THE ART OF LOCALIZATION: TECHNIQUES FOR ESTABLISHING RELIABLE CONTROL IN THE FIELD
The glue that holds your project together- controls points! What are they, and how do you localize them?
Control points are the foundation of your project; they serve as physical reference points for the project's spatial framework, establishing accurate elevations and real-time location. In simpler terms, they are a point on the ground or any permanent structure whose horizontal and vertical location/position is known. There should be a MINIMUM of 4 points surrounding the job site. They should be placed on the ground in anything you can get the point of a GPS rod on, like a hub, drill hole, pk nail, or iron rod. They CANNOT be placed under any obstructions and require open sky.
GNSS Localization/site calibration is the process of aligning GPS data with an accurate coordinate system (control points) to ensure precision. This process guarantees all components are properly aligned. Site Calibration is required when GNSS data needs to be integrated with existing surveys.
Use of a Control Network: Surveyors use benchmarks that are tied to global coordinate systems
GNSS Equipment & Total Stations: Equipment used to transfer control points on site and create a second set of control points/site-specific grid
Laser Scanning: The use of LIDAR or drones to check for changes and maintain the accuracy of the control points
Surveying Techniques: Triangulation, Trilateration, & Traversing
Triangulation
The three Ts in surveying, and what are they?
Triangulation: Trigonometric applications are used to determine unknown distances between stations. You solely use angles to conduct measurements. Best used for mountainous and complex terrain or large sites.
Trilateration: A simpler form of triangulation. Measures distances between control points by using GPS and EDM equipment, and is best used for flat surfaces.
Traversing: Measures the distance and angles between a series of points.
If your control points aren’t accurate, the entire project will be thrown off. It's essential to periodically check their accuracy and recalibrate if any changes occur due to weather or unforeseen factors.
If you have any more questions about Control Points or how to localize them, reach out to us at (877) 572-3414 or email us at info@eci3d.com!