How will you determine that a level has collimation error?
The main error is where the line of sight is not parallel to the horizontal line of collimation. In this case your levels will not be correct. A test for checking the level is known as the two peg test. This test determines the amount of error and if an error occurs notify the technician (the level must be serviced).
What type of error is collimation error?
The error of Collimation or simply the collimation error is a common type of error in reciprocal levelling. This type of error occurs when the axis of collimation is not truly horizontal when the instrument is level. The axis of collimation is tilted concerning the horizontal by a certain angle.
What is RL of collimation?
It consists of finding the elevation of the plane of collimation i.e. (H.I.) for every setting of the instrument and then obtaining the reduced levels of the points with reference to the respective plan of collimation.
What is the purpose of collimation error?
Collimation error is the largest potential source of systematic error for area leveling with unbalanced sight lengths, even with geodetic-quality levels.
Why does collimation error occur?
Collimation error is due to the line of sight of a survey instrument not coinciding with traversing gear, scales, or leveling devices. The collimation line is the line of sight, passing through the intersection of the crosshairs of the reticule.
What is collimation method?
In levelling, a method of calculating reduced levels by subtracting staff readings from the level of the line of sight (collimation line) of the instrument. This method is usually favoured where it is required to obtain the levels of many points from one set-up.
What is collimation error in the context of levelling and what does it lead to?
Alignment axially of parts of an optical system. Collimation error is due to the line of sight of a survey instrument not coinciding with traversing gear, scales, or leveling devices. The collimation line is the line of sight, passing through the intersection of the crosshairs of the reticule.
What is the difference between line of sight and line of collimation?
Line of sight is the imaginary line passing through the intersection of crosshairs and optical centre of the objective whereas Line of collimation is the imaginary line passing through the centre of the eyepiece and the optical centre of the objective.
What is height of collimation method?
Height of Collimation is the height of the horizontal plane through the telescope. In order to see the staff on the BM the instrument must be higher. To find the Height of Collimation (Instrument Height) add the staff reading to the level of the Bench Mark. Height of Collimation = BM + staff reading.
How can collimation error be reduced?
In differential leveling, the effect of a level’s collimation error can be almost entirely eliminated by carefully balancing the foresight length with the backsight length. However, in some settlement monitoring studies, the sheer number of points (or their close spacing) makes such balancing impractical.
What is called line of collimation?
The line of sight of the telescope of a surveying instrument, defined as the line through the rear nodal point of the objective lens of the telescope and the center of the reticle when they are in perfect alignment. See Also: line of sight.
What is GTS bench mark?
A G.T.S. (Great Trigonometrical Survey) benchmark is a permanently fixed reference survey station (or point), having known elevation with respect to a standard datum (mean sea level). These are established all over India by Survey of India department with greater precision.