AMTS (Automated Motorized Total Stations) provide automated optical monitoring of displacements and settlement in buildings, bridges, railways, roads, tunnels, support of excavation, retaining walls, embankments, and surcharged fills. Datasheet
Optical monitoring involves prisms, measurements with a total station, and processing.
Prisms are fixed to critical points on the structure, and the total station is used to record angles and distances to each prism. The measurements are offloaded to software that applies statistically-weighted adjustments and outputs coordinates for each prism.
Successive measurements are obtained at regular intervals and processed the same way. Changes in coordinates indicate that movement has occurred. The magnitude and direction of the movement is found by comparing current and initial coordinates.
AMTS systems automate these steps and deliver alerts, plots and reports via a project website.
AMTS at a project site in Boston
AMTS System Components
AMTS systems are designed to provide continuous, unattended monitoring. Components of the system include:
Prisms installed at monitoring points and control points.
AMTS consisting of a high-precision robotic total station managed by a controller. Multiple AMTS are deployed at some sites.
Controller that schedules and directs AMTS measurements and transmits the recorded data to the internet.
GeoCloud Server that performs quality checks, processes the measurements with MonStar least-squares software, and formats data for a website database.
GeoCloud Web Site that provides alarms, site views, graphs, and integration with standard geotechnical instrumentation.
This AMTS is monitoring rail-clip prisms installed on the track.
Careful placement of the AMTS and the prisms is important for creating strong geometric networks.
The AMTS must be positioned for clear lines-of-sight to monitoring points and control points. GEO's specialized mounting brackets and towers were developed for this purpose.
Monitoring points are prisms installed at specified locations on the structure. Measurements of these points reveal settlements and displacements. GEO deploys specialized prisms for different types of structures.
Control points are prisms installed at stable locations outside the zone of influence. Measurements of control points establish the exact position of the AMTS. GEO installs redundant control points to enhance precision and to provide the flexibility to relocate the AMTS as needed.
The AMTS must observe both control prisms and monitoring prisms for each measurement cycle. GEO programs the AMTS to record three pairs of observations for each prism to ensure that a complete and accurate set of measurements is obtained for each cycle.
Automated: Automatation provides continuous monitoring and rapid processing of measurements, allowing early identification of any unwanted displacements.
Accurate: Multiple observations from a fixed location and least-squares processing delivers accuracies similar to first-order surveys.
Cost-effective: AMTS systems provide wide-area coverage at a low-cost per monitored point. Unattended operation and automated processing also lower costs and save time.
Compatible: GEO’s MonStar software can output data as specified by the customer, suitable to combine with other geotechnical instrumentation or for use with CAD-generated plan views and as-builts.
AMTS configuration involves recording the initial location of all the prisms.
AMTS to GeoCloud Data Flow
Each AMTS measurement cycle consists of multiple observations of all prisms. Measurements are then transmitted to GeoCloud servers for processing.
GeoCloud directs measurements to Monstar for least-squares adjustments and quality checks. Monstar then formats data for import into the GeoCloud project database.
The import process checks for missing data, tests measurements against alarm thresholds, and then stores data in the project database. Planviews, trend plots, and reports are made available on the project website.
Rail & Metro
Structures and Excavation
Renovation of Structures
Structures near Tunnel