Starting in the 1970s, companies such as General Instrument (now SeaBeam Instruments, part of L3 Klein) in the United States, Krupp Atlas (now Atlas Hydrographic) and Elac Nautik (now part of L3 Communications) in Germany, Simrad (now Kongsberg Maritime) in Norway and RESON in Denmark developed systems that could be mounted to the hull of large ships, and then small boats (as technologies improved and operating frequencies increased).