This document presents a dual-channel wireless communication system for subterranean robots. It describes a system using both 5.8GHz WiFi radios for high-bandwidth communication and 915MHz telemetry modules for low-bandwidth communication. It also details small, lightweight "communication breadcrumbs" that can be dropped by aerial robots to extend the communication range underground. Experimental results from underground exploration missions are presented to evaluate the system.
A COOPERATIVE LOCALIZATION METHOD BASED ON V2I COMMUNICATION AND DISTANCE INF...IJCNCJournal
Relative positions are recent solutions to overcome the limited accuracy of GPS in urban environment.
Vehicle positions obtained using V2I communication are more accurate because the known roadside unit
(RSU) locations help predict errors in measurements over time. The accuracy of vehicle positions depends
more on the number of RSUs; however, the high installation cost limits the use of this approach. It also
depends on nonlinear localization nature. They were neglected in several research papers. In these studies,
the accumulated errors increased with time due to the linearity localization problem. In the present study,
a cooperative localization method based on V2I communication and distance information in vehicular
networks is proposed for improving the estimates of vehicles’ initial positions. This method assumes that
the virtual RSUs based on mobility measurements help reduce installation costs and facilitate in handling
fault environments. The extended Kalman filter algorithm is a well-known estimator in nonlinear problem,
but it requires well initial vehicle position vector and adaptive noise in measurements. Using the proposed
method, vehicles’ initial positions can be estimated accurately. The experimental results confirm that the
proposed method has superior accuracy than existing methods, giving a root mean square error of
approximately 1 m. In addition, it is shown that virtual RSUs can assist in estimating initial positions in
fault environments.
Challenging Issues in Inter-Satellite Optical Wireless Systems (IsOWC) and it...idescitation
Inter-satellite optical wireless communication
system (IsOWC), one of the important applications of FSO
(Free Space Optics) technology, will be deployed in space in
the near future because of providing power efficient and high
bandwidth allocation facilities unlike present microwave
satellite systems. In this paper, we have deliberated a
presentation of different challenging issues in achieving a
prolonged inter satellite link for an IsOWC system under
different situations and conditions. This work is also
emphasized on the suggested techniques to combat with the
degrading factors to put into practice of high speed IsOWC
system with minimum BER.
New case study: read how CCS Softbank trial in downtown Tokyo demonstrated non-line of sight links at 26GHz & 28GHz in dense urban canyons. SoftBank installed CCS Metnet self-organising microwave backhaul in the challenging metropolis of Tokyo, delivering valuable insight into the behaviour of 5G microwave.
Radiation beam scanning for leaky wave antenna by using slotsTELKOMNIKA JOURNAL
This paper provides an insight of a new, microstrip leaky wave antenna. It holds the ability to continue steer its beam at a swapping frequency. This is done with acceptable impedance matching while scanning and very little gain variation. Investigation is carried out on LWAs’ control radiation pattern in steps at a band frequency via vertical and horizontal slots. The enhancement is realized by etching horizontal and vertical slots on the radiation element. This study also presents a novel half-width microstrip leaky wave antenna (LWA). The antenna is made up of the following basic structures group’s vertical and horizontal slots. The reactance profile at the microstrip’s free edge and thus the main beam direction is changed once the control-cell states are changed. The radiation pattern direction changes by sweeping the operating frequency between 4 GHz to 6 GHz.The main beam may be directed by the antenna between 15o and 55o. C band achieved the measured peak gain of the antenna of 10 dBi at 4.3 GHz beam scanning range.
A COOPERATIVE LOCALIZATION METHOD BASED ON V2I COMMUNICATION AND DISTANCE INF...IJCNCJournal
Relative positions are recent solutions to overcome the limited accuracy of GPS in urban environment.
Vehicle positions obtained using V2I communication are more accurate because the known roadside unit
(RSU) locations help predict errors in measurements over time. The accuracy of vehicle positions depends
more on the number of RSUs; however, the high installation cost limits the use of this approach. It also
depends on nonlinear localization nature. They were neglected in several research papers. In these studies,
the accumulated errors increased with time due to the linearity localization problem. In the present study,
a cooperative localization method based on V2I communication and distance information in vehicular
networks is proposed for improving the estimates of vehicles’ initial positions. This method assumes that
the virtual RSUs based on mobility measurements help reduce installation costs and facilitate in handling
fault environments. The extended Kalman filter algorithm is a well-known estimator in nonlinear problem,
but it requires well initial vehicle position vector and adaptive noise in measurements. Using the proposed
method, vehicles’ initial positions can be estimated accurately. The experimental results confirm that the
proposed method has superior accuracy than existing methods, giving a root mean square error of
approximately 1 m. In addition, it is shown that virtual RSUs can assist in estimating initial positions in
fault environments.
Challenging Issues in Inter-Satellite Optical Wireless Systems (IsOWC) and it...idescitation
Inter-satellite optical wireless communication
system (IsOWC), one of the important applications of FSO
(Free Space Optics) technology, will be deployed in space in
the near future because of providing power efficient and high
bandwidth allocation facilities unlike present microwave
satellite systems. In this paper, we have deliberated a
presentation of different challenging issues in achieving a
prolonged inter satellite link for an IsOWC system under
different situations and conditions. This work is also
emphasized on the suggested techniques to combat with the
degrading factors to put into practice of high speed IsOWC
system with minimum BER.
New case study: read how CCS Softbank trial in downtown Tokyo demonstrated non-line of sight links at 26GHz & 28GHz in dense urban canyons. SoftBank installed CCS Metnet self-organising microwave backhaul in the challenging metropolis of Tokyo, delivering valuable insight into the behaviour of 5G microwave.
Radiation beam scanning for leaky wave antenna by using slotsTELKOMNIKA JOURNAL
This paper provides an insight of a new, microstrip leaky wave antenna. It holds the ability to continue steer its beam at a swapping frequency. This is done with acceptable impedance matching while scanning and very little gain variation. Investigation is carried out on LWAs’ control radiation pattern in steps at a band frequency via vertical and horizontal slots. The enhancement is realized by etching horizontal and vertical slots on the radiation element. This study also presents a novel half-width microstrip leaky wave antenna (LWA). The antenna is made up of the following basic structures group’s vertical and horizontal slots. The reactance profile at the microstrip’s free edge and thus the main beam direction is changed once the control-cell states are changed. The radiation pattern direction changes by sweeping the operating frequency between 4 GHz to 6 GHz.The main beam may be directed by the antenna between 15o and 55o. C band achieved the measured peak gain of the antenna of 10 dBi at 4.3 GHz beam scanning range.
The telecommunication system includes the
transmission of a data bearing electromagnetic signal
through a physical medium that differentiates the
transmitter from the receiver. The relative effect of these
elements on reliable communication relies on upon the rate
of data transmission, on the craved loyalty upon gathering,
and on whether communication must happen in "real
time", for example as in phone conversations and video
teleconferencing. Moreover, microwaves are generally
utilized for point-to-point communications. Doubtlessly,
the telecom area has got a considerable measure of profit
from that communication technology additionally causes
some exception issues. Working with equipment that
works in this district obliges exceptional knowledge and
skills impressively unique in relation to those required for
traditional electronic equipment. Be that as it may, this
paper has examined for the issues of microwave
installation and demonstrates the accurate solutions for
the successful mobile communication world.
