Remote Sensing Services: Lidar Systems

Spectrum Mapping owns and operates three LIDAR systems and three aircraft (single and twin-engine). With three aircraft and multiple systems, Spectrum has the in-house capacity to fly multiple systems on a single project or deploy them to separate projects, guaranteeing the correct system and configuration is selected for each project.

What does this mean for you, the client?

• Faster response time
• Faster acquisition time
• Faster delivery times

There is now no need to deal with multiple companies to acquire and process large area projects. This allows the client to have:

• A single point of contact through the entire project
• Standard data formats
• Consistent filtering of data to bare earth surfaces
• Standardized QA/QC processes
• final deliverables

LIDAR Systems

We have designed our systems to integrate various components such as digital cameras and hyperspectral systems so that all data is collected in a digital format in a single flight. Our LIDAR systems combine a medium-format digital camera subsystem with the LIDAR (Light Detection and Ranging) laser altimeter subsystem. The laser systems offer variable swath widths, up to 45kHz pulse rate, and a 70Hz scan rate to adapt to varying terrain and vegetation conditions. All four systems yield an absolute horizontal accuracy of 1.5 feet RMSE with a vertical accuracy of less than ½-foot RMSE for the LIDAR and image geopositioning systems. Relative positioning accuracy is ½-foot RMSE horizontal and ¼-foot RMSE vertical. The systems are flown in a fixed wing aircraft with a flight management system to facilitate maximum collection rate and minimize costs.

The scanning laser altimeter, which measures terrain directly, is integrated with an Inertial Measurement Unit (IMU) and Global Positioning System (GPS). The LIDAR releases a pulse of laser light, which bounces back from ground surface features. The travel time for this light is calculated determining the exact distance to the ground from the system. The laser pulse is repeated at a very high rate as a scanning mirror spreads the separate pulses back and forth perpendicular to the direction of flight. The time intervals for the light, mirror angle, and the system position and orientation data are recorded during the flight. The information from these systems is combined to calculate the exact position and orientation of the sensors as related to the earth surface at the exact time of data acquisition. The need for ground control panels, film development and stereo plotting are unnecessary for DEM generation and image rectification.

LIDAR System Specifications Laser Altitude 13,000 feet (4,000m) AGL Max Laser Swath Width 16,500 Feet (5,000m) Max Laser Scan FOV 75 Degrees Max Scan Rate Up to 70 Hz (FOV dependent) Laser Pulse Rate 24 - 45kHz Laser Returns 3 at 45kHz or 5 at 38kHz Nominal X/Y Ground Sample Distance 3 – 15 Feet (1-5m) X, Y, Z Positional Accuracy Less than 1 Foot (<30cm) RMSE Absolute

info@specmap.com