Side scan sonar

A side scan sonar is a sonar device that can look sideways. This can be compared with a radar, but uses ultrasound echoes instead of electromagnetic pulses. The sound pulses are usually on frequencies between 100 and 500 kHz. A higher frequency gives better resolution but less range.

This technique was developed by Professor Harold Edgerton[?] and ohters in the 1960s. It is commonly used for wreck search in underwater archaeology.

External links:

• Side Scan Sonar (http://www.abc.se/~pa/mar/sidescan.htm)