LiDAR
LiDAR, 'Light Detection And Ranging’ works in much the same way as sonar and radar, only by using a laser that is fired from a sensor or scanner. The laser then bounces back from the objects it hits and the sensor records the time it takes to return – with a simple equation using the time, multiplied by the speed of light (300,000km per second) and divided by two to counter the return journey, used to determine the distance traveled.
The process of firing the laser multiple times enables the sensor to see through topography such as Road, Buildings, Trees, Structures, etc,
The process of firing the laser multiple times enables the sensor to see through topography such as Road, Buildings, Trees, Structures, etc,
UAV Based LiDAR
Drone LiDAR is used for aerial surveying operations, a LiDAR drone incorporated a GPS/GNSS system in order to determine its exact position, along with an inertial measurement unit (IMU) to calculate for the movement of the Drone (in terms of pitch, roll and yaw as it bounce in the air). A high-end computer is to process all the data, possibly with pre-processing and Post Processing software for Geo-referencing, colorizing point cloud, convert data to multiple formats (las, laz, rcp) extracting ground
Mobile LiDAR
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Mobile surveying facilitates the collection of spatially correct data on a large scale. Rather than survey individual buildings or areas, mobile mapping systems can be deployed to map entire cities or hundreds (even thousands) of kilometers of transportation corridors. Imagine collecting a high-resolution data-set of an urban neighborhood in a few hours, or generating an engineering drawing of 60 km of highway in a single day. Mobile mapping systems make it happen.
Mobile LiDAR technology presents multiple benefits to transportation agencies, including safety, efficiency, accuracy, technical, and cost. It can simultaneously acquire imagery and scan data. |
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Mobile LiDAR Systems can provide survey/engineering quality data faster than static scanning. Airborne systems generally do not provide survey/engineering quality data. Mobile LiDAR systems have been utilized along navigable corridors for a variety of applications including earthwork quantities, slope stability, infrastructure analysis and inventory, pavement analysis, urban modeling, and railways.
Leica Pegasus: Two
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Leica Pegasus: Two, Mobile LiDAR can be used to obtain highly accurate 3D point data by safely driving a collection vehicle at highway speeds. The designers and contractors transition from 2D workflows to 3D model-based design and asset management, the ability to make efficient use of mobile LIDAR will only increase.
Application-specific workflow solutions: Pegasus:MapFactory for AutoCAD (or) ArcGIS software suite is the complete vectorization for the Pegasus:Two mobile sensor platform, covering the end to end workflow – from data collection to feature extraction. The interface combined with the semi-automated feature extractions allows to obtain the project deliverable fast. |
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Area of Application
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Goodland Surveys's Project Experience : LiDAR Survey
We have surveyed and delivered 100+ highway projects (108 and counts) from 2016 to 2019 to our clients (Consulting Engineers, Construction Companies & Government Sector). The projects are included pre-bid, DPR, Construction Re-engineering, Inspection, TOT and Smart Cities. There is water pipeline project was done with Mobile LiDAR which is planned along a road corridor. We used Mobile LiDAR for Road Junctions, Tunnel Survey, Railway (High-Speed Rail Corridor)
We combine the LiDAR Technology with conventional survey methods to deliver the data 100% complete without any shadow area. The advantage of conventional method is assuring the accuracy and quality of LiDAR data
We combine the LiDAR Technology with conventional survey methods to deliver the data 100% complete without any shadow area. The advantage of conventional method is assuring the accuracy and quality of LiDAR data
LiDAR Survey Workflow
Research our clients requirement:
Government entities,i.e., NHAI or other State Government Highway Departments have ready access to their set of specifications. These documents are more fluid than many believe, especially as they relate to emerging technologies like mobile LiDAR. These requirements also have specific survey and mapping sections. Designate a lead to read and understand these requirements. Knowledge of applicable specifications will help guide and properly constrain our workflow.
Establishing Ground Control Points
Good project plan for any survey requires proper geo-referencing. Mobile lidar, even though supplemented with GPS and inertial measurement unit (IMU) systems, still needs to be checked against higher accuracy reference points. This means
establishing visible control targets and referencing this control to the appropriate reference network.
Data Acquisition
Mobile LiDAR Data acquisition is required several DGPS observation. Rain or High Temperature will affect the data collection. A well trained surveyor cum operator shall drive and monitor the data collection.
Government entities,i.e., NHAI or other State Government Highway Departments have ready access to their set of specifications. These documents are more fluid than many believe, especially as they relate to emerging technologies like mobile LiDAR. These requirements also have specific survey and mapping sections. Designate a lead to read and understand these requirements. Knowledge of applicable specifications will help guide and properly constrain our workflow.
Establishing Ground Control Points
Good project plan for any survey requires proper geo-referencing. Mobile lidar, even though supplemented with GPS and inertial measurement unit (IMU) systems, still needs to be checked against higher accuracy reference points. This means
establishing visible control targets and referencing this control to the appropriate reference network.
Data Acquisition
Mobile LiDAR Data acquisition is required several DGPS observation. Rain or High Temperature will affect the data collection. A well trained surveyor cum operator shall drive and monitor the data collection.
Data Processing
Once the Ground Control Points and Mobile LiDAR Data is ready for processing, the following Processing and Mapping tasks shall be done
- Post processing is executing by combination of different software and different workflow, i.e., Trajectory Adjustment, extracting images and Scan data, Geo-reference of images and scan data, Manual Adjustment of Point Cloud, colorizing the point cloud, export to different type of formats (las, laz, rcp files)
- Point Cloud Data Matching (Manual Trajectory Adjustments)
- Line works, Preparing CAD files from Point Cloud (las to dwg/dgn file) CAD file includes all features that are visible from the air, breaklines, features such as paint striping, utility access panels, edge of pavement, water features, and etc.
- Point Cloud Data Classification (Ground, Trees, Water, Building, Power lines)
- Preparing DEM & DSM, Contour drawings and Ground Levels
- Incorporation of conventional survey data where the LiDAR creates shadow region
- Field check of drawing shall be done by a senior surveyor and update the same
- Delivery of Drawings, Reports, LiDAR Data set and necessary viewer software
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Deliverable
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