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Publication Citation: Surveying Through Solid Walls

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Author(s): William C. Stone;
Title: Surveying Through Solid Walls
Published: June 08, 1997
Abstract: A good metrology system in the automated environment must (1) measure the three dimensional position and attitude of any component to a reasonable degree of accuracy; (2) acquire these data fairly rapidly; and (3) be capable of making reliable measurements anywhere on site. A significant limitation for existing surveying systems (including GPS and laser based technologies) is the requirement for direct line-of-sight between the reference and roving surveying elements. Construction sites, as a rule, are highly unstructured environments and clutter is the norm. Recent fundamental research has been undertaken at NIST to develop a real-time Non-Line-of-Sight measurement system capable of tracking to 10 mm accuracy despite the presence of walls, ceilings, floors, and other obstructions. The new system determines the distance from a series of reference transmitters which broadcast pulse-synthesized baseband electromagnetic signals. Digital signal processing techniques are used to recover the time of flight (and hence distance) and to compensate for errors introduced as a result of material penetration and re-transmission of the signal. Results are disucssed.
Conference: Automation and Robotics in Construction
Proceedings: 14th International Symposium
Location: Pittsburgh, PA
Dates: June 8-11, 1997
Keywords: walls; electromagnetic wave propagation; metrology; non-line-of-sight; signal attenuation; spread spectrum radar; surveying; wireless communications
Research Areas: Building and Fire Research
PDF version: PDF Document Click here to retrieve PDF version of paper (2MB)