Sonar Navigation Using Rotating Transducer and Compass
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Solution Overview
Problem
Existing sonar navigation systems require the boat to be moving to determine the compass heading for accurately locating underwater objects, limiting their ability to scan and mark GPS positions while stationary or in a fixed position.
Innovation Solution
A sonar/compass configuration mounted on a 360-degree movable mechanism, using a side/forward scan sonar transducer attached to an electric trolling motor, allows for scanning and determining GPS positions of underwater objects from hundreds of feet away, even when the boat is stationary, by continuously storing compass heading, distance, and GPS position, and using these data to calculate the object's location.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If GPS movement data is used to calculate compass heading, then GPS position can be determined, but the boat must be moving which limits stationary scanning capability
Solution Approach 1:
A mechanical compass is introduced as an intermediary device to measure heading independently of boat movement. The compass is mechanically coupled to the sonar transducer assembly, allowing it to directly sense the orientation of the scanning beam without relying on GPS position changes. This mediator enables heading measurement whether the boat is moving or stationary.
Solution Approach 2:
The patent replaces the electronic/GPS-based heading determination system with a mechanical compass system. Instead of using GPS position changes to calculate heading (electronic method), a physical magnetic compass with a needle or card that aligns with magnetic north provides direct mechanical measurement of orientation. This mechanical approach works independently of boat motion.
2Area of stationary object
If sonar transducer is mounted on movable mechanism for 360-degree scanning, then large area coverage is achieved, but system complexity increases
Solution Approach 1:
The trolling motor lower unit is repurposed to serve multiple functions: it provides the mounting structure for the sonar transducer, acts as the rotational actuator for 360-degree scanning, and serves as part of the mechanical linkage for compass coupling. This multi-functionality reduces the need for separate dedicated components for each function.
Solution Approach 2:
The sonar transducer assembly is made dynamically rotatable rather than fixed in position. The mechanical coupling allows the transducer to rotate with the trolling motor's steering mechanism, enabling the scanning beam to sweep through 360 degrees horizontally. This dynamic positioning capability expands coverage area while utilizing existing movable components.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables accurate GPS positioning of underwater objects without the need for boat movement, allowing for precise navigation and auto-pilot guidance to these locations, while maintaining a safe distance to avoid scaring fish, and incorporating wind detection for improved navigation accuracy.
Implementation Method 1
The sonar transducer is used to send echo signals to determine the position of an object and the distance to the object in the water
Implementation Method 2
Using a compass mechanically in line with the pointing direction of the sonar beam allows for an improved method for determining the GPS position of an object in the water
Data Source
AI summary
A method for pre-determining an underwater objects GPS position using a rotatable scan sonar unit linked to a boat, magnetic compass and GPS receiver. This system determines the underwater objects GPS position using the objects distance, compass heading and a GPS receiver/sonar on a boat. This system will provide real time longitude and latitude positions of underwater objects seen with sonar at a distance from a boat, and will allow for precise autopilot navigation or fixed position fishing. The system can also be used to correct for GPS errors when using previously stored waypoints positions of an object. The computer determines an objects underwater GPS position using a sonar transducer and mounted on a 360 degree movable mechanism such as a trolling motor unit, or phased array of transducers and a compass to provide heading information and formulates the objects position based on the distance and heading of the object in relation to the boats current GPS position.