The "Underwater Sentry" for Billion-Yuan Net Pens: Dayu Electronics' Sonar Matrix Safeguards Eel Fry

Eel fry, often called "soft gold in water," can fetch thousands of yuan per fish. A single net pen brimming with these precious juveniles can hold assets worth up to one hundred million yuan. Yet this vast underwater wealth also attracts covetous eyes. In recent years, underwater theft targeting high-value fry has become frequent. In a case in Nanshu District, Guangzhou, a farmer's eel fry were stolen, with losses exceeding 250,000 yuan. Routine surface patrols have blind spots and are powerless against frogmen swimming underwater. Once an intrusion occurs, irretrievable economic losses can strike in an instant.

To protect this invisible battlefield of profit, Dayu Electronics has launched a dedicated security solution for high-end aquaculture: 16-beam ranging sensor + 8-beam hydrophone matrix. This innovative solution adopts a dual-mode concept of "deep fusion of active detection and passive listening," opening a new chapter in underwater security.

Active Detection: 16-Beam Ranging Sensor

When frogmen move underwater, they generate pressure waves by displacing water, and their mechanical breathing regulators release bubbles. Our 16-beam ranging sensor is an active sonar device that simultaneously transmits and receives multiple ultrasonic signals. It casts sound waves over key waters around the net pen, forming a covert and dense acoustic barrier. Once a frogman enters the sensing area, the system immediately captures anomalous echoes via high-density acoustic pulses. With the powerful resolution of up to 16 beams, it effectively filters out small-target interference from fish movement, precisely locks onto the high-risk intruder, and achieves 24/7 active vigilance with no blind spots.

Passive Listening: 8-Beam Hydrophone Matrix

When fully equipped and swimming, frogmen produce distinct mechanical noises and bubble sounds. Merely transmitting sound waves one-sidedly could, over time, alert frogmen and make them more stealthy. In response, Dayu Electronics' 8-beam hydrophone matrix demonstrates overwhelming advantages. This passive sensing system emits no signals of its own, focusing instead on silent listening underwater 24/7. It keenly picks up specific high-frequency noises from the frogmen's breathing apparatus. Even if intruders try to shut down propulsion and creep forward slowly, they cannot escape the matrix's precise "acoustic hunt."

The core advantage of this solution lies in the deep fusion of active and passive systems. The 16-beam ranging sensor provides precise spatial location information, while the 8-beam hydrophone matrix offers the target's acoustic signature and movement trends.

Data from both systems are fused and analyzed by a central processing unit, enabling the following functions:

Target Confirmation: When the passive system detects a suspicious sound source, the active system can immediately perform a focused scan of that area to confirm the target's presence.

Trajectory Tracking: Combining active ranging with passive directional information, the system can continuously track the frogman's movement trajectory and predict their intentions.

Intelligent Alerting: Based on preset perimeter zones and behavioral patterns, the system can automatically trigger tiered alerts and coordinate with surface surveillance equipment or security personnel.

Deployment Recommendation: Multiple sets of 16-beam sensors and 8-beam hydrophone matrices should be evenly arranged around the net pen to form a ring or grid monitoring network, ensuring full coverage without blind spots. Equipped with high-performance signal processing units, the system runs target detection, tracking, and identification algorithms to enable automated monitoring. The system should also feature wireless or wired communication capabilities to transmit alert messages and target data to a monitoring center in real time, and to interface with surface cameras, audible and visual alarms, and other devices.

Through the collaborative operation of the 16-beam ranging sensor and the 8-beam hydrophone matrix, this solution builds a robust underwater defense line for high-value eel fry net pens. This combined active-passive monitoring system not only enhances intrusion detection accuracy and response speed but also provides reliable technical support for intelligent security in aquaculture.