1. Address: na.skylark.swiftnav.com (North America) or eu.skylark.swiftnav.com (Europe)
    2. Port: 2101
    3. Username & Password
    4. Mountpoint: CRS
  3. Select the COM port identified in Step 1 for the output of the corrections (COM8 in this example as shown in Step 1).
    1. Baud Rate: 38400 bps
    2. Byte Size: 8
    3. Parity: None
    4. Stop Bits: 1
    5. Flow Control: None
  4. Verify that the NTRIP client is configured to read the position (NMEA GGA) from this COM port and to send it to Skylark CRS.
    Note: Skylark CRS requests an NMEA GGA sentence to be sent periodically to compute corrections for the receiver's location
  5. Start the NTRIP connection
  6. In u-center, Wait for Fix Mode to change to 3D/DGNSS/FLOAT