Electronic theodolite
For the successful application of this technique, one must have knowledge and understanding of the rules and general principles of geodetic measurements on the ground. And since there are different kinds of theodolites, this knowledge will help you quickly master each of them.
As a universal device( in comparison with the level), theodolites allow not only to make precise measurements of horizontal angles and technical leveling, but also to determine with the guaranteed accuracy the values of vertical angles.
For measuring vertical angles, a simplified theodolite, also called a goniometer, is also used. His samples can be seen on school educational grounds for studying natural history, etc. But, strangely enough, such a simplified device still retains its practical value and can be used to approximate the elevation angle of the selected object.
Theodolite device and principle of operation
Modern theodolites provide measurements of horizontal and vertical angles not only for geodetic work, but also for topographic surveying, mine surveying and mining in mines, tunnels, etc., construction work, azimuth definitions, other tasks,related to the need for accurate measurements and the transfer of projects into nature.
The basis of the theodolite design( in particular, the optical one, as the most traditional variant) that provides its work lies horizontal and vertical circles( limbs) with graduation in degrees and minutes, a system of optical( for aiming and removing measurement values) and mechanical(for installation, turning and fixing limbs and optics) devices.
In general, the principle is to place the telescope on the target, fixing the readings of the horizontal and vertical limbs, the projection of the values of which through the prism and mirror system can be seen with a scale microscope.
To improve the accuracy of the measurements are performed repeatedly. There are many methods of working with theodolites, for example, measuring the angles by semi-receivers, the results of which show the measurement values of the total reception, etc.
Modern classification of theodolites
The manufactured industrial instruments have different accuracy of measurement. In its magnitude, the classification of the theodolites differs. So technical varieties allow a measurement error of up to thirty minutes in both directions, their designation includes the letter and numbers T30.
A smaller value of errors( up to two and five minutes in both directions) is given by exact theodolites, denoted by T2 and T5, respectively. The least errors in measurements can be provided by high-precision( up to one minute in both directions) the theodolites T05 and T1.
Models of some types can be supplied with cylindrical alidade levels or compensators. This is also reflected in their notation( K - compensator).The device designs can have a repeating and unique system of axes. As a rule, the latter is used for a high-precision model. In the construction of repeating models, the presence of the fastening and guiding screw is mandatory.
But apart from these models of traditional theodolites, there are other varieties of them. These are also high-precision theodolites, such as gyro- and cinodolites( phototiodolites), total stations( as a kind of model of an electronic device with optical and laser guidance).
Modern types and models of theodolites are often equipped with electronics that allow you to calculate and memorize the coordinates of points on the spot, automatically translate the results of measurements into the desired coordinate system or percentages, exclude errors in the removal of values and their records. All these functions are taken over by the microprocessor control system.
Additional convenience( like, for example, backlight screen) allow you to work in low light conditions. Such an electronic theodolite can be equipped with a laser pointer and a plumb line, which significantly increases the accuracy of measurements and turns it into a total station( or laser theodolite).
Here, as in the case of traditional theodolites, there are many models. A distinctive feature of total stations is the high accuracy of measurements. The angle can be measured to within half a second, and the distance can be measured with an error of ½ millimeter per thousand meters.
By the way, and the usual optical theodolite construction can be integrated with laser roulettes or range finders, as well as laser plane builders, which undoubtedly increases the accuracy of the work performed.