Real-Time Position Measurement Integrated with CAD: Technologies and Their Protocols

Abstract

The consortium for advanced positioning system (CAPS) was formed in December 1992. The purpose of CAPS is to assist the Civil Engineering Research Foundation (CERF) with a Cooperative Research & Development Agreement (CRDA). CAPS will field and test a new real-time laser-based technology, real-time differential global positioning systems (DGPS), and total stations to determine areas of functionality and how to best integrate these measurement devices to improve the work process and as-building capabilities. The founding members of CAPS are Spatial Positioning Systems, Inc., Blacksburg, Virginia; Jacobus Technology, Inc., Gaithersburg, Maryland; Bechtel Corporation, San Francisco, California; and CERF, Washington, D.C. Integraph Corporation Huntsville, Alabama, joined CAPS in May 1993. The U.S. Army Corps of Engineers (Corps) is participating in CAPS through a CRDA with CERF. The objective of the CRDA is to create and field-test a system that improves quality, speed, and accuracy of construction layout and generates real-time as-builts. This effort encompasses the integration of the aforementioned new laser-based positioning system, total stations, and DGPS with computer-aided design (CAD)/ systems to form a real-time construction layout and as-built development system (RtCLADS). This paper presents three positioning technologies, their capabilities, their limitations, and the protocol needed to support the objectives of the CRDA.