It's all over the news today that Hummingbird just received a patent on it's Side Imaging® product. You can view the actual patent title abstract online (HERE). What hasn't made the rounds yet is that they wasted no time in filing a patent infringement lawsuit this morning against Navico for the Lowrance brand StructureScan™ imaging. You can read the following press release for more info.
One thing to keep in mind is what Hummingbird has actually patented here. If you read the patent title, 'SONAR IMAGING SYSTEM FOR MOUNTING TO WATERCRAFT', you'll see that it's not the actual side-imaging technology, but rather sounds like the ease or methodology of attaching said unit (via transducer) to a recreational watercraft (as opposed to the tow behind types used in high def./commercial versions of the technology).
Rumor has it that Navico/Lowrance had already expected such and that they had calculated on said royalty fees.
UPDATES:
Navico releases their response
You can now read the full patent at the U.S. Patent and Trademark Office at (7652952).
A transcript of the best public forum commentary I've come across so far on the situation from 'CatFan' over on the BBC boards:
"After reading HB's patent, I don't see any claim that wasn't prior art. Their main claim seems to be the hull-mounted transducer and the combination of a down-looking transducer and side-scan transducers in the same housing.
Starfish, DeepVision and Simrad all currently sell hull mounted side-scan sonars. Simrad holds "US Patent 5260912 - Side-looking fish finder" which was issued 9 November 1993, which specifically describes mounting the transducer on the boat. This patent expires in 2013.
Now try going to simrad.com to read about Simrad sonars. You'll find yourself at their parent company's web site. Navico.com.
I have an IEEE document from 1996 explaining the problems of using a side-scan sonar with a hull mounted transducer, and explaining why a towed side-scan transducer produces better images than a hull mounted transducer. It then goes on to explain how they overcame the problems and developed a system to allow them to mount the sidescan transducer to the hull of the boat and still get acceptable readings.
I expect you will see Navico file a countersuit alleging Johnson Outdoors has violated their patents, and then eventually they'll find a few things Lowrance is using that Humminbird has patented and a few things Humminbird is using that Lowrance has patented, the lawyers will get big checks and everything will proceed as it is.
Lowrance has had the advantage of knowing what the Humminbird units do for a few years, so their legal efforts are probably almost complete."