scholarly journals The Spoofing Detection of Dynamic Underwater Positioning Systems (DUPS) Based on Vehicles Retrofitted with Acoustic Speakers

Electronics ◽  
2021 ◽  
Vol 10 (17) ◽  
pp. 2089
Author(s):  
Łukasz Lemieszewski ◽  
Aleksandra Radomska-Zalas ◽  
Andrzej Perec ◽  
Larisa Dobryakova ◽  
Evgeny Ochin
Keyword(s):  
Atomic Clock ◽  
Acoustic Power ◽  
Universal Time ◽  
Time Of Arrival ◽  
Actual Problem ◽  
Positioning Systems ◽  
Underwater Positioning ◽  
Spoofing Detection ◽  
The Cost ◽  
Time Standard

The need of precision for underwater positioning and navigation should be considered as strict as those present at the sea surface. GNSS provides 4D positioning (XYZT). Each satellite contains two rubidium and two cesium atomic clocks. They are monitored by an atomic clock on the ground, and the entire system is constantly calibrated to a universal time standard, Coordinated Universal Time (UTC). GNSS receivers determine the time T to within 100 billionths of a second without the cost of owning, operating and maintaining an atomic clock. Of particular importance is the measurement of XYZT underwater. We assume that some surface vehicles are additionally equipped with an Acoustic Speaker, which transmits the XY coordinates of the vessel with an indication of accuracy and the time T of the vessel. Submarine vehicles determine their position by help of acoustic signals from several surface acoustic sources using the Time of Arrival (ToA) algorithm. Detection of Spoofing for the Dynamic Underwater Positioning Systems (DUPS) based on vehicles retrofitted with acoustic speakers is very actual problem. Underwater spoofing works as follows: N acoustic speaker on N ships transmit the coordinates . GNSS signals are susceptible to interference due to their very low power (−130 dBm) and can be easily jammed by other sources, which may be accidental or intentional. The spoofer, like an underwater vehicle, receives these signals from N vessels, distorts them and transmits with increased acoustic power. All receivers into the spoofed area will calculate the same coordinates, so the indication of the coincidence of coordinates from a pair of diversity receivers is an indication of spoofing detection.

scholarly journals Detection of Spoofing Used Against the GNSS-Like Underwater Navigation Systems

2020 ◽  
Author(s):  
Tomasz Abramowski ◽  
Mateusz Bilewski ◽  
Larisa Dobryakova ◽  
Evgeny Ochin ◽  
Janusz Uriasz ◽  
...  
Keyword(s):  
Practical Importance ◽  
Satellite System ◽  
Navigation Systems ◽  
Software Modeling ◽  
Static Mode ◽  
Positioning Systems ◽  
Detection Systems ◽  
Underwater Positioning ◽  
Spoofing Detection ◽  
Underwater Navigation

The purpose of the work is an underwater positioning safety study that used the GNSS-like underwater navigation systems. In the process of research, we used the methods of software modeling of underwater spoofing processes. The spoofing problem consists of three stages: design of spoofers, design of spoofing detection systems, and design of anti-spoofing systems. This article discusses some methods of spoofing detection. We briefly describe the known methods of underwater positioning systems. Unlike GNSS, currently only LNSS (Local Navigation Satellite System) can be considered in this case. Spoofing detection systems with one hydrophone are of great practical importance, as they allow for use of standard hydroacoustic equipment. However, detection of spoofing is not possible in static mode, which is with underwater vehicle at rest. In case of two hydrophones the detection of spoofing in static mode is possible. We discuss the navigation based on the use of an acoustically passive receiver. The receiver “listens” to the buoys and solves the problem of finding its own position using the coordinates of the buoys (such systems are called GNSS-like Underwater Positioning Systems or GNSS-like UPS). Depending on the scale of system service area, GNSS-like UPS-es are divided into global, regional, zonal and local systems. In this article, we take into account only the local class of GNSS-like UPS. The acoustic signal generator transmits a simulation of several buoy signals. If the level of the simulated signal exceeds the signal strength of actual buoys, the UPS receiver will “lock onto” the fake signal and then calculate a false position basing on it. The development of further research should be focused on the creation of hardware and software systems for conducting physical experiments at depths up to 400 m.

