Priority inheritance protocols: an approach to real-time synchronization

1990 ◽  
Vol 39 (9) ◽  
pp. 1175-1185 ◽  
Author(s):  
L. Sha ◽  
R. Rajkumar ◽  
J.P. Lehoczky
Keyword(s):  
Real Time ◽  
Time Synchronization

Accumulative Drifting Model of Inertial Navigation Platform under Elliptic Vibration

2014 ◽  
Vol 613 ◽  
pp. 269-278
Author(s):  
Zhen Xian Fu ◽  
Yu Rong Lin ◽  
Yang Liu ◽  
Xing Lin Chen
Keyword(s):  
Real Time ◽  
Time Synchronization ◽  
Inertial Navigation ◽  
Parameter Calibration ◽  
Testing Environment ◽  
Drift Model ◽  
General Elliptic ◽  
Elliptic Vibration ◽  
Proposed Model ◽  
Error Parameter

To facilitate the calibration of a precision inertial navigation platform, the drifting of the platform under vibratory testing environment is analyzed, and a simplified drift model is developed which features the accumulative rather than instantaneous impact of the vibration on the platform drifting. When applied to error parameter calibration for the platform, the proposed model entails much less computing load in drifting prediction, and removes the requirement of strict real-time synchronization between the vibration generating device and the drift-predicting programs. The form of vibration can be assumed to be elliptic, a relatively general one which allows the shaker to vibrate sinuoidally in two directions perpendicular to each other and with phase difference of 90 degree. Under certain circumstances, the elliptic vibration can be simplified to a linear or circular one, as is typical in practice. Simulations of the platform drifting error under linear, circular and general elliptic vibration shows that the accumulative model can well serve as an alternative to the conventional one in such test environments, and the merits of the proposed model become more prominent when the frequency of vibration gets higher.

An Information Real-Time Transmission Algorithm Based on the Android Platform

2014 ◽  
Vol 701-702 ◽  
pp. 943-946
Author(s):  
Nian Fang Hong
Keyword(s):  
Real Time ◽  
Data Transmission ◽  
Cell Phone ◽  
Streaming Media ◽  
Time Synchronization ◽  
Adaptive Streaming ◽  
Time Increase ◽  
Limited Bandwidth ◽  
Real Time Transmission ◽  
Media Data

In the wireless network environment, a large number of applications based on cell phone have emerged. But it has appeared some problems such as large amount of data and limited bandwidth and higher quality transmission in the mobile streaming media data transmission. To solve these problems, this paper designs a bandwidth adaptive streaming media real-time synchronization algorithm. Algorithm firstly analysis the state of the network, and then through real-time increase or decrease the factor method to effectively adjust the code flow rate, thus improve the QoS of streaming in transmission; to meet the learners' online learning, for subsequent teaching and interaction provides a good technical support.

Real-Time Measurement Method of Doppler Based on GPS Carrier Signals

2012 ◽  
Vol 226-228 ◽  
pp. 2050-2055 ◽  
Author(s):  
Shao Feng Dong ◽  
Bao Qiang Du ◽  
Wei Zhou
Keyword(s):  
Frequency Shift ◽  
Real Time ◽  
Measurement Method ◽  
Dynamic Range ◽  
Time Synchronization ◽  
Influencing Factor ◽  
Doppler Frequency ◽  
Time Measurement ◽  
Time Frequency ◽  
Real Time Measurement

According to Doppler effect of satellite on the time synchronization technology between satellite and the ground station, a real-time measurement method of Doppler is proposed based on GPS carrier signals. Using Doppler observations from GPS receiver, the method can real-timely measure Doppler frequency shift of GPS including dynamic Doppler and media Doppler whose error can be timely modified in the receiver end. Simulation results show that the frequency shift caused by dynamic Doppler, a main influencing factor in the course of transmission of time-frequency signal by GPS satellite, is between plus or minus several thousands Hz. Comparing to traditional measurement method of Doppler, the method makes it possible to fast track phase of signal in large dynamic range in synchronous technology.

