scholarly journals Single-Satellite Integrated Navigation Algorithm Based on Broadband LEO Constellation Communication Links

2021 ◽  
Vol 13 (4) ◽  
pp. 703
Author(s):  
Lvyang Ye ◽  
Yikang Yang ◽  
Xiaolun Jing ◽  
Jiangang Ma ◽  
Lingyu Deng ◽  
...  
Keyword(s):  
Real Time ◽  
Satellite Communication ◽  
The State ◽  
Earth Orbit ◽  
Integrated Navigation ◽  
Location Services ◽  
The Real ◽  
Navigation Algorithm ◽  
Communication Links ◽  
Leo Satellite

With the rapid development of satellite technology and the need to satisfy the increasing demand for location-based services, in challenging environments such as indoors, forests, and canyons, there is an urgent need to improve the position accuracy in these environments. However, traditional algorithms obtain the position solution through time redundancy in exchange for spatial redundancy, and they require continuous observations that cannot satisfy the real-time location services. In addition, they must also consider the clock bias between the satellite and receiver. Therefore, in this paper, we provide a single-satellite integrated navigation algorithm based on the elimination of clock bias for broadband low earth orbit (LEO) satellite communication links. First, we derive the principle of LEO satellite communication link clock bias elimination; then, we give the principle and process of the algorithm. Next, we model and analyze the error of the system. Subsequently, based on the unscented Kalman filter (UKF), we model the state vector and observation vector of our algorithm and give the state and observation equations. Finally, for different scenarios, we conduct qualitative and quantitative analysis through simulations, and the results show that, whether in an altimeter scenario or non-altimeter scenario, the performance indicators of our algorithm are significantly better than the inertial navigation system (INS), which can effectively overcome the divergence problem of INS; compared with the medium earth orbit (MEO) constellation, the navigation trajectory under the LEO constellation is closer to the real trajectory of the aircraft; and compared with the traditional algorithm, the accuracy of each item is improved by more than 95%. These results show that our algorithm not only significantly improves the position error, but also effectively suppresses the divergence of INS. The algorithm is more robust and can satisfy the requirements of cm-level real-time location services in challenging environments.

A Survey of Real-Time Industrial Wireless LAN Research

2015 ◽  
Vol 738-739 ◽  
pp. 1105-1110 ◽  
Author(s):  
Yuan Qing Qin ◽  
Ying Jie Cheng ◽  
Chun Jie Zhou
Keyword(s):  
Real Time ◽  
Future Development ◽  
Wireless Lan ◽  
State Of The Art ◽  
The State ◽  
Local Networks ◽  
The Real ◽  
Time Requirements ◽  
And Performance ◽  
Fundamental Mechanism

This paper mainly surveys the state-of-the-art on real-time communicaton in industrial wireless local networks(WLANs), and also identifys the suitable approaches to deal with the real-time requirements in future. Firstly, this paper summarizes the features of industrial WLANs and the challenges it encounters. Then according to the real-time problems of industrial WLAN, the fundamental mechanism of each recent representative resolution is analyzed in detail. Meanwhile, the characteristics and performance of these resolutions are adequately compared. Finally, this paper concludes the current of the research and discusses the future development of industrial WLANs.

scholarly journals Integration of the state observer RAPTOR in the real-time MARTe framework at RFX-mod

2017 ◽  
Vol 123 ◽  
pp. 616-619 ◽  
Author(s):  
Chiara Piron ◽  
Gabriele Manduchi ◽  
Paolo Bettini ◽  
Federico Felici ◽  
Claudio Finotti ◽  
...  
Keyword(s):  
Real Time ◽  
State Observer ◽  
The State ◽  
The Real

scholarly journals THE REAL-TIME ASSESSING METHOD FOR THE STATE OF NETWORK ELEMENTS TO PROVIDE FOR QUALITY PARAMETERS IN CORPORATE HIGH-SPEED MULTISERVICE COMMUNICATION NETWORKS

2020 ◽  
Vol 60 (2) ◽  
Author(s):  
Sergei A. Ageev ◽  
◽  
Nina S. Ageeva ◽  
Vladimir V. Karetnikov ◽  
Andrei A. Privalov ◽  
...  
Keyword(s):  
Real Time ◽  
Communication Networks ◽  
High Speed ◽  
Quality Parameters ◽  
The State ◽  
The Real ◽  
Assessing Method

scholarly journals A Role-Based Software Architecture to Support Mobile Service Computing in IoT Scenarios

