UAM-08160H Underwater Acoustic Modem | Ocean Noise Field Test

Overview

Shallow-water acoustic environments pose significant telemetry challenges due to multipath propagation, sea-surface scattering, tidal variations, and ambient vessel noise. This report documents the point-to-point (P2P) field performance of the UAM-08160H High-Speed Underwater Acoustic Modem under active marine noise conditions.

The trial was conducted on August 29, 2025, off the coast of Weihai, Shandong Province, China, in water depths exceeding 20 meters. Across baseline distances ranging from 1.0 km to 3.3 km and various immersion depth configurations, the UAM-08160H demonstrated robust noise rejection and decoding stability, logging a 0% packet loss rate across multiple test runs.

1. Test Setup & Configuration

• Modem Model: UAM-08160H High-Speed Underwater Acoustic Modem
• Hardware Terminals: C01-6 and C01-5 Underwater Acoustic Communication Units
• Operating Mode: Point-to-Point (P2P) messaging using unique device IDs
• Test Site: Offshore waters of Weihai City, Shandong Province, China
• Environmental Requirement: Water depth ≥ 20 meters with active ocean background noise
• Test Window: August 29, 2025, from 10:30 to 12:50

2. Methodology & Verification

1. Terminal Deployment: Modems were deployed from two support vessels, with transducer immersion depths adjusted (5 m, 8 m, and 10 m) depending on the test run.
2. Packet Transmission: Bidirectional messages were exchanged between vessel terminals using device IDs. Total packets sent and successfully received were logged in real time.
3. Data Logging: Field logs recorded GPS coordinates, deployment depths, baud rates (3 kbps / 6 kbps), and effective Packet Loss Rates (PLR) for each run.

3. Raw Field Data

The table below summarizes the empirical test data recorded across six configurations off the Weihai coast:

Experimental Data Record

Figure 1 Test Site Image

Table 1 Test Record Sheet

Test Process

At 12:20, arrived at the designated sea area with a node spacing of 6 km. Used CTD to measure hydrological information
At 12:40, two-way communication was successful at a distance of 7 km.
At 12:46, two-way communication was successful at a distance of 7.5 km.
At 12:50, two-way communication failed completely, and the hydrophone could not capture any acoustic signal. It is suspected that the vessel's drift caused the acoustic propagation path to be blocked by  Island.
From 13:07 to 15:30, positions were continuously adjusted and tests were conducted within the range of 6.5–8.2 km, with communication being generally normal.
At 15:50, at a distance of 9.2 km, the topside computer demodulated correctly.
At 16:09, at a distance of 9.7 km, during ship-to-ship communication, the topside computer demodulated correctly. The received signal was clear in the frequency domain but not obvious in the time domain.
At 16:15, at a distance of 10.2 km, during ship-to-ship communication, the topside computer demodulated correctly.
At 16:18 and 16:24, at a distance of 10.4 km, the submersible was navigating at a fixed depth of 5 m. At the receiving end, the topside computer demodulated correctly. The signal-to-noise ratio (SNR) was 21 dB, the frequency response was uneven, and frequency-selective fading was observed (at 10 kHz, 13–14 kHz).

Test Result

Dynamic stable communication at 8 km, two-way stable communication at 9.7 km, and one-way stable communication at 10.4 km.