1. Active Sonar Echo Analysis: Monostatic vs. Bistatic
Misbah 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 Bistatic
Time of arrivals vs. levels
Each color represents a different level .
Numbers indicate highlight and colors indicate level.
Cross Correlation
Numbers indicate highlight.
Monostatic Bistatic