Briefly describe what are the observation instruments for horizontal displacement measurement by the line-of-sight method and their application.

Commonly used line-of-sight method of horizontal displacement observation instruments are: total station, photoelectric rangefinder, pull the line instrument.

1, total station: total station is a high-precision measuring instrument, with height measurement, angle measurement, azimuth measurement, distance measurement and other functions, widely used in surveying engineering construction (such as highways, railroads, bridges, etc.). The measuring range of total station is wide, which can reach several kilometers, and because the measurement data is directly displayed in digital form, the data processing and analysis is convenient, and real-time display and dynamic data storage can be realized.

2, photoelectric rangefinder: photoelectric rangefinder is a precision measuring instrument, the use of laser distance measurement of objects. By irradiating a red laser on the surface of the object to be measured, and using the photoelectric rangefinder to collect the time of the reflected laser, you can calculate the distance from the surface of the object to the measuring instrument. The photoelectric rangefinder is highly accurate and fast, and is suitable for horizontal displacement measurements of buildings with a small range.

3, pulling the line instrument: pulling the line instrument is a traditional observation instrument, by pulling the line group and precision instruments, its principle is the use of pulling the line so that the different positions of the point interconnected, with the assistance of precision instruments, observation of pulling the line of the points on the line of sight in the position of the line of sight. Since the instrument only has a single axis rotation, it is necessary to measure the position of each point one by one in a certain order. The tie-line instrument is suitable for horizontal displacement measurement of small buildings.

There are also automatic leveling instruments, holographic photographic instruments, photogrammetric instruments, etc. that can be used for the observation of the line-of-sight method. Each instrument has applicability in different occasions, which instrument to use according to the actual situation to choose, the main factors to consider include the size of the object to be measured, shape, distance, accuracy requirements, observation conditions and measurement time and other factors.

Precautions for the use of observation instruments:

1, read the manual carefully before use: different types of observation instruments in the use of different, need to check the manual in detail before use, to understand how to correctly use, adjust the instrument.

2, check and calibrate the instrument: need to check the instrument before use of each part of the connection is tight, whether the instrument is damaged or abnormal conditions. You can carry out a level meter, goniometer and other conventional calibration to ensure the accuracy of the measurement results.

3, to ensure that the measurement is accurate: in the process of use, to improve the accuracy of observation, to prevent the sundial, barometer, thermometer and other instantaneous and sudden changes caused by the error. At the same time, in the measurement task, wind, rain, fog, haze and other weather changes will also have an impact on the need to choose the appropriate weather conditions to reduce the error.

4, instrument maintenance and maintenance: in the use and storage process, need to pay attention to maintenance and maintenance, such as ambient temperature, humidity, chemical solvents, vibration, etc. will have an impact on the observation instrument. The usual maintenance work includes cleaning, lubrication, rust prevention, storage and so on.