Barnard Microsystems Limited

In a LIDAR system, a LASER beam is used in place of a microwave beam, to detect the distance to a target.

A scanning LIDAR unit is used to:

• detect the distance to obstacles in front of the Unmanned Aircraft, to help with collision avoidance
• generate data for a Digital Elevation Map of the area under the Unmanned Aircraft
• detect the presence and height of trees, as shown in the plot above

See also altimeters

• New General Dynamics LIDAR

• Scanning eye safe laser LIDAR

• Example of LIDAR scan showing tree height

• LiteMapper LIDAR

The new General Dynamics scanning LIDAR seen at the AUVSI North America 2010 Conference.

AboveL enlargement of the document besides the GD scanning LIDAR.

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- from www.sickusa.com

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Three LIDAR scans, showing trees and the ground level, from http://denali.gsfc.nasa.gov/research/laser/slicer/slicer.html

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From www.litemapper.com

The LiteMapper system is a fully integrate sensor package for highly accurate 3D measurements of the Earth's surface. It includes

• High-resolution Laserscanner (scanning Lidar)
• High-accuracy Position and Orientation sensor system
• Control and data logging unit
• Flight guidance system
• Software for mission planning, system operation, data registration, geocoding, and processing
• Optional Digital Video system
• Optional Digital Camera system

All components are engineered for operation on airborne platforms. The compact and lightweight design and low power requirements make the LiteMapper system ideal for small survey aircraft and helicopters. A high degree of automation and tight integration with the flight guidance system make it easy to operate. A dedicated lidar operator is often not required.

Among LiteMappers special features are:

• full return waveform digitization (LiteMapper 5600) for accurate and detailled mapping of vertical structures (vegetation, infrastructure), improved reliability and accuracy of elevation measurements
• uniqe ability to collect true surface color information with each lidar measurement (LiteMapper 2800). Natural color and CIR true-ortho images at the lidar point density are available without additional processing.
• superior range resolution and measurement accuracy

LiteMapper 5600

Versatile mid-altitude system for high-resolution topographic and corridor mapping with fixed-wing aircraft and helicopters with full waveform digitization

Specifications:

• Range: up to 1500 m
• Range resolution: 15 mm
• Pulse repetition frequency: up to 200 kHz
• Scan pattern: parallel scan lines, near-equidistant samples
• Scan angle (fixed): ±22.5° (up to ±30° at reduced range)
• Scan rate: variable, up to 160 scans/sec
• Effective measurement rate: up to 133000 measurements/sec (@ ±30° FOV)
• Full waveform digitization
• " Unlimited" number of returns and intensities with each shot
• Target separation down to 0.5 m within single shot
• Detection of low ground vegetation down to 0.2 m height
• eye-safe (laser class 1)
• Sensor head dimensions: 560 x 200 x 210 mm , approx. 30 kg
• typical accuracy (flat target, 850 m AGL): 0.04 m vertical, 0.12 m horizontal (RMSE, excluding GPS errors)
• typical survey parameters (@ 120 kts flying speed):

Waveform profile through forest area. From www.litemapper.com .

" Accumulated waveform" (© GeoLas Consulting). From www.litemapper.com .

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