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Direction-Finding Sonar System for Autonomous Submarine. Nicole Rennalls, Estee Amana, Frederick Ealick, Mitcham Costley ECE Department Georgia Institute of Technology ECE4007 L01 December 1, 2008. Project Overview. Georgia Tech Marine Robotics Group. Autonomous Underwater Vehicle.
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Direction-Finding Sonar System for Autonomous Submarine Nicole Rennalls, Estee Amana, Frederick Ealick, Mitcham Costley ECE Department Georgia Institute of Technology ECE4007 L01 December 1, 2008
Navy Competition 2009 Bridge Rooftop Rooftop Practice Side Competition Side Launch Platform
Mission To build a sonar system under $400 to complete the “Rooftop” task, which improves upon previous design group efforts
Detect Ping Frequency: 20-30kHz 2s 1.3ms
Determine Direction Direction of Motion 60° Top View
Communication RS-232 Ethernet Sonar Group MRG Group
Time Delay Receiver #2 t2 t1< t2 t1 Receiver #1
Sonar System Block Diagram Variable Gain Amplifier Linux SBC Hydrophones ADC RS232 Pinger Measure Time Delay
Hydrophones Linux SBC Variable Gain Amplifier Hydrophones ADC RS232 Pinger Measure Time Delay
HydrophoneConstruction Teflon Cable BNC Connector Copper Tube Epoxy Filling Aluminum Foil Epoxy Filling Piezoelectric Crystal Cost: $87 Copper Disc
HydrophoneTesting PVC Pipe
Amplifiers Variable Gain Amplifier Linux SBC Hydrophones ADC RS232 Pinger Measure Time Delay
MAX4196 • Single-supply • Rail-to-rail output (within 200 mV) • Drawbacks: • Inconsistent gain across frequency band • Complexity associated with four stages • Gain adjustment difficult
Present Amplifier Design EL8171 Cost: $20
Intersil EL8171 • Single-supply • Rail-to-rail output (within 0 mV) • Advantages: • PMOS input • Stable gain across frequency band • Fewer stages
Automatic Gain Control Digital Potentiometer DS1802
Linux SBC Linux SBC Variable Gain Amplifier Hydrophones ADC RS232 Pinger Measure Time Delay
Sonar System Controller Receives 1000 samples/channel Averages 10 highest & 10 lowest samples Determines time delay Cost: $150
Cross-correlation V V2 Time (sec)
Cross-correlation of Real Data V V2 Sample #
Auto-calibration Pinger Hydrophone Direction of motion Goal: Eliminate error such as submarine design changes and trace lengths.
Previous Demonstration Proposal Laptop GT Pool Serial Cable Waterproof PVC Pipe Pinger Hydrophones Electronics
Current Test Configuration Hydrophone #1 Hydrophone #2
Remaining Work Complete amplifier on solder board Complete power supply circuit Eliminate reflections for demonstration
Project Schedule Test amplifier with pinger Complete hydrophones Mount hydrophones Integrate system Oct Nov Dec Demonstration Assemble circuit solder board Control gain Competition Date: June 2009