Showing papers by "J.M. Villadangos published in 2014"
12 May 2014
TL;DR: Simulations and real results show that by using the appropriate receive filter the mean absolute error in positioning can be reduced by a percentage of about 70% in an ultrasonic indoor positioning system.
Abstract: Accurate distance estimation is a key part for certain active sensing systems as ultrasonic Indoor Positioning Systems (IPSs). In these systems, receive filters play a key role for the achievement of robust and accurate position estimations. For that reason, this paper carries out the performance comparison of different receive filters, namely matched-filter, generalized cross-correlation function, adaptive generalized cross-correlation function and mismatched-filter in an ultrasonic indoor positioning system. Simulations and real results show that by using the appropriate receive filter the mean absolute error in positioning can be reduced by a percentage of about 70%.
8 citations
12 May 2014
TL;DR: In order to improve the detection process without applying common communications algorithms for interference compensation, that usually involve a high computational load, the use of Generalized Cross-Correlation (GCC) is here analyzed.
Abstract: Underwater Wireless Sensor Network applications require the design of efficient communications links due to the rough environment. Acoustic signals make feasible the data transmission based on Direct Sequence Code Division Multiple Access (DS-CDMA) techniques, because compensates the multipath effect and allow receivers to simultaneously distinguish among multiple independent emitters. For that purpose, cross-correlation techniques based on matched filtering are often used, by detecting at what e instant arrives maximum correlation value is provided. Inter-Symbol Interference (ISI) caused by the Auto-Correlation (AC) function of the used sequences, and the Cross-Correlation (CC) between them, is not null around maximum matching value. This implies that it is sometimes difficult to detect the accurate position of correlation maxima. In order to improve the detection process without applying common communications algorithms for interference compensation, that usually involve a high computational load, the use of Generalized Cross-Correlation (GCC) is here analyzed.
1 citations
11 Jun 2014
TL;DR: The use of Generalized Cross Correlation (GCC) is presented, which allows the components around the carrier frequency to be enhanced, improving the detection of the maximum correlation peak and hence the accuracy of measurement of difference distances.
Abstract: The use of Ultra -WideBand (UWB) techniques is considered an attractive solution for indoor Local Positioning Systems (LPS). In this case, the positioning is usually performed by hyperbolic trilateration techniques measuring the time difference of arrival (TDOA) between the received signals coming from the beacons placed in the environment. The detection of the true arrival instant for the used encoded signals is important in the accuracy of the system. The most widely used technique consist of performing the correlation between the received signal and the sequence to be detected. For that, matched filters are used and then, the instant at which appears the maximum of the correlation function is detected. In this paper the use of Generalized Cross Correlation (GCC) is presented. This allows the components around the carrier frequency to be enhanced, improving the detection of the maximum correlation peak and hence the accuracy of measurement of difference distances.