GPSS, or 'Global Positioning System Software', has been developed for use within cars, but it is also used to track a number of vehicles from a fixed Basestation. Many of the facilities are common to both types of application. e.g. map display and verbal description of where a selected vehicle is. It was designed for the future mass market - when we all have computers in our cars, but is rapidly being exploited by the military and police community.

In a typical system, the vehicles are equipped with GPS receivers - to automatically locate their position, and communications to exchange messages with the Basestation. This might share voice radio, or use Inmarsat-C satellite communications, Cellular Telephone, or the Securicor Datatrak system. Choice of communications bearer will depend upon trade-offs in vehicle equipment cost, communications rental cost, and communications coverage.

The Basestation is provided with a PC computer running the GPSS software. Regular position reports enable the vehicles to be automatically plotted on the displayed map. Coded messages can be used to report incidents from the vehicles - such as a breakdown or accident, and send orders from the Basestation to the vehicles.

Advantages

Multiple Vehicle Tracking. e.g. searching for the nearest village to a particular vehicle; calculation of where a selected destination is from the vehicle; output of this information by voice in addition to map display; use with voice recognition, in addition to conventional mouse and keyboard operation.

GPSS can also be used within a PC in the cab, providing all the obvious navigation aids - but also controlling communications and automatic logging of tasks.

GPSS for Police & Emergency Services
GPSS is being used in a wide spread of Police and Emergency Services applications, all of which involve GPS satellite based tracking of vehicles or other objects.

Remote Tracking - the requirement for a Control Room to know where its vehicles are, minute by minute, to task resources. This requires automatic communication between cars and base.





In-vehicle Tracking - to provide navigation and communication facilities in the vehicle, similar to those developed for future consumer in-car systems. A computer in the car, linked to its own GPS and data communications, provide the crew with a greater degree of autonomy. In addition to the obvious navigation aids it becomes feasible to co-ordinate multi-vehicle operations at a local level.

Covert Tracking - where the vehicle doesn't know it is being tracked. This includes a wide range of solutions which include hidden GPS pods or miniature transmitters that can be located using radio direction finding. Products developed to track wildlife as small as birds can be used to locate and follow any object - including clothing - on which the small transmitter is hidden.

GPS + Mobile Phone for Covert Tracking
In recent years the most popular technology for remote tracking involves a combination of GPS receiver and mobile 'phone. The GPS and 'phone will normally operate through glass, plastic or fabric, so is not difficult to install (e.g. hidden near front or rear window). It just needs a 12 volt supply, from the car battery. Typical current drain is between 0.1A and 0.2A, depending on whether the GPS is switched on (e.g. from the vehicle ignition). So even a small car's 35AH battery is often sufficient, without installing more complex power-saving devices. Some companies obviously specialise in hardware more suitable for covert installation.