AccuGrade GPS (CD700) Glossary Caterpillar


Auto Pan - With auto pan on, when the machine nearly reaches the edge of the screen, the map is moved and redrawn so the machine is near the opposite edge of the screen and heading toward the center.

Avoidance Zone - The avoidance zone is an area on the construction site that the machine should not enter. This area is shown on the display as a closed, straight sided polygon.

Base Station - A base station must be set up with the AccuGrade System which includes a GPS receiver and data radio. This station transmits CMR messages to the machine in order to improve position accuracy.

Compact Measurement Record (CMR) - A satellite measurement message that is broadcast by the base receiver. The RTK GPS receivers use CMR in order to calculate an accurate vector from the base to the rover.

Cross Slope - The average grade or slope of a parcel or area expressed as a percentage of vertical difference in elevation to the horizontal distance. A level surface has a cross slope of zero.

Data Card - The plug-in, removable storage card which holds all of the design and system files.

Dialog - A screen that allows you to enter text or numbers, or select options.

Differential Global Positioning System (DGPS) - A technique that uses GPS satellite technology and radio telemetry in order to calculate a position to better than 1 m accuracy.

Digital Terrain Model (DTM) - An electronic representation of the design in three dimensions. TINs and grids are two types of DTMs.

Firmware - Software that is stored in read-only memory (ROM) or programmable ROM (PROM). Firmware runs the AccuGrade System.

Global Positioning System (GPS) - A technique that uses satellite technology in order to calculate an accurate three-dimensional position.

Gridded DTM - A gridded DTM is a rectangular grid of points representing a three-dimensional surface. Also see DTM.

Heading - The direction in which the machine is moving.

Light Emitting Diode (LED) - A small, bright, and usually colored light that is used in electronic componentry.

Load - 1. To put data onto a data card so that the data card can be used. 2. To copy data into the display from the data card.

Northing/Easting/ Elevation (Nee) - Projected local coordinates that are used by a design.

Orientation - The direction the blade is facing.

Pan - To pan is to move around the screen at the same scale. Pan moves the plan sideways or up and down on the screen.

Position Dilution Of Precision (Pdop) - A measure of quality of the GPS position. PDOP values below seven are satisfactory. The ideal PDOP value is one. Values from two to four are good.

Slope - The forward and aft grade (or mainfall) of the machine.

Real-Time Kinematic - The term "real-time" literally means to be performed immediately, not at a later time. The term "kinematic" literally means to move around. Corrections for positions are obtained in "real time" in the GPS receiver.

Reference Station - See base station.

Rover - The GPS receiver on the machine. A single reference or base station can support an unlimited number of rovers.

Side Slope - The average grade or slope of ground expressed as a percentage, normally used in order to describe a cut or fill slope from the edge of a road to the natural ground surface. A vertical surface has a side slope of zero.

Soft Keys - The soft keys on the display activate the soft key label that is located beside the soft keys. The operation performed by the soft key varies depending on the current screen. Press the soft key in order to activate the information that pertains to the soft key label.

Triangular Irregular Network (TIN) - A mesh or network of triangles that represents a three-dimensional surface. Also see DTM.

Zoom In - Shows a smaller area of the graphical display in more detail.

Zoom Out - Shows a larger area of the graphical display in less detail.

Zoom All - Shows the full area at the maximum size that will fit on the screen.