Kovalev passive rangefinder

2021 ◽  
Vol 969 (3) ◽  
pp. 12-18
Author(s):  
S.V. Kovalev ◽  
D.A. Shapovalov
Keyword(s):  
Measurement Accuracy ◽  
Distance Measurement ◽  
Optical Path ◽  
Optical Scheme ◽  
Acceptable Error ◽  
Technical Result ◽  
Laser Range Finders ◽  
Digital Methods ◽  
Field Works ◽  
Photo Receiver

The authors present the results of longtime research on the development and improvement of a passive geodetic rangefinder based on the inbasis method of distance measurement. Actually, active laser range finders are not always effective at field works. An original compact optical scheme of a passive rangefinder based on a theodolite telescope and a mould photo receiver with application of digital methods for coordinate calculation is proposed. The distance and dimensions of the object are defined. The former is identified by the shift between the images on the horizontal axis. The merit of such a system is the absence of mechanical displacements. Its main advantage is an extremely simple optical path. The technical result is reduction in overall dimensions and weight, while maintaining an acceptable error in the passive range measurement. The use of Kovalev passive rangefinder is promising at performing geodetic measurements with total stations. There is also a description of the rangefinder sample as well as the calculations results according to the distance measurement accuracy.

scholarly journals Compact Laser Collimation System for Simultaneous Measurement of Five-Degree-of-Freedom Motion Errors

2020 ◽  
Vol 10 (15) ◽  
pp. 5057
Author(s):  
Chuang Sun ◽  
Sheng Cai ◽  
Yusheng Liu ◽  
Yanfeng Qiao
Keyword(s):  
Simultaneous Measurement ◽  
Measurement Accuracy ◽  
Measurement Data ◽  
Optical Path ◽  
Degree Of Freedom ◽  
Experimental Setup ◽  
Collimation System ◽  
Optical Configuration ◽  
Series Of Experiments ◽  
The Common

A compact laser collimation system is presented for the simultaneous measurement of five-degree-of-freedom motion errors. The optical configuration of the proposed system is designed, and the principle of the measurement of five-degree-of-freedom errors is described in detail. The resolution of the roll and the horizontal straightness is doubled compared with other laser collimation methods. A common optical path compensation method is provided to detect light drift in real time and compensate for straightness and angle errors. An experimental setup is constructed, and a series of experiments are performed to verify the feasibility and stability of the system. Compared with commercial instruments, the pitch and yaw residuals are ± 2.5 ″ and ± 3.5 ″ without correction, and the residuals are ± 1.9 ″ and ± 2.8 ″ after correction, respectively. The comparison deviations of the horizontal straightness and vertical straightness changed from ± 4.8   μ m to ± 2.8 μm and ± 5.9 μm to ± 3.6 μm, respectively. The comparison deviation of the roll is ± 4.3 ″ . The experimental results show that the data of the five-degree-of-freedom measurement system obtained are largely the same as the measurement data of commercial instruments. The common optical path compensation can effectively improve the measurement accuracy of the system.

scholarly journals Research on Focal Length Measurement Scheme of Self-Collimating Optical Instrument Based on Double Grating

Sensors ◽  
2020 ◽  
Vol 20 (9) ◽  
pp. 2718
Author(s):  
Wenchang Yang ◽  
Zhiqian Wang ◽  
Chengwu Shen ◽  
Yusheng Liu ◽  
Shaojin Liu ◽  
...  
Keyword(s):  
Measurement Accuracy ◽  
Focal Length ◽  
Optical Path ◽  
Good Resolution ◽  
Mean Square ◽  
Optical Instrument ◽  
Moiré Fringes ◽  
Measurement Resolution ◽  
Designed Experiment ◽  
Better Than

In this paper, we propose a scheme for measuring the focal length of a collimating optical instrument. First, a mathematical model for measuring the focal length of a collimator with double gratings is derived based on the moiré fringe formula and the principles of geometric optics. Mathematical simulation shows that a slight difference in the focal length of two collimators has an important influence on the imaging law of moiré fringes. Our solution has a good resolution ability for focal length differences within 5‰, especially in the small angle range below 4°. Thus, the focal length of collimators can be measured by the amplification of the slight difference. Further, owing to the relative reference measurement, the measurement resolution at the symmetrical position of focal length is poor. Then, in the designed experiment, a corresponding moiré image at different angles is acquired using collimators with known focal length. The experimental results indicate that the root mean square error (RMSE) of the collimator corresponding to grating angles of 2°–4° is better than 4.7‰, indicating an ideal measurement accuracy of the proposed scheme. This work demonstrates that our proposed scheme can achieve an ideal accuracy in the measurement of a symmetrical optical path.

scholarly journals The Impact of Radar Distance Measurement Accuracy on the Accuracy of Position Fixing in VTS Systems

2018 ◽  
Vol 25 (3) ◽  
pp. 5-13
Author(s):  
Krzysztof Czaplewski ◽  
Sambor Guze ◽  
Sławomir Świerczyński
Keyword(s):  
Measurement Accuracy ◽  
Distance Measurement ◽  
Large Vessel ◽  
Monitoring Systems ◽  
Gross Error ◽  
Radar Echo ◽  
The Impact ◽  
Source Of Information ◽  
Large Vessels ◽  
Made In

