Garmin nuvi 2595lmt GPS-Receivers

A GPS receiver can be a stand-alone handheld unit, a car navigation unit or a module for use with a Palmtop or PC.

Waterproofing is measured in different standards. The available standards are the following:

IPX-0 No special protection

IPX-1 Protected against falling water Equivalent to 3-5mm rainfall per minute for a duration of 10 minutes. Unit is placed in its normal operating position.

IPX-2 Protected against falling water when tilted up to 15 degrees - Same as IPX-1 but unit is tested in 4 fixed positions - tilted 15 degrees in each direction from normal operating position.

IPX-3 Protected against spraying water - Water spraying up to 60 degrees from vertical at 10 liters/min at a pressure of 80-100kN/m2 for 5 min.

IPX-4 Protected against splashing water - Same as IPX-3 but water is sprayed at all angles.

IPX-5 Protected against water jets - Water projected at all angles through a 6.3mm nozzle at a flow rate of 12.5 liters/min at a pressure of 30kN/m2 for 3 minutes from a distance of 3 meters.

IPX-6 Protected against heavy seas - Water projected at all angles through a 12.5mm nozzle at a flow rate of 100 liters/min at a pressure of 100kN/m2 for 3 minutes from a distance of 3 meters.

IPX-7 Protected against water immersion - Immersion for 30 minutes at a depth of 1 meter.

IPX-8 Protected against water submersion - The equipment is suitable for continual submersion in water under conditions which are identified by the manufacturer.

A sonar is used at sea as a sort of underwater radar.

Let's you control the GPS with your voice.

Detects and warns for Speed Cameras.

This feature lets you calculate and plan trips in advance, to see how long a certain path is or to make sure that you don’t miss any exits.

A FM-Transmitter can transfer music and Voice guidance through the cars audio system.

An altimeter can measure the height.

A speedometer shows the speed the vehicle travels in.

POI, Point of Interest. This is a function to add coordinates into the GPS for your own interests, such as speed-cameras, gas stations and all McDonalds in the country.

TMC, Traffic Message Channel.
This enables the GPS to draw alternative routes if it's announced that a road is closed or jammed. Very helpful if you don't want to be stuck in traffic.

To improve the accuracy of the GPS system, transmitters has been placed on various places in Europe and America. These beacons already know their exact position, and when they receive the GPS signals from the satellites, they calculate the error and transmit a correction factor. This technology is referred to as Differential GPS.

The most common receiver type is the 12 parallel channel receiver which can collect data from up to 12 satellites at one time.

Some GPS have a built in TV-tuner to watch TV.