gsm gprs based tracker

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GSM & GPS based car tracker




1.1 Project backgroundThe focus of a GPS based position is to make use of the information of vehicles location. Now a days the world has changed into a global village because of the advancement in communications, but unfortunately in Pakistan we are not taking full benefits of these efficient communication systems and fleet management systems an example of such inefficient system is of our Railways that is still working on the centuries old man handled signaling and operating systems which is very error prone and can easily lead to big mishaps in recent years we have been some disastrous train accidents which took many precious lives. The goal of our project is to make an automated position reporting system that can be installed in the trains or vehicles so that the exact point to point location of the trains or vehicles can be found and send to main control room through GSM technology rapidly. This management system will be helpful in two ways:

1) The management system will be helpful in locating the exact position of the trains or vehicles for keeping a double check on vehicles or trains.

2) This system will also be helpful in updating the passengers about the exact location of trains, buses and arrival time and also easy information will be available about cancellation and rescheduling.

Firstly we decided to use the GPS for locating the remote vehicle position and searches for a module that can be used for this purpose finally we got SIM548c which have both GPS as well as GSM module. We used 8041family microcontroller (89S52) for interfacing and sending the GPS data through SMS to user.1.2 Project Summary

We propose it to plan a system enclosed that is used for the advance and the positioning of any transports using the system of world-wide localization (GPS) and the total system for mobile communication (GSM). A GSM modem is used in order to send at a distance ,the position (latitude and longitude) of the vehicle. The modem of GPS will give without interruption to data the latitude and the longitude that the position of the vehicle indicates. The modem of GPS gives many parameters like yield, but only the data of NMEA that exit are read and shown above the visualization to liquid crystals. The same data are sent to the mobile apparatus to the other extremity from which the position of the vehicle it is tax. Data is stored in RAM of microcontroller. The hardware interfaces to microcontroller is GSM modem and GPS Receiver. This design uses RS-232 protocol for serial communication between the modems and microcontroller.

1.2.1 Design hardware tools

Sim548c GPS/GSM module Sim448c EVB board

GPS antenna GSM antenna

GSM cell phone Microcontroller (89S42) Serial cables

1.2.2 Design Software tool

Google Earth

Uvision ProteusCHAPTER # 2GPS

2.1 IntroductionGPS, which means Global Positioning System, is the only method capable to show your exact position on the earth anytime, in any weather, anywhere. The Global Navigation Satellite System (GNSS) is currently the only fully operational system but Russia has GLONASS, China has COMPASS each at changeable stages of development or testing. The GPS system is made up of collection of 24 satellites in 12-hour orbits, orbiting at 10,900 nautical miles, or 20,183 km. Four satellites in each of six orbital planes in a pattern designed to provide worldwide coverage 24 hours a day. A satellite has 12 hour orbital period and an inclination of 44 to the equatorial plane. The collection is designed to give visibility of 6 to 11 satellites at 4 degrees or more above the horizon anywhere in the world at any time. These satellites allow for accurate three-dimensional position and velocity information for users anywhere in the world. The satellites broadcast signal that can be detect by anyone with a GPS receiver. Using the receiver, you can find out your location with great accuracy.Fig .2.1 the NAVSTAR GPS Collection2.2 History of GPSThe GPS system, also sometimes historically known as NAVSTAR was initially developed for the US military back in the 70s although paid and operated by the military the GPS system can offer navigation benefits for civilian use the first of these satellites built by Rockwell international was launched into the orbit in 1978 in that year four satellites were launched to provide an initial system demonstration of the GPS concept.2.3 How GPS WorksThe Satellites, receivers and some of the math involved are highly technical, but the principles behind how GPS works are quite simple. Essentially the system is based on ranging and Trilateration, or a three dimensional form of triangulation.

Ranging: It is determined from the distance to the satellite from the time it takes to receive a signal. The time taken is determined from the code of the signal and accurate clocks used on the satellites. If you know the distance to one satellite than you can determine that your position is anywhere on the surface of a sphere at that distance from the satellite. If you know the distance to two satellites then you can determine your position to be anywhere on the intersection of surface of two spheres, which is a circle, thus reducing the possible area. Knowing the distance to three satellites allow you to determine your position to be anywhere the previous circle intersects with a third sphere and this will be one of two points. It is possible through some mathematics to determine that one of these two points is not on the earth so can be ignored. Thus with distance information from 3 satellites it is possible to determine your position.There are two signals used by the satellites, one on 1227.6MHz, the L2 channel, and the other on 1474.42MHz, the L1 channel. The use of two frequencies is mostly to allow for correction of errors caused by ionosphere delay, propagation time and Dopplers effect.

2.4 Sim548C GPS PartThe Modules GPS part is planned to use L1 Frequency (C/A Code) GPS receiver and perform the entire GPS signal processing, from antenna input to serial position data output. The processing steps involved are:

RF section

In the RF section the GPS signal detected by the antenna is amplified, filtered and converted to an intermediate frequency (IF). An A/D converter converts the analogue intermediate frequency into a digital IF signal.

GPS channels

The received digital IF signal bit stream is passed to the baseband section, where it is fed into the correlates. The function of the correlators is to acquire and track the satellite signals. There are 12 channels used in parallel, with each correlate looking for a characteristic PRN code sequence in the bit stream. Once the correlate has found a valid signal, pseudo range, carrier phase and orbit information can be extracted from the GPS signal.GPS core The on-board processor is running an algorithm that calculates the position, velocity and time [7]. This calculation is called navigation solution. Once the navigation solution is calculated, it can be transformed into the desired coordinate system, e.g. Latitude/Altitude. Serial interface of the GPS part

The GPS part of the module offers two serial interfaces, Allows for different protocols to operate on each port. Serial port A i. 2-wire serial interfaceii. Includes the GPS_RXA (receive) and TXA (transmit) linesiii. Supported baud rate: 1200 -114200bpsbut 4800 - 38400bps is a common rate rangeiv. Protocol: Default NMEA ,4800bps

v. Default output message: GGA,GSA,GSV,RMC,VTG

Update rate: Default 1Hz

vi. Datum WGS84 default (User configurable) [8].Serial port B i) 2-wire serial interface, Includes the GPS_RXB (receive) and GPS_TXB (transmit) lines.ii) Supported baud rate 1200-114200 bps.iii) Protocol: Default none [8].2.4 Data Form on Hyper terminal

Our data which is coming on hyper terminal is in NMEA 0183 format which is a specific format for gps devices, and $GPGGA is the string in this data which we are extracting from this data because in this string latitude longitude are included. We also used this command in order to fetch coordinates.

2.4.1 $GPGGARecommended minimum specific GPS data


Global Positioning System fix data.

164044.000: Time 3342.8601: Current Latitude.

N: North

07304.4436: Current Longitude

E: East

0 or 1 or 2 Fix Quality (1 for GPS fix) 08 No. of satellites 1.1 (Horizon Dilution of Precision) Relative accuracy of precision437.9,M Altitude-39.2,M Height of geoid00 Time since last DGPS update

0 DGPS reference station ID

*74 Checksum for transmission errors



3.1 IntroductionGSM (GLOBAL SYSTEM FOR MOBILE COMMUNICATION formally from Groupe Spcial Mobile) is the mainly admired standard formobile telephony systems now a days.GSM is successful because of multiple reasons including offer superior sound quality but the main advantage of GSM phone is ability to internationalize roaming facility.

3.2 GSM Overview


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