An Introduction to Spatial Positioning Systems, Inc.

Currently positioning in the construction industry is achieved using theodolites, levels, total stations, and chains or tapes. The problem with current methods is that they tend to be laborious, time consuming, expensive and are susceptible to errors in collecting, transcribing and reducing data.

In December of 1992 an industry consortium was formed with the purpose of developing and demonstrating a new real-time laser-based positioning system which could be linked to CAD and other database applications so that the data could be effectively transformed into useful information to help guide project activities. The founding members of the consortium include: Spatial Positioning Systems, Inc., Jacobus Technology, Inc., Bechtel Corporation, Civil Engineering Research Foundation (CERF), the Army Corp of Engineers, and Integraph Corporation which entered the consortium in June of 1993.

Spatial Positioning Systems, Inc., or SPSi was formed in June of 1990 by three Virginia Tech scientists and inventors. It was based on the design, creation and support of three dimensional positioning measurement systems. SPSi has since gone on to patent laser- based positioning technology in the pursuit of that goal.

The system itself is made up of two transmitters and a receiver. The transmitter is set on a tripod and has a front face plate so that light can be scattered about the site. The transmitter is powered with a 12 volt battery that gives power for up to 30 hours. The transmitters can also be wired to a standard outlet with the addition of an AC/ DC converter. The receiver is made up of two optical lenses mounted on a pole, a battery, and a data entry and retrieval system. All that is needed for the system to function is the known location of four points. When these points have been entered the system then self calibrates. Once calibrated any point may be found within the working envelope of the receivers.

The SPSi system has many applications in construction. Specifically it could be used in surveying, as-builts and alignment of equipment. The as-builts could be attained more easily since the information sent from the system can be sent immediately to CAD.

Outiside of construction an accurate positioning system also has uses. It could be used in the manufacturing of large components, docking of space vehicles, mid-air refueling of aircraft, environmental clean-up and hazardous waste handling.


"A Real-Time Laser-Based System for Collecting Construction Site Positioning Data." Dr. James Michael Wiliams, Jerry King and Eric Lundberg. October 26, 1993.

"Real-Time Position Measurement Integrated with CAD: A Survey of Technology and Protocols." Dr. Yvan J. Beliveau, James Michael Williams, M. Gerald King and Anthony R. Niles.

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