The Valeport VA500 Altimeter delivers a new approach to the problem of underwater positioning. State of the art signal processing technology provides stable repeatable readings while allowing the range to be extended to unrivalled distances for a 500kHz altimeter. Millimetre precision with 0.1m–100m range. RS232/RS485/05V & 0-10V analogue outputs with a wide range power supply address the needs of the ROV, AUV and Hydrographic community in a compact robust package.