scholarly journals Localization of a Power-Modulated Jammer

Sensors ◽  
2022 ◽  
Vol 22 (2) ◽  
pp. 646
Author(s):  
Pietro Tedeschi ◽  
Gabriele Oligeri ◽  
Roberto Di Pietro

Jamming is a malicious radio activity that represents a dreadful threat when employed in critical scenarios. Several techniques have been proposed to detect, locate, and mitigate jamming. Similarly, counter-counter-jamming techniques have been devised. This paper belongs to the latter thread. In particular, we propose a new jammer model: a power-modulated jammer that defies standard localization techniques. We provide several contributions: we first define a new mathematical model for the power-modulated jammer and then propose a throughout analysis of the localization error associated with the proposed power-modulated jammer, and we compare it with a standard power-constant jammer. Our results show that a power-modulated jammer can make the localization process completely ineffective—even under conservative assumptions of the shadowing process associated with the radio channel. Indeed, we prove that a constant-power jammer can be localized with high precision, even when coupled with a strong shadowing effect (σ ≈ 6 dBm). On the contrary, our power-modulated jammer, even in the presence of a very weak shadowing effect (σ < 2 dBm), presents a much wider localization error with respect to the constant-power jammer. In addition to being interesting on its own, we believe that our contribution also paves the way for further research in this area.

2012 ◽  
Vol 184-185 ◽  
pp. 789-792
Author(s):  
Bing Li ◽  
Yu Lan Wei ◽  
Meng Dan Jin ◽  
Ying Ying Fan

Put forward a method that use scatter points which got in different places to measure the involution cylindrical gears, give a mathematical model that use the discrete points to sure the total deviation of gear tooth profile. The experience results show that this way is of high precision in measurement points, measurement an error data processing less intervention, etc.


2017 ◽  
Vol 12 (6) ◽  
Author(s):  
Auni Aslah Mat Daud

A Galton board is an instrument invented in 1873 by Francis Galton (1822–1911). It is a box with a glass front and many horizontal nails or pins embedded in the back and a funnel. Galton and many modern statisticians claimed that a lead ball descending to the bottom of the Galton board would display random walk. In this study, a new mathematical model of Galton board is developed, to further improve three very recently proposed models. The novel contribution of this paper is the introduction of the velocity-dependent coefficient of restitution. The developed model is then analyzed using symbolic dynamics. The results of the symbolic dynamics analysis prove that the developed Galton board model does not behave the way Galton envisaged.


2013 ◽  
Vol 652-654 ◽  
pp. 2153-2158
Author(s):  
Wu Ji Jiang ◽  
Jing Wei

Controlling the tooth errors induced by the variation of diameter of grinding wheel is the key problem in the process of ZC1 worm grinding. In this paper, the influence of tooth errors by d1, m and z1 as the grinding wheel diameter changes are analyzed based on the mathematical model of the grinding process. A new mathematical model and truing principle for the grinding wheel of ZC1 worm is presented. The shape grinding wheel truing of ZC1 worm is carried out according to the model. The validity and feasibility of the mathematical model is proved by case studies. The mathematical model presented in this paper provides a new method for reducing the tooth errors of ZC1 worm and it can meet the high-performance and high-precision requirements of ZC1 worm grinding.


2001 ◽  
Author(s):  
Som Chattopadhyay

Abstract Positioning accuracy within the range of nanometers is required for high precision machining applications. The implementation of such a range is difficult through the slides because of (a) irregular nature of friction at the slider-guideway interface, and (b) complex motion characteristic at very low speeds. The complexity arises due to the local deformation at the interface prior to breakaway, which is known as microdynamics. In this work prior experimental results exhibiting microdynamics have been appraised, and mathematical model developed to understand this behavior.


2013 ◽  
Vol 303-306 ◽  
pp. 493-497
Author(s):  
Dong Chen ◽  
Hua Pei Wang ◽  
Qing Guo

To meet the demand for high precision measurements of radar cross section (RCS) in microwave anechoic chamber, the effect of angle repeatability of position servo system in background cancellation technology is analyzed and its error mathematical model is presented. Then a method of high speed synchronization angle measurement based on CPLD is proposed, which improves the precision of synchronization angle measurement in any fixed angle interval. The experiment results show that this method can effectively solve the accuracy of target RCS when rotating.


