Accurate positioning and the identification of transportation and other infrastructure (e.g., a traffic sign, the curb line) can be an immense task requiring the efficient collection of vast quantities of data. New technologies offer opportunities to greatly improve the effectiveness of mass and incremental data collection. One of the newly developed technologies for collecting infrastructure data is GPSVisionTM, which utilizes GPS integrated with an INS and state-of-the-art progressive scan CCD (charge coupled device) cameras. The result is that any object that is “seen” by the sets of cameras can be precisely located using a stand-alone global coordinate system in conjunction with our advanced soft-photogrammetric mathematical model. GPS provides accurate position data to the system. Because of low data rates and the requirement of viewing at least four satellites, the use of GPS alone is limited. In contrast, INS provides high rate position (X, Y, Z coordinates) and attitude (direction) information (400Hz), but its sensor errors tend to grow with time. By integrating GPS and INS, the accurate GPS position is used to update the INS, and the INS then produces the high rate, accurate position and attitude data of the system, even when the GPS signals are lost.
From a photogrammetric perspective, GPSVisionTM is a fix-based stereovision system with known position and attitude provided by the GPS/INS component. Just as a person uses two eyes to determine the distance of an object, every infrastructure feature that is “seen” by the cameras can be triangulated into a three-dimensional coordinate and then transferred into a global coordinate system (e.g., latitude, longitude, height).