GPS Based Voice Navigation System for Visually Impaired People

Global positioning system or GPS is a network of orbiting satellites used to locate positions anywhere in space back to earth. This kind of technology can be used in various areas like commercial usage, military, and civil services all over the world. GPS can be used for these purposes: perfect timing, trilateration, positioning of satellites and error connection. This system can be used universally for 24hours. Before discussing GPS based travel assistant for blind people let us know about the concept of GPS technology.

Global Positioning System
Global Positioning System

Introduction to Global Positioning System (GPS)

The global positioning system consists of three segments: space segment (SS), control segment (CS) and a user segment(US). Control and space segments are developed, operated and maintained by U.S air force; the user segment includes both civilian and military users and their GPS equipment.

GPS System
GPS System

Space Segment

This segment consists of 24 satellites from which 21 are navigational space vehicles and 3 are active spares orbiting at an altitude of 11000 nautical miles. These satellites are predictable and stable due to their high altitude. This system consists of six orbital planes that are inclined at 55 degrees and equally placed at about 60 degrees on the equatorial plane.

Control Segment

It comprises a master control station, an alternate motor-control station, six monitor stations, and four ground antennas. These monitor stations are positioned all over the world, to measure the signal from space vehicles which are incorporated into an orbital model of each satellite. Dedicated ground antennas are used for broadcasting signals to satellites.

User Segment

This system consists of receivers which can be handheld or installed on aircraft, ship, submarines, cars, and trucks. GPS receivers can decode, detect and process the signals to satellites. These signals can be changed into position, time and velocity. This segment can be used in different applications such as satellite positioning, shipping, military, surveying, and tracking.

This about GPS technology and as an application of this GPS here we are giving a project to guide the blind people as a voice navigation system.


GPS (Global Positioning System) Based Voice Navigation System for Blind People

The term blindness refers to the people who have no vision at all or people who have less vision. Most of the blind people take support from guide dogs to walk. We are explaining about the GPS and voice navigation system for blind people. In this blind people issues the commands and then receive the response using audio signals. GPS receiver is used to receive the values of the latitude and longitude continuously. With the advancement in technology usage of voice recognition is easier to send commands regarding directions to the blind people. As an application of this GPS technology here GPS based voice alert systems for the blind persons are explained practically in subsequent paragraphs.

Block Diagram of Voice Navigation System for Blind People
Block Diagram of Voice Navigation System for Blind People

Hardware and Software Components Used

This blind navigation system is built with the major components like microcontroller, GPS receiver, voice recognition module, voice playback unit, speaker, ultrasonic sensor and power supply unit. Let’s look at in detail about all these components.


This controller is of the ARM LPC2148 processor, which combines the microcontroller with high-speed flash memory ranging from 32 to 512 KB. It has on-chip flash program memory and on-chip static RAM. It has 10 bit A to D converters and supports for USB 2.0 full speed transfer. Due to low cost, low power consumption and ease of handling, this microcontroller is reliable for this project.

GPS Receiver

Global Positioning System or GPS receiver used in this project is GR87 which makes use of the broadcast signals come from GPS satellites. It provides a three-dimensional location such as longitude, latitude and altitude values from every position in this world in all weather conditions. The main features of this receiver are low power consumption, on-chip 1MB SRAM, 0.1Sec reacquisition time and multi-path mitigation hardware.

Voice Recognition Module

This module detects the user spoken word through a microphone. Speech analysis will take place by this unit after the input audio signal is taken. This system consists of two phases as a training phase and the other is a recognition phase. During the training phase speaker has to give speech signals to train the system and in other phase speaker has to give speech commands which are further matched with stored signals while they stored while training phase. This project uses the IC HM2007 as a recognition module.

Voice Playback Unit

It is of high-performance AP89085 IC fabricated with a CMOS processor with an embedded 2MB EPROM. It is a sound record and replies IC that can store the message upto 85sec. This recorded sound is retained even after the power supply is removed and this replayed sound is of high quality with the minimal noise level.

Ultrasonic Sensor

This sensor is used for detecting the obstacles on the way for the blind persons in this project. This sensor transmits an ultrasonic burst and correspondingly gives an output pulse based on the time required for the burst echo to return to the ultrasonic sensor. In this way depends on the echo pulse width, distance target is easily be detected and measured.

Speaker Unit

The speaker is used for guiding the visually impaired persons to navigating them based on the signals or the recorded sound of the voice playback unit.

MAX 232

To provide the communication between GPS receiver and microcontroller, MAX 232 is used. This is a standard serial binary data interconnection unit between the data terminal and the data communication unit. RS232 level signals from the GPS receiver are converted to TTL level signals of the microcontroller by this unit.

Software Components

Software tools like Embedded C, Keil IDE, and Uc-Flash are used in this project for programming the microcontroller.

Working of Voice Navigation System

The whole circuit is powered with a regulated DC power supply as shown in the block diagram. The GPS receiver used in this project is capable of receiving signals from 65 GPS (Global Positioning System) satellites. These received signals are transferred into precise position and timing information that can be read from RS232 port of this receiver. This longitude, latitude, altitude and timing data send to the microcontroller unit through MAX232 IC. These values are continuously processed in the microcontroller.

Working of Voice Navigation System
Working of Voice Navigation System

The Voice recognition module recognizes the user spoken words and correspondingly sends those signals to the microcontroller. The microcontroller compares that spoken place values (longitude, latitude, and altitude) with signals from GPS receiver. Upon this comparison, the microcontroller drives the voice playback unit for providing voice navigation to the user. Predefined voices are stored in this module as navigating commands to the blind persons. We can store the destination values for each voice of spoken command in the microcontroller for recognizing the destinations. The ultrasonic sensor detects the obstacle in the way onto the destination, so that microcontroller gets it and alerts the visually impaired persons.

This is about the global positioning system or GPS based voice navigation system for blind persons. I hope that you have a better understanding of the GPS with this practical application. Further, any help for implementing this project or any other electronics projects, especially for connecting the GPS receiver and its configuring process you can leave your comments below.

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