Keywords: lidar

Summary

This demo is designed to demonstrate an exaggerated LASER offset in a LIDAR system. In this case, we shoot a single pulse from a greatly offset laser (one that is 2 km behind the receiver) and angled forward such that is is illuminating the space vertically underneath the sensor. The primary reason for this demo is to show a laser instrument that is completely independent from the gated focal plane instrument (they are on different mounts in the platform).

Details

Important Files

The Scene

The scene is comprised of a single oak tree planted at [-12, 16.5, 0] on a flat plate. The reflectance properties are spectrally flat and not realistic (see "lidar.mat" and the "optical" directory). The GDB files are in the "geometry" directory. This is the same scene as LidarStatic1, for comparison purposes.

The Platform

The instrument is mounted on a static vehicle (see bistatic.ppd) directly above the tree.

Transmitter Properties

  • Laser wavelength: 1064 microns

  • Pulse length: 2 ns (-sigma to +sigma of the gaussian profile)

  • Pulse energy: 1 mJ

Receiver Properties

  • Focal length: 400 mm

  • Array size: 128 x 128 elements @ 50 micron pitch

  • Range gate resolution: 1 ns

Setup

The file "bistatic.xyz" is an ASCII/text point cloud that was produced via the new detector model and point cloud generator tool introduced in DIRSIG 4.3. This tool is available under the "Tools → Lidar Tools" menu in the GUI or as "simple_processor" from the command line. In this case, a simple linear mode detector was modeled. This 3D point cloud file was plotted in a simple 3D plotting program (gnuplot) to produce the plot in "bistatic.pdf". Note that the data is tilted because of the orientation of the laser — points on the ground closer to the laser source appear to be higher since the travel time is shorter than the far side. You can also see the "shadow" on the far side of the tree.