Accession Number:

ADA289879

Title:

Waveforms For Reducing Direct Blast Effects And Mutual Interference.

Descriptive Note:

Technical rept.,

Corporate Author:

NAVAL COMMAND CONTROL AND OCEAN SURVEILLANCE CENTER RDT AND E DIV SAN DIEGO CA

Personal Author(s):

• Ricks, R.

Report Date:

1994-10-01

Pagination or Media Count:

34.0

Abstract:

In bistatic sonar, the direct blast transmission can hide target echos. The potential for hiding target echos is dramatically reduced by dividing the transmission into a wavetrain of noncontiguous pulses with appropriate interpulse spacing. The potential for mutual interference between targets is also reduced for both bistatic and monostatic sonar systems. Strategies for determining the appropriate interpulse spacings are discussed. One approach is based on the Optical Orthogonal Codes OOC concept from the communication literature. Code search methods are also discussed and an exhaustive list of codes given for wavetrains of up to 12 pulses. To increase the duty cycle, a closely-related family of codes, noncircular Optical Orthogonal Codes NOOC, is developed assuming the pulse sequence is not retransmitted back to back. Properties of NOOCs are derived, methods of searching for the codes are discussed, and another exhaustive list of codes is given for wavetrains of up to 9 pulses. Finally, criteria for choosing a particular code in designing waveforms are discussed. MM

Descriptors:

• *BISTATIC SONAR
• *OPTICAL CIRCUITS
• *TARGET ECHOES
• ACOUSTIC WAVES
• WAVEFORMS
• BLAST WAVES
• AUTOCORRELATION
• UNDERWATER ACOUSTICS
• SONAR RECEIVERS
• TRANSMITTER RECEIVERS

Subject Categories:

• Line, Surface and Bulk Acoustic Wave Devices
• Acoustic Detection and Detectors

Distribution Statement:

APPROVED FOR PUBLIC RELEASE