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Active Sonar Echo Analysis: Monostatic vs. BistaticMisbah Dhuca, Westlake High School, Austin Tx
Supervisor: Jerry Mitchell, Signal and Information Sciences Laboratory, Applied Research Laboratories
Objective: Determine the differences between echoes created by monostatic sonar and bistatic sonar.
Approach: • Monostatic & bistatic active sonar
detecting a 688i attack submarine were simulated in Matlab.
• A set of highlights represented the target• Source and receiver locations, and aspect
of the target were chosen.• Levels were randomly assigned. • TOA of each echo was calculated.• Using an HFM signal as our transmit
signal, we emulated receive processing by cross correlating the transmit signal against itself.
• Plotted the cross correlation on a colormap.
Results: • Differences are in the submarine’s relative
orientation to the source and receiver.• Monostatic plot has hour glass shape • The graphs are identical at 30˚. • Direct blast masking would occur between
150˚ and 210˚ in the bistatic plot• Monostatic highlights approximately time
coincident at 90˚ and 270˚. • Bistatic highlights approximately time
coincident at 150˚ and 210˚.
Results
Highlights were defined relative to the center. Highlights of a 688i submarine: bow; forward hydropane; conning tower; and rudders. Submarine aspect was 0˚.
Monostatic active sonar places the source and receiver in the same position while bistatic sonar places them in different locations.
Source angle: 45˚ Receiver angle: 45˚Distance from source & receiver to center of submarine: 350 meters
Source angle: 30˚ Receiver angle: 120˚Distance from source & receiver to center of submarine: 350 meters
Monostatic BistaticTime of arrivals vs. levels
Each color represents a different level .
Numbers indicate highlight and colors indicate level.
Cross Correlation
Numbers indicate highlight.
Monostatic Bistatic