Evaluation of the clock stability of geodetic GPS receivers connected to an external oscillator

authored by: Ulrich Weinbach, Steffen Schön
Abstract: In this paper, we present a stability analysis of the hardware delays for a number of GPS receivers. The receivers were connected to the same external frequency standard. This setup allows us to study the stability of the differential hardware delays, because the influence of the frequency source is identical for all receivers and can thus be eliminated in the clock comparison. Based on experimental data we derive a lower limit of σ_y(τ) = 1-2·10^-16 at one day averaging time for the frequency stability of the clock difference if geodetic receivers of the same type are compared using ionosphere-free L3 observations on a zero baseline. This can be regarded as the lower limit for frequency comparison using state-of-the-art GPS equipment. It is shown that different receiver types may process the reference frequency differently. This can lead to a drift in the differential receiver clock offset if different receiver types are compared. The exact reason for this behavior is however not yet understood. By comparing zero and short baseline data we found multipath effects to increase the noise of the clock comparison by a factor of 4. No additional systematic deviations were observed. Finally, the benefits of receiver clock modeling are investigated using simulated observation scenarios and real data. It is shown that receiver clock modeling may considerably improve the height component in kinematic GNSS solutions whereas in the static case the gain is negligible.
Organisation(s): Institute of Geodesy
Type: Conference contribution
Pages: 3317-3328
Publication date: 2009
Publication status: Published
Peer reviewed: Yes
ASJC Scopus subject areas: Computer Networks and Communications, Information Systems, Electrical and Electronic Engineering, Communication
Electronic version(s): https://www.ion.org/sign-in.cfm (Access: Restricted)
: Details in the research portal "Research@Leibniz University"

BibTeX

@inproceedings{08f0e7a0457d40bf9821470bda3f8885,
title = "Evaluation of the clock stability of geodetic GPS receivers connected to an external oscillator",
abstract = "In this paper, we present a stability analysis of the hardware delays for a number of GPS receivers. The receivers were connected to the same external frequency standard. This setup allows us to study the stability of the differential hardware delays, because the influence of the frequency source is identical for all receivers and can thus be eliminated in the clock comparison. Based on experimental data we derive a lower limit of σy(τ) = 1-2·10-16 at one day averaging time for the frequency stability of the clock difference if geodetic receivers of the same type are compared using ionosphere-free L3 observations on a zero baseline. This can be regarded as the lower limit for frequency comparison using state-of-the-art GPS equipment. It is shown that different receiver types may process the reference frequency differently. This can lead to a drift in the differential receiver clock offset if different receiver types are compared. The exact reason for this behavior is however not yet understood. By comparing zero and short baseline data we found multipath effects to increase the noise of the clock comparison by a factor of 4. No additional systematic deviations were observed. Finally, the benefits of receiver clock modeling are investigated using simulated observation scenarios and real data. It is shown that receiver clock modeling may considerably improve the height component in kinematic GNSS solutions whereas in the static case the gain is negligible.",
author = "Ulrich Weinbach and Steffen Sch{\"o}n",
year = "2009",
language = "English",
isbn = "9781615677481",
series = "22nd International Technical Meeting of the Satellite Division of the Institute of Navigation 2009, ION GNSS 2009",
pages = "3317--3328",
booktitle = "Proceedings of the 22nd International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2009)",
note = "22nd International Technical Meeting of the Satellite Division of the Institute of Navigation 2009, ION GNSS 2009 ; Conference date: 22-09-2009 Through 25-09-2009",
}