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63 Technical Support Information for Inertial Mapping Systems Abstract GeoDZ Inc. will demonstrate a commercially available inertial mapping system (IMS) that can be deployed inside a duct or pipe. The IMS can produce an accurate mapping of the path that it has traveled relative to its starting and end points. If the entry and exit points are located using a high-accuracy GPS, then the x, y, and z coordinates of the intermediate piping can be captured regardless of pipe material, soil type, or depth. The current IMS product cannot be used in live or pressurized pipe. The demonstrations under SHRP 2 Project R01C will be lim- ited to storm drains or piping that is out of service. Technology Synopsis and Key Performance Indicators Title: Inertial Mapping for Utility Lines Targets: All pipe materials. Depth range: Unlimited, not dependent on soil types. Depth and position accuracy: The expected position (or location) accuracy for pipe is ±0.03% from the closest known (GPS-surveyed) point. The term âpositionâ is used because this is a mapping tool, producing x, y, z (3-D) coordinates in the state plane coordinate system (SPCS). The calibrated accu- racy is computed by the following: Accuracy3D = d/500 î° 0.15, where d is the distance in meters from the closest GPS marker location. This could be the entry or exit point of the pipeline, or intermediate markers along the pipeline trajectory. Application: The inertial mapping system (PROBE) is used in any open-ended or launch/trap-configured pipeline or conduit that is either empty or contains liquids, has minimal diameter restrictions or obstructions, and requires accurate 3-D mapping of the centerline and/or the precise trajectory to ascertain joint and bending geometry. Basic principle: The inertial mapping system (PROBE) is an autonomous electromechanical device that through the triad of accelerometers and gyros, measures and records the down- line distance, angular changes, and accelerations of the PROBE and that through postprocessing, computes a high-resolution 3-D pipe centerline. GPS surveying is used to establish the start, intermediate, and end points of the mapping survey. Results are uploaded into any industry geographic information system (GIS) for further viewing, integration, and analysis. Limitations: The PROBE system is limited as follows: (1) current battery/memory capacity is limited to 3 h of run time, and depending on pulling or flowing speed, this may be up to 3 km; (2) the calibrated accuracy is based on typical horizontal directional drilling (HDD)âinstalled pipe (long sweep radius, smooth pipe wall, constant operating tempera- ture, and the ability to pull at consistent velocity); and (3) the pipe trajectory (short radius bends pose challenges for pas- sage and degrade the position accuracy due to the heading sensitivity of the gyros). Additional notes: Challenges lie in the ability to insert/ extract these tools in a cost-effective, safe, and reliable man- ner. Development of a sound operations plan is required to manage the GPS survey, tool tracking, and site selection for intermediate points (or markers, similar to pigging above- ground markers, or AGMs) to keep the inertial errors to a minimal and acceptable level. A P P e n d I x H
