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This work presents an algorithm to improve the estimation of the position in indoor environments when using an Ultrasonic Local Positioning System (ULPS). This system is composed of several beacons, with an encoded transmission based on 255-bits Kasami sequences and a BPSK modulation. The received ultrasonic signals are processed to determine the time of arrival (ToA) for every beacon. The differences...
In this work the performance of the Sucessive Interference Cancelation (SIC) architecture combined with Matching Pursuit (SIC/MP) and Least Squares (SIC/LS) algorithms is statistically analyzed when they are used to mitigate multipath effect in an Acoustic Local Positioning System (ALPS). The experiments are carried out with sets of two hundred real signals acquired in positions where there exists...
This work proposes a novel method to estimate the Line-of-Sight Time-of-Flights (LOS-TOFs) in a broadband acoustic local positioning system (ALPS) with strong multipath interference. The proposed method is based on the Matching Pursuit channel estimation algorithm that provides a low complexity approximation to the Maximum Likelihood solution for sparse channels. A multichannel version of this algorithm...
The underwater channel is a highly variable medium due to the influence of several effects on the acoustic signal, and the physical variability of the environment. This behavior makes the underwater channel a very difficult one to model, and also a complex environment to work with. In acoustic-based positioning or sonar systems, where it is important to know accurately the time-of-flights of the signals,...
In wireless sensor networks (WSNs) the position information of individual nodes is a matter of vital importance because allows the implementation of necessary network functions such as routing, querying and other applications. The objective of this paper is to propose an algorithm of three-dimensional distributed range-free localization for WSNs, using an unmanned aerial vehicle (UAV) equipped with...
Soil roughness parameters have been traditionally retrieved using altimetric profiles acquired from profilometer devices. Measuring soil roughness using the technology called Terrestrial Laser Scanner (TLS) is an innovative method because of it is possible to get a three-dimensional surface more realistic than previous approaches. This paper shows a comparison between both techniques for different...
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