The Research and Development of Mechanical Product Turning Processing Cost Estimation System

2011 ◽  
Vol 121-126 ◽  
pp. 3612-3616
Author(s):  
Wen Quan Huang ◽  
Kai Shi Li ◽  
Hai Jun Liu
Keyword(s):  
Cost Estimation ◽  
Manufacturing Cost ◽  
Cost Information ◽  
Development Environment ◽  
Improve Design ◽  
Market Competitiveness ◽  
Processing Cost ◽  
Estimation System ◽  
The Cost ◽  
Time Standard

This paper adopts the method labor time standard, in the development environment of VC++, using Access database storage costs data, and the cost results output into Excel, developed mechanical product turning processing manufacturing cost estimation system. Using this system can realize turning processing cost estimation and feedback the cost information of mechanical product turning processing, make a design personnel to understand the cost information, to improve design, reduce the cost, improve the market competitiveness of products

scholarly journals Joint clock synchronization and position estimation in time of arrival–based passive positioning systems

2018 ◽  
Vol 14 (11) ◽  
pp. 155014771878689 ◽  
Author(s):  
Shenghong Li ◽  
Lingyun Lu ◽  
Mark Hedley ◽  
David Humphrey ◽  
Iain B Collings
Keyword(s):  
Clock Synchronization ◽  
Likelihood Estimation ◽  
Least Square Method ◽  
Position Estimation ◽  
Least Square ◽  
Time Of Arrival ◽  
Positioning Systems ◽  
Reference Node ◽  
Localization Scheme ◽  
Wireless Signal

A widely used scheme for target localization is to measure the time of arrival of a wireless signal emitted by a tag, which requires the clocks of the anchors (receivers at known locations) to be accurately synchronized. Conventional systems rely on transmissions from a timing reference node at a known location for clock synchronization and therefore are susceptible to reference node failure. In this article, we propose a novel localization scheme which jointly estimates anchor clock offsets and target positions. The system does not require timing reference nodes and is completely passive (non-intrusive). The positioning algorithm is formulated as a maximum likelihood estimation problem, which is solved efficiently using an iterative linear least square method. The Cramér–Rao lower bound of positioning error is also analyzed. It is shown that the performance of the proposed scheme improves with the number of targets in the system and approaches that of a system with perfectly synchronized anchors.

scholarly journals ESTIMATION OF THE EFFICIENCY OF THE LUBRICATION OF THE WORKING SURFACES OF THE SADDLE-COUPLING DEVICE OF THE FOREST TRUCK

2021 ◽  
Author(s):  
Valeriy Posmetev ◽  
Vadim Nikonov ◽  
Viktor Posmetev
Keyword(s):  
Computer Experiments ◽  
Base Plate ◽  
Optimal Number ◽  
Actual Problem ◽  
Premature Failure ◽  
Coupling Device ◽  
Excessive Consumption ◽  
Operational Factors ◽  
Friction Surfaces ◽  
The Cost

The importance of the need for further constructive improvement of fifth-wheel couplings of timber tractors with semi-trailers has been substantiated. The main operational factors arising during the movement of a timber tractor with a semitrailer in the process of hauling timber and affecting the premature failure of the main parts of the fifth wheel coupling are considered. The influence on the resource of the fifth wheel coupling device of strict fulfillment of the mandatory operations of periodic lubrication of the saddle and the base plate of the semitrailer in the process of connecting and disconnecting it with a timber tractor is given. Described is the actual problem associated with excessive consumption of lubricant in the process of applying it to the friction surfaces of the saddle and the base plate of the semitrailer by the traditional method of extrusion. A possible method of dosed supply of the required volume of lubricant through the optimal number of lubrication holes to the friction surfaces is considered, which makes it possible to significantly reduce the cost of maintaining the operable state of the fifth wheel coupling. In order to preliminary evaluate the application of this lubrication method, which ensures the effective functioning of the fifth wheel coupling of a timber tractor with a semitrailer, several series of computer experiments were performed to determine the optimal number of lubrication holes in the saddle that evenly and dosed distribute the lubricant between the saddle and the base plate of the semitrailer.

scholarly journals A Loose-Coupled Fusion of Inertial and UWB Assisted by a Decision-Making Algorithm for Localization of Emergency Responders

Electronics ◽  
2019 ◽  
Vol 8 (12) ◽  
pp. 1463 ◽  
Author(s):  
André G. Ferreira ◽  
Duarte Fernandes ◽  
André P. Catarino ◽  
Ana M. Rocha ◽  
João L. Monteiro
Keyword(s):  
Decision Making ◽  
Indoor Localization ◽  
Dead Reckoning ◽  
Time Of Arrival ◽  
Robust Solution ◽  
Localization Accuracy ◽  
Positioning Systems ◽  
Emergency Responders ◽  
Pedestrian Dead Reckoning ◽  
Non Line Of Sight

