GNSS/INS for High Accuracy Mobile Mapping. Olaf Gross 11 th Terrasolid European User Event Kittilä, Finland

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1 GNSS/INS for High Accuracy Mobile Mapping Olaf Gross 11 th Terrasolid European User Event Kittilä, Finland

2 IGI mbh Founded staff about half in R&D More than 380 customers in 60 different countries World-wide technical support IGI office in Kreuztal

3 IGIs Modular Sensor Systems Missionplanning Navigation GNSS/IMU Sensor Management

4 IGIs Mobile LiDAR Solutions

5 Georeferencing Workflow Scanner data Navigation data point cloud Office/Lab Calibration Measure lever arms & Determine Misalignments Apply misalignments and lever arms Calibration Is the Result satisfactory? yes Pointcloud

6 Missalignment Calibration workflow Drive suitable site with buildings: Good visibility to walls Clean, vertical walls Right driving pattern Search tie lines on building walls automatically Solve HRP misalignment angles

7 Calibration Mobile

8 Calibration driving pattern ( lot Large building with open area (parking Calibration driving pattern 1

9 Calibration of Train/Tram Data?! Engineers installing a RailMapper calibration field

10 Airborne Lidar & Mobile Mapping Same sensor technologies LiDAR, GNSS/INS, different kind of cameras point cloud Similar calibration and orientation strategies Differences: Kinematic conditions GNSS conditions Distance to the object

11 Kinematic Conditions - Standstill

12 GNSS conditions: Air vs. Ground

13 Distance to the Object of interest Airborne LiDAR / Photogrammetry focal length: 100mm pixel size: 6µm FOV (one pixel) = LiDAR Mobile Mapping point cloud distance: 5m accuracy: ~1cm angular error = 0.1

14 Resulting Requirements Application Position Orientation Airborne LiDAR or Airborne Photogrammetry cm dm Airborne Thermography dm LiDAR Mobile Mapping mm cm 0.1 Challenging! Easy! The IMU is 10 to 1000 times better than needed for Orientation of LiDAR Mobile Mapping But: Exceptional good IMU is a must to be able to provide required Position accuracies!

15 TERRAcontrol Technology Differential GNSS IMU Kalman Filter Position Velocity Attitude

16 GPS vs. GPS & GLONASS

17 GPS vs. GPS & GLONASS GPS only

18 GPS vs. GPS & GLONASS GPS & GLONASS

19 GPS vs. GPS & GLONASS GPS & GLONASS GPS only

20 TERRAcontrol Technology Differential GNSS Direct Inertial Aiding IMU Odometer Kalman Filter Position Velocity Attitude

21 Direct Inertial Aiding

22 Direct Inertial Aiding without inertial aiding with inertial aiding

23 Direct Inertial Aiding

24 Navigation ZUPT

25 Navigation ZUPT

26 TERRAcontrol Technologie TERRAoffice V5.2 compared to V5.3 Trajectory TERRAoffice 5.3 Trajectory TERRAoffice 5.2

27 TERRAcontrol Technologie IV TERRAoffice V5.2 compared to V5.3 Trajectory TERRAoffice 5.3 Trajectory TERRAoffice 5.2

28 Forward/Backward Processing GNSS gap

29 IMU Performance GPS only

30 IMU Performance

31 TERRAcontrol Technologie TERRAcontrol IMU-IIe Fiber optic gyros MEMS Accelerometers Data rate 400Hz Gyro Drift 0.03 /h

32 TERRAcontrol Technologie TERRAcontrol with IMU-IIe Integrated GNSS receiver with DIA+ (GPS/GLONASS) IMUIIe Real time navigation System accuracy (dgps): Position: <0.05m Velocity: 0.005m/s Roll/Pitch: Heading: 0.007

33 TERRAcontrol Technology StreetMapper Control Rack Thermal camera option for StreetMapper and RailMapper

34 Georeferencing Workflow Scanner data Navigation data point cloud Measure lever arms & Determine misalignments and Apply misalignments and lever arms Is the Result satisfactory? yes no Apply global or local adjustments Pointcloud

35 Terrasolid Tie Lines Matching based on intensity or xyz features in LIDAR Matching based on linear features in images

36 Geometric Correction Typical control points GCP-Marker e.g. 25cm x 25cm

37 TERRAcontrol Technologie IV Example: Tram System Helsinki

38 TERRAcontrol Technologie IV Example: Tram System Helsinki

39 TERRAcontrol Technologie IV Problem: Strong GNSS shadowing effects due to vegetation and buildings.

41 Examples

42 Recent project on UK Highway - Results

50 Conclusion A careful system calibration is a prerequisite for high accuracy Mobile Mapping. Local adjustments are generally much more important for Mobile Mapping than for airborne LiDAR. Combining a high performance GNSS/INS with a state of the art LiDAR and the current calibration and adjustment techniques allows for cm accuracies for a wide range of project conditions.

THE RAILMAPPER - A DEDICATED MOBILE LIDAR MAPPING SYSTEM FOR RAILWAY NETWORKS

THE RAILMAPPER - A DEDICATED MOBILE LIDAR MAPPING SYSTEM FOR RAILWAY NETWORKS Jens Kremer & Albrecht Grimm IGI mbh, Langenauer Straße 46, 57223 Kreuztal, Germany (j.kremer, a.grimm)@igi-systems.com ICWG