Cruise Report – 10 Patch Test

Cruise Report: R/V Surf Surveyor Cruise S1-00-CL, Mapping the Bathymetry of Crater Lake, Oregon, 2000

Patch Test


Despite the careful measurements of transducer alignments and offsets, the true geometry of the installed system can only be determined through the determination of the self-consistency of lake floor measurements. A full patch test procedure to check for proper system alignments and to calibrate any time delay and gyro misalignment was completed at Lake Tahoe, California a week prior to our arrival at Crater Lake . The EM1002 data were directly compared to data collected in Lake Tahoe during the 1998 mapping (Gardner et al., 1998; 2000). The static adjustments were determined from the patch test and entered into the Simrad software. We also conducted a series of patch tests once the boat was in Crater Lake whereby the system was run back and forth across both a flat area and a steep slope of the lake floor to determine if there were residual roll, pitch, heading, or timing offsets that required correction factors.


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