Curvilinear trajectory estimation of a supersonic bullet using ballistic shock wave arrivals at asynchronous acoustic sensor nodes

2017 ◽  
Vol 141 (6) ◽  
pp. 4543-4555 ◽  
Author(s):  
Kam W. Lo
Sensors ◽  
2021 ◽  
Vol 21 (3) ◽  
pp. 727
Author(s):  
Rahul Mourya ◽  
Mauro Dragone ◽  
Yvan Petillot

Underwater acoustic sensor networks (UWASNs) can revolutionize the subsea domain by enabling low-cost monitoring of subsea assets and the marine environment. Accurate localization of the UWASNs is essential for these applications. In general, range-based localization techniques are preferred for their high accuracy in estimated locations. However, they can be severely affected by variable sound speed, multipath spreading, and other effects of the acoustic channel. In addition, an inefficient localization scheme can consume a significant amount of energy, reducing the effective life of the battery-powered sensor nodes. In this paper, we propose robust, efficient, and practically implementable localization schemes for static UWASNs. The proposed schemes are based on the Time-Difference-of-Arrival (TDoA) measurements and the nodes are localized passively, i.e., by just listening to beacon signals from multiple anchors, thus saving both the channel bandwidth and energy. The robustness in location estimates is achieved by considering an appropriate statistical noise model based on a plausible acoustic channel model and certain practical assumptions. To overcome the practical challenges of deploying and maintaining multiple permanent anchors for TDoA measurements, we propose practical schemes of using a single or multiple surface vehicles as virtual anchors. The robustness of localization is evaluated by simulations under realistic settings. By combining a mobile anchor(s) scheme with a robust estimator, this paper presents a complete package of efficient, robust, and practically usable localization schemes for low-cost UWASNs.


Underwater Acoustic Sensor Networks offer very promising solutions to monitor the aqueous environments. Due to the distinctive characteristics of UASNs, it is very challenging to design a routing protocol that can achieve maximum data delivery ratio in the network. The main challenge is the communication medium (acoustic links) that is subject to temporary attenuation and high bit error rate (BER), which limits the throughput efficiency of the Network. Besides this, another major issue is the continuous movement of nodes due to water currents and the availability of limited resources. Due to nodes mobility distance among sensor nodes and consequently, BER varies, which have a direct impact on packet size, hence, leads to high packet loss and low data delivery ratio. To achieve a high data delivery ratio, the selection of optimal packet size is of utmost importance. Consequently, the selection of next-hop forwarding node based on optimal packet size is needed. Therefore, in this paper, we propose an adaptive routing protocol named Adaptive Packet Size Selection Based Routing (APSSR) Protocol for UASNs. APSSR determines the optimal packet size adaptively based on both varying distances between sensor nodes and BER and selects the next hop based on optimal packet size and BER. The simulation results show greater network performance in terms of Network Lifetime, Data Reception Ratio at Sink node, Average Network Delay, Packet Reception Ratio, and Packets Drop Ratio


2019 ◽  
Vol 8 (4) ◽  
pp. 55 ◽  
Author(s):  
Alberto Signori ◽  
Filippo Campagnaro ◽  
Fabian Steinmetz ◽  
Bernd-Christian Renner ◽  
Michele Zorzi

The Robotic Vessels as-a-Service (RoboVaaS) project intends to exploit the most advanced communication and marine vehicle technologies to revolutionize shipping and near-shore operations, offering on-demand and cost-effective robotic-aided services. In particular, the RoboVaaS vision includes a ship hull inspection service, a quay walls inspection service, an antigrounding service, and an environmental and bathymetry data collection service. In this paper, we present a study of the underwater environmental data collection service, performed by a low-cost autonomous vehicle equipped with both a commercial modem and a very low-cost acoustic modem prototype, the smartPORT Acoustic Underwater Modem (AHOI). The vehicle mules the data from a network of low cost submerged acoustic sensor nodes to a surface sink. To this end, an underwater acoustic network composed by both static and moving nodes has been implemented and simulated with the DESERT Underwater Framework, where the performance of the AHOI modem has been mapped in the form of lookup tables. The performance of the AHOI modem has been measured near the Port of Hamburg, where the RoboVaaS concept will be demonstrated with a real field evaluation. The transmission with the commercial modem, instead, has been simulated with the Bellhop ray tracer thanks to the World Ocean Simulation System (WOSS), by considering both the bathymetry and the sound speed profile of the Port of Hamburg. The set up of the polling-based MAC protocol parameters, such as the maximum backoff time of the sensor nodes, appears to be crucial for the network performance, in particular for the low-cost low-rate modems. In this work, to tune the maximum backoff time during the data collection mission, an adaptive mechanism has been implemented. Specifically, the maximum backoff time is updated based on the network density. This adaptive mechanism results in an 8% improvement of the network throughput.


