This document summarizes an object tracking system that uses RF transmitters attached to objects, receivers to detect the transmitted signals, and a mobile phone interface. Objects are tagged with unique IDs. When an object enters a receiver's range, its ID and location are stored in a database. Users can query an object's location by sending an SMS message via a GSM modem connected to the database. The modem retrieves the object's location and description from the database and sends it back in a return SMS. The system allows users to track objects entering or leaving receiver ranges and locate objects on demand. It provides a low-cost infrastructure for wide-area object tracking using existing cellular networks.

1. International Journal of Electronics and Communication Engineering & Technology (IJECET), ISSN 0976 –
INTERNATIONAL JOURNAL OF ELECTRONICS AND
6464(Print), ISSN 0976 – 6472(Online) Volume 4, Issue 5, September – October (2013), © IAEME
COMMUNICATION ENGINEERING & TECHNOLOGY (IJECET)
ISSN 0976 – 6464(Print)
ISSN 0976 – 6472(Online)
Volume 4, Issue 5, September – October, 2013, pp. 192-200
© IAEME: www.iaeme.com/ijecet.asp
Journal Impact Factor (2013): 5.8896 (Calculated by GISI)
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IJECET
©IAEME
LOCATING & MONITORING OBJECTS USING RF TRANSMITTERS &
RECEIVERS AND RETRIEVING DATA USING GSM
1
Jagannath N. Mohite,
2
Prof. J. G. Rana
1
2
ME (App.), JNEC, Aurangabad
Head, ECT Department, JNEC, Aurangabad
ABSTRACT
Locating physical items is a highly relevant application addressed by numerous systems.
Many of these systems share the drawback that costly infrastructure must be installed before a
significant physical area can be covered, that is, before these systems may be used in practice. In this
paper, we build on the ubiquitous infrastructure provided by the mobile phone network to design a
wide area system for locating objects. This system provide way for monitoring and locating objects
using Radio Frequency (RF) transmitters and receivers, and querying about the objects using mobile
phones. An object represents a real world entity. This system is based on RF transmitters that are
tagged to the objects of everyday use and have the capability of transmitting signals and a receiver
that detects the transmission of the tagged object and stores its corresponding location in the database
which is created specifically for information maintenance of the tagged objects. Mobile phones are
used to query the location of the tagged object by sending a message to the Subscriber Identity
Module (SIM) connected to a Global System for Mobile Communications (GSM) modem. This
GSM modem fetches the location and other relevant information from the database and encapsulates
this information into a message which is sent back to the mobile phone that has requested the
information.
Keywords: RF module, GSM modem, Identification and tracking system.
I.
INTRODUCTION
To be able to locate everyday objects at the touch of a button is a promising application of
ubiquitous computing Inexpensive sensing devices are expected to play a major role in future
computing systems. They aim to make the daily life of their users easier by monitoring everyday
physical processes and providing novel features based on the acquired data. What currently hinders
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most of the conceived systems from becoming commercial applications, however, is a lack of
adequate infrastructure of following types: First, a sensing infrastructure must be installed to perform
an efficient sensing task. Second, a communication infrastructure is required to distribute and
aggregate readings from multiple transmitters. Finally, a commercial infrastructure is needed to
manufacture and deploy the transmitting, receiving and communicating devices like GSM modem,
and to generate revenue from the system.
The mobile phone system provides a unique opportunity to overcome these difficulties.
Sensing technologies can be implemented using transmitters and a receiver and accessed from the
mobile handset via wireless mobile networks. Wide area communication is a core property of the
cellular network. It enables the integration of data from many transmitters and the support of
applications with backend services such as data storage. This system is effectively used in the
location of important items that are tagged and their location can be queried by various users.
