The basic structure of total station is summarized
Information comes from:the Internet posted on:2022-03-01
Total station can be used in almost all measurement fields. The electronic total station is composed of power supply part, angle measuring system, ranging system, data processing part, communication interface, display screen, keyboard, etc.
Compared with electronic theodolite and optical theodolite, the total station adds many special components, which makes the total station have more functions and more convenient to use than other angle measuring and ranging instruments. These special components constitute the unique characteristics of the total station in terms of structure.
Coaxial telescope
The telescope of the total station realizes the coaxialization of the collimation axis and the transmitting and receiving optical axis of the ranging light wave. The basic principle of coaxialization is that a beam splitting prism system is set between the telescopic objective and the focusing lens. Through this system, the multi-function of the telescope can be realized, that is, the target can be aimed, imaged on the crosshair reticle for angle measurement. At the same time, the external light path system of the ranging part can enable the modulated infrared light emitted by the photodiode of the ranging part to be reflected back through the same path after being shot to the reflective prism through the objective lens, and then the return light is received by the photodiode through the action of the light splitting prism; In order to measure the distance, another internal light path system needs to be set inside the instrument. The modulated infrared light emitted by the photodiode is transmitted to the photodiode through the optical waveguide in the light splitting prism system, and the phase difference of the modulated light from the internal and external light paths indirectly calculates the propagation time of the light and the measured distance.
Coaxiality enables the telescope to measure all basic measurement elements such as horizontal angle, vertical angle and oblique distance at the same time. In addition, the powerful and convenient data processing function of the total station makes the use of the total station extremely convenient.
Double axis automatic compensation
The principle of double axis automatic compensation has been introduced in the inspection and correction of the instrument. If the longitudinal axis of the total station tilts during operation, it will cause the error of angle observation, and the observation values on the left and right sides of the panel cannot be offset. The special double axis (or single axis) tilt automatic compensation system of the total station can monitor the tilt of the longitudinal axis and automatically correct the angle measurement error caused by the tilt of the longitudinal axis in the dial reading (the maximum tilt of the longitudinal axis of some total stations can be allowed to be ± 6 '). The angle error caused by the vertical axis tilt can also be calculated automatically by the microprocessor according to the vertical axis tilt correction calculation formula, and added to the dial reading for correction, so that the dial display reading is the correct value, that is, the so-called vertical axis tilt automatic compensation.
The structure adopted for biaxial automatic compensation (existing level, including TOPCON and Trimble): use a bubble (the bubble is not visible from the outside, and it is not a bubble described in the inspection and correction) to calibrate the absolute horizontal plane. The bubble is filled with liquid in the middle and gas at both ends. A light-emitting diode is placed on both sides of the upper part of the blister, and a photocell is placed on both sides of the lower part of the blister to receive the light emitted by the light-emitting diode through the blister. Then, the intensity of the light obtained by the two diodes is compared through the operation circuit. When in the initial position, i.e. absolute level, set the operation value to zero. When the total station instrument tilts during operation, the operation circuit calculates the difference of light intensity in real time, which is converted into the tilt displacement, and transmits this information to the control system to determine the value of automatic compensation. The automatic compensation method is initially calculated by the microprocessor and then corrected. In addition, there is another way, that is, the micro screw is driven by the stepping motor to correct the offset in the direction of the shaft, so as to ensure the absolute level of the shaft at all times.