TY - GEN

T1 - Evaluation of the clock stability of geodetic GPS receivers connected to an external oscillator

AU - Weinbach, Ulrich

AU - Schön, Steffen

PY - 2009

Y1 - 2009

N2 - 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.

AB - 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.

UR - http://www.scopus.com/inward/record.url?scp=77952186574&partnerID=8YFLogxK

M3 - Conference contribution

AN - SCOPUS:77952186574

SN - 9781615677481

T3 - 22nd International Technical Meeting of the Satellite Division of the Institute of Navigation 2009, ION GNSS 2009

SP - 3317

EP - 3328

BT - Proceedings of the 22nd International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2009)

T2 - 22nd International Technical Meeting of the Satellite Division of the Institute of Navigation 2009, ION GNSS 2009

Y2 - 22 September 2009 through 25 September 2009

ER -