S.M. Jesus sjesus@ualg.pt
Institute for Systems and Robotics, Universidade do Algarve,
Campus de Gambelas, PT-8005-139 Faro, Portugal.
Comments: download pdf.
Ref.: 153rd Meeting of the ASA, Salt Lake City, USA, June
2007.
Abstract
This work addresses the possibility of using successive transmissions
of time delayed channel probe pulses between two closely spaced
acoustic sensor arrays for forming an acoustic barrier for target
detection in shallow water. One array is a transmit-receive array (TRA)
while the other is a receive only vertical line array (VLA). The two
arrays are connected via cable or wireless. Time reversed replicas of
the acoustic channel response to the probe signals are retransmitted
into the ocean propagation plane to form focus peaks at each VLA
element. It is shown both theoretically and with simulated data that an
optimum disturbance detector can be build from the data received at the
VLA. This detector becomes sub optimal due to usual time reversal
drawbacks such as ocean non stationarity and spatial sampling
limitations. Real data tests are foreseen to take place during summer
2007 to answer questions such as allowable ranges and frequencies of
operation.
Acknowledgement: this work
was supported under project UAB (POCI/MAR/59008/2004), from FCT
(Portugal).