Who can tell me the principle and calculation method of theodolite? Be detailed!

Theodolite is the main angle measuring instrument in measurement. It consists of a telescope, a horizontal dial, a vertical dial, a level and a base. When measuring, put the theodolite on a tripod, aim the center of the instrument at the ground station with a vertical ball or optical collimator, level the instrument with a level instrument, aim the measuring target with a telescope, and measure the horizontal angle and vertical angle with a level dial and a vertical dial. According to the accuracy, it is divided into precision theodolite and ordinary theodolite; According to the reading equipment can be divided into optical theodolite and vernier theodolite; According to the shafting structure, it can be divided into retest theodolite and direction theodolite. In addition, there is a coded dial theodolite, which can automatically record dial readings according to coded perforations; An automatic tracking theodolite that can continuously and automatically aim at air targets; Gyro theodolite and laser theodolite that can determine the orientation of ground points quickly and independently by using gyro orientation principle; Universal theodolite for astronomical observation with three functions: theodolite, meridian instrument and zenith instrument; Phototheodolite, who combined the camera and theodolite for ground photogrammetry.

Theodolite is the mechanical part of the telescope, which enables the telescope to point in different directions. The theodolite has two perpendicular rotating shafts to adjust the azimuth and horizontal height of the telescope. This kind of bracket has simple structure and low cost, and is mainly used with ground telescopes (geodesy, bird watching, etc.). ). If it is used to observe celestial bodies, it is necessary to rotate two axes at the same time and change the rotation speed with time to track the celestial bodies. However, other celestial bodies in the field of view rotate relative to the target celestial bodies, and unless a mechanism to counteract the rotation of the field of view is added, it is not suitable for long-exposure celestial photography.

1, HR- right (clockwise) horizontal angle, HL- left (counterclockwise) horizontal angle.

2, the operation steps of theodolite (optical alignment method)

1. Erecting instruments: place the theodolite on the frame head, make the frame head approximately horizontal, and tighten the connecting screws.

2. Alignment: The purpose is to make the instrument center and the measuring station on the same vertical line. You can move the tripod and rotate the anchor screw to make the alignment mark exactly aim at the center of the measuring station.

3. Leveling: The purpose is to make the longitudinal axis of the instrument vertical and the horizontal dial horizontal. According to the definition of horizontal angle, it is the projection of the included angle between two directional lines on the horizontal plane, so the horizontal dial must be horizontal. Rough and flat: Stretch the legs of the tripod to center the bubble of the circular level. Check and accurately center: check whether the centering mark deviates from the grounding point. If there is deviation, loosen the connecting screw on the tripod, translate the instrument base, make the centering mark accurately align with the center of the measuring station, and tighten the connecting screw. Fine leveling: rotate the anchor screw to make the air bubble in the center of the pipeline level.

4. aiming and reading: ① eyepiece aiming: eyepiece focusing makes the crosshair clear. (2) aiming and objective aiming: aim at the target roughly, and focus the objective lens to make the target clear. Pay attention to eliminating parallax. Focus on the goal. ③ Reading: Adjust the lighting reflector to make the brightness of the reading window moderate, rotate the eyepiece of the reading microscope to make the line clear, and then read.

At present, many people use the total station. Here is the usage of the total station (taking Topcon total station as an example):

(1) Preparation before measurement

1) Install the battery (note: the battery should be fully charged before measurement)

① Insert the guide block at the bottom of the battery box into the guide hole of the battery.

② Press the top of the battery box until you hear a click. ③ Press the unlock button and take out the battery.

2) Placement of instruments.

① Choose one point as the observation point and the other two points as the observation point on the experimental site.

(2) put the total station in the point, center and horizontal position.

③ Place prisms at two points respectively.

3) Setting of vertical dial and horizontal dial indicator.

① Vertical dial indicator setting. Loosen the brake button of the vertical dial, rotate the telescope vertically for one turn (the telescope is on the left side of the dial, when the objective lens passes through the horizontal plane), and the vertical dial indicator is set. Then I heard a crisp sound, showing the vertical angle.

② Setting of horizontal dial indicator. Loosen the horizontal brake screw, rotate the aiming part by 360, and the horizontal dial indicator will be set automatically. Then it rang and showed the horizontal angle. At this point, the indicators of vertical dial and horizontal dial have been set. Note: The indicators of and must be reset whenever the instrument is turned on.

4) Focus and aim at the target. The operation steps are the same as those of a general theodolite, and attention should be paid to eliminating parallax.

(2) Angle measurement

1) First, judge whether it is in the angle measurement mode from the display screen, and if not, switch to the distance mode according to the operation.

2) Align the dial to the left with the left target A, press the zero key to make the reading of the horizontal dial display as 0 00' 00 ",rotate the aiming part clockwise, align with the right target B, and read the displayed reading.