Sensors ◽  
2019 ◽  
Vol 19 (21) ◽  
pp. 4801
Author(s):  
Mariano Finochietto ◽  
Gabriel M. Eggly ◽  
Rodrigo Santos ◽  
Javier Orozco ◽  
Sergio F. Ochoa ◽  
...  
Keyword(s):  
Real Time ◽  
The State ◽  
Mobile Service ◽  
Message Delivery ◽  
Time Interaction ◽  
Communication Links ◽  
Machine Theory ◽  
Dedicated Networks ◽  
Role Based

The interaction among components of an IoT-based system usually requires using low latency or real time for message delivery, depending on the application needs and the quality of the communication links among the components. Moreover, in some cases, this interaction should consider the use of communication links with poor or uncertain Quality of Service (QoS). Research efforts in communication support for IoT scenarios have overlooked the challenge of providing real-time interaction support in unstable links, making these systems use dedicated networks that are expensive and usually limited in terms of physical coverage and robustness. This paper presents an alternative to address such a communication challenge, through the use of a model that allows soft real-time interaction among components of an IoT-based system. The behavior of the proposed model was validated using state machine theory, opening an opportunity to explore a whole new branch of smart distributed solutions and to extend the state-of-the-art and the-state-of-the-practice in this particular IoT study scenario.

scholarly journals Terminal-Area Aircraft Intent Inference Approach Based on Online Trajectory Clustering

2015 ◽  
Vol 2015 ◽  
pp. 1-11
Author(s):  
Yang Yang ◽  
Jun Zhang ◽  
Kai-quan Cai
Keyword(s):  
Real Time ◽  
State Of The Art ◽  
Air Traffic ◽  
The State ◽  
Traffic Situation ◽  
Trajectory Clustering ◽  
The Real ◽  
Preliminary Results ◽  
Intent Modeling ◽  
Terminal Area

Terminal-area aircraft intent inference (T-AII) is a prerequisite to detect and avoid potential aircraft conflict in the terminal airspace. T-AII challenges the state-of-the-art AII approaches due to the uncertainties of air traffic situation, in particular due to the undefined flight routes and frequent maneuvers. In this paper, a novel T-AII approach is introduced to address the limitations by solving the problem with two steps that are intent modeling and intent inference. In the modeling step, an online trajectory clustering procedure is designed for recognizing the real-time available routes in replacing of the missed plan routes. In the inference step, we then present a probabilistic T-AII approach based on the multiple flight attributes to improve the inference performance in maneuvering scenarios. The proposed approach is validated with real radar trajectory and flight attributes data of 34 days collected from Chengdu terminal area in China. Preliminary results show the efficacy of the presented approach.

scholarly journals TVS: a trusted verification scheme for office documents based on blockchain

2022 ◽  
Author(s):  
Xue Zhai ◽  
Shanchen Pang ◽  
Min Wang ◽  
Sibo Qiao ◽  
Zhihan Lv
Keyword(s):  
Real Time ◽  
The State ◽  
Smart Contracts ◽  
Historical Records ◽  
Network Behavior ◽  
Real Time Monitoring ◽  
Verification Scheme ◽  
The Real ◽  
State Changes

AbstractTo realize the encryption of document information, authority authentication, and traceability of historical records, we propose a trusted verification scheme (TVS) for office documents to ensure security. Specifically, the scheme is realized by timestamps, smart contracts (or chaincode), and other blockchain technologies. It is based on the features of blockchain, such as security, credibility, immutability, and traceability of network behavior. And the TVS stores users and documents information through blockchain; it can monitor the state changes of office documents in real time by setting the trigger conditions of smart contracts. The experiment indicates that we have realized the real-time monitoring of data and the traceability of historical records. Moreover, we have achieved the purpose of document encryption and authority authentication, ensuring the authenticity and objectivity of data, avoiding the illegal tampering of malicious users to realize the trusted verification for documents.