2013 ◽  
Vol 5 (6) ◽  
pp. 633-637
Author(s):  
Giedrius Augustinavičius ◽  
Audrius Čereška

This paper presents the modeling of a flexure-based precisionpositioning system for micro-positioning uses. The positioningsystem is featured with monolithic architecture, flexure-basedjoints and ultra fine adjustment screws. Its workspace has beenevaluated via analytical approaches. Reduction mechanism isoptimally designed. The mathematical model of the positioningsystem has been derived, which is verified by resorting to finiteelement analysis (FEA). The established analytical and (FEA)models are helpful for a reliable architecture optimization andperformance improvement of the positioning system. Santrauka Straipsnyje pristatomas didelio tikslumo centravimo ir niveliavimo padėties nustatymo sistemos su besideformuojančiais mechanizmais kūrimas ir modeliavimas. Padėties nustatymo sistema optimizuota Solidworks Simulation programiniu paketu. Centravimo platformų poslinkiams apskaičiuoti sudarytas matematinis modelis, kurio patikimumas buvo patikrintas taikant baigtinių elementų metodą. Sudaryto matematinio modelio ir rezultatų, gautų pritaikius baigtinių elementų metodą, skirtumai buvo mažesni nei 10 %. Pasiūlyta modeliavimo metodika gali būti taikoma kuriant padėties nustatymo sistemas su besideformuojančiais mechanizmais.


2020 ◽  
Vol 142 (9) ◽  
Author(s):  
Michał Batsch

Abstract In this study, a mathematical model of the honing process for helical gears with external teeth was developed. The proposed novel method of obtaining the two-parameter envelope of a family of surfaces proved useful in simulated machining by means of a tool with a profile deviation. Based on performed simulations and industrial applications, it was found that this method can be useful in predicting the accuracy of machined gear and therefore can be used in the design process of honing tool for high precision aerospace gears. For the example provided, the average absolute prediction error of machined tooth profile was 0.28 µm.


1992 ◽  
Vol 114 (4) ◽  
pp. 435-441 ◽  
Author(s):  
J. R. Iversen ◽  
T. A. McMahon

Seven male subjects ran at 3.0 m/s on a motorized treadmill including a force platform under the tread. The subjects ran at each of five treadmill inclinations: + 0.17, +0.077, 0, -0.077, and -0.17 radians. The position of the subjects’ legs were read from cine´ films (100 frames/s). Results of the film and force plate analysis generally corroborated the “hanging triangle” hypothesis, which postulates that the angle between the leg and the vertical upon foot strike does not change as the treadmill is tipped up or down. A mathematical model of running, in which the leg is represented as a nonlinear spring, made satisfactory predictions of the way many parameters of running change with the treadmill angle, including the length of the leg at touchdown and liftoff and the peak leg force in the middle of a step. The peak leg force reaches a maximum at a treadmill angle near −0.12 radians, close to the downhill angle where other authors have found a minimum in the rate of oxygen consumption.


2013 ◽  
Vol 427-429 ◽  
pp. 660-663
Author(s):  
Zhi Qiang Wei

In order to meet the testing requirement of positive and reverse operation large torque load for new rudder, an electrical load simulator is designed. The system mathematical model is established and the feedforward compensation control of torque and rudder angle is adopted to restrain the surplus torque according to the principle of invariance. The high precision large torque load under positive and reverse operation for rudder is realized by torque and position hybrid control. The practical application shows that the proposed method can effectively restrain surplus torque and the system meets the high precision torque load under positive and reverse operation for rudder very well.


2013 ◽  
Vol 705 ◽  
pp. 596-601
Author(s):  
Xiao Jun Zhang ◽  
Chong Kang ◽  
Yi Chao Zhao ◽  
Yu Yuan Liu ◽  
Li Ming Fan ◽  
...  

In geophysical prospecting area, the issue how to obtain high precision and low scale geomagnetic charts has been a research focus all the times. In this article, the application based on normal Kriging method can be interpolation proved. Through interpolation and evaluation for the original geomagnetic grid based on Kriging algorithm, the new geomagnetic grid can be estimated by the way of data's transitivity. After that, the geomagnetic chart with high precision and low scale can finally be drawn. At the same time, its feasibility upon this sort of method has been verified.


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