Kamis, 10 Juli 2008

Geodesy and Total Station

Area of a science, techniques and the manufacture, that are dealing with developing tools and methods of measurements, and also methods of calculations of mutual and spatial position of objects, parameters of the Earth and its objects and change of these parameters in time.

Disciplines of geodesy

A. Theoretical geodesy, physical geodesy - is engaged in development of theories and methods of definitions of a figure of the Earth (its form and the sizes), an external gravitational field and their changes in time, using astronomic-geodetic, gravitational , satellite and other measurements of high accuracy;
B. Spheroid (al) geodesy, geodesy on the ellipsoid -studies geometry terrestrial ellipsoid, methods of the decision of geodetic problems on its surface and in three-dimensional space, the theory of its display on sphere, and also displays to planes with the purpose of introduction of flat rectangular coordinates
C. Basic geodetic survey - Studies means and methods of precision geodetic measurements, and also methods of mathematical processing of results of measurements with the purpose of construction and fastening on district of scheduled and high-altitude state geodetic networks (these three disciplines traditionally make the maintenance of the global geodesy - geodetic survey(ing), higher geodesy, higher survey(ing)).
The next tools are obligated tools for these measurement:

GPS total station)
D. Celestial geodesy, satellite geodesy, space geodesy - studies questions of use of supervision of artificial and natural satellites of the Earth for the decision of scientific and scientific and technical problems GEODESY (GPS total station)
E. Topography- studies tools and methods of geodetic measurements with the purpose of display of a terrestrial surface on topographical plans and cards;
F. Marine geodesy - Solves problems GEODESY within the World ocean;
G. Applied geodesy, engineering geodesy - studies methods of the geodetic measurements which are carried out at researches, designing, construction and operation of engineering constructions, installation of equipment, and also operation of natural resources;
The next tools are obligated tools for these measurement:

  1. total stations
  2. theodolites
  3. combined total station and others

J. mining geodesy, mine-survey - branch of GEODESY in a mountain science and techniques, is engaged in spatially-geometrical measurements in bowels of the Earth and their display to plans, cards and other documentation. Problems GEODESY solves in close cooperation with astronomy.


Tacheometer or Total station

Tacheometer allow making any goniometric measurements simultaneously with measurement of distances and on the base of received data to make engineering calculations, keeping all existing information.
Tacheometer widely use at geodetic both civil work and for solving other problems. Such universal device as electronic tachometer allows saving forces and time for the decision of all problems. An opportunity of transfer of the data picking during measurements through the special interface in a computer with the subsequent processing do tachometer the one of the most irreplaceable devices.
All tacheometer can be divided into three basic groups:

The elementary electronic tacheometer,

Devices of middle class

Electronic tacheometer (total station).

The basic properties are unsurpassed range, speed and accuracy of measurements.
Total stations are developed in view of the maximal convenience of work of the user.
High-efficiency electronic tacheometer are intended for the decision
It has the broad audience for sole of industrial problems.

The Total station is designed for measuring of slant distances, horizontal and vertical angles and elevations in topographic and geodetic works, tacheometric surveys, as well as for solution of application geodetic tasks. The measurement results can be recorded into the internal memory and transferred to a personal computer interface.

It is the geodetic device by means of which measurement of horizontal and vertical corners on district is made.
By means of a theodolite and level control, using thread a range finder, it is possible to carry out measurement of distances.

Theodolite is used for measuring angles in triangulation, polygon measurements, bridging, application geodesy, and astronomo-geodetic measurements.
The theodolite is also being produced and is intended for measuring angles both by standard and autocollimation methods, in industry when mounting elements and constructions of machines and mechanisms, for building industrial constructions and other purposes.

Model is intended for measuring angles in geodetic bridging, application geodesy, exploration and surveying works, theodolite surveys, on-ground mining surveys etc.