Physical Layer Technologies And Challenges In Mobile Satellite CommunicationsIDES Editor
The central features of the future fourth-generation
mobile communication systems are the provisioning of highspeed
data transmissions (up to 1 Gb/s) and interactive
multimedia services. For effective delivery of these services,
the network must satisfy some stringent quality-of-service
(QoS) metrics, defined typically in terms of maximum delay
and/or minimum throughput performances. Mobile satellite
systems will be fully integrated with the future terrestrial
cellular systems, playing important roles as back-bones or
access satellites, to provide ubiquitous global coverage to
diverse users. The challenges for future broadband satellite
systems, therefore, lie in the proper deployments of state-ofthe-
art satellite technologies to ensure seamless integration of
the satellite networks into the cellular systems and its QoS
frameworks, while achieving, to the extent possible, efficient
use of the precious satellite link resources. This paper presents
an overview of the future high-speed satellite mobile
communication systems, the technologies deployed or planned
for deployments, and the challenges.
Fuzzy based clustering and energy efficientIJCNCJournal
Underwater Wireless Sensor Network (UWSN) is a particular kind of sensor networks which is
characterized by using acoustic channels for communication. UWSN is challenged by great issues specially
the energy supply of sensor node which can be wasted rapidly by several factors. The most proposed
routing protocols for terrestrial sensor networks are not adequate for UWSN, thus new design of routing
protocols must be adapted to this constrain. In this paper we propose two new clustering algorithms based
on Fuzzy C-Means mechanisms. In the first proposition, the cluster head is elected initially based on the
closeness to the center of the cluster, then the node having the higher residual energy elects itself as a
cluster head. All non-cluster head nodes transmit sensed data to the cluster head. This latter performs data
aggregation and transmits the data directly to the base station. The second algorithm uses the same
principle in forming clusters and electing cluster heads but operates in multi-hop mode to forward data
from cluster heads to the underwater sink (uw-sink). Furthermore the two proposed algorithms are tested
for static and dynamic deployment. Simulation results demonstrate the effectiveness of the proposed
algorithms resulting in an extension of the network lifetime.
https://www.enoinstitute.com/product/satellite-communications-training-workshop/ - Satellite Communications Training Workshop course focuses on satellite communications payloads, systems engineering and architecture of satellite systems including application requirements such as digital video and broadband media, mobile services,
Satellite Communications Training - Resources:
Satellite communications training Study Guide by Darin L. Powers - Paperback & Kindle/Amazon
Satellite communications training Study Guide by Allen L. Johnson online, Kindle and Paperback/Amazon
Satellite communications training Study Guide by MALIBU RESEARCH ASSOCIATES INC CALABASAS CA - Paperback, Kindle/Amazon
Satellite communications training Study Guide by Brent Toland – Paperback/Amazon
Satellite communications training Prep Guide by James D. Coppola – Paperback/Amazon
Satellite communications training Study Guide by Herbert M. Bartman - KINDLE - EPUB - MOBI
Satellite communications Training Study Guide by Tony Radford and KC Murphy - Amazon Paperback
Satellite communications Training Study Guide by Timothy Pratt and Jeremy E. Allnutt - Paperback/Kindle Amazon
Satellite communications Training Study Guide by China Editorial DataGroup – Hardcover/Kindle/ Amazon
SATCOM Training Study Guide by Francesco Vatalaro and Fulvio Ananasso – Paperback/Kindle/ Amazon
SATCOM Training Study Guide by by National Aeronautics and Space Administration NASA Paperback/Kindle/ Amazon
SATCOM Training Study Guide by National Aeronautics and Space Administration NASA Kindle/Paperback/ Amazon
SATCOM Training Study Guide by Fulvio Ananasso and Francesco Vatalaro – Paperback/Amazon
SATCOM Training by R. A. Axford Kindle /Paperback/ Amazon
SATCOM Training by R. W. Major – Paperback/ Kindle/Amazon
Satellite Communications Training - Customize It (Onsite Only):
» If you are familiar with some aspects of Satellite Communications Training, we can omit or shorten their discussion.
» We can adjust the emphasis placed on the various topics or build the Satellite Communications Training course around the mix of technologies of interest to you (including technologies other than those included in this outline).
» If your background is nontechnical, we can exclude the more technical topics, include the topics that may be of special interest to you (e.g., as a manager or policy-maker), and present the Satellite Communications Training course in manner understandable to lay audiences.
GPSFR: GPS-Free Routing Protocol for Vehicular Networks with Directional Ante...ijwmn
Efficient and practical communications between large numbers of vehicles are critical in providing high level of safety and convenience to drivers. Crucial real-time information on road hazard, traffic conditions and driver services must be communicated to vehicles rapidly even in adverse environments, such as “urban canyons” and tunnels. We propose a novel routing protocol in vehicular networks that does not require position information (e.g. from GPS) but instead rely on relative position that can be determined dynamically. This GPS-Free Geographic Routing (GPSFR) protocol uses the estimated relative position of vehicles and greedily chooses the best next hop neighbor based on a Balance Advance (BADV) metric which balances between proximity and link stability in order to improve routing performance. In this paper, we focuses primarily on the complexity of routing in highways and solves routing problems that arise when vehicles are near interchanges, curves, and merge or exit lanes of highways. Our simulation results show that by taking relative velocity into account, GPSFR reduces link breakage to only 27% that of GPSR in the dense network. Consequently, GPSFR outperforms GPSR in terms of higher data delivery ratio, lower delay, less sensitivity of the network density and route paths’length
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
DOTNET 2013 IEEE MOBILECOMPUTING PROJECT Adaptive position update for geograp...IEEEGLOBALSOFTTECHNOLOGIES
To Get any Project for CSE, IT ECE, EEE Contact Me @ 09849539085, 09966235788 or mail us - ieeefinalsemprojects@gmail.com-Visit Our Website: www.finalyearprojects.org
Performance of modeling wireless networks in realistic environmentCSCJournals
A wireless network is realized by mobile devices which communicate over radio channels. Since, experiments of real life problem with real devices are very difficult, simulation is used very often. Among many other important properties that have to be defined for simulative experiments, the mobility model and the radio propagation model have to be selected carefully. Both have strong impact on the performance of mobile wireless networks, e.g., the performance of routing protocols varies with these models. There are many mobility and radio propagation models proposed in literature. Each of them was developed with different objectives and is not suited for every physical scenario. The radio propagation models used in common wireless network simulators, in general researcher consider simple radio propagation models and neglect obstacles in the propagation environment. In this paper, we study the performance of wireless networks simulation by consider different Radio propagation models with considering obstacles in the propagation environment. In this paper we analyzed the performance of wireless networks by OPNET Modeler .In this paper we quantify the parameters such as throughput, packet received attenuation.
Optical Wireless Communication (OWC) has attracted the researchers as an alternative broadband technology for wireless communication. In OWC optical beams are used to transport data through atmosphere or even vacuum. We have proposed an OWC model and analyze the transmission performance of OW channel for indoor/ outdoor application. The performance has been judged on the basis of key parameters like BER and OSNR. A theoretical model has also been presented and validated by the simulation results. The proposed OWC channel was simulated in Optisystem which is a powerful tool of Optical communication System
The telecommunication system includes the
transmission of a data bearing electromagnetic signal
through a physical medium that differentiates the
transmitter from the receiver. The relative effect of these
elements on reliable communication relies on upon the rate
of data transmission, on the craved loyalty upon gathering,
and on whether communication must happen in "real
time", for example as in phone conversations and video
teleconferencing. Moreover, microwaves are generally
utilized for point-to-point communications. Doubtlessly,
the telecom area has got a considerable measure of profit
from that communication technology additionally causes
some exception issues. Working with equipment that
works in this district obliges exceptional knowledge and
skills impressively unique in relation to those required for
traditional electronic equipment. Be that as it may, this
paper has examined for the issues of microwave
installation and demonstrates the accurate solutions for
the successful mobile communication world.
