OXTS Georeferencer - User Guide

OXTS Georeferencer combines data from an OxTS inertial navigation system (INS) with LiDAR scans to produce georeferenced 3D pointclouds of your survey environment. By fusing precise position and orientation data from the INS with the spatial measurements of the LiDAR, Georeferencer places every scanned point in an accurate real-world coordinate frame — giving you a survey-grade 3D map you can view, analyse, and export in standard formats including LAS, LAZ, and PCD.

File Inputs

Required Files

*Using a CSV file for LIDAR data

Georeferencer can accept LiDAR data as a CSV file instead of a PCAP or LCOM. To use this, you also need a config file that tells Georeferencer how to interpret the CSV columns.

The config file has the same name and location as the CSV file, but with a .cfg extension instead of .csv. For example:

survey_data.csv
survey_data.cfg

The config file defines which column in the CSV corresponds to each data field:

All parameters after reflectivity_column are optional.

Example Config file:

time_column=0
range_x_column=1
range_y_column=2
range_z_column=3
reflectivity_column=4
reflectivity_min=0
reflectivity_max=255
time_scaling_factor=1
range_scaling_factor=1

Scaling factors: The scaling factors are used to normalise values in the CSV to the units Georeferencer expects — seconds for time, and metres for range. If your CSV already uses seconds and metres, set both factors to 1 or omit them entirely.

For example, if your CSV records time in milliseconds, set time_scaling_factor=0.001 so that Georeferencer correctly interprets those values as seconds.

Optional Files

Setting up LIP and LIR

Measure the XYZ offsets from the INS measurement point (marked on the unit exterior) to the LiDAR centre and enter them into the LIP file.

For the LIR, check your LiDAR manual for its axis orientation. In Georeferencer's Hardware tab, rotate the 3D model — yaw first, then pitch, then roll — until the displayed axes match the physical setup. Aim for angles that are multiples of 90 degrees as a starting point, then refine using boresight calibration.

Always use the boresighted LIP and LIR files for surveys, not your original manual measurements. A boresighted file has a 1 flag on its fourth line.

Boresight Calibration

Boresighting refines your LIR and LIP values beyond what can be measured by eye. Do this once per hardware setup before carrying out surveys. A 0.1 degree angular error translates to roughly 10 cm of positional error at 15 m range, so this step is essential for survey-grade output.

Steps:

1. Set up retroreflective targets in a controlled environment and complete a survey run.
2. In Processing Options > Boresight Options, select LIR optimisation first. Only add LIP optimisation afterwards if further refinement is needed.
3. Set the reflectivity threshold to approximately 100. Raise to 150 if non-target points appear. Livox LiDAR always requires 150.
4. Increase iterations if boresighting only converges on one or two axes.

Key Processing Options

Processing and Output

Once all files are loaded, click Run Georeferencing. Output is saved to the folder containing the NCOM file, or a custom path set in the Files tab. Each run produces a pointcloud file (LAS, LAZ, or PCD), the LIP, LIR, and VAT files used, and two processing logs. The default output format is LAZ.

Troubleshooting

Tips for Best Results