VENUS Ranging Study
Abstract
The underwater acoustic propagation models OASES and PECan are employed to study transmission loss (TL) to the Victoria Experimental Network Under the Sea (VENUS) sensor nodes in the Strait of Georgia as a consequence of Her Majestys Canadian (HMC) ships operating at the Canadian Forces Maritime Experimental and Test Ranges (CFMETR). Four representative frequencies are studied for a shallow acoustic source, and both hydrophones and bottom-mounted seismometers are considered as receivers at each VENUS node. Bathymetry, measured conductivity, temperature, depth (CTDs), and sediment type are taken into account to study TL as affected by monthly changes in sound velocity profile. It is found that the VENUS node, Delta Dynamics Laboratory (DDL-06), displays the minimum TL at 130 Hz with OASES results indicating horizontal/vertical particle velocity seismic losses of 114/124 dB in February/December, and a PECan result giving pressure loss of 90 dB in January. The VENUS node, East Node (EN), has similar minimal TL values, whereas the Central Node (CN) has higher TL due to a shallowbank off Gabriola Island interfering with line-of-sight acoustic transmissions from CFMETR. It is important to note that the OASES modelling presented in this report, which is mainly used to provide seismic TL, is derived from a range-independent environment. Therefore, the OASES results are inherently less accurate than corresponding PECan results especially in the case of modelling TL to CN where there is significant variability in the bathymetry profile from CFMETR to this node. Three dimensional acoustic propagation with PECan is used to determine the extent that out-of-plane acoustic energy arriving at each node influences TL.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 2014
- Accession Number
- AD1004307
Entities
People
- G. J. Heard
- N. Pelavas
- S Pecknold
Organizations
- Defence Research and Development Canada