Doppler Shift Navigation for AUV Swarm Formation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current underwater vehicle navigation systems are expensive and unwieldy due to reliance on high-cost sensors and centralized control methods, limiting the scalability of autonomous underwater vehicle (AUV) swarms for oceanographic data collection.
Innovation Solution
A low-cost relative navigation system using a single-transducer system that adapts Doppler-shifted frequency and multi-frequency difference in absorption to inform heading and range without time-synchronization, allowing multiple AUVs to follow a leader using a custom acoustic package.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high-power sensors such as inertial navigation sensors (INS) are used for accurate navigation, then navigation precision is improved, but system cost increases to hundreds of thousands of dollars
Solution Approach 1:
The patent replaces expensive, high-precision inertial navigation sensors with inexpensive acoustic transducers that utilize Doppler shift measurements. Each vehicle uses a simple single-transducer system that achieves adequate navigation precision through relative positioning against a leader vehicle, sacrificing the need for costly INS while maintaining functional navigation capability for swarm operations
Solution Approach 2:
The patent substitutes mechanical/inertial navigation systems with an acoustic field-based navigation system. Instead of using gyroscopes, accelerometers, and inertial measurement units, the system uses acoustic transducers to emit and receive Doppler-shifted sound waves, replacing the mechanical sensing approach with an acoustic field measurement approach that is far less expensive
2Measurement precision
If centralized direct control and absolute positioning are used for multi-AUV navigation, then navigation accuracy is improved, but system complexity and cost increase
Solution Approach 1:
The patent divides the navigation system into a leader vehicle with a multi-frequency acoustic beacon and follower vehicles with single-transducer systems. This segmentation allows the complex function of absolute positioning to be replaced by relative positioning, where followers independently calculate their positions relative to the leader using Doppler shift measurements, eliminating the need for centralized control infrastructure
Solution Approach 2:
Each follower vehicle independently calculates its own position, velocity, and bearing relative to the leader using only its own single transducer and the acoustic signals from the leader. The system requires no external centralized control or coordination infrastructure, as each vehicle self-determines its navigation parameters through Doppler shift analysis of the received acoustic beacon
3Measurement precision
If geo-located acoustic beacons are deployed for navigation, then positioning accuracy is improved, but operational area is limited
Solution Approach 1:
The leader vehicle carries a self-contained multi-frequency acoustic beacon that provides navigation services to all follower vehicles within acoustic range. This single beacon serves multiple functions: providing position reference, velocity reference, and bearing information to the entire swarm, eliminating the need for multiple fixed geo-located beacons and enabling operation anywhere the leader can navigate
4Measurement precision
If frequent surfacing for GPS is performed to correct navigation drift, then positioning accuracy is improved, but mission continuity is disrupted
Solution Approach 1:
The acoustic Doppler-based relative navigation system allows follower vehicles to continuously maintain their positions relative to the leader throughout the entire mission duration. Unlike GPS-corrected inertial navigation that requires periodic surfacing, the acoustic system provides continuous underwater navigation capability, eliminating interruptions and maintaining mission continuity without sacrificing positioning accuracy within the swarm
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 scalable and cost-effective navigation of multiple AUVs, maintaining their formation and performing missions without the need for frequent surfacing or high-power sensors, while providing accurate positioning and communication.
Implementation Method 1
determine the Doppler shift of the received signals, as well as determine the bearing between the receiver and the source of the signals
Implementation Method 2
multi-frequency difference in absorption to inform range without time-synchronization
Data Source
AI summary
A device, system and method of use for the relative navigation in a fluid medium, the device having a receiver and a controller, the receiver capable of receiving signals through the fluid medium. The signals, produced by a source, are capable of undergoing Doppler shift, and the controller is capable of determining the Doppler shift of the signals and determining the bearing between the device and the source of the signals. The system further having a first vehicle capable of producing the signals and a second vehicle having the device and wherein the device determines the bearing of the second vehicle in relation to the first vehicle.