Results of the first aircraft experiment with the wide-angle airborne laser ranging system

The first aircraft experiment with the wide-angle airborne laser ranging system has been conducted in May 1998 over a small network of 1 km(2), equipped with 64 cube-corner retroreflectors. The ranging system was operated from a research aircraft (ARAT, Fokker 27) at an altitude of 1 km. Data have been collected during two 4-hour flights. The paper describes the data processing methods and presents the first results from this experiment. A precision of 2 cm has been achieved on the difference of vertical coordinates from two sets of similar to 3000 distance measurements. Results are consistent with simulations and a posteriori covariance. A drastic data sorting for outliers, due to strong overlap of reflected echoes, has been necessary. Hence, the actual number of measurements and the positioning precision became relatively small. Higher precision is expected in future experiments, once the instrument's link budget will be improved.