signal—A natural or artificial object or structure located at or near a survey station and used as a sighting point or target for survey measurements

signal, aerial—A guyed, balloon-suspended target for taking sights on points that cannot be seen from triangulation stations; particularly useful when locating points required for the control of aerial surveys. The control points are commonly chosen at road intersections, at corners of cultivated fields, or at bridge crossings, all of which are objects that are readily identified on a photographs, but usually cannot be seen from established triangulation stations. The balloon-type target may be suspended as high as 200 feet over the point.

signal, hand—Hand motions made by instrumentmen to transmit directions to their rodmen or chainmen.

signal, reference—The signal to which other signals are compared to determine differences in time, phase, frequency, or other values or quantities. In telemetry, the signal to which the times, phase, frequencies, or other characteristics of modulated waves carrying data are compared.

signal, triangulation- ¹ A rigid structure erected over or close to a triangulation station and used for supporting an instrument and sn observer, a target, or an instrument, observer and target, in a triangulation survey. ² Any object, natural or artificial, whose position is obtained in a triangulation survey. ³ A structure whose position is determined by triangulation, but whose primary purpose is to serve later in a hydrographic or topographic survey; a hydrographic or topographic signal

signal lamp—See target.

Signal to noise ratio—The ratio of signal strength to the interference (noise) in an incoming signal.

–

Source: NSPS “Definitions of Surveying and Related Terms“, used with permission.

Part of LearnCST’s exam text bundle.