TomTom, the Dutch navigation specialist, is taking US rival Garmin to court in The Hague on Thursday. The company claims that Garmin is copying the look and feel of its GPS based portable navigation systems.

Garmin and TomTom are chief rivals in the booming car navigation market. TomTom has a 30 per cent market share in Europe, while Garmin is at 16.7 per cent. In the US, Garmin leads with 50.8 per cent, with TomTom on 26.9 per cent.

Earlier this year, Garmin claimed that TomTom had infringed five US-patented Garmin technologies designed to "calculate which streets are important enough to a driver’s route to be displayed."

In March TomTom responded with a counter-claim that Garmin infringed three of its patents. A jury trial isn't expected until February 2007.

In August Garmin filed a second patent infringement lawsuit against TomTom, so obviously the Dutch company had to strike back - although this time not with patent claims. Details of the complaints were not released.

TomTom decline to comment on the case "until further notice".

Garmin International spokesman Ted Gartner declined to discuss the specifics of the case, but he told The Register: "We can say that Garmin is confident that its personal navigational devices do not infringe any design rights of TomTom and looks forward to a prompt and decisive ruling from the District Court of The Hague vindicating its position." ®