Author:
Marcel Baunach
Affiliation:
Graz University of Technology, Austria
Keyword(s):
Event Timestamping, Reaction Scheduling, Time Synchronization, Clock Drift Calculation, Information Tagging.
Related
Ontology
Subjects/Areas/Topics:
Connectivity and Communication
;
Data Manipulation
;
Platforms and Operating Systems
;
Programming and Middleware
;
Scheduling, Tasking and Control
;
Sensor Data Fusion
;
Sensor Networks
;
Software and Architectures
Abstract:
The precise temporal attribution of environmental events and measurements as well as the precise scheduling and execution of corresponding reactions is of utmost importance for networked sensor/actuator systems. Apart, achieving a well synchronized cooperation and interaction of these wirelessly communicating distributed systems is yet another challenge. This paper summarizes various related problems which mainly result from the discretization of time in digital systems. As an improvement, we'll present a novel technique for the automatic creation of highly precise event timestamps, as well as for the scheduling of related (re-)actions and processes. Integrated into an operating system kernel at the lowest possible software level, we achieve a symmetric error interval around an average temporal error close to 0 for both the timestamps and the scheduled reaction times. Based on this symmetry, we'll also introduce a dynamic self-calibration technique to achieve the temporally exact exe
cution of the corresponding actions. An application example will show that our approach allows to determine the clock drift between two (or more) independently running embedded systems without exchanging any explicit information, except for the mutual triggering of periodic interrupts.
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