Although Pioneer's AVIC-HD3 is indeed a GPS system, it is far, far more than that as well. At $3799 it is (at the time of writing) the most expensive GPS system we've tested by a country mile. However, in Pioneer's own words, it's more of an integrated, all-in-one system, offering a 7in screen, AM/FM radio, DVD player, hard drive for music storage, iPod connectivity and many more features.

Not only that, but it is a more comprehensive GPS device with the additional functionality of a 3D Gyro Sensor, that can calculate your position and direction, even when the GPS signal is lost, such as in a tunnel.

That said, if you're after a GPS system and a GPS system alone, the AVIC-HD3 is not for you. Unlike your standard navigation device, the Pioneer AVIC-HD3 is a fixed system that must be professionally installed into your car and cannot be easily removed. Apart from the cost, the only real flaw of this device is that some cars are not compatible. In order to install the 7in screen and all the hardware behind it your car must have two adjacent din slots free (din slots are the compartments where CD players and radios reside). If you have this then you're eligible.

Like most GPS systems the AVIC-HD3 offers a large overview map with points of interest (POI) and route selections. POIs include plenty of hotels and restaurants as well as petrol stations, toilets and more. Using the large touch screen menu you can select POIs in the immediate area or search for a specific place regardless of distance. The system will always offer you a choice of routes and will naturally choose the most efficient routes it knows. However, it will automatically learn routes you use on a regular basis, such as shortcuts through side-streets or routes you take to avoid traffic and traffic lights, and will use them as well.

All in all, it's a fairly standard GPS interface, but there are a few features which make this system that little bit more helpful. The first and most important of these is the 3D Gyro Sensor, a feature that detects how fast the car is moving and which way it's facing. When the GPS signal is lost the 3D Gyro sensor takes over. We took the system through Sydney's Harbour Tunnel and retained a constant report of our position and distance to destination, as well as receiving directional information. It's less important where the tunnel is simply A to B. However, changing lanes and taking off-ramps within a tunnel system would be impossible to keep track of without a GPS signal or a 3D Gyro Sensor-style device.

The other neat feature the AVIC-HD3 has on offer is that it will tell you which lane to be in to reach your next way point, both audibly and using a split screen graphic. This is particularly useful with complicated multi-lane environments. It can be controlled using voice commands, and has Bluetooth, allowing you to hook up a phone and receive/send calls through the main interface.

Also, 10GB of the hard drive is dedicated to music. Each CD you insert gets ripped onto the hard drive allowing you to build up a library within the car. If you have an iPod, you can buy an adapter and control your iPod using the 7in screen. Other features include a DVD player, G-force and voltage feedback from your car and with the purchase of a rear-car camera you can also get a reverse-cam view for easier, safer reversing.