User Guide

54A0049_7.0_EN / Leddar Pixell – User Guide 123 | 127
Appendix E. Converting Leddar Pixell Flash LiDAR
Sensor’s Angular Data and Distance Reporting and
Mapping to Real-World Coordinates Protocol
Each Leddar Pixell™ Cocoon LiDAR sensor is thoroughly calibrated on a dedicated production bench both
in angular positions and in absolute distance using various traceable targets and carefully selected scenes
to reach the required accuracy with precise angular mapping. The sensor comes with accessible internal
data providing the angular mapping done in production. This section explains how to transform this basic
internal mapping to precise Cartesian coordinates to map the “real world” as seen by the Leddar Pixell.
Mapping the Space Around the Platform with Sensor’s Echoes
The Leddar Pixell sensor reports echoes using a distance and segment number where the detection has
occurred for each echo in the list. The distance is a direct line-of-sight distance between the object detected
and the sensor. To position this echo in space around the platform on which the sensor is installed, different
ways of mapping the space could be used, as shown in Fig. 84 below.
Fig. 84: Coordinates with two well-known reference systems
The red dot could be located in space using either Cartesian coordinates {x, y, z} or spherical coordinates
{R, θ, ϕ}. The following equation set could be used to move from one to the other. The reference point of the
Leddar Pixell sensor is the origin 0, 0, 0, with the x-axis pointing forward and the y-axis pointing to the left.
x = Rcosθ cosϕ
Equation 1: Coordinate transformation for x
y = Rsinθ cosϕ
Equation 2: Coordinate transformation for y
z = Rsinϕ
Equation 3: Coordinate transformation for z