FLI-MAP Fx

FLI-MAP Fx LiDAR SYSTEM :

Light Detection And Ranging (LiDAR) has transformed the acquisition of digital elevation data (DEM) for the majority of photogrammetric mapping projects. This transformation has been realized with Fugro Horizons’ NEW crossover application high density FLI-MAP Fx. The FLI-MAP Fx integrates an accurate GPS positioning system with video imaging and a scanning reflector less laser rangefinder to provide fast and accurate aerial surveys. The system, aboard a specially equipped aircraft, is flown over the areas of interest collecting precise GPS, platform altitude and orientation (IMU), laser ranges, and imagery data at a data collection rate of either 150,000 200,000 or 250,000 ranges per second. In 1995, John Chance Land Surveys designed, custom built, and has since operated the proprietary FLI-MAP airborne laser mapping system. FLI-MAP is a cost-effective alternative to traditional surveying and mapping. FLI-MAP can quickly deliver accurate 3D survey information for engineering and design purposes. It is a proven technology that Fugro Horizons has now adapted to a fixed wing aircraft for high density data collection.

The laser fitted to the FLI-MAP Fx system is an FDA-certified Class 1 laser. It is eye-safe, including binocular eye-safe, at the aperture. There is no minimum altitude specified for FLI-MAP Fx operations to remain eye-safe. Regular bore-site calibration maintains consistently accurate data acquisition on each and every project. Prior to mobilizing to the project area, Fugro Horizons applies a proprietary J-Flight 3-D flight planning software concurrently with USGS DEM underlay to pre-determine the flight line length, altitude, and terrain to set the exact terrain following rates of decent and/or climb for the pilot to implement during each days flight mission.

The FLI-MAP Fx LiDAR system virtually paints the surface of the earth with laser pulses and records the elapsed time of the return of each pulse. This system provides for multiple returns of data from each laser pulse. The system incorporates a rotating mirror that triggers the laser pulse with four faces resulting in better positional accuracy as well as three look angles providing both better vegetation penetration and information about the face of objects that are not included in the "bare earth" elevation model.

The FLI-MAP Fx rotating mirror system also eliminates the torsion errors, inherent with oscillating mirror systems, leading to more accurate data acquisition across the entire field of view, as well as a more even point distribution in the cross track of the laser scan. For this reason, utilization of the efficiency of the FLI-MAP Fx, full field of view, results in a more cost effective acquisition while still maintaining optimal point accuracy. The rotating mirror also results in more uniform point density and distribution in both the laser sensor cross track and along track, also allowing a faster online acquisition speed that will still meet the point density requirement while reducing the online acquisition time.

Dense point spacing eliminates the need for break lines that define and control the topographic surface in areas where there are evenly sloped and in areas of a sharp slope change in topography. LiDAR acquisition with the FLI-MAP Fx is not daylight dependant, and therefore provides the ability to obtain data at times when conventional aerial photography cannot. The FLI-MAP Fx system is further equipped with a line scanner which colorizes the LiDAR points, in order to acquire the line scanner imagery to colorize the LiDAR point cloud, the acquisition needs to be limited to daylight hours.

This method of obtaining Digital Terrain Model (DTM) data benefits clients by meeting or exceeding the exacting standards while providing the most cost competitive terrain modeling solutions that technology has to offer.