This paper describes a prototype environmental parameter sampling system and the problems it is intended to address. Increasingly sophisticated sonar performance models are being developed in support of advanced sonar system. A graphic portrayal of the simulated performance of a notional sonar system is presented as an example of the sensitivity of a simulation to the input environmental parameters including the volume scattering profile. The prototype environmental sampling system is configured to provide an estimate of the volume scattering profile. Operationally, this profile is not available to simulation users. The prototype environmental parameter sampler will be used to demonstrate how simulation errors due to this critical environmental input can be eliminated. The use of the microcomputer based prototype hardware as a basis for estimating other environmental parameters will also be presented. [Work supported by NAVSEA.]