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Detection of spectrum holes in Cognitive Radio Networks (CRNs) is possible using theory of compressive sensing (CS). At the same time, these unlicensed Cognitive secondary users (SUs) must reliably detect the presence of licensed users or owners of spectrum holes to avoid interference. Precise localization of the transmitting nodes is a complicated but important problem for operation of Cognitive...
Impulse radio ultra-wideband (IR-UWB) ranging and localization have recently received significant attention due to the high accuracy and precision. This high accuracy can be exploited for many location aware applications in a wide variety of environments. Although most research efforts have focused on location-aware applications for indoor or outdoor environments, there are other environments, such...
In this study, we present an iterative method for finding target position using only range measurements from multi-static passive radar system. We formulate an optimization problem and use the gradient descent approach to locate target position. In addition, we show that for multi-receiver-single-transmitter system, our method requires only three receivers in order to converge to the correct position...
Indoor localization systems become more interesting for researchers because of the attractiveness of business cases in various application fields. A WiFi-based passive localization system can provide user location information to third-party providers of positioning services. However, indoor localization techniques are prone to multipath and Non-Line Of Sight (NLOS) propagation, which lead to significant...
Real Time Kinematic (RTK) Global Positioning System (GPS) uses carrier phase measurement from GPS signal and it has a high accuracy but has integer ambiguity resolution problem which causes cycle slips and requires good satellite visibility as well. RTK was originally developed for applications such as surveying; in our case the target application is the tracking and the control of a robot hexacopter...
A method to enhance the indoor positioning accuracy by alleviating the effect of multipath distortion is presented. Using this method the line-of-sight (LOS) and non-line-of-sight (NLOS) signals are separated in the frequency domain and multipath induced errors in the pseudorange measurements are decorrelated at a faster rate than under static antenna conditions, resulting in improved positioning...
Modern radiotherapy depends largely on accurate dose delivery to the given target volume. Before going into clinical use, the calibration of the photon and electron beams produced by radiotherapy machine has to be done. The overall accuracy in tumor dose delivery should be below 3 percent. But on an evaluation of errors in dose delivery in a clinical setting, to achieve this accuracy is not an easy...
This work presents a low cost RTK-GPS system for localization of unmanned surface vehicles. The system is based on the use of standard low cost L1 band receivers and in the RTKlib open source software library. Mission scenarios with multiple robotic vehicles are addressed as the ones envisioned in the ICARUS search and rescue case where the possibility of having a moving RTK base on a large USV and...
It is well known that geometry is of significance to the performance of multistatic radars. In multistatic passive radars the receiver placement is especially critical since the transmitters of opportunity are beyond control of radar designer. Instead of considering a single objective, we suggest to implement the receiver placement by using multiobjective optimization in this paper. Specifically,...
The quality of measuring the image is a complicated and difficult process since humans opinion score is affected by physical and psychological factors. Several techniques are proposed for measuring the image quality but any of this techniques is considered to be ideal for measuring the image quality. Image quality assessment plays a significant role in the field of image processing. Image quality...
The capability of one-way time service as an important index of satellite navigation system reflects the ability that a satellite navigation system broadcasts the system time to the clients. In this paper, the performance evaluation method of BD one-way time service is designed standing in the clients' position. The UTC(NTSC)-BDT result via Space signal reception method is obtained in NTSC, the performance...
In this paper, we develop a procedure for evaluating the performance of a single moving sensor system to estimate the range to a stationary emitter based on the discrete-time collection of bearing measurements along the trajectory travelled. We describe a numerical procedure to calculate the range p.d.f. from a chosen trajectory assuming a constant quality for the bearing measurements and use this...
We present matrix factorization as an enabling technique for analog-to-digital matrix multiplication (AD-MM). We show that factorization in the analog domain increases the total precision of AD-MM in precision-limited analog multiplication, reduces the number of analog-to-digital (A/D) conversions needed for overcomplete matrices, and avoids unneeded computations in the digital domain. Finally, we...
This paper describes a localization method for an IR-UWB (Impulse Radio Ultra Wideband) two-way ranging system developed for precise time-of-arrival measurements. The ranging system provides a time resolution of 275 ps, which allows precise indoor distance estimation with the accuracy of 4 cm. In this work, a two-way ranging algorithm has been extended into a localization algorithm without the need...
Scalable and automated monitoring processes for testing, debugging, and operation of VNFs and service-chains are crucial components towards achieving the aims of network softwarization - i.e., cheaper, faster, and shorter service deployment and network management processes. In this paper we present a decentralized monitoring approach aimed at supporting automated deployment and operation of VNFs and...
The paper describes two Wi-Fi lateration methods based on signal propagation model and signal strength data collection for indoor localization using Androidbased mobile device. The considered methods use log-normal path loss model for signal propagation and received signal strength measurement collection for distance estimation and lateration approach for localization. The indoor signal propagation...
Ranging signals in the urban environment suffer from significant attenuation and additive errors caused by reflections. Special design considerations for ranging-based positioning systems that operate in the Urban Canyon are presented. The tradeoff between acquisition sensitivity and acquisition time is presented. The integrity of the measurements is improved by verifying that the signals exhibit...
In this paper, we propose an adaptive tracking channel control mechanism for GNSS receivers in weak signal applications powered by renewable energy sources. The proposed technique dynamically adjusts tracking channels to get better time coverage and positioning availability under the desired accuracy requirement. A low-complexity hardware architecture is developed for power management and adaptive...
Various approaches exist to detect gestures and movements via smartphones. Most of them, however, require that the smartphone is carried on-body. The abscence of reliable ad-hoc on-line gesture detection from environmental sources inspired this project for on-line hand gesture detection on a smartphone using only WiFi RSSI. We highlight our line of work and explain problems at hand to provide information...
Over the last few years, indoor localization has been a very dynamic research area that has drawn great attention. Many methods have been proposed for indoor positioning as well as navigation services. A big number of them were based on Radio frequency (RF) technology and Radio Signal Strength Indicator (RSSI) for their simplicity of use. The main issues of the studies conducted in this field are...
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