Glossary

Civil Design, Engineering, & Construction terminology

Terms used in this help

benching	Benching is a process of aligning your GNSS position (latitude, longitude, and height) to a benchmark that has been added as a reference point. The calibration offsets your GNSS position to that of the benchmark, improving accuracy and providing a point that you can return to later.
AutoBase	AutoBase technology uses the position of the receiver to automatically select the correct base station; allowing for one button press operation of a base station. It shortens setup time associated with repeated daily base station setups at the same location on jobsites.
BaseAnywhere	BaseAnywhere technology allows the user to place the GNSS base station anywhere on site and does not require the base station to be setup on an existing control point. After the base is configured in BaseAnywhere mode it calculates an autonomous position and begins broadcasting corrections via radio or Wi-Fi. The rover is then used to bench into a control point which calculates the necessary offsets and parameters to allow for fully accurate RTK GNSS operations.
base station	Also called reference station. In construction, a base station is a receiver placed at a known point on a jobsite that tracks the same satellites as an RTK rover, and provides a real-time differential correction message stream through radio to the rover, to obtain centimeter level positions on a continuous real-time basis. A base station can also be a part of a virtual reference station network, or a location at which GNSS observations are collected over a period of time, for subsequent postprocessing to obtain the most accurate position for the location.
corridor	A corridor is a model of a linear feature such as a road or canal usually defined by one or more cross section templates consisting of template instructions. It also is a collection of corridor information expected to function together to define the corridor. These models can be parametric, meaning the geometry of the model can change based on input conditions. A corridor contains a main alignment, typically but not always the centerline, all sub alignments, the templates from which the corridor cross sections are defined, and all the information used to define the widening, slope ties, and super-elevations for the corridor. The term corridor is often used interchangeably with road in previous versions of the software.
DGPS	See real-time differential GPS.
design map	The map that provides live linework within a design for stakeout operations. The design map is a DXF, DWG, or VCL file.
differential correction	Differential correction is the process of correcting GNSS data collected on a rover with data collected simultaneously at a base station. Because the base station is on a known location, any errors in data collected at the base station can be measured, and the necessary corrections applied to the rover data. Differential correction can be done in real-time, or after the data is collected by postprocessing.
differential GPS	See real-time differential GPS.
elevation (elev, elv)	(1) Vertical distance (height) above or below mean sea level. (2) Vertical distance above or below the geoid. (3) Distance above or below Local Datum.
elevation mask	The angle below which the receiver will not track satellites. Normally set to 10 degrees to avoid interference problems caused by buildings and trees, atmospheric issues, and multipath errors.
feature	A feature is a physical object or event that has a location in the real world, which you want to collect position and/or descriptive information (attributes) about. Features can be classified as surface or non-surface features, and again as points, lines/breaklines, or boundaries/areas.
GLONASS	Global Orbiting Navigation Satellite System. GLONASS is a Soviet space-based navigation system comparable to the American GPS system. The operational system consists of 21 operational and 3 non-operational satellites in 3 orbit planes.
GNSS	Global Navigation Satellite System.
GPS	Global Positioning System. GPS is a space-based satellite navigation system consisting of multiple satellites in six orbit planes.
height	It can mean a target height or antenna height (for example, 2 m of rod height).
Here position	An autonomous instantaneous position derived from the GPS receiver’s uncorrected latitude, longitude, and height.
IBSS	Internet Base Station Service. This Trimble service makes the setup of an Internet-capable receiver as simple as possible. The base station can be connected to the Internet (cable or wirelessly). To access the distribution server, the user enters a password into the receiver. To use the server, the user must have a Trimble Connected Community or WorksManager site license.
Location GPS	Location GPS covers decimeter to submeter GNSS positioning techniques including Satellite Based Augmentation Systems (SBAS) such as WAAS, EGNOS, and MSAS), DGPS (reference station and rover operations), OmniSTAR VBS/HP/XP services, and Location RTK (decimeter-level RTK positioning).
Location RTK	Some applications such as vehicular-mounted site supervisor systems do not require Precision RTK accuracy. Location RTK is a mode in which, once initialized, the receiver will operate either in 10 cm horizontal and 10 cm vertical accuracy, or in 10 cm horizontal and 2 cm vertical accuracy.
Precision GPS	GPS positioning provided by techniques that typically deliver centimeter-level accuracy. These include RTK (Real-Time Kinematic) techniques and signals obtained from a VRS (Virtual Reference Station) system.
Project	A project that is to be worked on for a significant period. A project stores all design data and all executed work orders, so you can easily find data whether you are in the office or in the field.
postprocessing	Postprocessing is the processing of satellite data after it is collected to eliminate error. This involves using computer software to compare data from the rover with data collected at the base station.
real-time differential GPS	Also known as real-time differential correction or DGPS. Real-time differential GPS is the process of correcting GPS data as you collect it. Corrections are calculated at a base station and then sent to the receiver through a radio link. As the rover receives the position it applies the corrections to give you a very accurate position in the field. Most real-time differential correction methods apply corrections to code phase positions. While DGPS is a generic term, its common interpretation is that it entails the use of single-frequency code phase data sent from a GNSS base station to a rover GNSS receiver to provide sub-meter position accuracy. The rover receiver can be at a long range (greater than 100 km (62 miles)) from the base station.
Road job	A road job is the term that defines a complete road model within the Terramodel and Siteworks software. It is a collection of roadway information that is expected to function together to define a roadway or a portion of a roadway between specific stationing limits. A road job contains the main alignment and all sub alignments, the road templates, and all the information used to define widening and super elevation for the road. A single project can contain multiple road jobs for different roads also contained within that single construction project.
road model	The road model used by the Siteworks software is a Trimble Terramodel PRO file. This file can be used for both staking and grade checking operations. The Road model is a template-based model that provides full accuracy anywhere within the roadway surface.
rover receiver	A rover is any mobile GNSS receiver that is used to collect or update data in the field, typically at an unknown location.
Roving mode	Roving mode applies to the use of a rover receiver to collect data, stakeout, or control earthmoving machinery in real time using RTK techniques.
RTK	real-time kinematic. A real-time differential GPS method that uses carrier phase measurements for greater accuracy.
site map	The site map within the Siteworks software is stored as a part of the site data. The site map provides linework as a reference only and is not live, which is why you cannot select it for stakeout purposes.
station	A station is the running distance along the centerline of a corridor or road that starts at 0.0 and increments as you proceed along the route. This term is used primarily in the US, whereas the equivalent term chainage is used throughout many other areas of the world, such as Australia, Asia, Europe, and New Zealand.
surface model	The surface model used by the Siteworks software is a Trimble Terrain Model file (TTM file). It provides a 3D surface model that can be used for stakeout or grade checking operations.
work order	A work order covers a task to be performed by a crew on a single jobsite. A work order contains the reference to the appropriate design, required settings and tolerances for the task, and a record and report of all the data measured or staked out in the process of completing the task. A work order can cover a short-term task (such as the stakeout of a specific building pad) or a task that will last the duration of the project (such as the stakeout of storm water drainage) and that will be executed periodically as required during the project. When the project is complete, all the information regarding the task is stored in a single file that is easy to recall.