Mobile Node Localization Based On Color Filtering And Distance Measurement For Underwater Acoustic Sensor Networks

Mobile node localization for underwater acoustic sensor networks(UASNs) has become one of the important key technologies. In this article, the background of UASNs, overseas and domestic research status of UASNs, the system structure of UASNs, characteristics and application areas of UASNs are summarized. Furthermore, some existing classical ranging methods and some mobile node localization algorithms are analyzed and introduced.Furthermore, we summarize the existing classic mobile node localization methods. According to the characteristics of UASNs, we propose some mobile node localization algorithms.(1) We propose an anchor-color filtering localization algorithm based on the hierarchical structure(ACFL). In order to further improve the localization accuracy, another kind of localization algorithm is proposed which is named a projection-color filtering localization algorithm based on the projected distance(PCFL).The difference between the above two algorithms is that PCFL adopts the projected distances between the mobile node and the projection node of each task anchors, while ACFL employs the direct distances between the mobile node and each of the task anchors. The above two methods both employ the intersection signal region between the projection nodes of task anchors and the mobile node as the current sampling area in the communication area.At the same time, the hierarchical network model is proposed in the both two methods. The proportion factor of distance is used to calculate the RGB values of the mobile node and the samples. Samples can be picked out by comparing the nearness degrees of the RGB sequences between the samples and the mobile node. And the coordinates of the mobile nodes can be calculated using the weighted methods.The simulation experiments validate that PCFL and ACFL have better localization performance. Furthermore, the average localization error of PCFL can decline by about 30.4%than an anchor-free localization algorithm(AFLA).(2) In order to further decline the localization error, the new method is proposed which is an energy screening mobile localization algorithm based on distance measurement in time of flight(TOF) technology called ESDM-TOF. In this method, TOF is used to calculate thetransmission time of acoustic signals. At the same, introducing the scale factor and doing the normalization is used to decrease the localization error. In order to reduce the energy loss, task anchor nodes are picked out to localize the mobile node. The coordinates of mobile nodes are calculated using the Heron’s formulas, the plane equations and the least squares method.Simulation results show that the localization error of ESDM-TOF is less than other methods and its localization performance is better than other methods.