WirelessArray

WirelessArray is a GPS time-synchronized wireless array of distributed nodes with interchangeable sensor interfaces measuring and communicating high-fidelity data back to a centralized data acquisition center.

The WirelessArray system is composed of four major components:

1. the Wireless Sensing Nodes,
2. the Central Sensing Plate (optional),
3. the Field Data-Collection Architecture, and
4. the Data-Collection Server.

The Wireless Sensing Nodes are standalone Wi-Fi enabled weatherproof devices with a user-replaceable sensor module, data transmission and time synchronization hardware, and an ample battery with solar and USB-C charging capabilities. These nodes may be used, for example, as the distributed measurement points along the arms of an array spiral.

The Central Sensing Plate is used in the center of the measurement array to provide a way to tightly space sensors in a single, customizable apparatus. The Central Sensing Plate is customized for each system to meet the specific needs of the customer. Interchangeable multi-microphone array “petals” are installed flush with the plate surface and are connected to the data-collection system with a single wired ethernet cable. The Central Sensing Plate is optional and is typically only needed for applications where a dense configuration of microphones is required such as for a high frequency, small aperture array

Each system also requires a data-collection system to acquire and store the synchronized sensor data streams. This system is subdivided into the Field Data-Collection Architecture and the Data-Collection Server.

The Field Data-Collection Architecture is a custom configuration of one to many low-profile, environmentally hardened, off-the-shelf wireless access points (WAPs). Each WirelessArray’s Field Data-Collection Architecture is customized to meet customer requirements for data transfer speed, array size, and live data viewing.

The Data-Collection Server is the computer that is placed at a location from which the data acquisition system will be operated. It communicates with the Wireless Sensing Nodes and Central Sensing Plate to orchestrate data acquisition and data management such as retrieving data from the individual sensing nodes. A system interface (GUI) and example computer code are provided with each system for the client to use as-is or to customize and incorporate into their larger data processing architecture.

Through validation testing and small-scale test deployments, the system has demonstrated its ability to meet acoustic bandwidth, dynamic range, time synchronization, environmental, and battery life requirements for typical ground-test array deployments.

Features

• Wirelessly time synchronized via GPS to maintain simultaneous sampling across the full array.
• Environmentally hardened enclosures protect against the elements during long-term deployments.
• Capable data acquisition system with real-time monitoring software.
• High SPL MEMS microphone module available.
• Built-in TEDS for accurate, consistent calibration.
• Low-noise analog front end for interchangeable sensor modules.
• Sensor module has integrated temperature sensor outputs.
• Dedicated acquisition processor and embedded communication and control system.
• Solar panels and LiPo battery power for in situ recharging during long deployments.
• Smart power systems that automatically switch between battery, USB-C wall power, and solar power depending on current conditions and configurations.
• System and battery health monitoring.
• 4 GHz wireless communication.
• SD card for local storage on each node.
• USB port for field-technician use and system diagnostics.
• External antenna for long range wireless communication optionally available for expansive systems.

Benefits

• Order of magnitude faster deployment over wired systems saves time and money.
• Easily expandable and adjustable array size (meters to kilometers) and shape.
• Low acquisition cost per channel relative to existing solutions, enabling significant additional measurement capabilities (larger arrays and more channels) while preserving budgetary limitations.
• Each microphone module provides a temperature sensor output to allow for temperature compensation.
• No site power infrastructure required
• All-in-one measurement solution that can be used repeatedly in diverse testing scenarios.
• All system components are user-serviceable to ensure reliability during critical testing windows.
• Lower (recurring) cost array deployment including:
  • Elimination of the need to run cables for every sensor
  • Robustness against the environment, eliminating the need to cover and uncover the array each day of use (and to rapidly scramble to cover the array when inclement weather occurs mid test)

Applications

• Flyover phased array measurement
• Full-scale airframe noise source testing
• Engine stand noise testing
• Beamforming
• Sonic boom arrival detection
• Wind energy noise source localization
• Ramp noise testing

Sensor Housing Details

• Housings (IPx7) and microphones (IP55) are environmentally hardened
• Gasketed and removeable microphone module
• Top embedded solar panels
• USB-C charging and diagnostic port

Software

• Browser-based GUI system
  • Each node hosts its own web site/interface
  • Minimizes additional required software
  • Allows any endpoint to be used to configure nodes (e.g., cell phones, tablets)
  • Quick and reconfigurable design to allow for customization for specific end-user use cases
• Orchestration software
  • Installed on customer’s computer system
  • Application programmed in Python with web front-end to control one node, a subset of nodes, or all nodes simultaneously
  • Assists with
    • Hardware management
    • Troubleshooting
    • System calibration
    • Data acquisition
    • File storage and export
    • API for end users to develop custom data acquisition applications