SBIR-STTR Award

The Navy needs a multi-dimensional ambient noise model (MDAMN) which can account for the characteristics of noise due to wind, wave action, rain and shipping as a function of time, direction and location over a broad range of tactical frequencies and operational environments. Metron proposes to build an MDANM tool that aims to maximally leverage all available information sources and computes the directional noise field and associated array gain in an accurate and efficient manner. One of the key differentiators of the proposed product is its ability to adaptively adjust the underlying physics models and input data sources based on the use case parameters to provide proper tradeoff between speed and accuracy. A second differentiator is the combined use of Monte Carlo methods with real time shipping information to improve shipping noise estimates. The framework components of MDANM will be based on feedback from stakeholders and end-users for output to the next-generation Submarine Tactical Decision Aid (STDA). Enhancing the reliability and accuracy of detection modeling will lead to an increase the utility of TDAs, and allow operators to make better strategic and/or tactical recommendations.

Benefit:
The result of the proposed Phase I research will be a design plan for a new prototype multi-dimensional ambient noise model (MDANM) that will ultimately be capable of predicting the temporally dependent ambient noise field as a function of geographic position, direction, and time over a broad range of tactical frequencies (10s of Hz to 100s of kHz) and operational environments. The design plan will specify the proposed architecture, protocols, and formats for MDANM input and output to the next-generation Tactical Decision Aid (TDA). The Phase I Option period will prepare for workshops to be conducted at the beginning of Phase II. These workshops will help refine specifications for the data visualization and user interface in the MDANM tool. They will involve end-users of the proposed MDANM tool from the IUSS, Surface and Sub-surface groups.

Keywords:
Ambient, Ambient, Model, Propagation, TDA, danm, Physics, ASW, Noise

At its core, the process of predicting the spectral and directional structure of the ambient noise field, and how it manifests as beam-level noise, relies on properly accounting for the uncertainty that arises from the confluence of several types of noise sources and physical processes (i.e. wind, rain, shipping, ice noise, sound speed variability, scattering, etc.). Existing TDAs rely heavily on static databases when making ambient noise predictions, and this can lead to common situations in which TDA outputs differ substantially from current sensor observations. This has the ultimate effect of fostering mistrust in the TDAs. The basic approach of this effort is to make better use of all available information sources, including live sensor data for near-term (small tau) forecasts, and to combine these with modern machine learning and Monte Carlo algorithms designed to properly account for parameter-level uncertainty. This will result in better estimates of the horizontal and vertical noise field directionality, which can then be rendered into beam-level noise for different sensor types, sensor depths, sensor orientations, and operating frequencies.

Benefit:
We have identified two Navy projects as the initial transition clients of MDANM, and the focus of our Phase II effort will be to tailor transition ready models for use in these projects. These projects are the STDA development effort at NSWC Carderock and the ambient noise database (ANDB) development effort at NAVOCEANO. The full featured ambient noise modeling capability designed into MDANM will provide substantial value to other TDA variants such as USW-DSS, STDA-I, and SPPFS. During Phase I, we had several conversations and in-person meetings with the STDA development team at NSWC Carderock. The leadership of that team, Dave Sracic, indicated that our technical approach to modeling ambient noise is aligned to support the technology needs and program requirements for his sponsor programs. He also has agreed to support our proposed development approach that calls for sustained interaction between Metron and his team to ensure that MDANM is easily transitioned to the STDA product line. We also had several conversations with the ANDB development leadership, Lisa Pflug, and the acoustics department technical lead at NAVOCEANO, Mel Wagstaff. MDANM will be a critical tool needed for the continued development of the ANDB. During a sidebar conversation at the Ambient Noise workshop in June 2018 and follow-on meetings, we were able to refine our requirements using feedback from Ms. Pflug.

Keywords:
ASW, TDA, Ambient, Physics, Propagation, Noise, danm, Model