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In this paper, we describe a system that enables a low-cost quadrocopter coupled with a ground-based laptop to navigate autonomously in previously unknown and GPS-denied environments. Our system consists of three components: a monocular SLAM system, an extended Kalman filter for data fusion and state estimation and a PID controller to generate steering commands. Next to a working system, the main...
Speed and differential speed measurements are necessary for almost all of manufacturing steel processes. Use of incremental rotary encoder is the cheapest method for this purpose. Classical theoretical algorithms are analyzed in terms of error and sampling time. These methods are used for a Temper mill real case, showing the practical limitations in both speed and differential speed. A new differential...
Due to the economy recession all around the world, the performance of manufacturing industry has been significantly affected. The question of how to generate fast response to customers, maintain the high quality, accurate delivery rate and low risk become the crucial issue of keeping a company competitive. Supplier selection, one of the key factors for a successful production process has attracted...
In many Intelligent Transportation System (ITS) applications that crowd-source data from probe vehicles, a crucial step is to accurately map the GPS trajectories to the road network in real time. This process, known as map-matching, often needs to account for noise and sparseness of the data because (1) highly precise GPS traces are rarely available, and (2) dense trajectories are costly for live...
Inter-cell Interference (ICI) in the uplink of modern cellular communication systems with high frequency reuse is hard to predict, as fast scheduling and link adaptation lead to a high interference fluctuation. This fluctuation poses a big challenge for link adaptation algorithms that need an accurate SINR estimate to assign suitable modulation and coding schemes for transmission. To enable ICI prediction...
In this paper a detailed analysis of an UltraWideband correlation receiver is presented. The synchronization methods are discussed and analyzed in terms of practical realizability. All algorithms are implemented on FPGA and tested with a real UWB transceiver. The measurement results are then evaluated and compared to the ones found in the literature. Finally an application example for the correlation...
In this paper, we propose a delay-locked loop (DLL) with a closed-loop duty-cycle correction (DCC) circuit. The proposed DCC circuit does not require additional blocks for DCC, and this enables it to have a significantly reduced power consumption and area. To increase DCC accuracy, we also propose a duty cycle keeping fine delay line. The proposed DLL is implemented using a 0.13 μm process with a...
In this paper, we investigate the detection of multi-path signal propagation in a Time Difference of Arrival (TDOA) localization scenario. Usually, TDOA measurements are obtained by determining the absolute maximum of the cross correlation function of signals recorded at different sensor nodes in a sensor network. Multipath signal propagation causes multiple peaks in the cross correlation function...
Timeliness and accuracy are two major concerns in many real-time embedded systems working in dynamic environments. It has been emphasized in the literature that in various real-time applications such as control systems and Kalman filters, delay is one main source of inaccuracy in the system. In this paper, we present a solution based on scheduling algorithms for the problem of inaccuracy in such systems...
Timeliness in query response is the major quality metric for query processing in the real-time applications of Wireless Sensor Networks (WSNs). The structure of the query routing tree directly affects the whole query processing delay as it provides the path to forward a query to the relevant nodes and return the response to the sink. In the current literature, query routing structure is designed irrespective...
A new approach of indoor positioning has recently been proposed: the repealite system. It aims at providing a continuity of the positioning service through the use of GNSS (Global Navigation Satellite Systems) signals, thus leading to a single technological mean, the GNSS receiver, for both outdoors and indoors. A few error sources have to be dealt with in order to reach sub-meter accuracy, among...
With the intention of establishing the connectivity between the femtocell and the core network, it is essential to use public network that ultimately creates several challenges for the operators. Therefore, Synchronization is considered corner stone and has become one of the most significant issues in femtocellular networks to ensure a tolerable carrier offset as well as support received signals in...
Today, local data networks, many last-mile access networks and even some backbone networks are based on packet transmission protocols, especially the Ethernet. Generally, there are several protocols and standards, which could be used for the purpose of clock distribution (synchronization) over packet networks. One of the most accurate protocols is Precision Clock Synchronization Protocol (PTP, IEEE...
Femtocell technology has drawn considerable attention as a cost-effective mean to improve cellular coverage and capacity. Data loading and offloading to the macro Base Station (mBS) is supported through internet backhaul which exhibits the uniqueness of this technology. Interference is one of the most challenging phenomenon's that arise due to the non-synchronized femtocell. It is known that fBS and...
This paper presents an original development methodology for the use of SystemC to compare two different networks at the system level. A single cluster of a single channel network based on CSMA and multi-channel network cluster based on non-overlapping channels available for each node have been developed. In both network configurations a noiseless (error-free) channels are used, since the focus in...
This paper presents two fast and computationally efficient interferometric algorithms that allow high accuracy, unambiguous angle-of-arrival (AOA) estimates to be obtained using physically large wideband antennas that are suitable for electronic surveillance. The performance of the algorithms are compared against conventional interferometric techniques using simulations and are also verified experimentally.
We address the problem of passive estimation of the Time-Difference of Arrival (TDOA) of an unknown, stochastic signal, at two sensors. The key question addressed here is whether additional sensors, receiving the same signal at various relative delays, can serve to improve the accuracy in estimating the TDOA of interest between the first two sensors (without exploiting any underlying parameterization,...
State monitoring is widely used for detecting critical events and abnormalities of distributed systems. As the scale of such systems grows and the degree of workload consolidation increases in Cloud data centers, node failures and performance interferences, especially transient ones, become the norm rather than the exception. Hence, distributed state monitoring tasks are often exposed to impaired...
In this paper, we design an efficient method of simulating wireless networks that use CSMA/CA-based protocols in the MAC layer. In the method, a stochastic model to estimate the CSMA/CA frame transmission delay is naturally incorporated into the conventional fully event-based model. The stochastic model can simplify the interactions between a frame transmitter and its surrounding nodes, which alleviates...
This paper presents a low power UWB radar transceiver IC, which is used to make a radar system with precise range accuracy. The range accuracy is allowed by a variable delay circuit which can control the delay by 5 ps resolution. The detecting range of the transceiver is from 0.15 m to 8.4 m. The measurement results show that the maximum error is 3.75 mm. The circuit is implemented in a 0.13 µm CMOS...
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