Physical Layer Technologies And Challenges In Mobile Satellite CommunicationsIDES Editor
The central features of the future fourth-generation
mobile communication systems are the provisioning of highspeed
data transmissions (up to 1 Gb/s) and interactive
multimedia services. For effective delivery of these services,
the network must satisfy some stringent quality-of-service
(QoS) metrics, defined typically in terms of maximum delay
and/or minimum throughput performances. Mobile satellite
systems will be fully integrated with the future terrestrial
cellular systems, playing important roles as back-bones or
access satellites, to provide ubiquitous global coverage to
diverse users. The challenges for future broadband satellite
systems, therefore, lie in the proper deployments of state-ofthe-
art satellite technologies to ensure seamless integration of
the satellite networks into the cellular systems and its QoS
frameworks, while achieving, to the extent possible, efficient
use of the precious satellite link resources. This paper presents
an overview of the future high-speed satellite mobile
communication systems, the technologies deployed or planned
for deployments, and the challenges.
Fuzzy based clustering and energy efficientIJCNCJournal
Underwater Wireless Sensor Network (UWSN) is a particular kind of sensor networks which is
characterized by using acoustic channels for communication. UWSN is challenged by great issues specially
the energy supply of sensor node which can be wasted rapidly by several factors. The most proposed
routing protocols for terrestrial sensor networks are not adequate for UWSN, thus new design of routing
protocols must be adapted to this constrain. In this paper we propose two new clustering algorithms based
on Fuzzy C-Means mechanisms. In the first proposition, the cluster head is elected initially based on the
closeness to the center of the cluster, then the node having the higher residual energy elects itself as a
cluster head. All non-cluster head nodes transmit sensed data to the cluster head. This latter performs data
aggregation and transmits the data directly to the base station. The second algorithm uses the same
principle in forming clusters and electing cluster heads but operates in multi-hop mode to forward data
from cluster heads to the underwater sink (uw-sink). Furthermore the two proposed algorithms are tested
for static and dynamic deployment. Simulation results demonstrate the effectiveness of the proposed
algorithms resulting in an extension of the network lifetime.
https://www.enoinstitute.com/product/satellite-communications-training-workshop/ - Satellite Communications Training Workshop course focuses on satellite communications payloads, systems engineering and architecture of satellite systems including application requirements such as digital video and broadband media, mobile services,
Satellite Communications Training - Resources:
Satellite communications training Study Guide by Darin L. Powers - Paperback & Kindle/Amazon
Satellite communications training Study Guide by Allen L. Johnson online, Kindle and Paperback/Amazon
Satellite communications training Study Guide by MALIBU RESEARCH ASSOCIATES INC CALABASAS CA - Paperback, Kindle/Amazon
Satellite communications training Study Guide by Brent Toland – Paperback/Amazon
Satellite communications training Prep Guide by James D. Coppola – Paperback/Amazon
Satellite communications training Study Guide by Herbert M. Bartman - KINDLE - EPUB - MOBI
Satellite communications Training Study Guide by Tony Radford and KC Murphy - Amazon Paperback
Satellite communications Training Study Guide by Timothy Pratt and Jeremy E. Allnutt - Paperback/Kindle Amazon
Satellite communications Training Study Guide by China Editorial DataGroup – Hardcover/Kindle/ Amazon
SATCOM Training Study Guide by Francesco Vatalaro and Fulvio Ananasso – Paperback/Kindle/ Amazon
SATCOM Training Study Guide by by National Aeronautics and Space Administration NASA Paperback/Kindle/ Amazon
SATCOM Training Study Guide by National Aeronautics and Space Administration NASA Kindle/Paperback/ Amazon
SATCOM Training Study Guide by Fulvio Ananasso and Francesco Vatalaro – Paperback/Amazon
SATCOM Training by R. A. Axford Kindle /Paperback/ Amazon
SATCOM Training by R. W. Major – Paperback/ Kindle/Amazon
Satellite Communications Training - Customize It (Onsite Only):
» If you are familiar with some aspects of Satellite Communications Training, we can omit or shorten their discussion.
» We can adjust the emphasis placed on the various topics or build the Satellite Communications Training course around the mix of technologies of interest to you (including technologies other than those included in this outline).
» If your background is nontechnical, we can exclude the more technical topics, include the topics that may be of special interest to you (e.g., as a manager or policy-maker), and present the Satellite Communications Training course in manner understandable to lay audiences.
GPSFR: GPS-Free Routing Protocol for Vehicular Networks with Directional Ante...ijwmn
Efficient and practical communications between large numbers of vehicles are critical in providing high level of safety and convenience to drivers. Crucial real-time information on road hazard, traffic conditions and driver services must be communicated to vehicles rapidly even in adverse environments, such as “urban canyons” and tunnels. We propose a novel routing protocol in vehicular networks that does not require position information (e.g. from GPS) but instead rely on relative position that can be determined dynamically. This GPS-Free Geographic Routing (GPSFR) protocol uses the estimated relative position of vehicles and greedily chooses the best next hop neighbor based on a Balance Advance (BADV) metric which balances between proximity and link stability in order to improve routing performance. In this paper, we focuses primarily on the complexity of routing in highways and solves routing problems that arise when vehicles are near interchanges, curves, and merge or exit lanes of highways. Our simulation results show that by taking relative velocity into account, GPSFR reduces link breakage to only 27% that of GPSR in the dense network. Consequently, GPSFR outperforms GPSR in terms of higher data delivery ratio, lower delay, less sensitivity of the network density and route paths’length
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
DOTNET 2013 IEEE MOBILECOMPUTING PROJECT Adaptive position update for geograp...IEEEGLOBALSOFTTECHNOLOGIES
To Get any Project for CSE, IT ECE, EEE Contact Me @ 09849539085, 09966235788 or mail us - ieeefinalsemprojects@gmail.com-Visit Our Website: www.finalyearprojects.org
Performance of modeling wireless networks in realistic environmentCSCJournals
A wireless network is realized by mobile devices which communicate over radio channels. Since, experiments of real life problem with real devices are very difficult, simulation is used very often. Among many other important properties that have to be defined for simulative experiments, the mobility model and the radio propagation model have to be selected carefully. Both have strong impact on the performance of mobile wireless networks, e.g., the performance of routing protocols varies with these models. There are many mobility and radio propagation models proposed in literature. Each of them was developed with different objectives and is not suited for every physical scenario. The radio propagation models used in common wireless network simulators, in general researcher consider simple radio propagation models and neglect obstacles in the propagation environment. In this paper, we study the performance of wireless networks simulation by consider different Radio propagation models with considering obstacles in the propagation environment. In this paper we analyzed the performance of wireless networks by OPNET Modeler .In this paper we quantify the parameters such as throughput, packet received attenuation.
Optical Wireless Communication (OWC) has attracted the researchers as an alternative broadband technology for wireless communication. In OWC optical beams are used to transport data through atmosphere or even vacuum. We have proposed an OWC model and analyze the transmission performance of OW channel for indoor/ outdoor application. The performance has been judged on the basis of key parameters like BER and OSNR. A theoretical model has also been presented and validated by the simulation results. The proposed OWC channel was simulated in Optisystem which is a powerful tool of Optical communication System
Planning Non Line-of-Sight Wireless Backhaul NetworksFrank Rayal
This white paper provides an overview of the planning and design of Non-line-of-sight (NLOS) wireless backhaul systems. NLOS systems can be deployed anywhere very quickly and as a result provide a very cost effective solution both in terms of capital and operational expenditures than current wireless and wireline solutions that are significantly more expensive. The design of NLOS backhaul network is different from that of LOS microwave since detailed path analysis is no longer required. Rather, planning tools are used to provide an estimate of the performance at a location where small cell is desired. The paper sets the fundamentals of NLOS wireless backhaul network design and provides an example of how a planning tool can be used in this regard.