Combining different technologies is gaining significant popularity among researchers and industry for the development of indoor positioning systems (IPSs). These hybrid IPSs emerge as a robust solution for indoor localization as the drawbacks of each technology can be mitigated or even eliminated by using complementary technologies. However, fusing position estimates from different technologies is still very challenging and, therefore, a hot research topic. In this work, we pose fusing the ultrawideband (UWB) position estimates with the estimates provided by a pedestrian dead reckoning (PDR) by using a Kalman filter. To improve the IPS accuracy, a decision-making algorithm was developed that aims to assess the usability of UWB measurements based on the identification of non-line-of-sight (NLOS) conditions. Three different data fusion algorithms are tested, based on three different time-of-arrival positioning algorithms, and experimental results show a localization accuracy of below 1.5 m for a 99th percentile.

scholarly journals A Low-Cost IoT-Based System to Monitor the Location of a Whole Herd

Sensors ◽  
2019 ◽  
Vol 19 (10) ◽  
pp. 2298 ◽  
Author(s):  
Francisco Maroto-Molina ◽  
Jorge Navarro-García ◽  
Karen Príncipe-Aguirre ◽  
Ignacio Gómez-Maqueda ◽  
José E. Guerrero-Ginel ◽  
...  
Keyword(s):  
Low Cost ◽  
Beef Cows ◽  
Wireless Data ◽  
Large Variability ◽  
Grazing Behavior ◽  
Positioning Systems ◽  
Gps Collars ◽  
Wireless Data Transmission ◽  
Commercial Farms ◽  
The Cost

Animal location technologies have evolved considerably in the last 60 years. Nowadays, animal tracking solutions based on global positioning systems (GPS) are commercially available. However, existing devices have several constraints, mostly related to wireless data transmission and financial cost, which make impractical the monitorization of all the animals in a herd. The main objective of this work is to develop a low-cost solution to enable the monitorization of a whole herd. An IoT-based system, which requires some animals of the herd being fitted with GPS collars connected to a Sigfox network and the rest with low-cost Bluetooth tags, has been developed. Its performance has been tested in two commercial farms, raising sheep and beef cattle, through the monitorization of 50 females in each case. Several collar/tag ratios, which define the cost per animal of the solution, have been simulated. Results demonstrate that a low collar/tag ratio enable the monitorization of a whole sheep herd. A larger ratio is needed for beef cows because of their grazing behavior. Nevertheless, the optimal ratio depends on the purpose of location data. Large variability has been observed for the number of hourly and daily messages from collars and tags. The system effectiveness for the monitorization of all the animals in a herd has been certainly proved.

scholarly journals Dynamic Adjustment of Weighted GCC-PHAT for Position Estimation in an Ultrasonic Local Positioning System

Sensors ◽  
2021 ◽  
Vol 21 (21) ◽  
pp. 7051
Author(s):  
José Manuel Villadangos ◽  
Jesús Ureña ◽  
Juan Jesús García-Domínguez ◽  
Ana Jiménez-Martín ◽  
Álvaro Hernández ◽  
...  
Keyword(s):  
Indoor Localization ◽  
Weighting Factor ◽  
Position Estimation ◽  
Correlation Technique ◽  
Time Of Arrival ◽  
Dynamic Adjustment ◽  
Positioning Systems ◽  
Positioning Errors ◽  
Local Positioning System ◽  
Cross Correlation Technique

Ultrasonic local positioning systems (ULPS) have been brought to the attention of researchers as one of the possibilities that can be used for indoor localization. Acoustic systems combine a suitable trade-off between precision, ease of development, and cost. This work proposes a method for measuring the time of arrival of encoded emissions from a set of ultrasonic beacons, which are used to implement an accurate ULPS. This method uses the generalized cross-correlation technique with PHAT filter and weighting factor β (GCC-PHAT-β). To improve the performance of the GCC-PHAT-β in encoded emission detection, the employment is proposed of mixed-medium multiple-access techniques, based on code division and time division multiplexing of beacon emissions (CDMA and TDMA respectively), and to dynamically adjust the PHAT filter weighting factor. The receiver position is obtained by hyperbolic multilateration from the time differences of arrival (TDoA) between a reference beacon and the rest, thus avoiding the need for receiver synchronization. The results show how the dynamic adaptation of the weighting factor significantly reduces positioning errors from 20 cm to 2 cm in 80% of measurements. The simulated and real experiments prove that the proposed algorithms improve the performance of the ULPS in situations with lower signal-to-noise ratios (SNR) than 0 dB and in environments where the multipath effect makes it difficult to correctly detect the encoded ultrasonic emissions.