Sensors ◽  
2019 ◽  
Vol 19 (13) ◽  
pp. 2885 ◽  
Author(s):  
Sunhyo Kim ◽  
Jee Woong Choi

Underwater acoustic sensor networks have recently attracted considerable attention as demands on the Internet of Underwater Things (IoUT) increase. In terms of efficiency, it is important to achieve the maximum communication coverage using a limited number of sensor nodes while maintaining communication connectivity. In 2017, Kim and Choi proposed a new deployment algorithm using the communication performance surface, which is a geospatial information map representing the underwater acoustic communication performance of a targeted underwater area. In that work, each sensor node was a vertically separated hydrophone array, which measures acoustic pressure (a scalar quantity). Although an array receiver is an effective system to eliminate inter-symbol interference caused by multipath channel impulse responses in underwater communication environments, a large-scale receiver system degrades the spatial efficiency. In this paper, single-vector sensors measuring the particle velocity are used as underwater sensor nodes. A single-vector sensor can be considered to be a single-input multiple-output communication system because it measures the three directional components of particle velocity. Our simulation results show that the optimal deployment obtained using single-vector sensor nodes is more effective than that obtained using a hydrophone (three-channel vertical-pressure sensor) array.


2014 ◽  
Vol 933 ◽  
pp. 578-583
Author(s):  
Dong Hong Zhang ◽  
De Qiong Wu ◽  
Shan Shan Sun ◽  
Zhi Fu Fang

The traditional synchronous trigger of blasting shock wave field is lineate. Because distributed range of testing field is very wide, the cost is high, disposing line is very inconvenient, reliability of testing system is at a discount. Now a more power node acts as synchronization trigger which starts up all sensor nodes isochronously by broadcast. The author named a synchronization technology as priority sequence. Single broadcast synchronization precision measuring experiment is made by the same testing method as Elson. The new experiment result is the error accord expectation , standard deviation normal school. The standard deviation is 6.8 of Elsons. The precision is exceed demand of shock wave field testing.


2009 ◽  
Vol 5 (5) ◽  
pp. 596-618
Author(s):  
Shung Han Cho ◽  
Jinseok Lee ◽  
Sangjin Hong ◽  
WeDuke Cho

This article presents a method for dynamic data association in wireless sensor networks and addresses the issue of multiple objects tracking. The sensor node used in this article incorporates RFID reader and an acoustic sensor so that two different signals are cooperating for tracking and associating multiple objects. The RFID tag is used for object identification and an acoustic sensor is used for estimating object movements. In the heterogeneous sensor networks, our proposed association method is analyzed with association success, failure, and recovery cases. In addition, 2-dimensional (2D) particle filtering is used for estimating a objects state such as position and velocity. The performance is compared between a single sensor node and multiple sensor nodes in our proposed algorithm. In addition, the association performance with multiple sensor nodes is evaluated as a function of sampling time and object movement behavior. Finally, the effect of the two heterogeneous sensors range difference is analyzed and discussed.


2019 ◽  
Vol 2019 ◽  
pp. 1-11
Author(s):  
Shin Hur ◽  
EunJoong Lee ◽  
Jongseong Won ◽  
Duck-Gyu Lee ◽  
Kyungjun Song ◽  
...  

In this study, a shooting experiment is carried out with an acoustic sensor array that can detect shock wave at high-sound pressures and withstand the shock wave of the bullet. Delta- and H-type of acoustic sensor units are constructed. The measured values of the temporal arrival differences estimated based on the distance between the acoustic sensors are then compared with the theoretical calculations according to the types of bullets and shooting distance. In addition, an impact-point estimation system (IPES) is fabricated, which comprises delta- and H-type sensor units, a target, signal processing device, and an impact point estimation algorithm. The impact points on the target caused by the shooting experiment are compared with those calculated using the impact point estimation algorithm. Finally, the mean absolute error MAE between the actual and the calculated impact-point coordinates is calculated, and the performances of the delta- and H-type IPES are evaluated.


Sensors ◽  
2019 ◽  
Vol 20 (1) ◽  
pp. 124 ◽  
Author(s):  
Jose-Angel Fernandez-Prieto ◽  
Joaquín Cañada-Bago ◽  
Manuel-Angel Gadeo-Martos

Noise pollution is a problem that affects millions of people worldwide. Over the last few years, many researchers have devoted their attention to the design of wireless acoustic sensor networks (WASNs) to monitor the real data of continuous and precise noise levels and to create noise maps in real time and space. Although WASNs are becoming a reality in smart cities, some research studies argue that very few projects have been deployed around the world, with most of them deployed as pilots for only days or weeks, with a small number of nodes. In this paper, we describe the design and implementation of a complete system for a WASN deployed in the city of Linares (Jaén), Spain, which has been running continuously for ten months. The complete system covers the network topology design, hardware and software of the sensor nodes, protocols, and a private cloud web server platform. As a result, the information provided by the system for each location where the sensor nodes are deployed is as follows: LAeq for a given period of time; noise indicators Lden, Lday, Levening, and Lnight; percentile noise levels (LA01T, LA10T, LA50T, LA90T, and LA99T); a temporal evolution representation of noise levels; and the predominant frequency of the noise. Some comparisons have been made between the noise indicators calculated by the sensor nodes and those from a commercial sound level meter. The results suggest that the proposed system is perfectly suitable for use as a starting point to obtain accurate maps of the noise levels in smart cities.


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