Indoor Radio Propagation Model Analysis Wireless Node Distance and Free Space...IJERA Editor
Ultra wide bandwidth (UWB) signals are commonly defined as signals that have a large relative bandwidth
(bandwidth divided by the carrier frequency) or a large absolute bandwidth. Typical indoor environments contain
multiple walls and obstacles consisting of different materials. The RF ultra wideband (UWB) system is a
promising technology for indoor localisation owing to its high bandwidth that permits mitigation of the multipath
identification problem. The work proposed in this paper identifies exact position of transmitter and receiver
wireless nodes, calculates free space path loss and distance between two nodes by considering frequency
bandwidth using 2-point and 3-point Gaussian filter. Also in the paper three types of indoor radio propagation
models are analyzed at ultra wideband frequency range and results are compared to select best suitable model for
setting up indoor wireless connectivity and nodes in typical office, business and college environments and
WPAN applications.
System Consideration, Design and Implementation of Point To Point Microwave L...ijtsrd
Microwave technology is extremely used for point to point communications because it is more easily focused into narrower beams than radio waves, allowing frequency use, it is available higher data transmission rates and antenna sizes are smaller than at lower frequencies. The main aim of this system is to provide internet access for rural area using ePMP Force 180 5GHz subscriber module. The two sites are 1.45 km away from each other. GPS is used to determine the latitude and longitude of two sites location. Google Earth Pro software is used to check for line of sight in choosing potential terminal site locations. In this system, system consideration, design and analysis of line of sight microwave link and hardware implementations are to be carried out. In the analysis, path profile, Fresnel zone, link budget and other parameters are implemented using the link planner software Lay Nandar Soe | Kyaw Thet Zaw | Wai Phyo Aung "System Consideration, Design and Implementation of Point-To-Point Microwave Link for Internet Access" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-3 | Issue-5 , August 2019, URL: https://www.ijtsrd.com/papers/ijtsrd26769.pdf Paper URL: https://www.ijtsrd.com/engineering/electronics-and-communication-engineering/26769/system-consideration-design-and-implementation-of-point-to-point-microwave-link-for-internet-access/lay-nandar-soe
Unmanned aerial vehicles (UAVs) have become very popular recently for both civil uses and potential commercial uses, such as law enforcement, crop survey, grocery delivery, and photographing, although they were mainly used for military purposes before. Researchers need the help of simulations when they design and test new protocols for UAV networks because simulations can be done for a network of a size
that a test bed can hardly approach. In the simulation of an UAV network it is important to choose a radio propagation model for the links in the network. We study the shadowing radio propagation model in this paper and compare it with the free space model, both of which are available in the ns2 network simulation package. We also show how the choice of the parameters of the shadowing model would impact on the
network performance of a UAV network.
Secrecy performance analysis on spatial modeling of wireless communications w...IJECEIAES
In this paper, the secrecy performance of the spatial modeling for ground devices with randomly placed eavesdroppers when an unmanned aerial vehicle (UAV) acted as two hops decode and forward (DF) was investigated. We characterize the secrecy outage probability (SOP) and intercept probability (IP) expressions. Our capacity performance analysis is based on the Rayleigh fading distributions. After analytical results by Monte Carlo simulation, and the Gauss-Chebyshev parameter was selected to yield a close approximation, the results demonstrate the SOP with the average signal-to-noise ratio (SNR) between UAV and ground users among the eavesdroppers and the IP relationship with the ability to intercept the information of the ground users successfully.
Wideband Sensing for Cognitive Radio Systems in Heterogeneous Next Generation...CSCJournals
Mobile Next Generation Network (MNGN) is characterized as heterogeneous network where variety of access technologies are meant to coexist. Decisions on choosing an air interface that meets a particular need at a particular time will be shifted from the network’s side to (a more intelligent) user’s side. On top of that network operators and regularities have come to the realization that assigned spectrum bands are not utilized as they should be. Cognitive radio stands out as a candidate technology to address many emerging issues in MNGN such as capacity, quality of service and spectral efficiency. As a transmission strategy, cognitive radio systems depend greatly on sensing the radio environment. In this paper, we present a novel approach for interference characterization in cognitive radio networks based on wideband chirp signal. The results presented show that improved sensing accuracy is maintained at tolerable system complexity.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
Remote Monitoring and Control of Boat Using Lora TechnologyIJAEMSJORNAL
This work is a prototype boat that can travel in water. This robot is powered by rechargeable battery. The direction of the robot can be precise by an RF remote. This can be moved forward and reverse direction by using geared motors, also this robot can take sharp turnings towards left and right directions. In this work the LPC2148, DC Servomotors, RF Technology; L293D H-Bridge is used to drive the DC Servomotor. A high sensitive camera is also interfaced to capture the surrounding things and also to transmit to the remote place. The RF modules used here are STT-868 MHz Transmitter, STR-868 MHz Receiver. The three switches are connected to the RF transmitter through RF Encoder. The encoder constantly recites the position of the switches and permits the data to the RF transmitter and the transmitter transmits the data for further process.
A Hybrid Approach for Performance Enhancement of VANET using CSMA-MACA: a Reviewiosrjce
IOSR Journal of Computer Engineering (IOSR-JCE) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of computer engineering and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in computer technology. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
THE IMPORTANCE OF MARTIAN ATMOSPHERE SAMPLE RETURN.Sérgio Sacani
The return of a sample of near-surface atmosphere from Mars would facilitate answers to several first-order science questions surrounding the formation and evolution of the planet. One of the important aspects of terrestrial planet formation in general is the role that primary atmospheres played in influencing the chemistry and structure of the planets and their antecedents. Studies of the martian atmosphere can be used to investigate the role of a primary atmosphere in its history. Atmosphere samples would also inform our understanding of the near-surface chemistry of the planet, and ultimately the prospects for life. High-precision isotopic analyses of constituent gases are needed to address these questions, requiring that the analyses are made on returned samples rather than in situ.
Deep Behavioral Phenotyping in Systems Neuroscience for Functional Atlasing a...Ana Luísa Pinho
Functional Magnetic Resonance Imaging (fMRI) provides means to characterize brain activations in response to behavior. However, cognitive neuroscience has been limited to group-level effects referring to the performance of specific tasks. To obtain the functional profile of elementary cognitive mechanisms, the combination of brain responses to many tasks is required. Yet, to date, both structural atlases and parcellation-based activations do not fully account for cognitive function and still present several limitations. Further, they do not adapt overall to individual characteristics. In this talk, I will give an account of deep-behavioral phenotyping strategies, namely data-driven methods in large task-fMRI datasets, to optimize functional brain-data collection and improve inference of effects-of-interest related to mental processes. Key to this approach is the employment of fast multi-functional paradigms rich on features that can be well parametrized and, consequently, facilitate the creation of psycho-physiological constructs to be modelled with imaging data. Particular emphasis will be given to music stimuli when studying high-order cognitive mechanisms, due to their ecological nature and quality to enable complex behavior compounded by discrete entities. I will also discuss how deep-behavioral phenotyping and individualized models applied to neuroimaging data can better account for the subject-specific organization of domain-general cognitive systems in the human brain. Finally, the accumulation of functional brain signatures brings the possibility to clarify relationships among tasks and create a univocal link between brain systems and mental functions through: (1) the development of ontologies proposing an organization of cognitive processes; and (2) brain-network taxonomies describing functional specialization. To this end, tools to improve commensurability in cognitive science are necessary, such as public repositories, ontology-based platforms and automated meta-analysis tools. I will thus discuss some brain-atlasing resources currently under development, and their applicability in cognitive as well as clinical neuroscience.
