Underwater Acoustic Positioning via Inverted Base Station Architecture
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current underwater positioning systems, such as LBL, USBL, and reverse USBL, are limited in their ability to simultaneously position a large number of devices, require high energy consumption, are costly, and can detect the presence of devices, leading to issues in military applications and hydrodynamic resistance, while also being dependent on sound speed variations and requiring multiple acoustic beacons.
Innovation Solution
A positioning system using a base station with multiple acoustic transmitters, allowing devices to determine their position through hyperboloid or intersection loci without emitting detectable acoustic signals, reducing energy consumption and deployment time, and using synchronized clocks for precise timing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If active LBL or USBL systems are used to position underwater devices, then positioning accuracy is improved, but the devices become detectable by acoustic signals which is problematic for military applications
Solution Approach 1:
The patent inverts the traditional positioning architecture by making base stations active (emitting acoustic signals) and underwater devices passive (only receiving signals). This inversion allows devices to determine their position without transmitting acoustic signals, thereby maintaining positioning accuracy while eliminating acoustic detectability of the devices.
2Area of stationary object
If multiple independent beacons are deployed in LBL systems to position multiple devices, then positioning coverage is improved, but deployment cost and complexity increase
Solution Approach 1:
The patent makes each base station multi-functional by equipping it with multiple acoustic transmitters that can serve multiple devices simultaneously. A single base station can position multiple underwater devices at the same time, eliminating the need for multiple independent beacons and reducing overall system complexity and deployment cost.
Solution Approach 2:
The patent combines multiple transmitter functions into a single base station. Instead of having separate beacons for each device, multiple transmitters are merged into one base station that can serve multiple devices, thereby reducing the total number of base stations required while maintaining coverage.
3Measurement precision
If underwater devices transmit acoustic signals for positioning in USBL systems, then positioning accuracy is improved, but energy consumption increases
Solution Approach 1:
The patent inverts the active/passive roles in USBL systems. Instead of underwater devices transmitting acoustic signals and surface vessels receiving them, the patent makes base stations transmit and devices receive. This inversion maintains positioning accuracy while dramatically reducing device energy consumption since devices no longer need to transmit powerful acoustic signals.
4Measurement precision
If synchronized clocks are used in LBL systems to enable active positioning, then positioning precision is improved, but system complexity and cost increase
Solution Approach 1:
The patent extracts the synchronized clock requirement from the devices and places it only in the base stations. Since base stations are stationary and powered, they can afford the complexity of synchronized clocks. Devices, being mobile and energy-constrained, do not need clocks since they only receive timing information from base stations, thereby reducing device 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
Enables simultaneous and discreet positioning of multiple underwater devices with reduced energy consumption and cost, independent of sound speed variations, and requires fewer base stations, enhancing military and commercial applications by providing accurate and omnidirectional positioning.
Implementation Method 1
at least four acoustic emitters (d1, d2, d3, d4) forming an antenna (11), the distances between said acoustic emitters being known and said emitters (d1, d2, d3, d4) respectively emitting an acoustic signal (f1, f2, f3, f4) in a synchronized manner
Implementation Method 2
The computer of the acoustic transmitter/receiver on board the underwater device to be positioned calculates from the signals received the travel times of the acoustic waves between itself and each of the bottom beacons
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The invention relates to a positioning system having at least one underwater apparatus, said underwater apparatus comprising an acoustic receiver and a computer, said system comprising a base station placed in the sea environment, said base station transmitting an acoustic signal received by the acoustic receiver, wherein the acoustic receiver comprises a hydrophone, the base station comprises at least two acoustic transmitters forming an antenna, the distances between the acoustic transmitters of the antenna being known and said transmitters being synchronized therebetween. According to the invention, the computer comprises a means for calculating differences in arrival time and differences in phases of acoustic signals coming from the base station transmitters, and a means for calculating the possible geometric loci of the position of the apparatus relative to said base station and to the orientation thereof, and the position of the underwater apparatus is predetermined from these possible geometric loci.