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A guidance law of the missile interceptor with passive ranging system (e.g. image IR seeker) based on second-order sliding mode is proposed in this paper. The missile system equipped with the passive ranging system can provide good stealth ability during its course of tracking the trajectory of a maneuvering target, therefore enhancing the probability of successful interception. The passive ranging...
This article study the performance enhancement that can be achieved by the introduction in the system of inter-satellite link (ISL) technology in GNSS systems. The use of ISL can improve both dissemination latency from 100 to 5 minutes (or lower) and determination accuracy from values below 65 cm (67%) to values well below 10 cm (67%). In this paper an OD&TS scheme for processing both the classical...
Many Location Based Services (LBS) have emerged in the past few years. However, the provision of underlying positioning technologies to support these services in indoor environments is still challenging. The indoor environment with its propagation complexity presents a burden to achieve affordable, high accuracy and real-time positioning. A recent development, the Improved FOCUSS for Arrival Time...
Currently, ultra-wideband develops towards a suitable technology for wireless indoor localization with sub-meter accuracy. Still, the indoor channel complicates the correct interpretation of the measurement especially in non-line-of-sight scenarios. This paper deals with the range estimation in challenging indoor channels as a first step of robust indoor localization. Contrary to the classical hard-decision...
Location awareness for wireless sensor networks has attracted significant interests in recent years. In hostile environments, there may be malicious attacks to mislead the location estimation of target nodes. In this paper, we propose a novel secured localization method by applying cooperative semi-definite programming (SDP) algorithm. We also introduce residual normalization to improve the SDP approximation...
A fundamental problem when locating sensors in a network is to estimate the distance between pairs of sensors. Since security of sensor networks is vulnerable in the wireless environment, this paper proposes a secure ranging scheme which can provide secure position information for wireless sensor applications. By generalizing the asynchronous distance estimation technology (Distance Estimation via...
Short distance measurement based on RF Time-of-flight (TOF) is difficult because of high sampling clock resolution and wireless synchronization needs. For precise estimation, previous researchers have developed heterogeneous clock systems (HCSs) using Vernier effect of two clocks with different frequencies to measure TOF precisely. Besides, they have performed easier synchronization inside a main...
The localization of sensor nodes is one of the key issues for sensor network systems. Therefore, to obtain precise location information, several localization systems have been researched. However, they require an arranged space using a large number of anchor nodes whose locations are well known, or they need advance information such as radio conditions in the space. Otherwise, the systems cannot be...
A sub-mm ranging system, which estimates the time of flight of a RF signal between two nodes using Time of Arrival (ToA) estimation, is possible according to maximum likelihood estimator simulations and theoretical bounds on ToA estimation. In this paper we propose a frequency domain based ToA estimator for an indoor ranging system which is broken into 3 computational steps towards an efficiently...
This paper presents a novel ‘Energy Efficient Tracking’ (EET) algorithm that tries to meet the localization accuracy requirement, Pa, imposed by a generic location-based application while the energy consumption for ranging and communication is optimized. More specifically, given the set of range measurements performed by a mobile node with respect to its neighboring anchors (i.e., nodes whose exact...
This paper proposes a novel distance matrix reconstruction (DMR) algorithm from incomplete and inaccurate distance information for nodes localization in wireless sensor networks. By using DMR algorithm, we address an improvement for self-organizing isometric embedding (SIEMAP) based localization in which DMR is used instead of the original distance matrix. The core of DMR is finding an Euclidean distance...
Localization in previously unknown and GPS-denied areas is challenging, especially, when no infrastructure can be assumed. In this paper, we present a hybrid person localization approach for ad-hoc scenarios. Example applications are search and rescue operations, but also on construction sites or during maintenance tasks of large industrial plants. The outlined scheme is based on received signal strength...
In this paper we have proposed a technique for cooperative localization where localization is done in distributive fashion without using any additional broadcast by nodes. The method relies on a fixed scheduled ultra-wideband (UWB) pulse transmissions by nodes in a predetermined way. The advantages of the proposed method is simpler hardware, comparatively less pulse transmission in the system hence...
In the recent decades, short-range wireless has become of great importance in the applications of Intelligent Transportation Systems (ITS); especially, that serve traffic management and safety. Various approaches are concerned with optimal positioning of a vehicle and Base-Stations (BSs) placement within a specific area. The optimization problem stands as an exhaustive challenge. This paper discuses...
In this paper, a tracking scheme based on adaptive weighted technique is proposed to reduce the computational load of traditional data-fusion algorithm for heterogeneous measurements. For the location-estimation technique with the data fusion of radio-based ranging measurement and speed-based sensing measurement, the proposed tracking scheme based on the Bayesian approach is handled by a state space...
In this paper, we study a positioning method working in DVB-T single frequency networks (SFNs). These networks have several properties useful for positioning (synchronized emitters at fixed and known location, high SNR, OFDM signals containing pilot subcarriers). Thus, their signals may be used as signals-of-opportunity when the user enters a GNSS hostile environment (e.g. dense urban or indoor areas)...
We present a novel method for computing depth of field and geometry from a single 2D image. This technique, unlike the existing ones measures the absolute depth of field and distances in the scene from single image only using the concept of triangulation. This algorithm requires minimum inputs such as camera height, camera pitch angle and camera field of view for computing the depth of field and 3D...
Due to the decentralized nature of structured P2P systems, there is no a direct way for a single node of getting aggregate statistics about the whole network, such as its current size. In this paper we focus on the problem of estimating the size of one of the most popular structured P2P networks, Chord, using a sampling-based approach. With this approach, a node calculates an estimate of the network...
This work analyzes the impact of medium access control (MAC) layer on the performance of real-time cooperative positioning in ad-hoc mobile wireless networks. The probability mass function (pmf) of the latency introduced by the MAC layer is here derived to assess the influence of MAC parameters on the latency and then operate on those to improve the positioning performance while reducing the number...
Localization in wireless sensor networks is an important functionality that is required for tracking personnel and assets in industrial environments, especially for emergency response. Current commercial localization systems such as GPS suffer from the limitations of either high cost or low availability in many situations (e.g., in-door environments that exclude direct line-of-sight signal reception)...
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