Earliest Galaxies in the JADES Origins Field: Luminosity Function and Cosmic ...Sérgio Sacani
We characterize the earliest galaxy population in the JADES Origins Field (JOF), the deepest
imaging field observed with JWST. We make use of the ancillary Hubble optical images (5 filters
spanning 0.4−0.9µm) and novel JWST images with 14 filters spanning 0.8−5µm, including 7 mediumband filters, and reaching total exposure times of up to 46 hours per filter. We combine all our data
at > 2.3µm to construct an ultradeep image, reaching as deep as ≈ 31.4 AB mag in the stack and
30.3-31.0 AB mag (5σ, r = 0.1” circular aperture) in individual filters. We measure photometric
redshifts and use robust selection criteria to identify a sample of eight galaxy candidates at redshifts
z = 11.5 − 15. These objects show compact half-light radii of R1/2 ∼ 50 − 200pc, stellar masses of
M⋆ ∼ 107−108M⊙, and star-formation rates of SFR ∼ 0.1−1 M⊙ yr−1
. Our search finds no candidates
at 15 < z < 20, placing upper limits at these redshifts. We develop a forward modeling approach to
infer the properties of the evolving luminosity function without binning in redshift or luminosity that
marginalizes over the photometric redshift uncertainty of our candidate galaxies and incorporates the
impact of non-detections. We find a z = 12 luminosity function in good agreement with prior results,
and that the luminosity function normalization and UV luminosity density decline by a factor of ∼ 2.5
from z = 12 to z = 14. We discuss the possible implications of our results in the context of theoretical
models for evolution of the dark matter halo mass function.
Seminar of U.V. Spectroscopy by SAMIR PANDASAMIR PANDA
Spectroscopy is a branch of science dealing the study of interaction of electromagnetic radiation with matter.
Ultraviolet-visible spectroscopy refers to absorption spectroscopy or reflect spectroscopy in the UV-VIS spectral region.
Ultraviolet-visible spectroscopy is an analytical method that can measure the amount of light received by the analyte.
DERIVATION OF MODIFIED BERNOULLI EQUATION WITH VISCOUS EFFECTS AND TERMINAL V...Wasswaderrick3
In this book, we use conservation of energy techniques on a fluid element to derive the Modified Bernoulli equation of flow with viscous or friction effects. We derive the general equation of flow/ velocity and then from this we derive the Pouiselle flow equation, the transition flow equation and the turbulent flow equation. In the situations where there are no viscous effects , the equation reduces to the Bernoulli equation. From experimental results, we are able to include other terms in the Bernoulli equation. We also look at cases where pressure gradients exist. We use the Modified Bernoulli equation to derive equations of flow rate for pipes of different cross sectional areas connected together. We also extend our techniques of energy conservation to a sphere falling in a viscous medium under the effect of gravity. We demonstrate Stokes equation of terminal velocity and turbulent flow equation. We look at a way of calculating the time taken for a body to fall in a viscous medium. We also look at the general equation of terminal velocity.
This presentation explores a brief idea about the structural and functional attributes of nucleotides, the structure and function of genetic materials along with the impact of UV rays and pH upon them.
Slide 1: Title Slide
Extrachromosomal Inheritance
Slide 2: Introduction to Extrachromosomal Inheritance
Definition: Extrachromosomal inheritance refers to the transmission of genetic material that is not found within the nucleus.
Key Components: Involves genes located in mitochondria, chloroplasts, and plasmids.
Slide 3: Mitochondrial Inheritance
Mitochondria: Organelles responsible for energy production.
Mitochondrial DNA (mtDNA): Circular DNA molecule found in mitochondria.
Inheritance Pattern: Maternally inherited, meaning it is passed from mothers to all their offspring.
Diseases: Examples include Leber’s hereditary optic neuropathy (LHON) and mitochondrial myopathy.
Slide 4: Chloroplast Inheritance
Chloroplasts: Organelles responsible for photosynthesis in plants.
Chloroplast DNA (cpDNA): Circular DNA molecule found in chloroplasts.
Inheritance Pattern: Often maternally inherited in most plants, but can vary in some species.
Examples: Variegation in plants, where leaf color patterns are determined by chloroplast DNA.
Slide 5: Plasmid Inheritance
Plasmids: Small, circular DNA molecules found in bacteria and some eukaryotes.
Features: Can carry antibiotic resistance genes and can be transferred between cells through processes like conjugation.
Significance: Important in biotechnology for gene cloning and genetic engineering.
Slide 6: Mechanisms of Extrachromosomal Inheritance
Non-Mendelian Patterns: Do not follow Mendel’s laws of inheritance.
Cytoplasmic Segregation: During cell division, organelles like mitochondria and chloroplasts are randomly distributed to daughter cells.
Heteroplasmy: Presence of more than one type of organellar genome within a cell, leading to variation in expression.
Slide 7: Examples of Extrachromosomal Inheritance
Four O’clock Plant (Mirabilis jalapa): Shows variegated leaves due to different cpDNA in leaf cells.
Petite Mutants in Yeast: Result from mutations in mitochondrial DNA affecting respiration.
Slide 8: Importance of Extrachromosomal Inheritance
Evolution: Provides insight into the evolution of eukaryotic cells.
Medicine: Understanding mitochondrial inheritance helps in diagnosing and treating mitochondrial diseases.
Agriculture: Chloroplast inheritance can be used in plant breeding and genetic modification.
Slide 9: Recent Research and Advances
Gene Editing: Techniques like CRISPR-Cas9 are being used to edit mitochondrial and chloroplast DNA.
Therapies: Development of mitochondrial replacement therapy (MRT) for preventing mitochondrial diseases.
Slide 10: Conclusion
Summary: Extrachromosomal inheritance involves the transmission of genetic material outside the nucleus and plays a crucial role in genetics, medicine, and biotechnology.
Future Directions: Continued research and technological advancements hold promise for new treatments and applications.
Slide 11: Questions and Discussion
Invite Audience: Open the floor for any questions or further discussion on the topic.
A self deployed multi-channel wireless communications system for subterranean robots
1. A Self-Deployed Multi-Channel Wireless
Communications System for Subterranean Robots
Frank Mascarich
Autonomous Robots Lab
University of Nevada, Reno
fmascarich@nevada.unr.edu
Huan Nguyen
Autonomous Robots Lab
University of Nevada, Reno
huann@nevada.unr.edu
Tung Dang
Autonomous Robots Lab
University of Nevada, Reno
tung.dang@nevada.unr.edu
Shehryar Khattak
Autonomous Robots Lab
University of Nevada, Reno
shehryar@nevada.unr.edu
Christos Papachristos
Autonomous Robots Lab
University of Nevada, Reno
cpapachristos@unr.edu
Kostas Alexis
Autonomous Robots Lab
University of Nevada, Reno
kalexis@unr.edu
Abstract—In this paper we present an experimental results-
driven system design to enable more robust and self-deployed
wireless communications for robotic systems autonomously op-
erating in underground environments such as mines, caves,
and tunnels. Subterranean environments pose severe chal-
lenges for wireless communications as wireless signal suffers
extra power loss due to tunnel’s curvatures; the existence of
corners, junctions and large obstacles inside the mines; the
changes in cross section of a passage and the tilt of sidewalls.
