Connect PIX4Dcatch to the viDoc RTK rover


The viDoc RTK rover is a GNSS RTK receiver. It allows PIX4Dcatch to geolocate the images acquired by your mobile device with centimeter accuracy. It is important to connect the device to the viDoc RTK rover correctly to ensure accurate results.

Connect PIX4Dcatch to the viDoc RTK rover

PIX4Dcatch connects to the viDoc RTK rover via Bluetooth. Be sure the Bluetooth function is toggled on in the device settings.

  1. Turn on the viDoc RTK rover with a single long press. The green light on the rover indicates it is turned on.
  2. Start PIX4Dcatch. Pix4Dcatch_logo.jpg
  3. Select the signal indicator in the top-left corner of the screen and select viDoc RTK via Bluetooth.


    Select viDoc RTK via Bluetooth.

  4. In the RTK Device Settings dialog:

    PIX4Dcatch RTK device settings iOS Android

    RTK Device Settings dialog for iPhone(iOs) and Android.

    • When using a device with an unknown offset, measure and enter the Camera Offset Values. If the field contains zero values, the PIX4Dcatch is unable to recognize the offset, and it has to be configured.

      For more information: How to measure the offset - PIX4Dcatch RTK.

    • Select the viDoc RTK rover under RTK Bluetooth Device. A green check will indicate the connection.
      • It is possible to select the minimum elevation angle from which to receive the satellite's position, as well as select the constellations (satellite networks) to use.


        • Tap the arrow_right.png menu to access the Satellites settings: PIX4Dcatch_RTK_satellites_settings.jpg
          • Minimum elevation selection
            • Default value 10°
            • Range from 0° up to 45°
            • Incrementation of 5°
            Note: As this angle is increased, there will be fewer satellites seen. In an empty area, it is recommended to keep the default value of 10°.
            • 0° selection is not recommended due to greater atmospheric distortion from the horizontal satellites.
            • 45° could end up with really few satellites visible.
          • Constellations, select satellite networks to include in the localization.
            • GPS, cannot be turned off due to hardware limitations
            • SBAS
            • GALILEO
            • QZSS
            • GLONASS
            • BEIDU
        • Tap Apply to save the settings.
    • Enter the NTRIP details and tap Validate:
      • Hostname / IP (if IP is available, please use that as it is more stable)
      • Port number
      • Username
      • Password

      For more information: What is NTRIP?

    • When the connection is established, select Choose mountpoint and select the preferred mountpoint.
      Tip: When selecting a mountpoint, there can be several options depending on the service provider. Mountpoint names can indicate how it is set up, and understanding a few common terms can help with this selection. Contact the NTRIP provider when uncertain.
      • Nearest vs. Net vs. VRS
        • Nearest: Single Base RTK corrections for the nearest reference station.
        • Net: Averages the position from the closest 3 base stations.
        • VRS: Averages the position from the closest 3 base stations and creates a virtual base somewhere on the site.
      • MSM: Multiple Signal Messages - More messages sent with the RTCM 3.2 correction format.
      • RTCM: (Radio Technical Commission for Maritime Services) Open source correction format to send accurate position information.
        • RTCM 2.3: GPS Only
        • RTCM 3.1: GPS + GLONASS
        • RTCM 3.2: GPS (including L5) + GLONASS + Galileo + BDS
      • CMR: A Trimble-specific correction format. CMR and CMR+ are open to public use.
        • CMR: GPS Only
        • CMR+: GPS + GLONASS
        • CMRx: compressed, GPS (including L5) + GLONASS + Galileo + BDS
      • iMAX (Individualized Master Auxillary Correction): A Leica network that uses a real reference station as the source for the network corrections, so there is consistency and traceability for the corrections received by the rover.
    • Select the NTRIP coordinate system.
      Important: Select the coordinate reference system used by the NTRIP service to broadcast its corrections as the NTRIP Coordinate System. If uncertain, contact the NTRIP service provider for this information.

      We have identified several coordinate reference systems commonly used for broadcasting NTRIP corrections from various regions.

      Country or region Coordinate reference system
      Europe ETRS 89 (EPSG: 4258)
      United States NAD83(2011) (EPSG: 6318)
      Japan JGD2011 (EPSG:6668)
      Singapore SVY21 (EPSG:4757)
  5. Tap Connect.

A successful connection to the NTRIP service is indicated with a green Pix4Dcatch_ViDoc_RTK_fix_green.jpg RTK icon.

Important: Please ensure that the device clock is synchronized. To synchronize the clock:

iPhone or iPad:

  • Open the Settings app.
  • Tap General.
  • Tap Date & Time.
  • Verify that Set Automatically is toggled on.


  • Open the Settings app.
  • Tap General management.
  • Tap Date and time.
  • Verify that the Automatic date and time is toggled on.
Tip: Download the viDoc Quickstart Checklist for on-site reference. The checklist includes the steps to connect to the viDoc RTK and provides space to enter unique log-in details as well as general capture guidance for new users.

Other Languages: viDocスタートガイド

With the device properly connected to the viDoc RTK rover, it is ready to capture a project and measure points.
For more information: Capture a project with PIX4Dcatch and viDoc RTK rover.

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