Vehicle Tracking System using GPS

As it has always been a logistic nightmare to track out the vehicles on the way. In order to solve this problem of tracing out the vehicles on the way a vehicle tracking system based on Global Positioning System (GPS) has been devised. The system uses Global Positioning System as its base technology. For the communication purpose the system is set to be configured with the available terrestrial network.

Working of GPS:

The feasibility studies were started in 1960’s. The Pentagon appropriates funding for this system in 1973 and the first satellite related to this topic was launched in 1978, and the system declared fully operational in 1995.

The official name of the system was NAVSTAR GPS (Navigation Satellite Timing And Ranging Global Positioning System) and is developed by US Department of Defence. The Global Positioning System is a worldwide positioning system based on the functioning of the 29 satellites. These satellites keep transmitting the signals at a particular frequency to the earth. The GPS listeners, on earth tune to that particular frequency and listen to the signals sent by the satellite. For positioning any device which is equipped with the GPS listener, signals from three or more satellites is required. The signals from three satellites determine the latitude and longitude of the device on the earth. But the signal from four satellites determines the latitude, longitude and altitude of that device on the earth. More the signals from the satellite more will be the accuracy of the position of the device.

Use of GPS for vehicle tracking system:

For locating or tracking the vehicles, the system uses the GPS as its base technology to locate the vehicle on the earth. For this the vehicle is equipped with the GPS listener. Once the vehicle is located on the earth then the next step is to send this information to the control centre for the mapping of the vehicles. That’s here the terrestrial network comes into scene. The system uses the terrestrial network such as the available CDMA or GSM mobile network for communicating with the control center.

Once the vehicles is located then it is it sends its information such as the latitude, longitude, altitude, speed(derived), etc. to the terrestrial network. The terrestrial network then sends this information to the control center where the vehicle is mapped on the electronic map on the computer. If there is some information that is to be send to the person in the vehicle then it is sent to the terrestrial network. The terrestrial network sends this information to the device in the vehicle. For this the system use the Short Messaging Service (SMS), thus the information that is sent by the control centre to the person in the vehicle appears as SMS to him. Thus, it is fully two way communications between the control center and the device.

The location is represented by the Position Fix. A position fix is based on real – time satellite tracking and is defined by set of co-ordinates. It changes as the GPS receiver moves. Position shows the approximation of the receiver’s true location.

The path which the receiver must follow is denoted by the waypoint. A waypoint is the set of co-ordinates entered into the receiver. The position fix is matched with the waypoint within some allowed error limits. If it is within the error limits, the vehicle is following the correct path unless it is on wrong path and the control centre is sent information about this.