scholarly journals Anti-interference pulsed laser ranging system

2020 ◽  
pp. 8-14
Author(s):  
A. V. Sadchenko ◽  
O. A. Kushnirenko ◽  
E. K. Koshelev
Keyword(s):  
Measurement Accuracy ◽  
Pulsed Laser ◽  
Cost Effective ◽  
Laser Rangefinder ◽  
Probe Signal ◽  
Coding Sequence ◽  
Probing Signal ◽  
Real Value ◽  
Range Interval ◽  
Correlation Properties

Pulsed laser rangefinders prove to be cost-effective and practical devices when used at distances of several tens of kilometers due to their compactness, portability and energy efficiency. However, the measurement accuracy is significantly reduced by the presence of pulsed interference affecting the input of the optical receiver both during the sensing period and when the reflected signal is being received. Using the algorithms with the accumulation and subsequent processing of the results of several successive measurements reduces the speed of decision-making and does not guarantee the convergence of the results to the real value of the distance. The paper proposes a structural diagram of a laser rangefinder with the ability to detect pulsed interference in the range interval and correct errors that occur in the structure of the signal reflected from the target. The basis of the rangefinder circuit is a logical consistent filter, the structure of which contains multipliers (multiplication operations). The following requirements were formulated for the structure of the probe signal: — the first element should always be set to +1 to synchronize the receiver decider; — the weight of the coding sequence is equal to half its length; — the length of the coding sequence is even. Based on the requirements for coding sequences, the optimal structures of binary probing signals of length 8 were found, providing the best corrective ability. Comparison of the correlation properties of the found sequences and the sequences that are constructed using the Walsh functions showed the advantage of the optimal sequences by the criterion of the minimum level of the ACF side lobes. The simulation of the rangefinder under pulsed noise conditions has shown that the logical filter is advisable to use for those cases when the duration of the obstacle does not exceed 1/3 of the duration of the probing signal.

Distribution and Correlation of the Coding Sequence Lengths in Bacterial Genomes

2008 ◽  
Vol 59 (11) ◽  
Author(s):  
Vasile V. Morariu
Keyword(s):  
Correlation Analysis ◽  
Exponential Function ◽  
Short Range ◽  
Statistical Physics ◽  
Bacterial Genomes ◽  
Coding Sequence ◽  
Correlation Properties ◽  
Short Range Correlations ◽  
Fluctuating System

The length of coding sequence (CDS) series in bacterial genomes were regarded as a fluctuating system and characterized by the methods of statistical physics. The distribution and the correlation properties of CDS for 47 genomes were investigated. The distribution was found to be approximated by an exponential function while the correlation analysis revealed short range correlations.

Measurement accuracy of the SG-3 laser rangefinder

1990 ◽  
Vol 33 (11) ◽  
pp. 1138-1140
Author(s):  
A. S. Maslennikov ◽  
V. S. Slastenov
Keyword(s):  
Measurement Accuracy ◽  
Laser Rangefinder

Transforming a Laser Micromachiner into a Direct-Write Tool for Electronic Materials

2008 ◽  
Vol 5 (3) ◽  
pp. 116-121 ◽  
Author(s):  
Aaron D. Halvorsen ◽  
Pooja Vaidya ◽  
Matthew Robinson ◽  
Douglas L. Schulz
Keyword(s):  
Rapid Prototyping ◽  
Polymer Composites ◽  
Electronic Materials ◽  
Sensor Arrays ◽  
Pulsed Laser ◽  
Cost Effective ◽  
Laser Evaporation ◽  
Direct Write ◽  
Effective Manner ◽  
Conventional Laser

A conventional laser micromachining system is configured for use as a matrix-assisted pulsed laser evaporation direct-write (MAPLE-DW) system in a straightforward and cost-effective manner. The simplicity of the method is illustrated by highlighting the process for MAPLE-DW of polymer composites used in chemical gas sensor arrays. Important aspects are considered, including ribbon preparation, ribbon aging, and computerized process control for rapid prototyping.

scholarly journals An improved transmitter system to accurately measure wet-bulb temperature of air

2019 ◽  
Vol 52 (7-8) ◽  
pp. 1002-1007
Author(s):  
Liangwen Yan ◽  
Peng Yu ◽  
Sijung Hu ◽  
Qiu Gao ◽  
Wei Li ◽  
...  
Keyword(s):  
Real Time ◽  
Latent Heat ◽  
Measurement Accuracy ◽  
Cost Effective ◽  
Mean Value ◽  
Experimental Results ◽  
Iteration Algorithm ◽  
Good Consistency ◽  
The Mean ◽  
Good Agreement

A cost-effective measurement of wet-bulb temperature of air has great benefits to fulfill a growing demand of industry, cultivation agriculture, and medication. Applying an appropriate algorithm to wet-bulb temperature of air measurement can effectively improve the accuracy and speed of its measurement. The study aims to research how an improved transmitter system along with the latent heat–based iteration algorithm is used to precisely measure wet-bulb temperature of air. The work consists of (1) simulation of the iteration algorithm and (2) validation via experimental protocol. The simulation results through latent heat–based iteration algorithm were in good agreement ( R2≥ 0.99) with the reference. The performance of the improved wet-bulb temperature of air transmitter system was tested by a latent heat–based iteration algorithm experimental setup. The experimental results demonstrate that the improved wet-bulb temperature of air in a good consistency with commercial wet-bulb temperature of air in a range of temperature (15°C–34°C) and relative humidity (28.8%–76.2%). The Bland–Altman plot also shows that the mean value and the standard deviation of the differences between these two systems are 0.14°C and 0.29°C, respectively, which indicates that the improved wet-bulb temperature of air has a good agreement as well. Compared with the commercial wet-bulb temperature of air transmitter system, an advanced processor (STM32F103C8T6) and real-time operating system was applied in the improved wet-bulb temperature of air transmitter system. The experimental results show that its measurement accuracy is closer to the previous study. This study provides an alternative and cost-effective solution to accurately and real-time measure wet-bulb temperature of air.

