Global Positioning System (GPS) :
Introduced by the US initially for servicing the interest of Defense, GPS is a satellite-based navigation system made up of a network of 24 satellites, transmitting on two frequencies to enable the coarse and accurate position to be determined on objects which are equipped to receive and process satellite signal from a minimum of three satellites, using the triangulation method.
Apart from the real-time position, the receiver also outputs time, velocity, and a host of other object-related parameters. GPS works in any weather conditions, anywhere in the world, 24 hours a day. There are no subscription fees or setup charges to use GPRS.
GPRS (General Packet Radio Service) :
GPRS is the main method of communication between the GPS Tracking unit and the server. GPRS, being a 2.5G mobile technology, is ubiquitously available in most of the countries. It is also ideally suitable for data transfer between a central location and mobile devices.
Use of GPRS has the following additional advantages:
- Packet switching: GPRS involves overlaying a packet-based air interface on the existing circuit-switched GSM network. The GPRS information is split into packets before being transmitted and reassembled at the destination.
- Immediacy Provides instant connections to send or receive the message subject to the availability of radio coverage.
- The higher speed of data transfer (currently available data transfer rates are 14.4 kbps to 26 kbps) are possible with a theoretical maximum of 171.2 kbps.
- Spectrum Efficiency: GPRS radio resources are used only when transmitting and / or receiving data.
- Concurrency: The available radio resources can be concurrently shared between several users.
- Efficient use of radio resources: Potentially large number of users can share the same bandwidth.
- Maximize the usage of network resources in a dynamic and flexible way.
- Reduce SMS traffic data load, Interfacing the in-vehicle GPS unit with a GPRS modem facilitates real-time transmission of the positional information to a Control Station, without limitation on data size, thereby overcoming the 160 character limitation of SMS used in GSM. Also, by storing GPS data in the Flash memory of the in-vehicle unit at regular intervals (typically one data string every few seconds), bulk data can be transmitted to a Control Station at pre-defined intervals.
However, the disadvantages are:
- Higher Network Service costs.
- Dark areas in coverage may prevent communication.
- Transit delays.
GSM/ CDMA Communication Network :
Considering the expansion of mobile communication services in India for the past few years, interfacing the in-vehicle unit with GSM/GPRS/CDMA communication networks offers an effective solution.
The advantages, therefore, are:
- Larger network coverage.
- Facilitates providing two-way voice and data communication between the in-vehicle unit and the Control Station.
- Sends vehicle location and other information as an SMS or GPRS message.
- SMS advantage: Storage and forward facility for messages as a facility offered by the Network Service Providers.
Web Based GPS Tracking system allows users to securely log in and track their assets in real-time over the Internet. The system allows users to locate their vehicles anytime and anywhere.
Also, it can replay a past trace of the vehicle’s route history. It can also remotely control the car such as run alarms and locking devices. A lot of shipment companies globally use GPS Tracking Systems in their transport vehicles.
It is very important for large fleets, especially when they have a big number of trucks and staff, to manage these huge numbers of vehicles and people.
What does the Vehicle Tracking System comprise?
The GPS based Vehicle Tracking System comprises of an in-vehicle tracking system that consists of a GPS receiver unit, CDMA/GSM Modem, on-device Data Storage unit, other peripherals, and a web-based application. Through this system, the users will have the facility to monitor the movement and gather entire information of any vehicle.
Variants of Vehicle Tracking System:
1. Passive :
In the Passive System configuration, the in-vehicle unit captures positional updates every few minutes, and stores the data in its Flash Memory.
The data can be reviewed at a later time with a manual or automatic data download facility. In the manual data download, the in-vehicle unit needs to be physically connected to a computer, whereas in the automatic download mode use of Bluetooth/Radio/GSM/ Modem device is used to transfer the data to the server or computer.
The advantages and disadvantages in the Passive system are :
- Low cost and one-time investment.
- High resolution, providing detailed information.
- No coverage area limitation.
- No need to rely on network functionality.
- No real-time location information is available.
- Cannot be used to locate vehicles for dispatch and customer services.
- Too late in many instances to capture exceptions.
Active (Real-time) :
- Exception Reporting
- Continuous Tracking
In the Active System configuration, the in-vehicle unit transmits the positional data strings to a centralized and /or distributed information system in real-time time using Radio/GSM/GPRS/CDMA network.
In the Exception Reporting system, it sends alerts to the fleet operator when violations or vehicle-related events like break downs, emergencies, etc are detected.
The continuous positional data can also be stored on the in-vehicle unit and downloaded onto the system computer as in the case of passive systems.
Whereas in continuous GPS Vehicle Tracking System, the positional update is sent every few seconds to the centralized/ distributed information system enabling real-time applications.
The advantages and disadvantages in Active systems are seen:
- Near Real-time continuous track of the vehicles
- Quick response to customer needs and emergencies
- Alerts fleet operators for immediate corrective action
- Long term dependence on network carrier and service provider
The Potential Customers of a Vehicle Tracking System includes:
- BPO Companies or Call Centres
- Call Taxi operators
- Ambulance, Police and other Emergency Service Providers
- Public Transportation System
- Municipal Corporations
- Freight carriers of Industrial and Agricultural produce
- Transportation Industry