Making use of these unique properties of mobile phones and the cellular network, we present a
system which is concerned with monitoring and locating objects by means of mobile phones. The
objects that are tagged with the hardware i.e. the transmitters in the vicinity are detected by the
corresponding receivers and the location are queried using a mobile phone by means of a GSM
modem. The dual technique employed in this project is: First, object sensing using the RF
transmitters and receivers. Second, user interface provided by the mobile phone aid for sensing and
querying the personal items simultaneously.
This system allowed us to identify a particular challenge that is common to many applications
that makes use of large people-centric infrastructure provided by mobile phones and the cellular
network. The challenge is to answer the question of whether a system based on RF transmitters and
receiver can provide sufficient coverage in relatively short period of time. In an extensive evaluation,
which includes a real world experiment with our object localization prototype, we therefore analyzed
the properties of the coverage obtained given a wide range of different operational parameters such
as the distance between transmitter and receivers, objects in the path of transmission and range of the
transmitters used. In addition to confirming the feasibility of object localization based on mobile
phones, the study can provide valuable guidelines for the design of future people-centric sensing
systems in general.
II.
SYSTEM MODEL
This section presents an overview of the system and introduces the functionality of each of
the individual components.
A. Overview
This article is a novel approach in locating and also retrieving product related information
using mobile phones. It is difficult to go and locate objects manually or search for them in a short
period of time especially when object location is unknown. In this paper we are attempting to locate
objects irrespective of its distance from the user who is trying to track the object. Objects can be
located more easily if they are equipped with Bluetooth or Infra-Red facilities which nowadays are
commonly found in electronic devices likes Personal Digital Assistant (PDA), laptops. However the
drawback of this is the limited range. But we are extending the idea to locate objects both stationary
and mobile using RF transmitters and receivers with greater range. On a larger scale this project can
be implemented for locating landmarks in a city or items in a warehouse. The implementation is
based on two criteria. Firstly, we assume that the objects being tagged are accompanied with a
unique ID. Secondly, each receiver is given a unique location ID that determines the current location
of the object.
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B. Architecture
The system architecture comprises of three parts that is the sensing functionality, storing
functionality and querying service. The sensing functionality comprises of RF transmitters and
receivers that are used to sense the presence of tagged objects within the region. The storage
functionality is used to store all relevant information of the object in the database. The operator
provides a user with a database service in which the user can store application data such as reports
and other information regarding the objects. The querying service is used by the user for querying
necessary information associated with the object using GSM network and Short message service
(SMS)[2,6].
The choice of transmitter architecture is determined by two important factors: wanted and
unwanted emission requirements and the number of oscillators and external filters. In general, the
architecture and frequency planning of the transmitter must be selected in conjunction with those of
the receiver so as to allow sharing hardware and possibly power.
C. Object Tracking
The object tracking application is used for locating and managing objects using Use case via
mobile phones. Use cases are specified for various functions such as detecting of objects within the
sensing range, notify objects that have left the sensing range, querying about objects, identifying new
objects entering and leaving the sensing range. These use cases are defined as follows:
Out-Region: This Use case allows the user to set up their cell phones to keep track of objects which
leave the receiver sensing region. This includes tracing of object location before and after the loss
event. Most recent location of the object will be stored and notification will be sent when an object
leaves the sensing region using Out-Region(obj) function.
In-Region: This Use case allows the user to set up their cell phones to keep track of all objects within
the receiver sensing region. This includes tracing of objects location and storing it in the database.
Current location of the object will be stored and notification will be sent to indicate the presence of
object in the sensing region using In-Region(obj) function.
Find: This Use case allows the user to query an object from the list of objects that are already being
detected and stored in the database. The system will forward this query to the GSM modem, which
looks for the corresponding object in the database. Various object search strategies can be employed
such as string matching, keyword followed by the object name e.g., Locate CRO or just CRO. The
GSM modem will notify the user with a short message containing object’s location and its
description using ObjLocation() and ObjDescription() function.
