Calibration Unit for Hydrophone Line Arrays
Final rept. Dec 1971-Sep 1976
NAVAL UNDERSEA CENTER SAN DIEGO CA
Pagination or Media Count:
A calibration method applicable for long line array segments is investigated. A theoretical discussion is given on the corrections required to modify measured receiver sensitivity curves obtained by use of a simple calibration device. These corrections are for the effects of phase difference, spherical spreading, and image interference. Curves are presented from which the calibration corrections can be obtained for array segments of 3 to 24 layers and for calibration units having radii to 3 meters and covering a frequency spectrum up to 10 kHz. A calibration unit constructed at NUC in 1972 is described, and test results using this unit are presented. Errors associated with this unit due to phase differences are less than -0.1 dB below 1 kHz, spherical spreading losses are no more than -0.2 dB, and image interference effects range from 0 dB at 10 Hz to 0.1 dB at 1 kHz, indicating that no correction to the measured receiver sensitivity is required for this calibration unit.
- Acoustic Detection and Detectors