Abstract The main source of information on the situation across the sea basins used by operators of shipping monitoring systems is a network of coastal radar stations. Presently, it is possible to gather navigational information from many individual radar stations simultaneously, which may be used for improving the accuracy of vessel position fixing. However, without making other estimates, we obtain an inconsistent image comprising multiple echoes of the same ship, and as such it is impossible to say which echo presents the vessel on the move. Another problem is the method of performing radar observations, which significantly affects the accuracy of position fixing. The estimated radar distance is encumbered with a gross error in the case of large vessels, as the position of a large vessel is not the same as the position of the edge of the radar echo to which the estimation is made. In this paper, the authors present a method to adjust the measured radar distance. The proposed method may be automated easily, which would significantly enhance VTS positioning processes.

scholarly journals Evaluation of Distance Measurement Accuracy by Odometer for Pipelines Pigs

2006 ◽  
Vol 49 (1) ◽  
pp. 038-042 ◽  
Author(s):  
Sergiy Sadovnychiy ◽  
Juan López ◽  
Volodymyr Ponomaryov ◽  
Andriy Sadovnychyy
Keyword(s):  
Measurement Accuracy ◽  
Distance Measurement

Improve a 3D distance measurement accuracy in stereo vision systems using optimization methods’ approach

2017 ◽  
Vol 25 (1) ◽  
pp. 24-32 ◽  
Author(s):  
J.C. Rodríguez-Quiñonez ◽  
O. Sergiyenko ◽  
W. Flores-Fuentes ◽  
M. Rivas-lopez ◽  
D. Hernandez-Balbuena ◽  
...  
Keyword(s):  
Stereo Vision ◽  
Measurement Accuracy ◽  
Optimization Methods ◽  
Distance Measurement ◽  
Vision Systems

scholarly journals Evaluation of Distance Measurement Accuracy by Odometer for Pipelines Pigs

2006 ◽  
Vol 49 (1) ◽  
pp. 38-42 ◽  
Author(s):  
Sergiy Sadovnychiy ◽  
Juan López ◽  
Volodymyr Ponomaryov ◽  
Andriy Sadovnychyy
Keyword(s):  
Measurement Accuracy ◽  
Distance Measurement

scholarly journals Thickness Measurement for Glass Slides Based on Chromatic Confocal Microscopy with Inclined Illumination

Photonics ◽  
2021 ◽  
Vol 8 (5) ◽  
pp. 170
Author(s):  
Qing Yu ◽  
Yali Zhang ◽  
Wenjian Shang ◽  
Shengchao Dong ◽  
Chong Wang ◽  
...  
Keyword(s):  
Confocal Microscopy ◽  
Measurement Accuracy ◽  
Signal To Noise Ratio ◽  
Thickness Measurement ◽  
Experimental Methodology ◽  
Measuring System ◽  
Optical Scheme ◽  
Beam Splitting ◽  
Glass Slides ◽  
Better Than

Chromatic confocal microscopy is a widely used method to measure the thickness of transparent specimens. In conventional configurations, both the illumination and imaging axes are perpendicular to the test specimen. The reflection will be very weak when measuring high-transparency specimens. In order to overcome this limitation, a special chromatic confocal measuring system was developed based on inclined illumination. This design was able to significantly improve the signal-to-noise ratio. Compared with conventional designs, the proposed system was also featured by its biaxial optical scheme, instead of a coaxial one. This biaxial design improved the flexibility of the system and also increased the energy efficiency by avoiding light beam splitting. Based on this design, a prototype was built by the authors’ team. In this paper, the theoretical model of this specially designed chromatic confocal system is analyzed, and the calculating formula for the thickness of transparent specimen is provided accordingly. In order to verify its measurement performance, two experimental methodology and results are presented. The experimental results show that the repeatability is better than 0.54 μm, and the axial measurement accuracy of the system could reach the micron level.

scholarly journals Two-Wavelength Laser Interferometer System Which Reduces the Uncertainty Caused by the Fluctuation of the Refractive Index of Air

2011 ◽  
Vol 5 (2) ◽  
pp. 126-131 ◽  
Author(s):  
Kaoru Miyata ◽  
◽  
Hidekazu Oozeki ◽  
Hideyuki Nakagawa ◽  
Hiroki Masuda ◽  
...  
Keyword(s):  
Refractive Index ◽  
Uncertainty Analysis ◽  
Measurement Accuracy ◽  
Laser Interferometer ◽  
Optical Path ◽  
Highly Sensitive ◽  
Industrial Use ◽  
Laser Interferometers ◽  
532 Nm

Laser interferometers are widely used to measure highly sensitive length and displacement, e.g., in which refractive index fluctuations of air adversely affect measurement accuracy. To compensate for these effects, the two-wavelength interferometer studied has not yet proved practical in industrial use. We studied the interferometer’s performance and practicality, using uncertainty analysis to extract its features. Based on our results, we developed a two-wavelengthMichelson interferometer with wavelengths of 1064 nm and 532 nm. It was calibrated and evaluated using a highprecision laser interferometer whose optical path was in a vacuum. Results confirmed measurement accuracy of 100 nm/50 mm (k=2) under unstable air conditions - superior to a traditional laser interferometer.

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