Active Sonar Fan Beam Elevation Angle Propagation Path Calculation
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Solution Overview
Problem
Existing cross fan beam methods for active sonar struggle to acquire accurate information about long-distance targets due to variations in propagation paths and unclear elevation angle relationships, limiting their application to short-distance targets.
Innovation Solution
An active sonar system comprising a fan beam transmitter, receiver, propagation path calculator, path time calculator, and horizontal distance calculator, which transmits fan beams with different elevation angles, calculates propagation paths and path times based on acoustic velocity profiles, and determines horizontal distances to echo sources, enabling accurate information acquisition for long-distance targets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If cross fan beam method is used for long-distance target detection, then the detection range is extended, but the accuracy of information acquisition deteriorates due to propagation path variations and unclear elevation angle relationships
Solution Approach 1:
The system performs preliminary calculation of propagation paths for multiple transmitted fan beams at different elevation angles before receiving echo sounds. By pre-calculating the expected propagation paths and arrival times based on acoustic velocity profiles, the system can accurately associate received echoes with their corresponding transmitted beams even at long distances, thus maintaining measurement precision while extending detection range
Solution Approach 2:
The system uses feedback from the calculated propagation paths and arrival times to correct and refine the association between transmitted fan beams and received echoes. By continuously comparing expected arrival times with actual reception times and adjusting the correspondence relationships, the system maintains accurate information acquisition for long-distance targets despite propagation path variations
2Loss of information
If multiple transmitted fan beams at different elevation angles are used, then two-dimensional information can be obtained, but the complexity of calculating and matching propagation paths increases
Solution Approach 1:
The system segments the propagation path calculation by treating each transmitted fan beam independently. For each beam at a specific elevation angle, the propagation path is calculated separately based on its own transmission time and elevation angle parameters. This segmentation approach simplifies the overall calculation process by breaking down the complex multi-beam problem into manageable individual beam calculations, while still achieving complete two-dimensional information acquisition
Solution Approach 2:
The system performs preliminary calculation of propagation paths for each transmitted fan beam before the actual echo reception. By pre-calculating the propagation characteristics of multiple beams at different elevation angles, the system establishes a reference framework that simplifies the subsequent matching process between transmitted beams and received echoes, reducing the real-time computational complexity
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
The system effectively acquires and processes echo sound information for long-distance targets by accounting for varied propagation paths and elevation angles, enhancing the capability to form accurate images and track targets over extended ranges.
Implementation Method 1
transmits a plurality of transmitted fan beams whose elevation angles are mutually different
Implementation Method 2
receives a plurality of received fan beams... receives an echo sound
Implementation Method 3
calculates a propagation path of each of the transmitted fan beams based on an acoustic velocity profile for a medium and the elevation angle
Implementation Method 4
calculates a path time based on a time point of transmission of a transmitted fan beam and a receiving time point of an echo
Data Source
AI summary
In order to acquire echo sound information about a long-distance target, an active sonar comprises a fan beam transmitter, a fan beam receiver, a propagation path calculator, a path time calculator, and a horizontal distance calculator. The active sonar transmits a plurality of transmitted fan beams horizontally wide and vertically narrow, and the elevation angles of them are mutually deferent, and receives received fan beams vertically wide and horizontally narrow. The propagation path calculator calculates a propagation path of each of the transmitted fan beams based on the profile of medium and the elevation angle of the transmission. The path time calculator calculates a path time which is the time period from the transmission to the reception. The horizontal distance calculator calculates a horizontal distance from the active sonar to a generation source point of each echo sounds based on the propagation path and the path time.