The HODGSON And RAM Composite Acoustic Model – HARCAM – is a dedicated propagation loss system designed to produce accurate acoustic propagation loss data over a very wide frequency band – from 10Hz to over 500kHz. All data input and output is based on ASCII text files with one variant producing simple, common theme, graphical output suitable for quality control and logging purposes. It is aimed at users who need to produce large quantities of propagation loss data, in an efficient manner and ideally using a computer that can run unattended. This makes HARCAM particularly suited to users involved in underwater acoustics research and environmental impact assessment. HARCAM is supplied with the same supporting data sets as WADER.
A unique feature of HARCAM is that it uses two models, HODGSON and RAM, to produce accurate propagation loss data at high and low frequencies respectively. In addition, it utilises HODGSON to provide surface and absorption loss data to correct RAM output in the 250-1000Hzrange where these parameters are important and where RAM is unable to include the effect of sea surface and absorption losses. In essence, the two models form a symbiotic relationship to produce accurate, consistent propagation loss data from a single user interface over a frequency band that covers all operational sonars.
*Data availability is limited in littoral waters, however, a facility exists for users to input their own additional high-resolution data if available.