Query
In-Region
Out-Region
Find
Gate
Trigger
In-Region
(Obj)
Out-Region
(Obj)
In-Region
(Obj)
In-Region
(Any)
Report
Obj-description ( )
Obj-Location ( )
In-Region(obj )
Out-Region
(Obj)
Obj Descriptive()
Objlocation()
Obj location()
In-Region(Obj)
Tmax
∞
∞
A
∞
Nmax
B1
∞
B2
B3
Qmax
∞
∞
C
∞
Table1- Parameter setting for 4 use cases
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Gate: This Use case act as a gatekeeper keeping track of new objects entering the sensing region and
old objects leaving the sensing region by sending corresponding notifications. The data is
correspondingly updated in the database. This Use case provides useful information that helps in
Find query.
Query services and functions implementing the above use cases are provided in Table I. The
parameter A, B1, B2, B3 and C in the table represent the values used in actual system. Trigger
service is used to indicate when the query should produce a result. If the queried object is in the
sensing region then query produces a result otherwise it sends a default message “Object Not
Found”. Report service specifies the information the query should generate if the object is found.
The report consists of location and complete description of the object e.g., a restaurant object
consists of a report specifying the location, type, theme and facilities. Different system limits can be
specified using the following parameters.
Tmax: maximum time taken by a query or the maximum query time.
Nmax: maximum number of objects detected by the receiver.
Qmax: maximum no of reports that can be generated by the system.
For Out-Region scenario Tmax, Nmax, Qmax all are irrelevant since the object is outside the sensing
region of the system. In In-Region scenario Nmax is relevant as it specifies the maximum number of
objects the receiver can detect and if the system exceeds this limit then unused objects or out of
region objects should be replaced by new ones. In Find scenario Tmax and Qmax are relevant .Tmax is
dependent upon the network traffic and distance between the user and the GSM modem. Tmax is also
limited by the effective search strategy employed in the system. The Find query is sent to backend
database of the system is sent. Qmax is limited on the number of objects stored in the database.
Maximum number of reports is proportional to the maximum number of objects stored in the
database .Gate scenario is concerned with Nmax parameter, when an object is identified it verifies
with the Nmax before its information is stored in the database.
III.
SYSTEM DESIGN
The system design provides the details of the components employed in the system. It consists
of RF transmitters incorporated into the objects, RF receiver, and a database to store all the relevant
information regarding the objects and a GSM modem used for sending and receiving SMS regarding
querying of the objects and its location. The components of the system are provided in Fig.1.
The RF transmitters operate in a radio frequency range of 3 KHz to 300 GHz. RF transmitters
are programmed at different frequencies and integrated with objects to be located. Each RF
transmitter will be associated with a unique ID.RF transmitters can be used to operate in low
frequency range as well as high frequency range depending upon its application. Frequency range
switch is used to select the desired frequency range for each transmitter. Modulation techniques
employed by the transmitter are Amplitude modulation (AM), Frequency modulation (FM),
Frequency shift key (FSK), Amplitude shift key (ASK), Phase shift key (PSK). Data rate is the
amount of data transmitted in bits per second. RF transmitters are available in market with a wide
range of specifications e.g., LR series, LC series, HP3 series. RF transmitters transmit the unique ID
via the communication network.
RF receivers are electronic devices that separate radio signals from one another and use
demodulator to convert specific signals into audio, video, or data formats. Radio techniques limit
localized interference and noise. Each RF receiver is associated with a unique location ID. This ID is
used to determine the location of the object. RF receivers display the unique object ID being
detected; all the relevant data of this object are stored in the database along with its location. RF
receivers are also available in market with various specifications e.g., MC33591, U4311B.
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An object could be a stationary or a mobile object. It could represent any real world entity.
The objects are incorporated with transmitters that are programmed with different frequencies and
identified by a unique ID. The RF receivers are used to identify these objects within the region. The
area of the region depends upon the receiver used. The wireless communication network is built on
User Datagram Protocol (UDP) or Transmission Control Protocol (TCP) running over Internet
Protocol (IP).
