GPS Vehicle Tracking

GPS (Ground Positioning System) vehicle tracking uses satellite technology to plot a vehicle’s global position. This is the most accurate way for a tracking unit to identify its location and is generally accurate within 10 metres.

How does it work?

GPS vehicle tracking works through satellites in space transmitting a time and location signal. The tracking device that is installed into the vehicle receives this signal from multiple satellites (usually a minimum of 4) and uses the information to calculate its longitude and latitude. The tracking device than sends this information at set intervals via the mobile phone network to a secure server where it is than made available to the user via the tracking application.

GPS Technology:

GPS Antennas need to receive signals from a minimum of 4 satellites in able to accurately locate its position. The GPS constellation always has a minimum of 24 satellites operating which means that there is always a minimum of 4 satellites within line of site at any time, any where on Earth. There are currently (March 2009) 32 active satellites in the GPS constellation which means that GPS receivers are able to receive more signals improving the receiver’s accuracy. It used to be that when vehicles (fitted with a tracking system) were travelling through forested areas or cities with high rise buildings the signal would reflect of tall objects and could result in the tracking system miss locating its position. Improvements in today’s technology have overcome this issue through improved GPS antennas.

GPS Restrictions

GPS vehicle tracking can be restricted when in certain locations/environments or when installed incorrectly. When vehicles enter locations such as tunnels, underground car parks and vehicle depots the GPS signal can be obstructed and is not received by the antenna. This results in the vehicles location being reported back as ‘unavailable’ or ‘unknown’ etc. This does not normally cause a problem as the tracking unit will start reporting its location again as soon as it is clear of the obstruction.

Many tracking applications are able to plot the vehicles position on a satellite image overlay and where possible you can see a satellite ‘birds eye’ view of the vehicles last know location i.e. just before a tunnel or outside a vehicle depot/warehouse etc.

It is essential that the antenna is installed in a suitable position by the engineer installing the tracking system. This is a location where the antennas ‘line of sight’ will not be obstructed by a metallic object usually directly under the top of the vehicles dashboard. Some vehicles have polarized or heated front windscreens; these types of windscreens are metallic and can obstruct a GPS signal. Where this is the case the engineer needs to install the antenna in a more suitable position in the vehicle.

GPS vehicle tracking is the most common type of vehicle tracking system on the market today due to the its ability to quickly and accurately record the vehicles location and record the vehicles mileage and speed precisely. GPS is a free service and no subscription is required.