Two additions to the Sony nav-u range have been unveiled at CES.

The NV-U73T and NV-U83T offer old favourites including text-to-speech voice commands and real-time-traffic capability.

However, they also offer new safety features, including the super suction cup mounting system.

This system means that both devices are easy to mount on the windshield or dashboard, "providing a tight, virtually unmovable attachment", says Sony.

The system is made using a flexible non-adhesive gel, which grips the surface of the dashboard so the touch screen can be mounted closer for an easier reach.

The high-end NV-U83T model also adds another safety feature - Bluetooth technology for making hands-free phone calls.

It has a built-in microphone, so that drivers can use voice commands to initiate calls via compatible Bluetooth-enabled cell phones. The nav-u system connects automatically so drivers can keep their hands on the steering wheel and their eyes on the road.

This new model also has a large, 4.8-inch (screen size measured diagonally), 16 x 9 aspect ratio touch-screen display (with anti-glare coating) and ultra-thin footprint.

The NV-U83T model also offers a new facility called POSITION Plus, which "provides constant, more accurate positioning and assured interruption-free guidance", even if the GPS signal is weak.

In addition to the SiRF Star III GPS chip, POSITION Plus includes a pressure sensor, gyro sensor and an acceleration sensor.

Sony explains: "The nav-u device uses these additional sensors to calibrate where drivers are so they can safely plan ahead and won’t miss turns coming out of tunnels or from in-between tall buildings."

Both devices offer a new dual view feature, which zooms in and shows certain landmarks to help drivers make the correct turns at the right time.

On motorways, dual view shows a 3D rendition of the approaching intersection with lane guide information to let drivers know exactly where they need to be to negotiate the junction, explains Sony.

Another new shared Sony function is gesture command, which lets drivers jump to commands with one stroke on the touch-screen display, "eliminating the need to dig down on the menu".

It explains: "If drivers want to go home, they just draw a roof (or inverted "V") and the destination becomes home". Other gesture command features include take me home, zoom in or out and call home.

This nav-u device is also the first Sony portable navigation device to show brand icons for restaurants hotels, gas stations and stores.

Both systems come with nearly five million points of interest, making it easy to find destinations nationwide.

The devices come with US and Canadian maps on their 2GB flash memory. Maps of Alaska, Canada, Hawaii and Puerto Rico also come pre-installed.

They also come with a Memory Stick Pro Duo slot for future expansion capabilities.

The NV-U73T model comes with a 4.3-inch (screen size measured diagonally), 16 x 9 aspect ratio display. Its features include text-to-speech functionality, the dual view feature, super suction cup mounting system and gesture command.

The NV-U83T device features all of this plus Bluetooth hands-free calling capability, a larger display and POSITION Plus signal management.

The NV-U73T and NV-U83T models are expected to sell for about $350 and $500, respectively.