ANALYZING THE REAL-TIME PROPERTIES OF A U.S. NAVY SIGNAL PROCESSING SYSTEM

2001 ◽  
Vol 08 (04) ◽  
pp. 301-322 ◽  
Author(s):  
STEVE GODDARD ◽  
KEVIN JEFFAY
Keyword(s):  
Signal Processing ◽  
Real Time ◽  
State Of The Art ◽  
Low Frequency ◽  
Processing System ◽  
The State ◽  
Signal Processing System ◽  
Processing Application ◽  
The Real ◽  
On Line

The state of the art in verifying the real-time requirements of applications developed using general processing graph models relies on simulation or off-line scheduling. We extend the state of the art by presenting analytical methods that support the analysis of cyclic processing graphs executed with on-line schedulers. We show that it is possible to compute the latency inherent in a processing graph independent of the hardware hosting the application. We also show how to compute the real-time execution rate of each node in the graph. Using the execution rate of each node and the time it takes per execution on a given processor, the resulting CPU utilization can be computed, as shown here for the Directed Low Frequency Analysis and Recording (DIFAR) acoustic signal processing application from the Airborne Low Frequency Sonar (ALFS) system of the SH-60B LAMPS MK III anti-submarine helicopter.

Approach for Detecting Soft Faults in GPS/INS Integrated Navigation based on LS-SVM and AIME

2017 ◽  
Vol 70 (3) ◽  
pp. 561-579 ◽  
Author(s):  
Lina Zhong ◽  
Jianye Liu ◽  
Rongbing Li ◽  
Rong Wang
Keyword(s):  
Kalman Filter ◽  
Fault Detection ◽  
Real Time ◽  
Support Vector ◽  
Observation Data ◽  
Navigation Systems ◽  
Integrated Navigation ◽  
The Real ◽  
Time Performance ◽  
Soft Fault

In life-critical applications, the real-time detection of faults is very important in Global Positioning System/Inertial Navigation System (GPS/INS) integrated navigation systems. A new fault detection method for soft fault detection is developed in this paper with the purpose of improving real-time performance. In general, the innovation information obtained from a Kalman filter is used for test statistic calculations in Autonomous Integrity Monitored Extrapolation (AIME). However, the innovation of the Kalman filter is degraded by error tracking and closed-loop correction effects, leading to time delays in soft fault detection. Therefore, the key issue of improving real-time performance is providing accurate innovation to AIME. In this paper, the proposed algorithm incorporates Least Squares-Support Vector Machine (LS-SVM) regression theory into AIME. Because the LS-SVM has a good regression and prediction performance, the proposed method provides replaced innovation obtained from the LS-SVM driven by real-time observation data. Based on the replaced innovation, the test statistics can follow fault amplitudes more accurately; finally, the real-time performance of soft fault detection can be improved. Theoretical analysis and physical simulations demonstrate that the proposed method can effectively improve the detection instantaneity.

scholarly journals Performance optimization of task intensive real time applications on multicore ECUs - a hybrid scheduler

2019 ◽  
Vol 8 (2) ◽  
pp. 114
Author(s):  
Geetishree Mishra ◽  
Rajeshwari Hegde
Keyword(s):  
Real Time ◽  
Performance Optimization ◽  
State Of The Art ◽  
Multicore Processors ◽  
Scheduling Algorithm ◽  
Electronic System ◽  
Current Approach ◽  
The State ◽  
Thermal Dissipation ◽  
The Real

In the current approach of Automotive electronic system design, the multicore processors have prevailed to achieve high computing performance at low thermal dissipation. Multicore processors offer functional parallelism that helps in meeting the safety critical requirements of vehicles. The number of ECUs in high-end cars could be reduced by conglomerating more functions into a multicore ECU. AUTOSAR stack has been designed to support the applications developed for multicore ECUs. The real challenges lie in adapting new design methods while developing sophisticated applications with multicore constraints. It is imperative to utilize the most of multicore computational capability towards enhancing the overall performance of ECUs. In this context the scheduling of the real time multitasking software components by the operating system is one of the key issues to be addressed. In this paper, the state of the art scheduling algorithm is reviewed and its merits and limitations are identified. A hybrid scheduler has been proposed, tested and compared with the state of the art algorithm that offers better performance in terms of CPU utilization, average response time and deadline missing rate both in normal and high load conditions.

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