Last Modified: December 3, 2014
OSystems GPS/IMU Connections
- Set up the Osystems GPS/IMU as per instructions. Differential GPS will be required for sufficient tracking accuracy.
- Connect the serial port of the GPS/IMU to the port used for the Intersense tracker.
- Configure the GPS/IMU to export data at 50 hz with the command
LOG INSPVASA ONTIME 0.02
- Select Novatel GPS/IMU from the Pos/Rot tracking menu.
Measure the offset from the right side of the GPS/IMU unit at its coordinate origin (marked by a survey marker) to the camera’s image sensor. Enter the offset as shown above.
Switch to Observer View to make sure that the offset to the image sensor has the correct signs.
Transforming the GPS/IMU tracking data into a local coordinate system set up with a total station is very similar to the technique used with encoded cranes:
- Set all of the camera offsets in the main tracking panel to 0.
- Make sure that the status in the bottom line of the Novatel configuration panel says ‘INS\_SOLUTION\_GOOD’ before proceeding.
- Measure the location of the marker on the GPS/IMU with the total station.
- Click Tracker Offset in the Novatel configuration panel, and enter the northing, easting, and elevation into the panel.
- Rotate the Offset Pan until a CG object at a surveyed location lines up with the live action object horizontally and click OK.
- Click Edit on the Camera Sensor Offsets and adjust the tilt and roll by subtle amounts (< 0.5 degree) to align the scene. Deselect Edit when done.
Adjusting Pan Offset
Depending on the IMU used, you may need to adjust the pan offset in the configuration panel during the shoot to keep surveyed points lined up with CG points. This offset can range up to 5 degrees.