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Alignment-based Monitoring


Alignment-Based Monitoring Provides Meaning to Movement Data

Monitoring movement of roads, railways, pipelines, bridges, and the like, are commonly tracked relative to conventional coordinate positions such as Northing and Easting positions.

The Trimble 4D Control v6.2 solution re-aligns that thinking.

Monitoring assets like tunnels, roads, and railways require any potential movement to be expressed with regard to the path, or alignment, of the object. Yet, in most monitoring applications, the reference points are defined by the axis of a set x,y,z coordinate system—not the object that is being monitored.

For example, with alignment-based monitoring, the displacement of a railway is tracked relative to the path of the rail line and is reported relative to the direction of the rail, instead of in a traditional coordinate system, making interpretation and analysis of the data more meaningful, as shown in Image 1.


Coordinate vs Relative Displacements

Instead of coordinate system related values—delta Northing (dN), delta Easting (dE) and delta Height (dH)—the displacements within the Trimble 4D Control (T4D) solution are available as delta Station (dStation), delta Offset (dOffset) and delta Vertical (dVertical) values.

These values—dStation, dOffset and dVertical—are associated with and refer to an alignment definition that mathematically defines the geometry of a monitoring object. “dStation” represents a displacement along the alignment (forward and backward), whereas “dOffset” (horizontally, left and right) and “dVertical” (up and down) are values perpendicular to the alignment.

alignment map view

Image 2: Maps view in T4D Web of a tunnel alignment with monitoring sensors located along the tunnel design.

Further, the 2D geometry of an alignment can be visualized next to the sensors on the Maps page of Trimble 4D Control Web. This page visualizes the movement direction and magnitude relative to the alignment object as shown in Image 2 above.

alignment based scatter

Image 3. Scatterplot analysis of alignment-based monitoring data in T4D Web

You can schedule reports and analysis with delta Station, Offset, and Vertical position data alongside your current deliverables in T4D. You can also combine alignment-based values with other geotechnical and environmental data in your analysis such as temperature, pressure, and humidity. By creating alarm conditions, simple or complex, based on alignment values to warn stakeholders of movement trends in real-time, the alignment position data will provide additional insights into the movement trends relative to the object.

alignment chart

Image 4. Displacement chart showing a target's movement relative to a building wall using the alignment-based monitoring tool in T4D Web.

Re-align your thinking and put alignment-based monitoring to work on your next project.

For more information, view this webinar recording, or contact the Trimble Monitoring team here.