Relative positioning precision of the wide-angle airborne laser ranging system

The positioning precision of ground-based targets is studied as a function of instrument and experiment parameters of the wide-angle airborne laser ranging system (WA-ALRS). The models for range measurements, validated in previous ground-based experiments, are used for simulating aircraft measurements. It is shown that the positioning precision, evaluated from the a posteriori covariance matrix, can be optimized with respect to laser beam divergence, aircraft altitude and number of targets for a given instrument performance. The number of laser shots is then adjusted to yield the desired precision. A precision of ∼1 mm is achieved in the vertical coordinate in a specific experiment assuming only random errors. Most of the systematic errors are believed to be compensated by the adjustment of additional parameters such as trajectory offsets.