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      Connect PIX4Dcatch to the Pix4D supported RTK devices

       

      The Pix4D-supported RTK device is a GNSS receiver which allows PIX4Dcatch to geolocate the images captured by your mobile device with centimeter accuracy. It is important to connect the device to the Pix4D-supported RTK device correctly to ensure accurate results.

      This article explains how to connect the mobile device (phone or tablet) with the Pix4D-supported RTK device. The overall workflow consists of the following steps: Initialize Connection, Select Minimum Elevation, Select Constellations, Set Camera Offset Values, Enter NTRIP Credentials, Select Mountpoint and Select NTRIP CRS.

      IN THIS ARTICLE

      Initialize Connection
      Select Minimum Elevation
      Select Constellations
      Set Camera Offset Values
      NTRIP Credentials
      Select Mountpoint
      Select NTRIP CRS

      Initialize Connection

      1. Before you initialize the connection to the Pix4D-supported RTK device, please make sure that Bluetooth is activated from the mobile device settings.
      2. Turn on the Pix4D-supported RTK device with a single long press and wait until the green light appears.
      3. Start PIX4Dcatchunnamed (5).png
      4. On the top-left corner of the screen, click on the GPS signal indicator and select RTK via Bluetooth

        IMG_FAD75390AA41-1.jpeg

      5. The RTK Device Settings dialog opens. Click on the device search bar and select your RTK device identifier.

        imgonline-com-ua-twotoone-pSyY1d0nfpEq.png

      Select Minimum Elevation

      1. Below the field where your RTK rover identifier is shown, click on the satellite bar (GPS, SBAS, GALILEO...). A new window will open and display the minimum elevation.
      2. The default minimum elevation value is 10°.
      3. The minimum elevation value ranges from 0° to 40° and increments by 5°.
      4. Tap on the right field (where the default value is displayed) and choose a different value from the dropdown list.

      RTKrover_SatelliteSystems.png

      RTKrover_minElevation.PNG

      Note: The more this value increases, the less satellites will be seen. In an empty area, it is recommended to keep the default value of 10°. 0° is not recommended due to greater atmospheric distortion from the horizontal satellites. 45° could end up with really few satellites visible.

      Select Constellations

      1. In the Constellations section, the satellite navigation systems used for the geopositioning can be included or excluded.
      2. To include or exclude a satellite navigation system, toggle on/off the right button.
      3. The following constellations are available: GPS (cannot be deactivated due to hardware limitations), SBAS, GALILEO, QZSS, GLONASS, BEIDOU.

      RTKrover_constellations.PNG

      Set Camera Offset Values

      1. When using the Pix4D-supported RTK devices with a mobile device, the first step is to set the offset between the antenna and the mobile device camera (camera offset).
      2. There are multiple combinations of mobile devices (phones and tablets) with the Pix4D-supported RTK devices where the camera offsets have been measured. These offsets are automatically recognized inside the app.
      3. If the mobile device has an unknown offset, it needs to be measured and filled out in the Camera Offset Values (X, Y, Z). If the X, Y, Z fields contain zero values, the app is unable to recognize the offset, and it has to be configured.
      4. The screenshot below shows all the possible camera offset options: SPC+, SPC and Custom.

      Catch_Camera_Offset_Options.png

      NTRIP Credentials

      1. Enter the NTRIP details:
        • Hostname / IP (if IP is available, please use that as it is more reliable)
        • Port number
        • Username
        • Password
      2. Click on Validate NTRIP.

      RTKrover_NTRIP_credentials.png

      For more information: What is NTRIP?

      Important: Please ensure that the device clock is synchronized. To synchronize the clock:
      • iPhone or iPad: go to Settings > General > Date & Time > toggle on Set Automatically
      • Android: go to Settings > General management > Date & Time > toggle on Automatic date and time

      Select Mountpoint

      1. After the NTRIP credentials have been validated, go to the Mountpoint section and select the preferred GNSS correction option.
      2. Depending on the CORS network, you can select a single base station or a triangulated network of the nearest base stations available.
      Tip: Depending on the NTRIP service provider, there can be numerous mountpoint options to choose from. For more information about the available options, contact the NTRIP provider.

      RTKrover_mountpoint.PNG

      Mountpoint Options

      Mountpoint Options

      Description

      Nearest | Net | 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
      Compact Measurement Record - 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 NTRIP CRS

      1. Go to the NTRIP Coordinate Reference System section.
      2. Select the coordinate reference system used by the NTRIP service to broadcast its correction.
      3. For more information about the CRS used, contact the NTRIP provider.
      4. The Connect button gets activated in blue after all the above-mentioned fields are shown with a green check box.
      5. Click on Connect.
      6. A successful connection to the NTRIP service is indicated with a green Pix4Dcatch_Pix4D-adapted RTK devices_RTK_fix_green.jpg RTK icon.

      RTKrover_NTRIPcrs.PNG

      RTKrover_connected.PNG

      NTRIP CRS Options

      We compiled a list of coordinate reference systems commonly used for broadcasting NTRIP corrections from various regions. For more information, please check the table below.

      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)

      Next Steps

      With the device properly connected to the Pix4D-supported RTK device, you are now ready to capture a project and measure points.To proceed, please go to Capture a project with PIX4Dcatch.