This paper presents results from the first two Space Shuttle test flights of the TriDAR vision system. TriDAR was developed as a proximity operations sensor for autonomous rendezvous and docking (AR&D) missions to noncooperative targets in space. The system does not require the use of cooperative markers, such as retro‐reflectors, on the target spacecraft. TriDAR includes a hybrid three‐dimensional (3D) sensor along with embedded model based tracking algorithms to provide six‐degree‐of‐freedom (6 DOF) relative pose information in real time. A thermal imager is also included to provide range and bearing information for far‐range rendezvous operations. In partnership with the Canadian Space Agency (CSA) and NASA, Neptec has space‐qualified the TriDAR vision system and integrated it on board Space Shuttle Discovery to fly as a detailed test objective (DTO) on the STS‐128 and STS‐131 missions to the International Space Station (ISS). The objective of the TriDAR DTO missions was to demonstrate the system's ability to perform acquisition and tracking of a known target in space autonomously and provide real‐time relative navigation cues. Knowledge (reference 3D model) about the target can be obtained on the ground or in orbit. Autonomous operations involved automatic acquisition of the ISS and real‐time tracking, as well as detection and recovery from system malfunctions and/or loss of tracking. © 2012 Wiley Periodicals, Inc.

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Kinematic mapping is used for preliminary development of an algorithm for the approximate synthesis of planar four-bar mechanisms for rigid body guidance. Both dyad type and dimensions are determined. Planar mechanism coupler motions are represented as the curves of intersection of a pair of quadric constraint surfaces, one for each of two dyads. The problem reduces to identifying the two best constraint surfaces in the pencil of quadrics containing the curve. The overdetermined synthesis equations are linear in the unknown surface shape coefficients, and their products. Non-trivial solutions exist only in the nullspace of the coefficient matrix. While the algorithm remains incomplete, results presented herein are encouraging.

Neptec has developed a vision system for autonomous rendezvous and docking in space that does not require the use of cooperative markers, such as retroreflectors, on the target spacecraft. 12 The system uses an active TriDAR 3D sensor along with embedded model based tracking algorithms to provide, out of the box, 6 degree of freedom (6DOF) relative pose information in realtime. The TriDAR (triangulation + LIDAR) sensing technology combines active triangulation and Time-ofFlight (TOF) ranging techniques within a single optical path. This design takes advantage of the complementary nature of these two technologies to provide optimal 3 dimensional data from several kilometers all the way to docking. A thermal imager is also included to provide bearing information at long range.

A new solid-state, high-resolution acoustic imaging technology has been applied in hydraulically fractured wells to image and quantify perforation erosion. The downhole device captures detailed full-lateral logs of horizontal wells, without the need for clear fluids to facilitate measurements. This paper discusses how the imaging technology functions, lab testing that validated the measurements, and field testing completed with several operators in a variety of reservoirs and basins. This high-resolution, acoustic-based downhole imaging technology provided a 360-degree view inside a variety of wells. Instead of optics, the imaging technology used high-frequency sound waves to image a full lateral through opaque fluids at sub-millimetric levels. The imaging tool was conveyed on either tractor or e-coil to continuously log the wellbore between 15 and 30ft/min, completing a full azimuthal scan that imaged individual perforations regardless of orientation. A range of imaging techniques quantified and measured each perforation to determine the extent of erosion in each perforation, cluster, and stage sustained during the hydraulic fracturing process. The acoustic imaging technology was initially tested in the lab with calibration jigs and perforated pipe samples to validate its accuracy. The technology was then field deployed by several operators and used to assess perforation erosion in extended horizontal wells by scanning the entire well from toe to heel and measuring thousands of perforations in a single log. The data gathered quantified the perforation diameter, perforation erosion range, perforation orientation dependency, cluster efficiency, perforation erosion bias, and discovered the presence of significant casing damage around areas where plugs were set. The image results showed the distribution, size, and measured diameter for each perforation in each cluster. The results noted toe or heel biases and how these changed in different well types and designs in different basins. The data allowed operators to reach conclusions regarding erosion and cluster efficiency across the entire lateral in various wells in the Montney, Permian, and Anadarko basins. Wells across North America were scanned in several other basins for comparison purposes using various completion designs from different operators. The high-resolution acoustic imaging technology offers a robust 360-degree view of long horizontal wells and perforation measurements post-fracture. Over 35,000 perforations have been measured using the technology in the field across various well types with different designs. The technology has proven to be a valuable tool in improving and optimizing completion designs by providing detailed feedback on where designs are working effectively and where they can be improved.