Distance measuring system using ultrasonic ranging
Distance measuring systems altimeters and aircraft
Distance sensing apparatus
Distance sensing device
Diver orientation apparatus and method
Doppler consistent hyperbolic frequency modulation
Doppler velocimeter for monitoring groundwater flow
Drag antenna
Dual mode sonar system
Dual reference surface transducer
Dual-head multibeam sonar apparatus and method for tracking obje
Dynamic filter tuning for pulse-echo ranging systems
Dynamic underwater position tracking of small objects
Echo detection in pulse-echo ranging systems
Echo location system for vision-impaired persons
Echo ranging apparatus and method
Echo sounder with CRT display
Echo sounders
Echo sounders
Echo-sounding apparatus