To effectively use an Pix4D supported RTK device with a mobile device, the initial step is configuring the setup correctly. This involves setting the camera offset between the antenna and the mobile device's camera. This offset, whether measured automatically by PIX4Dcatch (SPC and SPC+) or manually by the user, is crucial for accurately computing locations captured by Pix4D supported RTK devices, ensuring precise measurements for scans or ground control points (GCPs).
IN THIS ARTICLE
Which Version of Pix4D supported RTK devices do I have?
Mount the viDoc distributed by Pix4D RTK to the Device
Smartphone model
Tablet model
Devices with a Known Camera Offset
Camera Offset Measurements
How to Manually Measure the Camera Offset
Measure the X axis
Measure the Y axis
Measure the Z axis
Enter the Camera Offset Values
Which Version of viDoc distributed by Pix4D do I have?
Currently, the Pix4D supported RTK devices has different versions that require different offset values: viDoc distributed by Pix4D compatible with SPC+ connector (Pix4D supported RTK devices P01) and viDoc distributed by Pix4D compatible with SPC connector. This section describes how to identify the Pix4D supported RTK devices version, in order to set the correct camera offset values and achieve the best available accuracy of the reconstruction.
Important: The list of compatible iOS mobile devices with SPC/SPC+ connectors and viDoc distributed by Pix4D models is available here.
Smartphone type with SPC+ connector
Since SP Connect released a new version of their adapter called SPC+, Pix4D released Pix4D supported RTK devices P01, a new version of the viDoc distributed by Pix4D RTK device that is now compatible with the new SPC+ cases. This device version is indicated by the additional Pix4D logo and the rounded shape of the new SPC+ mount type. Manual offset measurement is only needed in the following situations:
- PIX4Dcatch does not recognise the device
- A custom case is used
Important: The list of compatible iOS mobile devices with SPC/SPC+ connectors and viDoc distributed by Pix4D models is available here.
P01 label extension
Connector on Pix4D supported RTK devices
Connector on the SPC+ case
Smartphone type with SPC connector
This Pix4D supported RTK devices version is compatible with the old SPC cases and can be recognized easily by the rectangular mount type and the black label without the Pix4D logo. Manual offset measurement is only needed in the following situations:
- PIX4Dcatch does not recognise the device
- SPC universal case is used
- A custom case is used
Important: The list of compatible iOS mobile devices with SPC/SPC+ connectors and viDoc distributed by Pix4D models is available here.
Connector on Pix4D supported RTK devices
Connector on the SPC case
Mount the viDoc distributed by Pix4D to the Device
The viDoc distributed by Pix4D is a GNSS RTK receiver that allows PIX4Dcatch to geolocate the images acquired by your mobile device with centimeter accuracy. The viDoc distributed by Pix4D RTK device can be coupled with mobile phones (iOS and Android) or with tablets using the SP connectors (cases or clamps) provided by SP Connect. For a complete list of device combinations, please refer to this summary.
Note: The SP connectors can be obtained when purchasing the viDoc distributed by Pix4D RTK device. They can also be purchased directly from SP Connect and most electronic, bicycle, and motorcycle shops. Refer to the manufacturer's instructions for further details when mounting for the first time.
If the mobile device does not have a custom case available (e.g. Android phones), the universal clamp can be used.
If the mobile device does not have a custom case available (e.g. Android phones), the universal clamp can be used.
Important: After mounting the viDoc distributed by Pix4D to the mobile device, please check if the camera offset has been automatically calculated for you. If your mount is not available in this list, you need to measure the camera offset manually. For more information: Manually Measure Camera Offset
Smartphone model
Important: The list of compatible iOS mobile devices with SPC/SPC+ connectors and viDoc distributed by Pix4D models is available here.
First, insert the phone into its compatible SP-connect case. Then, mount the case to the RTK device by following the instructions provided with the SP-connect case.
Important: Ensure proper orientation of the mobile device after mounting it to the viDoc distributed by Pix4D with the antenna pointing up.
Device type
Orientation
iPhone
Portrait
iPad
Landscape
Android
Portrait
Tablet model
Important: The list of compatible iOS mobile devices with SPC/SPC+ connectors and viDoc distributed by Pix4D models is available here.
Compatible SP-Connect Case:
Insert the tablet into the suitable SP-connect case. After that, secure the case to the RTK device by following the guidelines provided with the SP-connect case, ensure the table is in landscape mode
Holder with clamp:
Loosen the screw on the bottom of the viDoc distributed by Pix4D, and carefully insert the tablet into the clamp. Use the iPad's magnets to center the viDoc distributed by Pix4D. Tighten the screw to secure the tablet, and ensure that the tablet is in landscape mode.
