PIX4Dcatch RTK connection Dialog: Accuracy, Status and HDOP


When using the viDoc RTK rover with PIX4Dcatch, the RTK dialog screen displays the current strength and accuracy of the RTK connection. Understanding this dialog can help inform when the device is ready for optimal capture and when reception and accuracy fluctuate, allowing for appropriate adjustments during capture.


RTK dialog
   Status and HDOP

The RTK dialog

PIX4Dcatch RTK fix information dialog

The RTK dialog with an optimal connection.

Once the viDoc RTK rover is successfully connected to PIX4Dcatch, the RTK dialog will be visible. This screen displays information that can be used to monitor the status of the connection and the resulting accuracies.

The Header

PIX4Dcatch RTK dialog header

RTK dialog header.

The header contains the RTK connection icon, access to the RTK device, and Bluetooth settings dialogs.

  • Pix4Dcatch ViDoc RTK fix green icon The green RTK icon indicates the successful connection to the viDoc RTK rover.
  • tune icon The RTK device settings icon displays the current settings input for the RTK connection. 
  • arrow down expand menu iconThe Bluetooth settings icon displays the current Bluetooth device selected.


PIX4Dcatch RTK dialog battery

RTK dialog battery level indicator.

Indicates the battery level for the viDoc RTK rover. It would be advised to charge before each use.


PIX4Dcatch RTK dialog accuracy levels

RTK dialog horizontal and vertical accuracy level.

Indicates the accuracy to which the viDoc RTK rover is expected to achieve.

Note: The accuracy values can vary and depend on multiple factors, for example:
  • Blocked and reflected GNSS signal, close to buildings, trees, and/or bridges.
  • Rapid movements of the device.
  • Poor cellular reception.
  • Maintain an upright antenna position for better performance.

After the RTK fix is established, the Horizontal Accuracy and Vertical Accuracy should be in the range of a few centimeters. In ideal conditions, the values are close to 0.01m/0.03ft.

For more information, see GNSS and viDoc RTK rover best practices.

Status and HDOP


RTK dialog Status and HPOP indicators.

Once the viDoc RTK rover is successfully connected to PIX4Dcatch, wait for the RTK fix. For an optimal experience, make sure the antenna is not obstructed and that you have a good internet connection.

Check the Status and the HDOP during the acquisition to ensure optimal conditions. The status can fluctuate due to the visibility of available satellites. If RTK Fixed is lost, move slowly and deliberately to a point where RTK Fixed returns. Whenever possible, avoid overhead obstructions. PIX4Dcatch can adjust for the reduced reception once RTK Fixed returns.

Status (in order of quality) Explanation
No fix The data is not valid, there are not enough satellites visible, or there are internet connection problems.
Autonomous GNSS fix Only GNSS is used for the data measurement. No fixing of ambiguities, the reading can have more than 10 m difference.
DGNSS Only Only Differential GNSS is used for data measurements. DGNSS is an enhancement to GNSS which determines its location based on the reference station, no fixing of ambiguities, the reading can have up to 10 m difference.
RTK Float The device does not have enough satellites in common with the base station (i.e., Mount Point), or the reflected signals of satellites are received. The accuracy of the determined position can be in the range of 1 m.
RTK Fixed The GNSS rover and base station (i.e., Mount Point) can see at least five satellites in common, and the rover is receiving corrections from the base station. The accuracy of the determined position can be in the range of a few centimeters.

HDOP (Horizontal Dilution of Precision) indicates the current quality of the position and distribution of the satellites.

Generally, the HDOP value is considered ideal below 1. To have centimeter-level accuracy, it has been observed that for the highest accuracies, we should take the readings with a value lower than 0.65.

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