Using a viDoc RTK rover with PIX4Dcatch enables RTK centimeter grade absolute accuracies when capturing 3D scans and ground control points with a mobile device.
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Before starting the image acquisition, charge the viDoc RTK rover for 6 hours.
1. Mount the viDoc RTK rover to the mobile device.
2. Turn on the viDoc RTK rover with a single long press. The green light on the rover indicates it is turned on.
3. Open the device settings and turn on Bluetooth if not already on.
4. Start PIX4Dcatch.
5. Select the signal indicator in the top-left corner of the screen and select viDoc RTK via Bluetooth.
Select viDoc RTK via Bluetooth.
6. In the RTK Device Settings dialog:
RTK Device Settings dialog for iPhone(iOs) and Android.
- When using an Android device, measure and enter the Camera Offset Values.
For more information: How to measure the offset - PIX4Dcatch(Android) with viDoc RTK rover.
- Select the viDoc RTK rover under Available Bluetooth Devices.
- Enter the NTRIP details and tap Validate:
- Hostname / IP
- Port number
For more information: What is NTRIP.
- When the connection is established, select Choose mountpoint and select the preferred mountpoint.
- Select the input coordinate system.
7. Tap Connect.
A successful connection to the NTRIP service is indicated with a green RTK icon.
Once the viDoc RTK rover is successfully connected to PIX4Dcatch, wait for RTK fixed. For an optimal experience, make sure the antenna is not obstructed and that you have a good internet connection.
RTK dialog with optimal values.
Check the Status and the HDOP during the acquisition to ensure optimal conditions.
|No fix||The data is not valid, there are not enough satellites visible, or there are internet connection problems.|
|Autonomous GNSS fix||Only Differential GNSS is used for data measurements. DGNSS is an enhancement to GNSS, which determines its location based on a reference station, with no fixing of ambiguities. The accuracy of the determined position can be in the range of 10 m or more.|
|DGNSS Only||The data is not valid, there are not enough satellites visible, or there are internet connection problems.|
|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 how good the position and distribution of the satellites are.
Generally, the HDOP value is considered ideal below 1, and to have centimeter-level accuracy, from some testing, it has been observed that for better accuracy, we should take the readings which have a value lower than 0.65.
The accuracy values can vary and depend on multiple factors, for example:
- Blocked and reflected GNSS signal, close to buildings, trees, or bridges.
- Rapid movements of the device.
- Poor cellular reception.
For more information: GNSS and viDoc RTK rover best practices.
For more information: Capturing a dataset - PIX4Dcatch.
With a captured PIX4Dcatch project, there are several options for processing a 3D model. Directly upload and process to PIX4Dcloud / PIX4Dcloud Advanced for the most immediate results, or export the project and process using PIX4Dmatic or PIX4Dmapper.