Abstract: A reverberation backscatter measurement system for providing in situ measment of acoustic backscatter levels from point source scatterers or the target size of individual scatterers within or at the boundaries of the transmitting medium. The volume scattering strength, a calculated value from measured data, is the logarithmic ratio of the reflected intensity to the incident intensity at a unit distance from the acoustic center of the scatterers. The system accurately measures the parameters of volume scattering strength (S) and target strength (TS) and has application in the measurement and determination of sonar system performance and target strengths of vessels and their wakes. It also may be used in fisheries for biological studies in zooplankton population and distribution assessments. A data processing system is also provided to effectively and accurately process reflected signals indicating target strength and scattering strength.