Johnson Outdoors on Jan. 27 announced the suit, saying that it owns the patent to the break-through fish-finder technology and that Lowrance's LSS-1 StructrueScan Imaging System breaks that patent.
Lowrance vowed to continue selling and supporting their side-scan module in a news release issued the same day.
Johnson Outdoors says they began the patent application for their Side Imaging sonar, which produces detailed and recognizable images of underwater objects, in 2004. The Humminbird 900 Side Imaging series was introduced the following year.
The patent was granted by the U.S. Patent and Trademark Office on Jan. 26, Johnson Outdoors said in a news release.
"Our intellectual property policy is very simple: We will respect the property of others and fiercely protect that of our own, Johnson Outdoors' Kelly Grindle said in the release. "We were diligent throughout the Side Imaging sonar technology patent application process to ensure we achieved both because real innovation brings real value which our customers and consumers expect and demand.
"By taking steps to protect our ideas and inventions, we help ensure our ability to continue to bring forward meaningful advances and innovative products that excite consumers and build our customers' business."
Lowrance introduced the LSS-1 StructureScan sonar imaging modules in February 2009, and the company claims it "is based on Navico's known and reliable sonar technology, yet it also features additional new technology not available from others ."
The initial introduction of the side-scan technology was followed a few months laterwith the addition of the company's DownScan Imaging technology, Lowrance said.
"We are confident in the uniqueness and value of Lowrance LSS-1 StructureScan sonar imaging," said Louis Chemi of Navico Americas, Lowrance's parent company. "We also wish to assure our customers that the sale and distribution of StructurScan sonar imaging will absolutely continue as planned with full Lowrance support for years to come.
"Navico will vigorously defend the recent legal proceedings initiated by Johnson Outdoors."