Real time numerical dynamic orbit determination of geostationary satellite for time synchronization service

2003 ◽  
Vol 7 (5) ◽  
pp. 385-395 ◽  
Author(s):  
Bang-Yeop Kim ◽  
Jae-Cheol Yoon ◽  
Kyu-Hong Choi ◽  
Young-Keun Chang
Keyword(s):  
Real Time ◽  
Orbit Determination ◽  
Time Synchronization ◽  
Geostationary Satellite

LXI Precision Time Protocol Applied Research

2013 ◽  
Vol 330 ◽  
pp. 561-564 ◽  
Author(s):  
Ming Li ◽  
Chun Ping Wang ◽  
Zhi Qiang Wang
Keyword(s):  
Real Time ◽  
Applied Research ◽  
Time Synchronization ◽  
Local Area Network ◽  
Local Area ◽  
Test System ◽  
Area Network ◽  
Automatic Test System ◽  
Precision Time ◽  
Precise Time

In order to meet the real-time demands of some equipment networked test, the time synchronization techniques of ATS based traditional instrument buses are compared with the techniques of LXI ATS. Accordingly，the necessity of LXI ATS time synchronization technique study is put forward. The sorts of time synchronization techniques based on Local Area Network are analyzed. In addition, some methods which could improve the level of LXI data real-time communications are presented. Afterwards, technique realizations of PTP are studied in detail. Local Area Network techniques and IEEE 1588 Precise Time Protocol are adopted in the LXI Automatic Test System which designed in the paper, and the level of time synchronization precision in the system is improved.

A Real-Time, Three-Dimensional, Rapidly Updating, Heterogeneous Radar Merger Technique for Reflectivity, Velocity, and Derived Products

2006 ◽  
Vol 21 (5) ◽  
pp. 802-823 ◽  
Author(s):  
Valliappa Lakshmanan ◽  
Travis Smith ◽  
Kurt Hondl ◽  
Gregory J. Stumpf ◽  
Arthur Witt
Keyword(s):  
Real Time ◽  
Time Synchronization ◽  
Three Dimensional ◽  
Radar Data ◽  
Streaming Data ◽  
Weather Radars ◽  
Beam Geometry ◽  
Time Stamps ◽  
Scalar Products ◽  
Radar Calibration

Abstract With the advent of real-time streaming data from various radar networks, including most Weather Surveillance Radars-1988 Doppler and several Terminal Doppler Weather Radars, it is now possible to combine data in real time to form 3D multiple-radar grids. Herein, a technique for taking the base radar data (reflectivity and radial velocity) and derived products from multiple radars and combining them in real time into a rapidly updating 3D merged grid is described. An estimate of that radar product combined from all the different radars can be extracted from the 3D grid at any time. This is accomplished through a formulation that accounts for the varying radar beam geometry with range, vertical gaps between radar scans, the lack of time synchronization between radars, storm movement, varying beam resolutions between different types of radars, beam blockage due to terrain, differing radar calibration, and inaccurate time stamps on radar data. Techniques for merging scalar products like reflectivity, and innovative, real-time techniques for combining velocity and velocity-derived products are demonstrated. Precomputation techniques that can be utilized to perform the merger in real time and derived products that can be computed from these three-dimensional merger grids are described.

Low Power, Accurate Time Synchronization MAC Protocol for Real-Time Wireless Data Acquisition

2013 ◽  
Vol 60 (5) ◽  
pp. 3683-3688 ◽  
Author(s):  
Jie Zhang ◽  
Jie Wu ◽  
Zhao Han ◽  
Liefeng Liu ◽  
Kaiyun Tian ◽  
...  
Keyword(s):  
Low Power ◽  
Data Acquisition ◽  
Real Time ◽  
Time Synchronization ◽  
Mac Protocol ◽  
Wireless Data ◽  
Wireless Data Acquisition
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