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Best Practices for EchoONE

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RESEPI User Manual
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Introduction #

EchoONE is the latest and most capable LiDAR system that has been offered to date by Inertial Labs. It combines some of the best-in-class inertial technologies and navigation filtering from Inertial Labs, a VIAVI Solutions company, and a powerful LiDAR, precision calibrated from Teledyne Optech. With this system you will be able to capture, and process the best data that is currently available from the RESEPI product line up. With the additional features of this system, in order to get the most out of your product, this brief document was put together in order to offer some general suggestions and guidance to ensure your data is properly suited for the job at hand. Because of the 90-degree Field of View (FOV) of EchoONE, and the two scanning modes of 400kHz and 600kHz we can generalize some suggestions based on general industry recommendations for point density and accuracy for two main markets. Again, these are highly generalized suggestions and are in no way a perfect suggestion for a jobs’ requirements that EchoONE might be used for. Our technical support team stands ready to provide additional feedback as needed based on additional input the customer can provide for their specific job. But to fulfill the purpose of this article, as generally suggested guidelines the first use case we will provide suggestions for is Topographic Mapping, generally speaking; and the second is Inspection, which is also generalized.
  1. General Topographic Mapping:
    1. Point Density: Lower requirements than inspection, 50-100 points per square meter is generally more than sufficient.
    2. Accuracy: Two to ten centimeters is generally sufficient for topographic mapping.
    3. Goals: With typically lower requirements than inspection for point density and accuracy, topographic mapping missions often prioritize ground point coverage and speed of capture. Users want to fly higher, and faster to cover more ground as quickly as possible without sacrificing the need for sufficient ground coverage to make a quality surface or terrain model.
  2. General Inspection:
    1. Point Density: 100+ points per square meter.
    2. Accuracy: Large variations based on use case with most common requirements needing accuracy to be no more than a handful of centimeters. Desired accuracy should be >3cm to generally catch and encompass most inspection related applications.
    3. Goals: With much higher requirements than topographic mapping for both density and accuracy, an inspection mission will take extra time to ensure details and fidelity is maintained across the entire mission. Users will often fly lower, and slower to make sure that they capture all the detail that is needed to make actionable analysis from the data that is captured.

Mission Planning and Data Processing #

  1. Flight Plan:
    1. Topographic Mapping:
      1. Suggested Altitude: 100m – 120m AGL
      2. Flight Line Overlap: 20-30%
      3. Flight Speed in AOI: 10 – 12m/s
      4. Mission Type: single grid or down and back is sufficient
      5. Calibration Maneuvers: static alignment of 30 seconds, lateral velocity of 5m/s for 5 seconds, figure eight, proceed to mission. After mission, return home, and perform an additional 30 seconds of static alignment
    2. Inspection:
      1. Suggested Altitude: 50m – 70m AGL
      2. Flight Line Overlap: 50-60%
      3. Flight Speed in AOI: 5 – 8m/s
      4. Mission Type: single grid is generally sufficient but if time permits double grid
      5. Calibration Maneuvers: static alignment of 30 seconds, lateral velocity of 5m/s for 5 seconds, figure eight, proceed to mission. After mission, return home, and perform an additional 30 seconds of static alignment
  2. LiDAR Scan Mode:
    1. Topographic Mapping: 400kHz
    2. Inspection: 600kHz
  3. Data Processing in PCMasterPro, Suggested Workflow:
    1. Topographic Mapping:
      1. Standard post processing mission, run the generated ppk.pcmp file from project directory;
      2. Cut flight lines to remove turns and calibration maneuvers;
      3. In the Cloud Filters menu, enable the Angular Rate filter to remove points captured at rotational velocity above 20 deg/s;
      4. Refine as needed (coordinate system, etc) and export;
    2. Inspection:
      1. Standard post processing mission, run the generated ppk.pcmp file from project directory;
      2. Cut flight lines to remove turns and calibration maneuvers;
      3. Perform standard statistical outlier removal;
      4. In the Cloud Filters menu, enable the Angular Rate filter to remove points captured at rotational velocity above 20 deg/s;
      5. In the Cloud Filters menu, enable the field of view filter trimming out areas of point cloud that are less accurate and precise. Set the minimum value to 235 and the maximum value to 305. This enables an effective 70-degree field of view for your LiDAR.
      6. Import ground control points into PCMasterPro;
      7. Refine as needed (coordinate system, etc);
      8. Upon export, leverage the Strip Alignment feature within PCMasterPro by checking the box for “Apply Strip Align”. Be sure to export point cloud with “Remove Collected Outliers” also selected.