Geofisica pura e applicata

, Volume 45, Issue 1, pp 27–39 | Cite as

The computation of gravity differences from observations with a Worden gravimeter and the resultant errors

  • Thomas Murphy
Article
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Summary

The methods of computation of the gravity difference between two stations depend on the assumed behaviour of the zero drift. When this drift is taken as following a quadratic law with respect to time, then the various methods give virtually the same value for the gravity difference and the estimated errors in it are also the same. In adjusting a network of gravity connections it is proposed that, to form a system of weighting, the estimated errors in the connections should be used in the place of the probable errors, which are unobtainable as the number of independent observations is too small. The estimated errors have been based on the standard deviation of an observation which is probably a characteristic of one gravimeter and one observer. The standard deviation of a single observation with a Worden gravimeter was found to be ±0.014 mgal as a result of a special set of experiments under field conditions. Large random errors have been observed in a Worden gravimeter and the cause is attributed to changes in the filament of the bulb which produces the reading index line.

Keywords

Probable Error Single Observation Resultant Error Zero Drift Index Line 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Zusammenfassung

Die Methoden der Berechnung der Schweredifferenzen zwischen zwei Stationen hängt von dem vorausgesetzten Verhalten der Nullpunkts-Änderung (Drift) ab. Wenn angenommen wird, dass diese Drift ein quadratisches Gesetz rücksichtlich der Zeit befolgt, dann geben die verschiedenen Methoden im wesentlichen den gleichen Wert der Schweredifferenz und ihres geschätzten Fehlers. Für die Ausgleichung eines Netzes von Schwereverbindungen wird, um ein System von Gewichten zu bilden, vorgeschlagen, dass die geschätzten Fehler in den Verbindungen anstatt der wahrscheinlichen Fehler verwendet werden, welche nicht abgeleitet werden können, da die Zahl der unabhängigen Beobachtungen zu klein ist. Die geschätzten Fehler wurden auf die mittlere Abweichung einer Beobachtung gegründet, welche wahrscheinlich eine charakteristische Eigenschaft eines Schweremessers und eines Beobachters ist. Als Resultat eines speziellen Satzes von Feldexperimenten wurde als mittlerer Fehler einer einzelnen Beobachtungen mit einemWorden-Schweremesser ±0.014 mgal gefunden.

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Copyright information

© Istituto Geofisico Italiano 1960

Authors and Affiliations

  • Thomas Murphy
    • 1
  1. 1.School of Cosmic Physics in the Dublin Institute for Advanced StudiesDublinIreland

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