Target Tracking in Confined Environments with Uncertain Sensor Positions

To ensure safety in confined environments such as mines or subway tunnels, a (wireless) sensor network can be deployed to monitor various environmental conditions. One of its most important applications is to track personnel, mobile equipment and vehicles. However, the state-of-the-art algorithms assume that the positions of the sensors are perfectly known, which is not necessarily true due to imprecise placement and/or dropping of sensors. Therefore, we propose an automatic approach for simultaneous refinement of sensors' positions and target tracking. We divide the considered area in a finite number of cells, define dynamic and measurement models, and apply a discrete variant of belief propagation which can efficiently solve this high-dimensional problem, and handle all non-Gaussian uncertainties expected in this kind of environments. Finally, we use ray-tracing simulation to generate an artificial mine-like environment and generate synthetic measurement data. According to our extensive simulation study, the proposed approach performs significantly better than standard Bayesian target tracking and localization algorithms, and provides robustness against outliers.Comment: IEEE Transactions on Vehicular Technology, 201

Adaptive Energy Efficient Scheduling (AEES) for Fault Tolerant Coverage in Sensor Networks

For many sensor network applications it is necessary to provide full sensing coverage to a security-sensitive area. To actively monitor the set of target the subset of sensors are redundantly deployed. One of the major challenges in devising such network lies in the constrained energy and to tolerate unexpected failure to prolong the life span of the network. In this we rapidly restore the field monitoring, by periodically refreshing and switching the cover to tackle unanticipated failure in an energy efficient manner, because energy is the most critical resource considering the irreplaceable of batteries of the sensor nodes. In the same time it should amenably support more than one sensor at a time with different degree in distributed approach that periodically selects the covers and switch between them to extend coverage time and tolerate unexpected failures at runtime. In this scheme the sensor is an autonomous system that has the authority to decide how to cover its sensing range. It also incorporates a novel technique for offline cover update (OCU) to facilitate asynchronous transition between covers. This approach is robust to failure pattern is no uniform. DOI: 10.17762/ijritcc2321-8169.15013

Target tracking in wireless sensor networks

The problem being tackled here relates to the problem of target tracking in wireless sensor networks. It is a specific problem in localization. Localization primarily refers to the detection of spatial coordinates of a node or an object. Target tracking deals with finding spatial coordinates of a moving object and being able to track its movements. In the tracking scheme illustrated, sensors are deployed in a triangular fashion in a hexagonal mesh such that the hexagon is divided into a number of equilateral triangles. The technique used for detection is the trilateration technique in which intersection of three circles is used to determine the object location. While the object is being tracked by three sensors, distance to it from a fourth sensor is also being calculated simultaneously. The difference is that closest three sensors detect at a frequency of one second while the fourth sensor detects the object location at twice the frequency. Using the distance information from the fourth sensor and a simple mathematical technique, location of object is predicted for every half second as well. The key thing to note is that the forth sensor node is not used for detection but only for estimation of the object at half second intervals and hence does not utilize much power. Using this technique, tracking capability of the system is increased. The scheme proposed can theoretically detect objects moving at speeds of up to 33 m/s unlike the paper [16] on which it is based which can detect objects moving only up to speeds of 5 m/s. While the earlier system [16] has been demonstrated with four sensors as well, but for that the arrangement of sensor nodes is a square. The technique demonstrated does not involve a change in the arrangement and utilizes the hexagonal mesh arrangement. Some other scenarios have been tackled such as when displacement of the object is zero at the end of one second. Its movement is predicted during that time interval. Also, incase an object moves in a circle, such motions are also tracked

Fault Detection In Wireless Sensor Network Using Distributed Approach

In recent days, Wireless Sensor Networks are emerging as a promising and interesting area. Wireless Sensor Network consists of a large number of heterogeneous/homogeneous sensor nodes which communicates through wireless medium and works cooperatively to sense or monitor the environment. The number of sensor nodes in a network can vary from hundreds to thousands. The node senses data from Environment and sends these data to the gateway node. Mostly WSNs are used for applications such as military surveillance and disaster monitoring. We propose a distributed localized faulty sensor detection algorithm where each sensor identifies its own status to be either ”good” or ”faulty” which is then supported by its neighbors as they also check the node behavior. Finally, the algorithm is tested under different number of faulty sensors in the same area. Our Simulation results demonstrate that the time consumed to find out the faulty nodes in our proposed algorithm is relatively less with a large number of faulty sensors existing in the network

Distributed Fault Detection In Wireless Sensor Network

In recent days, WSNs are emerging as a promising and interesting area. Wireless Sensor Network consists of a large number of heterogeneous/homogeneous sensor nodes which communicates through wireless medium and works cooperatively to sense or monitor the environment. The number of sensor nodes in a network can vary from hundreds to thousands. The node senses data from environment and sends these data to the gateway node. Mostly WSNs are used for applications such as military surveillance and disaster monitoring. We propose a distributed localized faulty sensor detection algorithm where each sensor identifies its own status to be either ”good” or ”faulty” which is then supported by its neighbors as they also check the node behavior. Finally, the algorithm is tested under different number of faulty sensors in the same area. Our Simulation results demonstrate that the time consumed to find out the faulty nodes in our proposed algorithm is relatively less with a large number of faulty sensors existing in the networ

LOCALIZATION AND TRACKING OF 4G COGNITIVE RADIO

The 4G network provides a significant improvement in performance, but service providers are still faced with the annual increase in usage of cell phones and wireless devices. Spectrum efficiency is the most prominent issue in handling the high number of users. The cognitive radio is capable of changing its transmission and/or reception parameters according to the demands of the network. In the 4G network, the cognitive radio is seen as a solution to spectrum efficiency. With the high number of users, it also means that there is a need to effectively localize and track the 4G cognitive radio (4G-CR) signal for various purposes such as urban environment warfare, national security, surveillance, intelligence, and emergency rescue. The localization errors from previous proposed methods of time-difference-of-arrival (TDOA) measurements were analyzed in this thesis. The localization errors obtained are close to the differential-distance errors derived from the TDOA measurement algorithms. In addition, the localization of 4G-CR requires an adaptive tracking method, which is also discussed in this thesis.Civilian, ST Electronics, SingaporeApproved for public release; distribution is unlimited

Accurate location estimation of moving object In Wireless Sensor network

One of the central issues in wirless sensor networks is track the location, of moving object which have overhead of saving data, an accurate estimation of the target location of object with energy constraint .We do not have any mechanism which control and maintain data .The wireless communication bandwidth is also very limited. Some field which is using this technique are flood and typhoon detection, forest fire detection, temperature and humidity and ones we have these information use these information back to a central air conditioning and ventilation. In this research paper, we propose protocol based on the prediction and adaptive based algorithm which is using less sensor node reduced by an accurate estimation of the target location. We had shown that our tracking method performs well in terms of energy saving regardless of mobility pattern of the mobile target. We extends the life time of network with less sensor node. Once a new object is detected, a mobile agent will be initiated to track the roaming path of the object