When performing installation and construction works, accuracy is very important. And to make complex constructions, as they say, "by eye" in such cases is unacceptable. There are a large number of geodetic instruments that allow you to correctly perform measurements and calculations. For example, levels, measuring tapes, tachometers and other devices.
Among them, theodolite should be distinguished. This is the main high-frequency device that ensures the correct operation of surveyors. Theodolites are optical and electronic. They perform angular surveys, while measuring both horizontal and vertical angles.
Areas of use
This survey instrument is used in the following areas:
- when it is necessary to build topographic maps and plans or a whole network of geodetic points in a triangle-formed area;
- when you need to determine the location of points on the site in relation to each other;
- to perform construction work, for example, when you need to fix the horizontal or vertical structure of buildings (piles, columns, etc.);
Working with theodolite is not difficult. To perform complex calculations and measurements, it is necessary to acquire certain skills.
Device classification
Theodolites have several varieties. It:
- Optical theodolites. Devices of this type are the most common. They are accurate and reliable for field use. Theodolites of this type are popular among surveyors. They have several advantages over electronic counterparts: they do not need batteries for operation and are easy to use. Optical theodolites can perform work in a fairly wide temperature range, even at low temperatures. Theodolites of this kind have minimal capabilities. Reports are performed on a goniometer scale. If the tool does not contain internal memory, then it will be necessary to acquire a field log in which all data will be entered.
- Laser theodolites are also not difficult to operate. This device uses a laser beam, which serves as an accurate pointer. The device combines the functions of two devices - a visor and a high-frequency electronic instrument for measurements. The device is equipped with a powerful processor, which performs all the calculations and displays the results on the display of the device. The ease of use and convenience of such a theodolite are obvious.
- In digital theodolites do not use vertical and horizontal circles containing degree markings. Instead, barcode discs are used. The device performs measurements in an automated way. The design of such a device contains a storage device. Theodolite stores data in internal memory. Digital theodolites should not be used in difficult climates and at low temperatures, as these devices contain power supplies and an LCD display.
- Phototheodolites and film theodolites belong to the category of instruments having a specific purpose. The design of the first combines theodolite and camera, which determines the topographic coordinates. The main purpose of film theodolites is to fix the trajectory of the movement of objects both on the ground and in the air.
Instrument design
By their design, theodolites are divided into the following types:
- Simple. In theodolite schemes, alidad and limb rotate independently.
- Repetitive. The rotation of the limb and alidade can occur either individually or jointly.
Theodolites in their accuracy are divided into:
- Technical, having an error of 15 - 60 arc seconds.
- Accurate with an error of less than 10 seconds.
- High precision. Allow to carry out measurements with an error of up to 1 arc second.
General device
Theodolite contains the following elements:
- Sight pipe. It has a certain magnification. This part is fixed on two columns that are mounted on the tribrach.
- Counting mechanisms. These include a vertical and horizontal circle (limb). The first is in the column, and the second is at the base of the device.
- Bar or scale microscope. This theodolite reading device is used in mechanical tools. In the first, the countdown is done on a dash index, and in the second - on a scale. The microscope is designed to read readings from the limbs.
- Alidade. It is a rotary ruler that has a rigid connection to the limb case. It contains a reading mechanism - noniuses.
- Fixing and guiding screws. During adjustment and adjustment, these screws impart a gentle movement to the instrument mechanisms.
- Center With this integrated optical plummet, precise centering over the point is performed.
- Tripod Tripod. This element is used when performing work on a specific area. Theodolite is installed on it.
What is the principle of the device?
The mechanical theodolite works according to the following principle. The user observes images of various points of the structure through the eyepiece of a telescope. When the sight is aimed at the observed point, both the vertical and horizontal angles are fixed in the eyepiece of the microscope, which has a dashed or scale marking. The first is the angle of inclination, and the second is the angle of direction.
The specialist sequentially directs the pipe to the control points of the structure, measures the angles, and then writes these indicators to the log. All this is done when an optical theodolite is used. Measurements of angles made by the surveyor play an important role. They allow you to find out how correctly the project is being implemented.
When using electronic devices in operation, there is no need for visual fixation of angles. After all, the electronic sensors of the horizontal and vertical circles automatically transfer all the data to the LCD display of the device in a digital form familiar to humans. Also, all data is stored in the device memory. The use of electronic theodolites provides an increase in specialist productivity and eliminates errors associated with incorrect visual readings of available readings in the case of measuring angles on an optical model.
How to work with theodolite?
How to determine whether the required point of the measuring angle has been correctly fixed? All theodolites are equipped with levels. During installation, they must be accurately set. By adjusting the screws, you can get the desired level. The accuracy of the center of the limb is set using a plumb or optical plummet. When you find out what elements the device consists of, you can start working with the theodolite.
Installation and setup of the device
How to use this tool? First you need to install the device on a tripod. Then it is necessary to determine two reference points on which the instrument’s telescope will be guided. First, it is pointed to the first point. Next, fixation of the device and measure using a vertical thread. Then carry out the countdown in a horizontal circle. All data must be logged, then release the commit. Next, you need to track the second point. To do this, turn the theodolite clockwise. At the next stage, the pipe is turned through the zenith.
Next, you need to change the position of the circle and point the pipe to a point. If there are slight differences in the measurements, then the average value will be correct. During the measurement, the limb should have a value of zero or close to it. The rotation of the alidade must be stopped at the moment when the strokes coincide with zero values on the limb and the microscope. All the above measurements are performed in a circle.
Device selection
Before choosing a device, you should determine the type of work that will be performed on the theodolite. In most cases, the simplest device that has average characteristics is suitable. Typically, such devices are inexpensive. When choosing a theodolite device, you should not pay much attention to such parameters as data transfer and internal memory, since they do not have functional use.
Theodolite instruction manual
Each theodolite comes with standard instructions for use. The user manual describes the sequence of work on the device. Using this small book, you can deal with theodolite without any help. The user manual is also a warranty card and a data sheet of the device. The average price of the electronic theodolite is 50-70 thousand rubles.
How is theodolite designed?
The theodolite instructions contain a minimum of information about the device. It includes the following data:
- critical technical specifications;
- scope of application;
- assignment of buttons;
- how to install the instrument and prepare for measurement;
- how to use the device;
- targeting;
- how to check and adjust the tool;
- device care.
The paper manual is compact and versatile, which is a big advantage. It does not take up much space and you can take it with you. Such instructions will not freeze the LCD display and do not charge. From it at any time you can find out the necessary information, even if you are in the field, on the construction site or quarry.
The instructions for theodolite device have all the information about the instrument that will help you perform the setup and verification.
Domestic theodolite
Theodolite 4T30P is the most popular geodetic instrument of domestic production. It is manufactured by the Ural Optical and Mechanical Plant. This theodolite belongs to the category of technical precision instruments. Theodolite 4t30p has the following advantages:
- readings are taken using a scale microscope;
- you can use the three-part method. In this case, a removable stand with an integrated optical plummet is used;
- contains a direct-image telescope;
- Limb rearrangement is performed by rotating a special screw of the device;
- there is a removable tribrach;
- the device can be used in different climatic regions;
- light weight;
- small dimensions of the device.
Theodolite is successfully used in the following areas:
- Agriculture;
- geodesy;
- landscape design;
- geology;
- forestry.
This theodolite is often used in harsh field conditions. Theodolite price is approximately 50-60 thousand rubles.
Thus, the choice of theodolite is yours, which directly depends on the scope of work.