This is especially the case when high-bandwidth and low-power
wireless communications are considered as commonly found in
autonomous robots. In response to these challenges, we present
a multi-modal communication solution that a) relies on the
integration of both dual 5.8GHz WiFi radios (high bandwidth
channel), as well as 915MHz telemetry modules (low bandwidth
channel), while at the same time b) utilizes both high-gain
directional antennas outside of the underground environment
and communication “breadcrumbs” within the subterranean
setting. The communication breadcrumbs correspond to a
highly integrated, lightweight and self-contained solution of dual
radio WiFi and small patch 6dBi antennas, a 915MHz ultra
low-power module with a 3dBi wire antenna, alongside battery
for approximately 2 hours of operation. Finally, we present
an integrated robotic solution – the “Aerial Scouts”- that are
not only capable of autonomously exploring in the underground
domain but also ferrying and dropping the aforementioned
communication breadcrumbs on their own – thus autonomously
extending their network as they go. For evaluation purposes
we present experimental results from underground exploration
missions where we relate the location of the robot, the self-
deployed communications network and the measured received
signal strength indicator (RSSI) over several points of the 3D
reconstructed map of the environment.
TABLE OF CONTENTS
1. INTRODUCTION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
2. RELATED WORK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2
3. SYSTEM DESIGN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2
4. EXPERIMENTAL EVALUATION . . . . . . . . . . . . . . . . . . . . . .5
5. CONCLUSIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
ACKNOWLEDGMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
BIOGRAPHY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
1. INTRODUCTION
Underground environments such as mines, caves, and tun-
nels constitute valuable deployment domain for autonomous
978-1-7281-2734-7/20/$31.00 c
2020 IEEE
Figure 1. Instance of an subterranean aerial robotic
deployment utilizing the dual channel wireless
communication system.
robotic systems. These settings contain serious hazards to
human workers. The collapse of mines and tunnels, fires,
rock falls, the concentration of dangerous gasses, and flood-
ing all pose significant risk to human life. Autonomous robots
have previously been successfully deployed for many real-
world tasks, such as industrial inspection [1, 2], infrastructure
surveying [3, 4], exploration and mapping [5, 6], search and
rescue operations [7, 8] and disaster response [9–11], and
hence can be utilized to mitigate the risks in many common
underground tasks as well. However, subterranean envi-
ronments pose several significant challenges to autonomous
robotic operations [12]. Dark, muddy, dusty, and complex,
confined geometry create hazards to perception, mapping,
and autonomy. The ability to monitor and command these
systems is greatly hampered by the challenges of wireless
communication in such environments. The constrained, com-
plex geometry causes often unpredictable radio frequency
effects. Furthermore, the highly variable density and radio
frequency absorption properties of earthen materials also
causes hard to model radio frequency propagation in such
settings. These radio frequency effects greatly influence the
ability of robotic systems to communicate with each other and
with their human supervisors.
Many relevant applications preclude the use of any already-
installed communication infrastructure. For example, a mine
fire may destroy any such wireless communication network
used during normal mine operations. Additionally, deploy-
ments in tunnels and caves without any communication in-
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2. frastructure also represent valuable robotic scenarios. There-
fore, robotic systems engaged in these environments must
have the ability to deploy their own communication systems
during operation. In the case of aerial robots, burdened
by payload and endurance considerations, this implies the
development of lightweight independent modules capable of
being dropped from the aerial platform.
Motivated by these challenges, this paper presents a dual
channel communication system for robotic communication
providing a high-bandwidth but short range, 5.8GHz WiFi
mesh network for information-dense messages such as im-
ages and point clouds alongside a low-bandwidth, but long
range 915MHz mesh network for short messages such as
odometry, high-level autonomy commands from human oper-
ators, and the detection of objects of interest. The system con-
sists of two unique, deployable communication breadcrumbs,
each comprised of a radio module, battery and necessary
electronic components alongside a mechanical design allow-
ing the modules to be deployed from both aerial and ground
robots. Specifically, this paper details the system design of
the two communication breadcrumb modules as well as the
aerial robotic systems responsible for deploying the afore-
mentioned modules, called the ”Aerial Scouts”. Additionally,
this paper presents an experimental evaluation of the modules
in a deployment scenario within a mine.
The remainder of the paper is organized as follows: Section 2
overviews the related work. Section 3 details both the radio
communication modules and the aerial scouts, followed by an
experimental evaluation of the presented system by robotic
field deployments in an underground mine in Section 4.
Finally, conclusions are drawn in Section 5.
2. RELATED WORK
Wireless communication technologies has been deployed in
underground mines since before the early 2000’s for human-
human, human-machine and machine-machine communica-
tion [13]. Since then, researchers have thoroughly inves-
tigated characteristics of wireless communication in under-
ground settings. [14] shows that large scale fading, the
variation of received signal strength over large distance, in
underground environments follows Lognormal distribution,
however the path loss exponent is higher than within indoor
environments [15]. This can be explained by the fact that
multipath signals induced by irregular, rough walls con-
tribute negatively to the total signal power. Additionally,
UHF signals suffer extra power losses due to tunnel’s cur-
vatures [16], corners and junctions inside the mines [17],
changes in the cross-section of a passage [18], the tilt angle of
sidewall [19] and the existence of large vehicles or obstacles
in the mines [20].
Driven by the fact that high frequency signals can offer better
coverage in straight and line-of-sight (LOS) tunnel while
signals with lower frequencies may have better coverage
when there are obstacles, corners or junctions [13], as well
as the fact that lower frequencies propagate much farther
given equal output power, in this work, we develop a dual-
channel communication system: independent 5.8GHz Wifi
and 915MHz mesh networks. The choice of the 5.8GHz WiFi
band over the 2.4GHz band is driven not only by the fact that
it is capable of higher bandwidths but also because 5.8GHz
shows lower pathloss exponent compare to 2.4GHz in non
light-of-sight situations [21]. Also, as suggested in [17], both
channels use directional antennas at the ground station, as
depicted in Figure 2, aligning the antennae with the axis of the
tunnel to maximize the component of the transmitted power
along the tunnel axis. However, unlike [17], which uses 90-
degree reflectors to compensate for the drop in RSSI around
corners, the Aerial Scout platform described in Section 3,
drops breadcrumb repeaters which extend the range of their
respective networks.
3. SYSTEM DESIGN
Radio frequency communication in subterranean settings
must tackle several significant challenges. As described in
Section 2, complex, confined geometries cause erratic and un-
reliable reflections and interference across many frequencies.
Nonetheless, the requirements of many robotic deployment
scenarios in subterranean environments require periodic, if
not constant communication with other robots and potentially
their human operators.
The types of messages distributed amongst such robot-human
teams can be bifurcated into two categories: high-bandwidth
messages contain several megabytes of data per message, and
low-bandwidth messages contain several bytes to hundreds
of bytes of data in each message. High-bandwidth messages
include image and point cloud data for the purposes of map-
sharing, co-localization of robotic collaborators, and critical
supervision by human operators. Such messages may vary
their transmission rate at the cost of precision and complete-
ness.
Low-bandwidth messages include relatively short messages
such as odometry and pose information measuring in the
range of hundreds of bytes as well as even shorter messages
such as high-level autonomy commands from a human or
robotic supervisor which may be as short as a single byte or
less. These low-bandwidth communications also represent
emergency or other mission-critical messages which must be
transmitted to the robot quickly and with guaranteed delivery.
High-bandwidth messages, on the other hand, may be loss
tolerant. For example, images and map data transmitted back
to a human operator do not necessarily have to be delivered
at the full frame rate of the camera, sensor or algorithm.