Database represents a storage device like hard disk. Size of the database depends upon the
application. Database is attached to the GSM modem. A GSM modem can be an external device or a
PC Card / PCMCIA Card. GSM modem requires a SIM card from a wireless carrier in order to
operate. All SIM cards are associated with a Personal Identity Number (PIN) used to unlock the
mobile station (MS). All the queries regarding the objects are sent to this SIM via the GSM network.
GSM modems support a common set of standard AT commands used to provide Short message
service e.g., SIM300_HD_V1.07.
User agent is a potential user who sends short message queries regarding the object using
mobile devices such as cell phone, PDA. The queries are sent to the GSM modem via the GSM
network using the find use case. The GSM modem interacts with the database and sends back the
corresponding information to the user via the GSM network.
Figure1 System development
IV. PROTOCOL STACK
The protocol stack provides the integration and functionality of various parts of the model as
shown in Fig.2. The protocol stack can be divided into two parts: the hardware specification, which
describes the protocols for RF transmitters, RF receivers and database, and the software
specification, which provides protocols and function needed to query information from the GSM
modem. The protocol stack comprises of the following elements RF transmitters are integrated to the
objects. They are programmed to use a particular frequency in the radio frequency range. An RF
transmitter generally includes a modulator that modulates an input signal and a radio frequency
power amplifier that is coupled to the modulator to amplify the modulated input signal. The radio
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frequency power amplifier is coupled to an antenna that transmits the amplified modulated input
signal. The modulation techniques are as follows:
Figure 2 Protocol Stack
1) AM causes the baseband signal to vary the amplitude of the carrier wave to create the desired
information content.
2) FM causes the instantaneous frequency of a sine wave carrier to depart from the centre frequency
by an amount proportional to the instantaneous value of the modulating signal.
3) ASK transmits data by varying the amplitude of the transmitted signal.
4) FSK is a digital modulation scheme using two or more output frequencies.
5) PSK is a digital modulation scheme in which the phase of the transmitted signal is varied in
accordance with the baseband data signal. Each RF transmitter transmits a unique ID that represents
the object associated with it to the corresponding receiver.
This data signal is transmitted using wireless network with TCP/IP and UDP protocol. RF receivers
are located in each region with a unique location ID. This Location ID is used to locate the region in
which RF receiver is placed. RF receivers use wireless network to receive the signals transmitted by
the RF transmitters within its sensing region. RF receiver displays the unique ID of the object
detected along with its location ID. These IDs are sent to the front end. Visual studio along with
programming language like java, .NET, VB can be used to create a front end forms to enter the
description of the object and send it to the data base. RF receivers detect all signals transmitted in the
radio frequency range.
Database comprises of secondary memory devices such as hard disk. Size of the database is directly
proportional to the area of application. RF receivers are used to store the description and location of
the objects in the database. And the GSM modem is used to query the objects from the database. The
database can be created using software toolkit like My SQL. The database is integrated to RF
receivers and GSM modem using programming languages like .NET, J2ME, Java, VB running on
Windows or Linux Operating System (OS).Database should be frequently updated to provide valid
data to the users of the system. Radio frequency specifies the air interface, which also includes the
frequencies used, modulation technique employed and power transmitted. Radio frequency operates
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over a range of 3 KHz to 300 GHz. Baseband provides a description of basic connection
establishment, packet formats, timing and basic Quality of service (QoS) parameters used by the
system. Link manager is used for link set-up and management of connections between devices like
database, GSM modem, transmitters and receivers. Link manager performs functions such as
synchronization, capability management, and quality of service, power control, transmission mode
and authentication. The network applications make use of standard TCP and UDP protocol.
