*3.2.1. "GPSVisionTM" achieved by the "LAMBDA TECH International" company (Guangping He, 1996)*

The Mobile Mapping Equipment "GPSVisionTM" (fig. 5) achieved by the "LAMBDA TECH International" company from Fort Wayne (USA), which is equipped with a positioning module composed of a GPS receiver with double frequency, an Inertial Navigation System (INS) and a linear Distance of running Measuring Instrument (DMI), in combination with four digital video cameras of high resolution. The digital video cameras are mounted above the vehicle and they can be oriented forward, to each side or backward in correspondence with the application needs, so that due to the fact that the video cameras pairs see, at a certain moment, the same field area from different positions, by using some triangulation algorithms, it is possible to calculate the locations relative to the lab vehicle of the sighted targets.

The main characteristics of the system are:


sign. Stereo imagery allows for multiple views of the same object with 3D capabilities and the ability to recreate image views where the original cameras never took a picture;

GPS Positioning of Some Objectives Which are Situated

at Great Distances from the Roads by Means of a "Mobile Slide Monitor – MSM" 161

*3.2.2. "GPSVanTM" achieved by the "Mapping Center" from the Ohio State University* 

A similar example of a mobile system for mapping and data collection, which can map railroads, thoroughfares and transport infrastructures (as for example, roads, circulation signs and bridges) during its displacement at posted road speeds is represented by "GPSVan™" system achieved by the Mapping Center from the Ohio State University and which is also composed of two main components: a positioning module and an imagery module. This imagery module includes, also, in this case, a stereo metric system with two video cameras which record the stereo images of the roads during the displacement on the respective arteries of the lab vehicle. Each video frame is time marked with the GPS signal and the geodesic coordinates (latitude, longitude and ellipsoidal height, respectively) are

From the above presented aspects, it results that both the GPSVisionTM and GPSVan™ equipments represent, in their essence, a fix-based stereovision system with known position and attitude, provided by the GPS/INS component and, respectively, by the GPS/DRS component. This fixed base is represented by the distance, on the hood width of the lab vehicle, between the optical distances of the two video cameras, mounting distance which in the case of both GPSVisionTM and GPSVan™ equipments is approximately of 1.2 meters. As a consequence of the fixed base reduced value, the difference between the angles of sighting directions of the two video cameras is under the minimum value it can be measured by the optical system when the sighted targets are situated at a distance, greater then approximately 40 meters, in respect to lab vehicle. This limitation of the observing distance, at a quite reduced value, represents in its essence the main disadvantage of the stereo metric systems, which are based on the use of a pair of video cameras, mounted on the same lab

**4. Originality of the proposed Mobile Slide Monitor (MSM)** 

which the sighted targets from the terrain can be positioned.

Conceptually this Mobile Slide Monitor - MSM involves:

The static regime systems, previously described, achieve the stability monitoring of the constructions by using precision optical systems or GPS equipment with differential regime functioning, but to which the follower receiver is attached in a fixed montage on the surveyed construction. As opposed to these systems the monitoring system presented here has the advantage that it permits measurements to be rapidly performed, at preset time interval, with a reduced cost on a multitude of objectives and with a minimum delay between the moment of some defection occurence and the moment of its identification and

Taking account of the above-mentioned characteristics of the bi-cameral stereo-metric systems, the INOE 2000 Institute from Bucharest elaborated the Invention Patent RO 126294 A2/2009 whose main objective was to increase up to U200 – 300 metersU, the distance up to

*(Brzezinska et al., 2004)* 

attributed to each image.

vehicle.

alarming.


**Figure 5.** GPSVision™ - with four video cameras achieved by the "LAMBDA TECH INTERNATIONAL" Company (USA) for objectives that are closed to the road arteries

## *3.2.2. "GPSVanTM" achieved by the "Mapping Center" from the Ohio State University (Brzezinska et al., 2004)*

160 Cartography – A Tool for Spatial Analysis

front of the camera lenses;

sign. Stereo imagery allows for multiple views of the same object with 3D capabilities and the ability to recreate image views where the original cameras never took a picture; GPSVision™ specified absolute accuracy for terrestrial data positions is **one meter or less** depending on the distance bewtween the feature to be extracted and the camera lens. Depending on the image spacing this accuracy can be increased. The GPSVision™ system was designed to deliver sub-meter RMS positions when visible features are within the camera field of view of both image pairs and **no farther than 30 meters** in

 From a photogrammetric perspective, GPSVision™ 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); GPSVision™ Feature Extraction software is executable on Microsoft Windows operating systems. It is driven by an external rule base and is language neutral. The user interacts with the software by pointing at features of interest seen in the stereo image pairs with the mouse or stylus. Then, the software triangulates the relative position of the selected feature and transfers it into the global coordinate system and

 From an application perspective, the GPSVision™ system is used to collect digital images along highways, state roads, residential streets, alleys, and railroads while traveling at posted speed limits. These geo-referenced digital images are used for video log applications but most importantly, the software is used to position visible physical features, such as poles, curb lines, traffic signs, manholes, pedestals and building locations. In addition, the GPS/INS positioning component creates base maps of the route network for Geographic Information Systems (GIS) base map and Computer

positioned to within one meter or less of their actual location;

**Figure 5.** GPSVision™ - with four video cameras achieved by the "LAMBDA TECH INTERNATIONAL" Company (USA) for objectives that are closed to the road arteries

Aided Drafting and Design (CADD) applications.

A similar example of a mobile system for mapping and data collection, which can map railroads, thoroughfares and transport infrastructures (as for example, roads, circulation signs and bridges) during its displacement at posted road speeds is represented by "GPSVan™" system achieved by the Mapping Center from the Ohio State University and which is also composed of two main components: a positioning module and an imagery module. This imagery module includes, also, in this case, a stereo metric system with two video cameras which record the stereo images of the roads during the displacement on the respective arteries of the lab vehicle. Each video frame is time marked with the GPS signal and the geodesic coordinates (latitude, longitude and ellipsoidal height, respectively) are attributed to each image.

From the above presented aspects, it results that both the GPSVisionTM and GPSVan™ equipments represent, in their essence, a fix-based stereovision system with known position and attitude, provided by the GPS/INS component and, respectively, by the GPS/DRS component. This fixed base is represented by the distance, on the hood width of the lab vehicle, between the optical distances of the two video cameras, mounting distance which in the case of both GPSVisionTM and GPSVan™ equipments is approximately of 1.2 meters. As a consequence of the fixed base reduced value, the difference between the angles of sighting directions of the two video cameras is under the minimum value it can be measured by the optical system when the sighted targets are situated at a distance, greater then approximately 40 meters, in respect to lab vehicle. This limitation of the observing distance, at a quite reduced value, represents in its essence the main disadvantage of the stereo metric systems, which are based on the use of a pair of video cameras, mounted on the same lab vehicle.