Communication Architecture
Both the division of message size into high-bandwidth and
low-bandwidth and the relative reliability requirements of
the two message types lend to the design of a dual-channel
communication architecture. In this work, a high-bandwidth
5.8Ghz WiFi mesh network is deployed along side a low-
bandwidth 915MHz DigiMesh network. Mesh networks pro-
vide the delivery of packets of information across a dynamic
set of nodes. Nodes exchange messages and re-organize
the network using a wide variety of meshing algorithms,
whose operation is not the focus of this work. In this paper,
both networks are capable of dynamically reorganizing their
networks when new nodes are added or removed from the
network, or when nodes are moved within the network such
that the path over which messages must travel between two
clients changes. Figure 3 depicts the network architecture,
while Table 1 shows the employed division of messages
between the two communication channels.
High-Bandwidth Communication Module Design
The high-bandwidth communication module employs an
ACKSYS EmbedAir1000, which consists of an 89mm x
51mm x 28mm, 45 gram dual-radio module, small 3dBi patch
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3. Table 1. Message Description
High-Bandwidth Messages
Message Type Description Size(Typ.) Rate
Images 640x480 Mono 1MB 5Hz
Object Detection Images 640x480 Color 3MB <1Hz
Maps Updates only 1MB 2Hz
Low-Bandwidth Messages
Message Type Description Size(Typ.) Rate
Pose Position & Orientation <200B 10Hz
Object Detections Object Type String & Position < 200B < 1Hz
High-Level Autonomy Commands
Take-Off - 1B <1Hz
Land - 1B <1Hz
Drop Payload Drops Comms Module 1B <1Hz
Start Exploration Starts Autonomy 1B <1Hz
Stop Exploration Stops Autonomy 1B <1Hz
Return to Home - 1B <1Hz
Go To Position Position & Orientation <100B <1Hz
Figure 2. Image depicting ground station antennae
configuration. The two square antennae on the left side of
the image are the 5.8Ghz antennae connected to the
ACKSYS EmbedAir1000 module. The upper antenna
carries the traffic of the mesh network radio, while the lower
antenna broadcasts an access point for Aerial Scouts to
connect to the ground station when in proximity. The other,
triangular shaped antenna is the low frequency antenna for
the low-bandwidth mesh network.
antennas and a 2000 mAh single cell battery. The first radio,
supporting IEEE 802.11AC, is used to form the mesh network
and connect to other high-bandwidth nodes within range. The
second radio, supporting IEEE 802.11n broadcasts a stan-
dard 5.8GHz WiFi access point, to which clients, including
human operators and the robots in the network, connect.
The utilization of dual radio modules greatly improves the
capacity of the network as the two radios can transmit or
receive simultaneously. In ideal laboratory conditions, the
mesh network was found to be capable of 164 Mbps across
two nodes, between two clients connected to each node’s
access point. Furthermore, the addition of more nodes to the
mesh network did not significantly effect the overall network
throughput. At the base station, to maximize the initial range
of the network, a high-gain, directional antenna is directed at
the entrance of the underground environment.
Figure 3. Network diagram depicting the dual channel
network architecture.
The utilization of standard WiFi access point provides many
benefits to the communication system. First, no additional
radio components are required to be carried on board the
robot, the Aerial Scout, which is detailed in subsection 3,
as well as the vast majority of modern robotic systems are
capable of communicating over standard WiFi networks.
Second, the utilization of standard WiFi networking allows
for the utilization of other standard networking protocols
and systems. In the presented field deployments, the Aerial
Scouts utilize the ROS framework [22] to send and receive
messages both internally, between various software systems
for command, perception, and control, as well as externally
with other Aerial Scouts and human operators. To simplify
the communication network across disparate systems, the
Nimbro Network package [23] was employed for explicit
control over the transmission of messages and their respective
bandwidth consumption. The Nimbro Network package also
allows multiple ROS masters to run independently, permitting
the operation of multiple robots with few minor modifications
to their respective network configurations.
Low-Bandwidth Communication Module Design
The low-bandwidth communication module employs a Digi
XBee-PRO 900HP 915MHz radio module which supports
the proprietary DigiMesh mesh networking topology. The
DigiMesh topology is a wireless mesh which features de-
centralized network organization, homogeneous node types,
dynamic routing, self-healing mesh properties, and message
re-transmission protocols. At the base-station, a high-gain,
directional antenna is utilized to maximize the initial range
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4. Figure 4. Image depicting the high-bandwidth breadcrumb
module connected to a servo-less payload release
mechanism.
Figure 5. Images depicting the low-bandwidth mesh
breadcrumb. The image on the left shows the breadcrumb
module in its state while in flight, connected to the servo-less
payload release mechanism. The image on the right shows
the breadcrumb module in its released state, with its arms
deployed as a self-righting mechanism.
of the low-bandwidth network. On board each robot, a small
XBee-PRO module is mounted utilizing a short, 3dBi whip
antenna, and communicates over a USB-Serial interface with
the Aerial Scout’s high-level processor.
The low-bandwidth breadcrumb module utilizes the same
XBee-PRO module, and is mounted within a custom designed
mechanism depicted in Figure 5. The module is equipped
with spring-loaded arms to ensure the module lands right-
side-up. The arms are folded together, loading the springs
when the modules are mounted onto the Aerial Scout’s
deployment mechanism. When released during flight, the
spring mechanism opens, preventing the module from landing
upside-down. Both laboratory and field tests indicated that
the bandwidth and range performance of the module was
greatly affected by the final orientation of the radio’s antenna
with respect to the ground.
Figure 6. Diagram depicting the Aerial Scout’s sensing and
compute system.
The module weighs only 34 grams when utilizing a 1000mAh
battery permitting more than 2 hours of operation under
heavy communication load. The module is capable of uti-
lizing larger batteries, permitting longer operation at the cost
of additional payload. During laboratory testing, the low-
bandwidth communications network achieved bidirectional
throughput rates of 21 Kbps, with several hundred meters
between nodes. This throughput exceeded the requirements
of the low-bandwidth channel messages. In field testing,
including the experiment described in Section 4, the range of
the module was found to be greatly reduced in subterranean
environments, reaching a maximum of 212 meters, along
a nearly straight line-of-sight path. Similar to the high-
bandwidth network, the inclusion of additional nodes did not
affect total network throughput.
Aerial Scouts
Figure 6 depicts the Aerial Scout platform deployed during
the experiments. The Aerial platform is based on a DJI
Matrice M100 quadrotor. The robot utilizes a 64-beam
Ouster OS1 3D LiDAR capable of providing pointclouds at
10Hz upto 100m in range with-in a horizontal and vertical
field-of-view 360◦
and 33.2◦
,respectively for localization and
mapping purposes [24]. The odometry estimates is then fused
with inertial measurements from the autopilot of the robot to
provide higher pose update rate, which is utilized by a Model
Predictive Controller [25] to guide the robot along paths gen-
erated by the exploration planner. The localization system is
further enhanced with visual-thermal-inertial odometry [26–
28], using a loosely-coupled filtering approach [29] to im-
prove its robustness. For this purpose, a FLIR Tau 2 thermal
camera mounted on the robot provides thermal images of
640×512 resolution at 30Hz. A FLIR BlackFly visible light
camera, with shutter–synchronized LEDs, provided visual
images of 640 × 512 resolution at 20Hz and a VectorNav
VN–100 IMU provideed inertial measurements at an update
rate of 200Hz. All of the aforementioned components of lo-
calization, mapping, control, and path planning are executed
in real-time and on-board the robot using an Intel NUC-i7
(NUC7i7BNH) computer.