Devices with a Known Camera Offset
This list contains the combinations of mobile devices (phones and tablets) with the Pix4D supported RTK devices where the camera offsets are already measured. PIX4Dcatch will automatically fill in the X, Y, Z fields with the correct camera offset values.
Smartphone model
Compatibility with the case type
[iPhone]
SPC
SPC+
iPhone 15 Pro Max
❌
✅
iPhone 15 Pro
❌
✅
iPhone 14 Pro Max
✅*
✅
iPhone 14 Pro
✅*
✅
iPhone 13 Pro Max
✅
✅
iPhone 13 Pro
✅
✅
iPhone 12 Pro Max
✅
✅
iPhone 12 Pro
✅
✅
iPhone 11 Pro Max
✅
✅
iPhone 11 Pro
✅
✅
iPhone XR
✅
✅
* Warning: This configuration is not recommended due to partial camera sensor occlusion.
Tablet model
Compatibility with the case type
[iPad]
SPC
SPC+
iPad Pro 12.9-inch (4th, 5th and 6th generation)
✅
✅
iPad Pro 11-inch (2nd, 3rd and 4th generation)
✅
✅
Important: If the Pix4D supported RTK devices is not mounted with an SP-connect case, then offset values need to be measured manually, as described below. In PIX4Dcatch, there is an option to overwrite the autodetected values with the manually measured ones.
Camera Offset Measurements
When initiating the connection to the Pix4D supported RTK devices, the dialog RTK Device Settings opens. The section Camera Offset allows the user to set the X, Y, Z offset values properly. The available options depend on the combination of the viDoc distributed by Pix4D RTK device version, the mobile device and the device case. The following options are available: SPC, SPC+ (in tablet and older mobile app versions: Automatic) and Custom.
The options SPC and SPC+ are only available if the combinations of the viDoc distributed by Pix4D RTK device version, the mobile device and the device case are known. The option Custom is always available and intended to be used by universal or specific cases. This option requires measuring the camera offsets manually and setting them in PIX4Dcatch. The camera offset value selection is saved for the next measurements and modifications are only needed if the setup changes.
How to Manually Measure the Camera Offset
Mount the device to the Pix4D supported RTK devices using the appropriate SP-connect case. Phone cases can be purchased separately from the SP-connect website. The SP-connect universal phone mount can be used if the specific model is unavailable. SP-connect cases are also available in most bicycle and motorcycle shops.
Place the device in landscape mode and the display to the front. Notate the orientation of the X, Y, and Z axes and how they relate to the point of origin on the antenna to measure from. The point of origin resides in the middle of the screw mount at the base of the antenna. It will also be necessary to determine which lens to measure from for devices with multiple camera lenses.
Important: If you use iPad, make sure the device is in landscape mode and the antenna is pointing upwards, like in the image above. The X and Y offset values will need to be entered as negative values.
Tip: If you don't know which camera lens to measure from, start PIX4Dcatch and then place something in front of each camera lens. The lens blocked is the appropriate lens to measure from.
Important: When using the universal mount, the lens and device must be below the antenna when mounting the device to the viDoc distributed by Pix4D.
Measure the X axis (Y axis for iPad)
Measure the value from the antenna base to the center of the lens along the axis for the X axis offset.
Measure the Y axis (X axis for iPad)
Measure the value from the center of the antenna to the center of the lens along the axis for the Y axis offset.
Measure the Z axis
Measure the depth from the center of the antenna to the center of the lens for the Z axis offset.
Important: Most cases and adaptors are adding extra offset on top of the screen. Make sure that Z axis offset is measured to the lens and not the case/adaptor.
Enter the camera offset values
With the camera offsets properly measured and recorded, they can be included in the appropriate Camera Offset Values field of the RTK Device Settings dialog. Depending on the device's geographical region, centimeters or inches will be the displayed measurement unit.
Important: Ensure that camera offset values are defined in the correct measurement units. For Android phones, setting the unit is not directly available and it is tightened to the language settings. It can be adjusted in the Android global settings under Languages (or App languages). For iOS, setting the unit is available under the General settings -> Language & Region -> Measurement system.
The camera offset is now properly set in the Camera Offset Values X, Y, Z fields. Continue with the RTK Device Settings dialog to complete the viDoc distributed by Pix4D RTK connection to the device.