Emission and Fuel Reduction for Offshore Support Vessels through Hybrid Technology

2016 ◽  
Vol 32 (04) ◽  
pp. 195-205
Author(s):  
Haakon E. Lindstad ◽  
Inge Sandaas
Keyword(s):  
Fuel Consumption ◽  
Combustion Engine ◽  
Climate Impact ◽  
Climate Mitigation ◽  
Positioning Systems ◽  
Safety Standards ◽  
Oil Companies ◽  
Hybrid Technologies ◽  
The Cost ◽  
The Impact

Traditionally, offshore support vessels have been designed to ensure that they can perform their duties at nearly any sea state. This has been achieved through multiple engines and advanced dynamic positioning systems. This in combination with high safety standards set by the oil companies has resulted in a general operational pattern with vessels running multiple engines at low-to-medium loads to be prepared for unexpected incidents to happen at any time. At medium-to-high power, the combustion engine produces each kilowatt hour with the lowest fuel consumption and the lowest emissions. When engines operate at low power, fuel consumption per kilowatt hour produced increases. For the cost of the operation, this increase in specific fuel consumption at lower loads makes a small impact compared to the total cost of the operation, while for emissions low loads implies that emissions of exhaust gases such as nitrogen oxides and aerosols such as black carbon increases rapidly due to less favorable combustion conditions. This study investigates potential emission and fuel consumption reductions, which can be achieved by introduction of hybrid technologies including their climate mitigation potential. In this context, hybrid means engines of different sizes, battery storage of energy to take peak power requirements, and power management systems with a more balanced focus on reducing emissions and energy consumption while maintaining a high safety standard. Our results indicate that hybrid technologies reduce both emissions and fuel consumption, and that the climate impact of the emission reduction is much larger than the impact due to the reduction in fuel consumption alone.

scholarly journals Accuracy Bounds for Array-Based Positioning in Dense Multipath Channels

Sensors ◽  
2018 ◽  
Vol 18 (12) ◽  
pp. 4249 ◽  
Author(s):  
Thomas Wilding ◽  
Stefan Grebien ◽  
Ulrich Mühlmann ◽  
Klaus Witrisal
Keyword(s):  
Error Bound ◽  
Antenna Arrays ◽  
Estimation Error ◽  
Position Estimation ◽  
Position Error ◽  
Time Of Arrival ◽  
Angle Of Arrival ◽  
Multipath Interference ◽  
Positioning Systems ◽  
Performance Loss

The accuracy of radio-based positioning systems will be limited by multipath interference in realistic application scenarios. This paper derives closed-form expressions for the Cramér–Rao lower bound (CRLB) on the achievable time-of-arrival (ToA) and angle-of-arrival (AoA) estimation-error variances, considering the presence of multipath radio channels, and extends these results to position estimation. The derivations are based on channel models comprising deterministic, specular multipath components as well as stochastic, diffuse/dense multipath. The derived CRLBs thus allow an evaluation of the influence of channel parameters, the geometric configuration of the environment, and system parameters such as signal bandwidth and array geometry. Our results quantify how the ToA and AoA accuracies decrease when the signal bandwidth is reduced, because more multipath will then interfere with the useful LoS component. Antenna arrays can (partly) compensate this performance loss, exploiting diversity among the multipath interference. For example, the AoA accuracy with a 16-element linear array at 1 MHz bandwidth is similar to a two-element array at 1 GHz , in the magnitude order of one degree. The ToA accuracy, on the other hand, still scales by a factor of 100 from the cm-regime to the m-regime because of the dominating influence of the signal bandwidth. The position error bound shows the relationship between the range and angle information under realistic indoor channel conditions and their different scaling behaviors as a function of the anchor–agent placement. Specular multipath components have a maximum detrimental influence near the walls. It is shown for an L-shaped room that a fairly even distribution of the position error bound can be achieved throughout the environment, using two anchors equipped with 2 × 2 -array antennas. The accuracy limit due to multipath increases from the 1–10-cm-range at 1 GHz bandwidth to the 0.5–1-m-range at 100 MHz .

Study on GNSS Time Reference System and its Traceability

2012 ◽  
Vol 263-266 ◽  
pp. 2031-2034
Author(s):  
Shao Wu Dong
Keyword(s):  
Global Navigation Satellite System ◽  
Satellite System ◽  
Time Measurement ◽  
Universal Time ◽  
Navigation Satellite ◽  
Reference Systems ◽  
Internal Time ◽  
Precision Time ◽  
Global Navigation Satellite ◽  
Time Standard

This paper introduces briefly international standard time scale---theCoordinated Universal Time (UTC) and its realization, the time references and their traceability of Global Navigation Satellite System (GNSS). GNSS is based on precision time measurement, an uniform internal time reference is necessary to ensure all parts in a GNSS run synchronously. All GNSS system have precision time reference systems, at the same time, it is necessary that the time reference should be traced to the international legal time standard, UTC, to ensure global time synchronous and uniform, it can be realized by establishing time comparison link with national time standard. A possible solution of GNSS time reference and its traceability for COMPASS is discussed.

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