 |
| Titel |
Geopotential difference determination using optical atomic clocks via coaxial cable time transfer technique |
| VerfasserIn |
Zi-Yu Shen, WenBin Shen |
| Konferenz |
EGU General Assembly 2014
|
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250097562
|
| Publikation (Nr.) |
 EGU/EGU2014-13159.pdf |
|
|
|
|
|
| Zusammenfassung |
| According to general theory of relativity, two clocks located at different positions A and B on
ground with different geopotentials run at different rates. If the clock at A runs
faster by dt/T than the clock at B, the geopotential difference between A and B is
dW=9.0*10E16 dt/T m2/s2. Thus one can determine the geopotential difference
between A and B by comparing the running rates of the clocks located at these
two positions. Due to the fact that the present time transfer technique provides
time comparison accuracy by higher than 10ps via 100m coaxial cable, and the
to-date most precise optical atomic clocks achieve a stability of 10E-18 level, the
relativistic geodesy method for determining geopotential may be realizable in the near
future. In this study, we proposed, designed and described in detail an approach
for determining the geopotential difference between two positions based upon a
simulation experiment. We selected two stations A and B whose spatial distance is
about 100m and height difference is about 30m. It is assumed that each station is
equipped with an optical atomic clock with its instability about 3.2*10E-16/sqrt
(Tao) (where Tao is time in second), and these two clocks are priori synchronized.
It is noted that such a kind of optical atomic clock with so high a stability was
generated in 2013 in USA. The two stations A and B are connected with a coaxial cable
for time transfer. In the simulation experiment we first set the true value of the
geopotential difference between A and B, and consequently the clocks’ running
rate difference between A and B can be a priori calculated. Then we generated
simulated data sets of time comparison, which are contaminated by various possible
error sources. Thereafter we estimated the clocks’ running rate difference and the
corresponding geopotential difference by least squares estimate using the simulated
data sets. Finally the accuracy in determining the geopotential difference using
the proposed approach was assessed by comparing the true input value and the
estimated one. Our simulation experiment results show that the accuracy is around
0.5m2/s2 (equivalent to 5 cm in height) after a period of observation in four hours. This
study is supported by National 973 Project China (grant Nos. 2013CB733301 and
2013CB733305), NSFC (grant Nos. 41174011, 41210006, 41128003, 41021061, 40974015). |
|
|
|
|
|
|