Theodolites are easy and reliable in operation. The compensator on the vertical circle allows to make rapid and accurate measurements. Differing from foreign analogous the theodolites permit to carry out works at lower temperatures.

On all theodolites it is possible to mount light range finders of various design The device can be equipped with geodetic tripod.

The theodolites are intended for measuring of horizontal and vertical angles and distances with the help of a crosshair range finder, levelling by means of the telescope level, determination of magnetic azimuth against the compass.
Advantageous features of theodolites:

- readout is made with the help of the scale microscope,
- detachable support with the built-in optical centering device permitting to work in a three-tripod way,
- erect image telescope,
- serviceability of the instruments under any climatic conditions,
- light mass.

Due to small size and light weight, ease in operation, rapidity of dial reading, the theodolites are widely used in construction, agriculture, engineering explorations and surveys, particularly, in expedition conditions.

The instruments may be completed with geodetic tripod of, built-in optical centering device and lantern to illuminate the microscope scale.

Optical-mechanical theodolites apply to measurement of corners in a triangulation, polygonal network, in geodetic networks of a condensation, in applied geodesy, astro-geodetic measurements.

Polygonal network (from Greek polygonos - polygonal), a method of definition of mutual position of points of a terrestrial surface for construction of a basic geodetic network by measurement of lengths of the direct lines connecting these points, and horizontal corners between them.

By means of these devices it is possible to carry out:
Measurements of corners in theodolitic and tachometer courses;
Breakdowns of scheduled and high-altitude survey networks;
Leveling by a horizontal beam by means of a level at a pipe and so forth

Theodolites are executed in ergonomic execution, have the direct image and are reliable in work. Presence of the equaliser at a vertical circle allows making measurements quickly and precisely.
On some theodolites it is possible to establish range finders of light of various designs, and on other theodolites it is possible to establish in addition manual laser range finders of various designs.

If necessary and to desire of the customer devices can be completed with a geodetic support, fastening for manual laser range finders, a roulette, etc. Also, on delivered supports can be established universal the screws allowing fix the device of domestic or import manufacture.
The laser theodolite is irreplaceable at work in tunnels, underground developments, in conditions of weak light exposure.

Theodolites are subdivided on optical and electronic.

Optical theodolites are Theodolites that intendeded for measurement of horizontal and vertical corners.

Electronic theodolites differ from optical theodolites that exception of a mistake counting as value of corners are deduced on the display.
Accuracy of a theodolite differs from 30 “up to 1 ".
Electronic theodolites is modern devices for corners measurement. At use of electronic theodolites mistakes of removal of readout are excluded - values of corners are deduced on the display
Theodolite establish on a support of little table of a geodetic sign, elevating screws and on a level result a vertical axis in steep position, turns of a pipe about vertical and horizontal axes direct it at a vised point and make readout on circles. It gives a direction, and corners receive as a difference of two adjacent directions. In modern theodolites circles produce from optical glass, diameter of divisions of 6-18 sm, the most common interval between divisions 20 ' or 10 ', counted as devices serve scaled microscopes with accuracy calculation1 '-6 ". Optical micrometers with accuracy calculation up to 0,2-0,3 ".
In 60th 20 century for definition of a direction of a true (geographical) meridian began to apply so-called giro theodolites and various gyroscopic nozzles on theodolites. The error of definition of directions makes giro theodolites 5-10 ".
Of axial, fixing and directing devices of goniometric tools demand much. For example, in precision theodolites angular fluctuations of vertical axes do not exceed 2 ", in tools admissible abnormality of the form of their pins on which the telescope rotates, makes shares of micron. Fixing devices should not cause elastic deformations in axial systems and displacement of fixed parts of the tool during the moment of fastening. Directing devices should carry out rather thin movings of parts the tool

Total Station high-efficiency measuring system

The basic characteristics and advantages:
- DR-measurements without a reflector
- A visible laser bunch
- Simplicity in work
- Graphic support
- The protected and easy design

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