Atmospheric Contribution to the Laser Ranging Jitter

The ultimate goal of the satellite laser ranging is the millimeter precision and accuracy. To achieve this goal, all the individual contributors to the ranging error budget must be well below millimeter level. The best existing ground based ranging systems are capable to achieve millimeter ranging precision when ranging to short distance terrestrial targets. However, ranging to Earth orbiting satellites the best precision obtained is typically 3 time worse, about 3 millimeters RMS. As this value is obtained even for satellite targets not spreading the echo signal, there is a speculation, that the remaining contribution to the random error budget is contributed from the atmosphere. The ground targets ranging experiments demonstrated an increase of the ranging jitter by a factor of 0.9 psec for 100 meters atmospheric path increase [12] thus supporting this idea, as well. We have used the available the atmospheric modelling code to simulate the propagation of the optical signal in the satellite laser ranging experiment.