The 3D laser range finder.

The 3D laser range finder (Fig. 1) [23] is built on the basis of a SICK 2D range finder by extension with a mount and a small servomotor. The 2D laser range finder is attached in the center of rotation to the mount for achieving a controlled pitch motion with a standard servo.

Figure 1: Kurt3D in a natural environment. Left to right: Lawn, forest track, pavement.

The area of up to $180^{\circ}$(h)$\times 120^{\circ}$(v) is scanned with different horizontal (181, 361, 721) and vertical (128, 256, 400, 500) resolutions. A plane with 181 data points is scanned in 13 ms by the 2D laser range finder (rotating mirror device). Planes with more data points, e.g., 361, 721, duplicate or quadruplicate this time. Thus a scan with 181 $\times$ 256 data points needs 3.4 seconds. Scanning the environment with a mobile robot is done in a stop-scan-go fashion.