Location of Wire Faults Using Chaotic Signal Generated by an Improved Colpitts Oscillator

2014 ◽  
Vol 24 (04) ◽  
pp. 1450053 ◽  
Author(s):  
Hang Xu ◽  
Bingjie Wang ◽  
Jingxia Li ◽  
Anbang Wang ◽  
Yuncai Wang
Keyword(s):  
Reference Signal ◽  
Chaotic Signal ◽  
Digital Signals ◽  
Probe Signal ◽  
Excellent Correlation ◽  
Colpitts Oscillator ◽  
Numerical Studies ◽  
Maximum Range ◽  
Short Circuits ◽  
Correlation Properties

We propose a method to locate wire faults using a chaotic signal generated by an improved Colpitts oscillator. The chaotic signal is divided into two parts: one serves as a reference signal, and the other serves as a probe signal which is sent down to the wire. The fault is detected by correlating the reference signal with the probe signal back-reflected from the fault. Experimental and numerical studies show that the chaotic signal generated by the improved Colpitts oscillator has a broad spectrum and excellent correlation properties. Using this chaotic signal, we experimentally prove our method can be used to locate open circuits, short circuits, impedance discontinuities and other different damage cases on wires, and also demonstrate its ability for testing live wires through the numerical simulation. The results show that a spatial resolution of 0.2 m and a maximum range of about 930 m can be achieved. Furthermore, the interference margin is about 167 dB for the digital signals such as Mil-Std 1553 data on wire.

System design of a pulsed laser rangefinder

1991 ◽  
Vol 30 (3) ◽  
pp. 323 ◽  
Author(s):  
Hoyt N. Burns
Keyword(s):  
System Design ◽  
Pulsed Laser ◽  
Laser Rangefinder ◽  
Pulsed Laser Rangefinder

scholarly journals Laser rangefinder of relatively eye-safe wavelength range

2021 ◽  
Vol 26 (1) ◽  
pp. 41-48
Author(s):  
M. Dzyubenko ◽  
◽  
I. Kolenov ◽  
V. Pelipenko ◽  
N. Dakhov ◽  
...  
Keyword(s):  
Pulsed Laser ◽  
Wavelength Region ◽  
Single Pulse ◽  
Pulse Mode ◽  
Operating Conditions ◽  
Semiconductor Diode ◽  
Laser Rangefinder ◽  
Visual Channel ◽  
Object Distance ◽  
Pulsed Laser Rangefinder

Subject and Purpose. The development and prototype making of a laser rangefinder operating in the 1.50…1.70 μm spectral region is reported. This wavelength region is attractive to both laser producers and laser users for, first of all, relative eye-safety of radiation. Methods and Methodology. The paraxial scheme of rangefinder construction is used, involving a software-controlled power supply of laser radiation with technical arrangements providing its adaptation to varying operating conditions. The alignment of the transceiver channels is provided with laser beam visualization methods. Results. A pulsed laser rangefinder operating at a 1.54 μm wavelength has been developed, a prototype has been made. The rangefinder essentially consists of the transmitting and receiving channels and the visual channel for targeting. The radiation source is a pulsed laser on ytterbium-erbium glass with semiconductor diode pumping and modulated Q-factor. The laser provides a 6 mJ power pulse of 25 ns duration and 5 mrad radiation divergence. A laser light spot of a required aperture is formed using a Galilean telescope system. For the photodetector of the reflected radiation, a pin-photodiode with a photosensitive area diagonal of 0.3 mm and a 2.5 ns time resolution is used. The echo signal processing module has been developed and performed, providing a high-precision registration of a time delay between the starting and reflected pulses. An effective method with the use of a charge-coupled device and an LCD monitor has been proposed and implemented for the alignment of all the three rangefinder channels. The rangefinder can operate in a single-pulse or repetitive-pulse mode with a probing pulse repetition rate of 1 Hz. Conclusion. A pulsed laser rangefinder operating in a relatively eye-safe spectrum region has been developed, a prototype has been made. The field tests have shown that the created rangefinder measures an object distance within 140…7 000 m with a measurement error no worse than 3 m.

scholarly journals Modified Staff-ball Technique for Densely Vegetated Areas

2020 ◽  
Author(s):  
Paul Pop
Keyword(s):  
Western Ghats ◽  
Cost Effective ◽  
Avian Species ◽  
Laser Rangefinder ◽  
Effective Technique ◽  
Imaginary Circle ◽  
Main Equipment ◽  
Cost Effective Technique

Abstract Staff-ball technique is a method used to measure the horizontal cover of vegetation in an area. For the occupancy study of two threatened avian species, a modified version of this method has been developed, employed and standardized in the field, to collect data that has been used as proxy for visibility of these species through the undergrowth in plantations within Western Ghats, India. This modified cost-effective technique is very useful in areas which are highly vegetated with undulating terrain, as opposed to its original use in grasslands. Two staffs and a ball are the main equipment used, wherein a central staff with ball is placed within vegetation and viewed using a peripheral staff at a fixed height from different points in an imaginary circle. A weakness of this technique is the difficulty in alignment with the central staff-ball, which may be rectified by the use of a laser rangefinder.

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