Underwater Acoustic Data Logging Apparatus

Key Components & Capabilities

Hydrophone Array

• Linear range: 1Hz to 100kHz ±2dB
• Receiving Sensitivity: -208dBV re 1μPa (40μV / Pascal)
• Transmitting Sensitivity: 140dB SPL re 1μPa, 1Vrms input at 1meter, 90kHz
• Maximum Input Voltage: 30V p-p (continuous); 150V p-p (<10% duty cycle, <100KHz)
• Horizontal Directivity(20kHz): ±0.2dB
• Horizontal Directivity (100kHz): ±1dB
• Vertical Directivity (20kHz): ±1dB
• Vertical Directivity (100kHz): +6dB -11dB
• Operating depth: 200m
• Survival depth: 350m
• Operating temperature range: -10°C to +80°C
• Nominal capacitance: 5nF +/- 15% (plus cable @ 118pF/m)
• Output connection: BNC (standard)

AVS

• VS-301 provides 3-axis particle velocity and omnidirectional pressure sensing, enabling full 3D acoustic field measurements.
• Output sensitivity: 10 V/g
• Full scale input range: 0.5 g pk
• Frequency response 3.0 Hz – 2.0 kHz
• Transverse sensitivity, max: <5%
• Temperature accuracy: ±1% °C
• Pressure range: 800 psi (Operational, max)

Data Acquisition System

• 4 x NI-9232 C Series modules (3 channels each, 24-bit resolution, 102.4 kS/s)
• Integrated in a CompactDAQ cDAQ-9185 chassis with Gigabit Ethernet connectivity for high-speed data streaming
• Fully synchronized multi-channel sampling, enabling advanced spatial and temporal analysis

Data Logging Unit

• Raspberry Pi 5 (8GB RAM) as the core logging controller
• Equipped with NVMe SSD HAT and 512GB NVMe SSD
• Capable of recording over 47 hours of continuous 10-channel 24-bit/102.4 kS/s audio
• Low-power, compact, and field-deployable