The objective of this project was to demonstrate and validate the Bearing and Amplitude Measurement and Analysis System (BAMAS) noise monitoring system before military installations make a significant investment in this new technology for blast noise monitoring. In particular, the project was designed to ensure that the BAMAS system accurately detects and classifies military noises generated from testing and training activities, as well as properly rejects non-military noise sources, a problem that has historically plagued other commercially available noise monitoring systems. In addition, the project sought to demonstrate that BAMAS can cover a large area (i.e., greater than 1000 km2) and can run continuously over long periods of time even amidst inclement weather conditions.

Technology Description

The BAMAS noise monitoring system is a network of advanced noise monitors designed for detection, localization, and classification of military blast and aircraft noise. Military blast noise is predominately characterized by impulses created by explosions, impacts, and large caliber artillery. These loud, low frequency, and short-duration acoustic pulses negatively affect residential communities near military installations and often result in lawsuits and training curfews or restrictions. The BAMAS system is intended to be used by Noise Managers at Department of Defense (DoD) installations to monitor noise emissions by quantifying the magnitude, frequency, location, and time of exceedingly loud noise events to ensure compliance with local noise limits and restrictions, and to make short- and long-term testing and training decisions based on measured acoustic noise levels. BAMAS noise monitors are designed for remote, free standing operation, and feature low-power data recorders for real-time signal analysis with continuous, low data-rate connectivity to a base station computer. They also feature a Type 1 microphone for accurate sound pressure measurements as well as a microphone array to facilitate wind mitigation and sound directional of arrival estimation.

Demonstration Results

This project successfully demonstrated the autonomy and reliability of a large network of BAMAS noise monitors over the course of a 1-year remote deployment at two U.S. Army installations. Data collected at both demonstration sites helped facilitate validation of the systems’ improved blast detection/classification and wind noise rejection capabilities. During the on-site data collection effort, BAMAS noise monitors were demonstrated to be actively monitoring 97% of the time while operating on solar power. They reported >95% of military noise events, exceeding the operating threshold, and successfully rejected >99.99% of wind events during periods of high wind.

Implementation Issues

As part of this project, a website tool was developed to provide Noise Managers with improved access to real-time and historical noise data. This website is accessible on all internet capable devices, including smart phones, tablets, and computers. The noise monitors have now been in operation for more than 3 years and have required only minor repairs associated with their disassembly transport and reinstallation.