The trajectory (path of an object) is the route that - in our specific case - the mobile/airborne/unmanned scanner has travelled. Most commonly, the trajectory is represented as a polyline, where each vertex represents a position that the positioning systems have recorded. The standard scanning systems use a GPS antenna which is capable of recording 20-100 positions per second (20-100Hz antenna), capable of recording multiple frequencies and accompanied by other devices such as IMUs (Inertial Measurement Units) or DMIs (Distance Measurement Instrument or Odometer), which together provide an accurate position or the position can be calculated later in the office. These points are connected with lines and give the sensor a path. The trajectory is essential to calculate the point cloud from the raw laser-scanned data and can commonly be exported to SHP or text-based formats for further use during extraction or in GIS systems.
PCS can handle natively the text-based trajectory format from RiProcess. Still, other software might be capable of exporting similar files or, based on the header information, the user can manually build it if every information is available. Regarding trajectories, the same rule applies to the point clouds: PCS can handle only projections with a dedicated elevation/Z value. WGS84 or other ECEF projections are not supported.
PCS supports trajectories with the following header:
Time[s],Easting[m],Northing[m],Elevation[m],Roll[deg],Pitch[deg],Yaw[deg]
In the trajectory file, the following rules shall be followed:
Exporting to SHP format from the post-processing environment is recommended as it is more convenient to use the SHP file.
If there is a direct intention to use the trajectory file itself, and the provided information is insufficient to re-create the text file or if PCS does not load it, please contact us.