Operations Support

GeoLas Consulting provides on-site survey operation support to customers renting or purchasing LIDAR systems:

  • Project planning
  • System integration, installation, and testing
  • Boresight calibration
  • On-site data quality control and evaluation
  • Hands-on training


Quality Control

We provide data quality control services and project supervision to LIDAR operators, to detect quality impairing influencences or omissions early on, and to ensure smooth project flow, and to help identify data deficiencies before they end up in the customer's hands. We also provide independent data quality assesment services for end customers seeking a second opinion on delivered data.

  • Checking of flight planning, ground control distribution, GPS reference data sources
  • GPS and trajectory data quality assessment
  • Geometrical data quality:
    • point density
    • noise
    • relative accuracy (intra-line and inter-line deviations)
    • absolute accuracy (vs. reference/ground control data)
    • residual outliers, artifacts
  • Classification results
  • Completeness of data coverage, formats, and products


Troubleshooting

During the more than 20 years of airborne lidar operations and data processing we have been able to help numerous customers with issues and problems they encountered with malfunctioning airborne LIDAR hardware and corrupt or flawed data. We have gathered extensive experience in

  • analyzing LIDAR data from many different sensors and in many formats, both raw and processed,
  • identifying errors and artifacts,
  • extracting and modelling systematic errors,
  • developing software tools to correct systematic errors automatically,
  • and filtering out raw data file errors / extracting useful parts of corrupted files.

In several cases we were able correct/improve or recover the data to an extent that our customers could avoid expensive re-flights, and in many cases we were even able to pin-point the underlying hardware problems letting them get their systems fixed before more spoilt data was collected.

Examples of troubles shot:

  • identification of erroneous installation-, transformation- and map projection parameters causing missmatch of overlapping swaths,
  • modelling and correction of uncompensated range walk due to intensity variations, that caused vertical artifacts of several decimeters in a flood-plain mapping project,
  • detection and filtering of firmware-effected spikes in binary full-waveform raw data, causing processing errors and numerouse false returns,
  • modelling and correction of a scan angle timing error in an oscillating-mirror scanner, causing warping of the swath edges,
  • detection, visualization, and semi-automatic removal of a crosshatch pattern of artifacts caused by an electrical interference superimposed on the ranging signal due to a bad electrical ground connection,
  • modelling and automatic compensation of a circular pattern superimposed on height values from a Palmer scanner due to a defective mechanical bearing in the laserscanner,
  • early identification of a degrading laser source based on the analysis of full-waveform data irregularities
  • analyis of scan-to-scan roll angle variations and compensation by trajectory data filtering, caused by propeller/rotor-induced vibrations of an inadequately mounted IMU in one case, and an insufficiently vibration-isolated laserscanner system in another,
  • detection, analysis, modelling, and compensation of large dynamic roll-angle errors, that turned out to be caused by IMU non-linearities during a highly turbulent flight mission.
  • ...

In other situations, after data analysis we were able to help our customer to interpret data flaws and understand their genesis, thus enabling them to avoid or correct similar effects themselves.

Let us know if you are struggeling with data flaws or lidar system issues impeding your operations or quality requirements. We will be glad to assist!

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