CALIBRATING LARSEN-500 LIDAR BATHYMETRY IN DOLPHIN AND UNION STRAIT USING DENSE ACOUSTIC GROUND-TRUTH

Dolphin and Union Strait, in the Canadian Arctic, was surveyed in the summer of 1990 using the Larsen 500 scanning Lidar bathymeter. As part of the 1993 Arctic hydrographic surveys, five test areas within the L idar-surveyed area were chosen for detailed acoustic measurements. The se data were used to calibrate the Lidar depths prior to integration w ith acoustic soundings in hydrographic field sheet construction. For t he calibration, geostatistical software was used to bring the two data types to common grid points, and to estimate the total error surface of both Lidar and acoustic measurements due to errors in depth measure ment and reduction, positioning system errors and errors in interpolat ion due to the roughness of the bathymetry. The differences in the two data sets are examined and the reasons for biases are discussed. A pr ecision estimate of the Lidar depth measurements was made based on the difference residuals and the a priori estimates of precision of each of the measured data sets.