Transmission Control Protocol sends the data directly between two components, and stay connected
for the duration of the transfer. User Datagram Protocol sends the data packets it into the network
without requiring prior connections and provides best effort service. TCP/UDP protocol runs over
standard IP protocol. TCP/UDP over IP is described in [3]. GSM modem is integrated to the
database. E.g., VB platform are used to interface GSM with the database. It makes use of standard
AT modem commands for sending and receiving SMS. Each GSM modem is associated with a SIM
that is used by the user to query Information about an object. All SMS are sent to the SIM of the
GSM modem. GSM network is used for transmission of messages from the mobile station to the
GSM modem. User interface consists of cell phones, PDA and so on. They are used to query about
the object by sending SMS to the GSM modem via the network.
V.
RESULTS
Fig.3 shows the actual GUI which we see after running code. In this icon which looks like a
telephone shape is used for serial communication (NOT SHOWN IN RESULT WINDOW). Two
shapes for two serial communication; one is for microcontroller & other one is for GSM Modem.
GSM Communication section is just for read only purpose & works with GSM Modem & cannot be
edited. Object Database is used with microcontroller circuit.
Now first we have to update database in order to get its location. For that first connect
microcontroller & other circuitry to serial port. It will receive data A106. From that A1 is shelve
location number & 06 is device identification number. In location column A1 data will get added
automatically and also an image of the object is displayed & we can see it in object database section
as shown in fig.3
Figure 3 Result
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In GSM communication section, we have to send sms as CRO or any required object (not
case sensitive). After sending sms VB code will read received sms. It will check which device you
want to search. Then it will compare received sms with available database. If VB founds data then it
will sms back ” Name: CRO LOCATION A1” on same number from which sms has been received.
VB will send sms containing name of searched device & its current location. In GSM
communication we will have data whenever someone sends sms. It will show mobile number of sms
sender, its name if available, then received time, date & actual message. Data available on result
window can’t be edited while project is running.
V. CONSTRAINTS
The constraints that limit the design of the system are:
Frequency: If two or more transmitters are programmed to operate at the same frequency, then it is
not possible to run them simultaneously. The transmitter closer to the receiver will be detected.
Range: The range of detection may vary from a few meters to several kilometers depending on the
transmitters used. Higher range transmitters increase the overall cost of the system.
Reliability: Since electronic circuits are used, reliability is a factor of concern. The operation of
equipments depends on the lifetime of hardware.
Power Consumption: The power consumption increases as higher capacity transmitters and receivers
are used.
Analysis Performance: For small companies and organizations with relatively few hundred messages
passing in and out simultaneously from the GSM modem is feasible. However for global
organizations where several thousand messages per minute could be anticipated, then the
performance of GSM modem degrades.
VI. APPLICATIONS
The system being developed has a wide range of applications. Based on the capacity of
transmitters and receiver, the usability can range from a small house or building to a large area such
as a city. Some of the applications are as follows:
• Locating landmarks in a city: A transmitter can be attached to each landmark and its location and
related description can be stored in a database. A visitor to the city can query from any mobile phone
and get information about the location.
• Managing items in a warehouse: Finding an item in a huge warehouse is a task that can be
accomplished using the design.
• Usage as emergency services: A helpline number attached to the GSM can be used by people to
locate hospitals, fire station and police station in case of emergencies.
• Locating personal objects: Objects used by people on a daily basis like spectacles, wallet, and so
on may get displaced very often. Using transmitter and receiver, these objects can be tracked.
• Organization support: Within an institution it can be used to locate libraries, canteens, departments
and sport complex.
VI. CONCLUSION
A comprehensive system for managing and identifying essential objects relying on mobile
phones as omnipresent object-sensing devices is presented. Significant effort was spent on modeling
and testing the system for detecting objects under various circumstances. The results are encouraging
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but due to the constraints of cost, implementation was not done on large scale basis. The system
provides a relatively less accurate positioning for moving objects, but the total overhead for
distributing an object search query remains acceptably low. The system does not change the basic
fact that the objects out of sensing region will not be detected. For objects within the sensing region,
system is feasible.
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