 |
| Titel |
An approach for determining the orthometric height using GPS signals and the preliminary experimental results |
| VerfasserIn |
W. B. Shen, W. Tian, K. Hou |
| Konferenz |
EGU General Assembly 2009
|
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250022348
|
|
|
|
|
|
| Zusammenfassung |
| Theoretically, given the frequency shift of an electromagnetic wave signal between two points
P and Q which are located on ground, one could determine the orthometric height difference
between these two points based on the gravity frequency shift equation. Further, the
orthometric height difference between points P and Q could be determined by using the GPS
signals (Shen et al. 1993, 2008). Signals with frequency f are emitted by the GPS satellite,
and two receivers at P and Q receive simultaneously the signals with the frequencies fP and
fQ, respectively. Then, one could determine the signal’s frequency shift between P and Q
due to the geopotential difference, which is just the same as the frequency shift of a
signal propagating from P directly to Q. This is referred to as the GPS approach. In
practice, the accuracy in determining the orthometric height difference between
two points by GPS approach depends on the stability of the time-keeping system,
which is realized by atomic clocks. At present, the stability of the time-keeping
system has achieved 6 × 10-16. With the quick development of time and frequency
science, the stability of the time-keeping system might achieve 10-18 in few years. In
the present paper, we use the GPS Doppler observations (D1 and D2 in RENIX
files) at several stations, and calculate the frequency shifts among different stations.
Then, based on the gravity frequency shift equation we determine the geopotential
difference and the orthometric height difference between every pair of these stations.
Preliminary results show that the accuracy in the height determination is about 100 m,
which is due to the fact that the stabilities of the time-keeping systems combined
with the observations are around 10-13 ~ 10-14. One byproduct of our study is
that our results support the general relativity theory: there exists the relativistic
gravity frequency shift effect. Further investigations are in process to determine the
orthometric height with successive accuracy, based on the GPS approach. This
study is supported by National 863 Project of China (Grant No.: 2006AA12Z211) |
|
|
|
|
|
|