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To realize the full potential of satellite laser ranging for accurate geodesy, it is crucial that all systematic effects in the measurements are taken into account. This paper derives new values for the so-called center-of-mass corrections for three geodetic satellites that are regularly tracked and used in geodetic studies. Optical responses of the twin satellites, Starlette and Stella, and the LARES satellite are retrieved from kHz single-photon laser-ranging data observed at Herstmonceux and Potsdam. The detection timing inside single-photon systems, C-SPAD-based systems and photomultiplier-based systems is numerically simulated, and the center-of-mass corrections are derived to be in the range of 74 to 82 mm for Starlette and Stella, and 127-135 mm for LARES. The system dependence is below 1 cm, but should not be ignored for millimeter accuracy. The longtime standard center-of-mass correction 75 mm of Starlette and Stella is revealed to be too small for the current laser-ranging stations on average, which is considered to have resulted in a non-negligible systematic error in geodetic products. [ABSTRACT FROM AUTHOR]

Abstract: We numerically examined various retroreflectors as laser ranging targets for future missions to the Moon. The geometric conditions, such as the angle of incidence and velocity aberration, with lunar targets are much more restricted than those with most of the earth-orbiting artificial satellites. The numerical optical response simulation carried out in this study indicates that a single retroreflector with a diameter of 150–250mm performs similar to the existing Apollo retroreflector arrays. Further, no dihedral angle is required for small retroreflectors with diameters below 150mm for uncoated ones and below 100mm for coated and hollow ones. Retroreflectors with larger diameters require dihedral angles of 0.20, 0.25, and 0.35arcsec for coated, uncoated and hollow types, respectively. The objective of this fundamental study is to underlie the development of future laser ranging targets that are to be placed on the Moon. [Copyright &y& Elsevier]

The Graz kHz Satellite Laser Ranging (SLR) system is the first system operating with a 2-kHz-repetition-rate laser. Using Graz 2-kHz SLR data only, we applied a new analytical approach to determine the spin period of the passive satellite AJISAI. This method analyzes the range measurements to the single corner-cube-reflector panels of AJISAI, allowing accurate determination of an actual attitude of this satellite during day and night. Using Graz kHz SLR data of more than five years, we processed 877 passes of AJISAI (October 9, 2003-December 22, 2008) and calculated its spin period (∼2 s) with an accuracy of 0.0042% (84 μs). This spin period (T ) is increasing, following an exponential trend: T = 1.9028 · Exp (0.014859 · (Year - 2003.0)) s. This slow down is mainly caused by the gravitational andmagnetic fields of the Earth. The high accuracy allows, for the first time, the detection of small perturbations of the spin period caused by nongravitational effects related to the solar energy flux to which the satellite is exposed. [ABSTRACT FROM AUTHOR]

The spin rate and spin axis orientation of the Laser Geodynamics Satellite 2 (LAGEOS-2) satellite were determined by analysis of photometric observation data. A photometer system developed at the Space Geodesy Facility at Herstmonceux, U.K., was used to time solar glints from the rotating satellite. It was found that the spin rate of LAGEOS-2 slowed by 38% per year between March 2000 and November 2002 and that the spin axis undergoes a slow, complex precession with respect to the earth's rotation axis. Moreover, the analysis revealed that the direction of the spin was the reverse of that of the earth's rotation and that the optical alignment of a reflector surface on LAGEOS-2 can deviate from its position vector by up to 15 arcmin. [ABSTRACT FROM AUTHOR]

Presents information on a study which modeled the detection timing of laser pulse returned from the satellite AJISAI for a single-photon laser ranging system. Modeling of center-of-mass correction for AJISAI; Range bias estimation; Conclusions.