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5. Figure 7. This figure depicts the results of the evaluation of the dual channel communications system at the Comstock Mine
in Virginia City, Nevada. In each of the maps, point clouds are colored by the RSSI value of the respective communications
channel where green indicates the greatest RSSI, and red indicates the weakest RSSI. The left-most map depicts the relative
RSSI of the WiFi channel through out the mine in the first flight which took place without any WiFi breadcrumbs placed
within the mine. It should be noted that the transition from green to red in the middle of the mine indicates where the WiFi
signal was lost. The second map from the left shows the RSSI value of the WiFi channel in the second flight after a WiFi
breadcrumb was placed at the position indicated by the label ’A’. It should be noted that the robot only lost communication
briefly within the drift adjacent to the placement of the WiFi breadcrumb. The third image from the left indicates the RSSI
value of the low-bandwidth communications network during the first flight, where the fourth image from the left depicts the
RSSI value of the low-bandwidth communications network in the second flight. It should be noted that in both flights, the
low-bandwidth communications network maintained a connection to the Aerial Scout throughout the mission other than a
brief period of less than four seconds withing the third drift. The fourth image from the left also depicts the location of the
low-bandwidth breadcrumb placed at the position indicated by the label ’B’.
4. EXPERIMENTAL EVALUATION
To evaluate the proposed communication network, the system
is evaluated in a field deployment at the Comstock Mine,
located in Virginia City, Nevada. This mine is an exploratory
portal mine consisting of a main drift extending roughly
165m from the portal and several short drifts extending off
the right side of the main drift, ranging in length from 12 to
47 meters. The experiment consists of two flights, the first of
which utilizes only radios at the ground station, and onboard
the robot, and the second of which includes both wireless
breadcrumbs deployed within the mine. Figure 7 depicts
colorized point clouds from the experiment in which points
are colored with respect to nearest measured RSSI value of
both the high-bandwidth and low-bandwidth communication
networks.
The first flight demonstrates that the maximum range of
the low-bandwidth communication channel greatly exceeds
that of the high-bandwidth communication channel, covering
nearly the entirety of the mine without any breadcrumb
modules. It should be noted that in this particular hard-
rock mine, the lower frequency of the low-bandwidth com-
munication channel is capable of reflecting around the turns
and corners of the mine much better than the high-frequency,
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6. high-bandwidth communication network.
The second flight demonstrates the extension of the high-
bandwidth communication network when a breadcrumb mod-
ule is deployed. Due to the reduced performance of the
module when located on the ground, as opposed to in flight,
the module was deployed within the maximum range of the
base station’s high-bandwidth antenna. The short strip of red
immediately below the position of the deployed node shows
the transition period as the robot’s onboard WiFi connection
switched between the access point provided by the base
station and the access point of the breadcrumb module.
5. CONCLUSIONS
In this work a pair of self-deployable networking modules
was presented enabling robust and reliable communication
between autonomous robotic systems and human operators in
subterranean settings. A bifurcation of the relevant network
data was presented which encourages the deployment of a
dual channel system, one channel affording high-bandwidth
for information-dense messages, and another channel guar-
anteeing delivery of short, mission critical messages. The
work presented the overall communication architecture, the
mechanical and electrical design of the two breadcrumb
modules, as well as the Aerial Scout platform which en-
ables deployment of the breadcrumb modules at the edges
of the communication network. Finally, a field deployment
inside an underground mine was presented to demonstrate the
robustness and limitations of the described communications
system.
Further development of this work includes thorough evalua-
tion of the modules in a number of subterranean settings char-
acterized by unique geometries and material properties. Such
an evaluation should consider the various effects concrete,
hard and soft rock on various communication frequencies.
Further mechanical design improvements may reduce the
weight of the breadcrumb modules, enabling the Aerial Scout
platform to ferry additional modules, further extending its
range and capabilities.
ACKNOWLEDGMENTS
This material is based upon work supported by the Defense
Advanced Research Projects Agency (DARPA) under Agree-
ment No. HR00111820045. The presented content and ideas
are solely those of the authors.
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BIOGRAPHY[
Frank Mascarich earned his B.S.
in Computer Science and Engineering
from the University of Nevada, Reno in
2016 with a focus in embedded systems,
and his Master’s in Computer Science
and Engineering from the University of
Nevada, Reno in 2018. Frank is cur-
rently an PhD student and Graduate Re-
search Assistant with the Autonomous
Robots Lab at the University of Nevada,
Reno. His research focuses on perception and navigation
in degraded visual environments and developing robots and
sensory systems for dirty, dull and dangerous applications.
Huan Nguyen received his B.S. and
M.S. degrees in Electrical Engineering
from Ho Chi Minh University of Tech-
nology in 2016 and 2018 respectively.
He is currently a PhD student in Au-
tonomous Robots Lab at the University
of Nevada, Reno. His research interests
are in the areas of control, motion plan-
ning and path planning for autonomous
mobile robots.
Tung Dang received his B.S. and M.S.
degrees in Electrical Engineering from
Ho Chi Minh City University of Tech-
nology in 2013 and 2015 respectively.
He is currently working towards his PhD
with Autonomous Robots Lab at the Uni-
versity of Nevada, Reno. His research
interests are in the areas of active per-
ception, path planning and control for
autonomous mobile robots.
Shehryar Khattak earned his B.S. in
Mechanical Engineering from Ghulam
Ishaq Khan Institute of Engineering Sci-
ences and Technology, Pakistan in 2009
and M.S. in Aerospace Engineering from
Korea Advanced Institute of Science and
Technology, Daejeon in 2012. From Au-
gust 2012 to December 2015, he worked
as a Research Engineer at Samsung
Electronics in Suwon, South Korea. Cur-
rently, Shehryar is pursuing his Ph.D. in Computer Science
and Engineering from the University of Nevada, Reno. His
current research is related to robot perception and path plan-
ning with focus on development of localization and mapping
algorithms exploiting multi-sensor information.
Christos Papachristos is an Assistant
Professor at the Computer Science En-
gineering Department of the University
of Nevada, Reno. Previously, he held the
position of Research Assistant Professor
at the University of Nevada, Reno in
affiliation with the Autonomous Robots
Lab, where he focused his robotics
research on enabling operational re-
silience and autonomous exploration,
consistent high-fidelity mapping, and characterization of
complex GPS-denied degraded visual environments including
7
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8. underground mines and tunnels. Dr. Papachristos obtained
his Ph.D. in aerial robotics at the University of Patras in
Greece. He is the author of more than 50 publications,
and has acted as co-PI or Senior Personnel in multi-million
projects in the US and the EU.
Kostas Alexis obtained his Ph.D. in
the field of aerial robotics control and
collaboration from the University of Pa-
tras, Greece in 2011. His Ph.D. re-
search was supported by the Greek
National-European Commission Excel-
lence scholarship. Being awarded a
Swiss Government fellowship he moved
to ETH Zurich. From 2011 to June
2015 he held the position of Senior Re-
searcher at the Autonomous Systems Lab, ETH Zurich. Cur-
rently, Dr. Alexis is an Assistant Professor at the University
of Nevada, Reno and director of the Autonomous Robots
Lab. His research interests lie in the fields of robotics and
autonomy with a particular emphasis in the topics of control
and planning and extensive experience in aerial robotics
including the co-development of the AtlantikSolar UAV – a
solar powered small aerial robot that demonstrated 81.5h
of continuous flight. He is the author of more than 70
publications and has received multiple best paper awards.
8
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