Engineering topics

Leick, A.

Publications and source records attributed to Leick, A..

4 records

NASA NTRS1980

Potentialities of lunar laser range - Differencing for measuring the earth's orientation

An investigation of range differences for their capabilities in determining the orientation of the earth in an earth-moon reference system is presented. Each pair of two coobserving stations forms an observational unit which is preferably located along a meridian or parallel; for a time interval from the instant of the first simultaneous observation of the most eastern line to the last observation of the most western line, a variance analysis shows that the pole position and the earth rotation can be computed independently of errors in the adopted lunar ephemeris. It is concluded that if the stations are within 10 to 15 deg in north-south or east-west direction the standard deviations of the parameters do not increase significantly.

Leick, A.↗

NASA NTRS1978

Earth orientation from lunar laser range-differencing

For the optimal use of high precision lunar laser ranging (LLR), an investigation regarding a clear definition of the underlying coordinate systems, identification of estimable quantities, favorable station geometry and optimal observation schedule is given.

Leick, A.↗

NASA NTRS1978

The observability of the celestial pole and its nutations

The expected motion characteristics of the real earth are systematically analysed based on available dynamical theories for the rigid model, the elastic earth model and the earth model with liquid core. The various axes which are implicit in the dynamical theories are investigated regarding observability on the basis of astronomical observations and suitability for defining reference directions. The observational insignificance of the ''diurnal polar motion'' is demonstrated. A special effort is made to clarify customarily used terminology.

Leick, A.↗

NASA NTRS1975

Satellite triangulation in Europe from WEST and ISAGEX data

Observational data that was acquired during the West European Satellite Triangulation (WEST) program and the International Satellite Geodesy Experiment (ISAGEX) campaign was obtained for the purpose of performing a geometric solution to improve the present values of coordinates of the European stations in the OSU WN14 solutions, adding some new stations and assessing the quality of the WN14 solution with the help of the additional data available. The status of the data as received, the preprocessing required and the preliminary tests carried out for the initial screening of the data are described. The adjustment computations carried out and the results of the adjustments are discussed.

Leick, A.↗