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Investigation of Pole Placement Technique for Clock Steering

Schmidt, Tobias D. and Gödel, Marion and Furthner, Johann (2018) Investigation of Pole Placement Technique for Clock Steering. In: Proceedings of the 49th Annual Precise Time and Time Interval Systems and Applications Meeting, January 29 - 1, 2018, pp. 22-29. PTTI 2018, Reston, USA. ISSN 2333-2069

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Official URL: http://dx.doi.org/10.33012/2018.15603

Abstract

The development of robust and accurate time scales is a key parameter for various future applications, i.e., in the global navigation satellite system sector. A promising concept is the composite clock approach which combines several clocks to produce a time scale which performs better than the individual inputs. One method to generate a composite time uses a Kalman filter to compute the Implicit Ensemble Mean (IEM). This produces only a software timescale but a physical realization may also be required, e.g. to create a Universal Coordinate Time contribution in a time lab. In a simplified manner, this can be achieved by combining the IEM with phase measurements of a real clock in a second Kalman filter. The second Kalman filter generates control values which can be applied to the real clock in turn steering its behavior to the generated IEM. To date, these control values are primarily calculated using the Linear Quadratic Gaussian (LQG) control technique. LQG control is a very flexible technique where the user can tune three different parameters to optimize the control values. However, this flexibility also makes it difficult to find the best parameter set for a given scenario. In this paper we investigate the use of an alternate technique to generate the aforementioned control values. This Pole Placement (PP) technique is designed for use in a closed loop system such as the one defined in the composite clock approach. One determines the poles of the system and moves them to desired pole locations. The poles are obtained by identifying the eigenvalues of the system’s state transition matrix. The benefit of this technique is that only one parameter, the desired pole location, must be fed into the system. This allows for significant simplification of the control value optimization. To evaluate this technique, we performed simulations in which two fictional clocks are steered against each other. We demonstrate sufficient steering performance using PP thus allowing for easier optimization of the control parameters in future applications.

Item URL in elib:https://elib.dlr.de/126875/
Document Type:Conference or Workshop Item (Speech)
Title:Investigation of Pole Placement Technique for Clock Steering
Authors:
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Schmidt, Tobias D.Tobias.Schmidt (at) dlr.deUNSPECIFIED
Gödel, MarionUNSPECIFIEDUNSPECIFIED
Furthner, JohannJohann.Furthner (at) dlr.deUNSPECIFIED
Date:2018
Journal or Publication Title:Proceedings of the 49th Annual Precise Time and Time Interval Systems and Applications Meeting, January 29 - 1, 2018
Refereed publication:No
Open Access:No
In SCOPUS:No
In ISI Web of Science:No
Page Range:pp. 22-29
ISSN:2333-2069
Status:Published
Keywords:Clock steering, Pole Placement, Linear quadratic Gaussian control
Event Title:PTTI 2018
Event Location:Reston, USA
Event Type:international Conference
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Space
HGF - Program Themes:Communication and Navigation
DLR - Research area:Raumfahrt
DLR - Program:R KN - Kommunikation und Navigation
DLR - Research theme (Project):R - Vorhaben GNSS2/Neue Dienste und Produkte
Location: Oberpfaffenhofen
Institutes and Institutions:Institute of Communication and Navigation > Navigation
Deposited By: Schmidt, Tobias
Deposited On:26 Mar 2019 09:56
Last Modified:26 Mar 2019 09:56

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