Direct inventory taking of underwater objects using a handheld GPS receiver

The paper presents application of the GPS - Thales Mobile Mapper satellite navigation receiver for conducting the direct underwater inventory and location of objects on the bottom of inland water reservoirs. The design description of the measurement set consisting of the manual GPS/GIS receiver, specialist watertight casing with function keys and floating GPS antenna is presented. The possibilities of using the set directly in underwater navigation conducted by a scuba diver on shallow depth were investigated. The results of search for obstacles located earlier using the hydroacoustic methods: the single beam echo sounder (SBES) and sidescan sonar (SSS) were described. The analysis of accuracy of the underwater GPS navigation was also conducted.