3) The same method can be used for stock right observation.

4) If measuring the vertical angle, you can read the display reading of the vertical dial at the same time as reading the horizontal dial.

(3) Distance measurement

1) First, judge whether it is in the ranging mode from the display screen. If not, press the operation key to switch to the coordinate mode.

2) Align the center of the prism. At this time, the animation of the arrow can be displayed on the display screen, and the coordinate measurement can be completed at the end of the advance to get the distance. HD is the horizontal distance and VD is the inclined distance.

(4) Coordinate measurement

1) First, judge whether it is in the coordinate measurement mode from the display screen. If not, press the operation key to switch to the coordinate mode.

2) Enter the coordinates of the O point and the back viewpoint of the site, as well as the instrument height and prism height.

3) Align the center of the prism. At this time, the animation of the forward arrow can be displayed on the display screen, and the coordinate measurement is completed at the end of the forward movement to get the coordinates of the point.

Fourth, matters needing attention

1) When transporting instruments, the original packing boxes shall be used for transportation and handling.

2) When moving the instrument and tripod at close range, please keep the instrument upright.

3) Please turn it off before unplugging the plug. During the measurement, if the plug is unplugged, the data may be lost.

4) Please turn off the battery before replacing it.

5) The instrument can only be stored in a dry room. When charging, the ambient temperature should be between 10~30℃.

6) Total station is a precise and expensive measuring instrument, which should be protected from sun, rain and collision. It is forbidden to aim the instrument directly at the sun.

The basic operations of theodolite are centering, leveling, aiming and reading.

(1) alignment

The purpose of centering is to make the center of instrument dial and the center of station mark on the same vertical line.

The operation steps are as follows: open the tripod, adjust the tripod legs to make them suitable in height, and make the frame head level by visual inspection, and the center of the frame head is roughly aligned with the measuring table. Take out the theodolite from the box, put it on the frame head, tighten the connecting screws and hang up the hammer ball. If the tip of the hammer ball is far away from the measuring station, it is necessary to move the tripod so that the tip of the hammer ball is roughly aligned with the measuring station, and then step on the tip of the tripod. Loosen the connecting screw slightly, move the instrument on the frame head until the tip of the hammer ball is precisely aligned with the measuring station, and then tighten the connecting screw. (

2) Leveling

The purpose of leveling is to adjust the foot screw, so that the bubble in the leveling tube is centered, the vertical axis of the theodolite is vertical, and the leveling dial is in a horizontal position.

The operation steps are as follows: 1. Rotate the sighting part to make the leveling tube parallel to any pair of foot spirals (as shown in Figure 3-7a). Turn these two anchor screws to center the air bubble in the leveling tube. 2. Rotate the aiming part by 90, and turn the third foot screw to center the bubble in the leveling tube (as shown in Figure 3-7b). Figure 3-7 is horizontal. 3. Repeat the above steps until the bubbles in the leveling tube are concentrated in these two positions. When the optical centering device is used for centering and leveling, firstly, the initial centering is carried out by visual inspection (hammer ball can also be used), the eyepiece of the centering device is rotated to see the scribing circle on the reticle, and then the eyepiece barrel of the centering device is stretched to make the image of the ground mark point clear. Turn the anchor screw to move the image of the marking point to the center of the scribing circle. Then, by stretching the tripod legs, adjust the length of the tripod to center the bubble of the theodolite circular level, and then adjust the foot screws to make the instrument level accurately. Then observe the ground marking points through the centering device. If the center of the circle is offset, loosen the connecting screw slightly and move the instrument at the head of the frame to center it accurately. At this time, if the bubbles in the leveling tube are deviated, the instrument will be leveled again, and so on until the centering and leveling are completed at the same time.

aim at

The steps of aiming at the target are as follows: 1. Eyepiece aiming: aim the telescope at the bright background and turn the eyepiece aiming screw to make the crosshair image clear. 2. Rough aiming: Loosen the brake screw of the sight and telescope, turn the sight and telescope, aim at the target through the sight on the telescope, and then tighten the brake screw. 3. Objective alignment: Turn the objective alignment screw located on the lens barrel to make the target image clear, and check whether there is parallax. If parallax is found, realign the light until parallax is eliminated. 4. Accurate aiming: Turn the micro screw to make the crosshair aim at the target accurately. When observing the horizontal angle, aim at the bottom of the target as much as possible. When the target width is larger than the cross-filament double-filament distance, it is appropriate to use monofilament for equal division. When the target is narrower than the distance between two wires, it should be clamped with two wires; When observing the vertical angle, aim at the target position with the central part of the crosshair.

read

Before reading, adjust the position and opening and closing angle of the mirror to make the brightness in the field of vision of the reading microscope appropriate, then turn the eyepiece of the reading microscope to aim at the light to make the reading window image clear, and then read as described above.