Effects of the Sensors Arrangement on the Efficiency of Multi-Transmitter and Multi-Receiver Passive Radar

Passive radar is of interest in many aspects. These radars accomplish target localization by receiver sensors. In this paper, we investigate the effect of the sensors arrangement on the performance of multi-transmitter and multi-receiver passive radar and present a method to maximize target localization accuracy on the important locations by the optimal arrangement of receiver sensors. The proposed method is based on the Cramer-Rao lower band. The optimal placement of receiver sensors can be achieved with the help of the proposed method. We investigate the types of sensors arrangement for better accuracy in the surveillance area. The provided Cramer-Rao lower band is developed for the use of time difference of arrival measurements and the angle of arrival measurements. As illustrated in the simulations results, the joint use of both the time difference of arrival and the angle of arrival is better than the use of them alone. Furthermore, the blind areas caused by the receiver sensors arrangement are eliminated by the joint use of measurement. On the other hand, the target localization efficiency increases with the increasing distance between sensors and their dispersion in the environment

Effects of the Sensors Arrangement on the Efficiency of Multi-Transmitter and Multi-Receiver Passive Radar

883-889Passive radar is of interest in many aspects. These radars accomplish target localization by receiver sensors. In this paper, we investigate the effect of the sensors arrangement on the performance of multi-transmitter and multi-receiver passive radar and present a method to maximize target localization accuracy on the important locations by the optimal arrangement of receiver sensors. The proposed method is based on the Cramer-Rao lower band. The optimal placement of receiver sensors can be achieved with the help of the proposed method. We investigate the types of sensors arrangement for better accuracy in the surveillance area. The provided Cramer-Rao lower band is developed for the use of time difference of arrival measurements and the angle of arrival measurements. As illustrated in the simulations results, the joint use of both the time difference of arrival and the angle of arrival is better than the use of them alone. Furthermore, the blind areas caused by the receiver sensors arrangement are eliminated by the joint use of measurement. On the other hand, the target localization efficiency increases with the increasing distance between sensors and their dispersion in the environment

Stochastic modeling of hello flooding in slotted CSMA/CA wireless sensor networks

Broadcasting a request or challenge is a classic method of collecting local information in distributed wireless networks. Neighbor discovery is known to be a fundamental element in ad hoc and sensor networks topology formation, which takes advantage of such methods. Most of the current neighbor discovery protocols rely on a challenge or request broadcast by the discovering node called Hello. Hello flooding attack was specifically designed to exploit the broadcasting nature of these protocols in order to convince a large group of nodes that the sender is their neighbor by using very high transmission power. Several studies have been done to mitigate the effectiveness of the flooding threats but little effort has been made in modeling and analyzing this problem. Arguing that random channel access protocols must be inevitably employed in neighbor discovery, we propose an analytical approach for stochastic modeling of the challenge-broadcasting scenarios in networks using slotted carrier sense multiple access with collision avoidance (CSMA/CA) protocols. We model the nonstationary channel right after issuance of the request by a recursive method and then put forward an approach to find the broadcaster's approximate payoff. The model also supports the cases where the broadcaster is a malicious node with an abnormally high transmission and reception rang e, which is found in severe flooding attacks. We investigate the applications of the model in finding the optimal attack range for the flooding adversaries and deriving a flood-resilient medium access control (MAC) protocol design framework to increase the security of challenge-response protocols. The latter one is especially relevant to mobile networks as it provides a low-cost solution. This paper describes the detailed analysis of the proposed theoretical framework as well as the comprehensive evaluations that have been carried out via simulations.15 page(s