This is a project report presentation entitled as "GPS DATA INTERFACING WITH GOOGLE THROUGH WIRELESS COMMUNICATION".

1. FINAL PRESENTATION ON
GPS DATA INTERFACIGN WITH GOOGLE
MAP THROUGH WIRELESS
COMMUNICATION
Guided by
Mr. Ganesh Roy
Assistant Professor
Dept. of IE, CIT Kokrajhar
Prepared by
Bijit Kumar Bhuyan(Gau-c-11/L-210)
Wasim Akram(Gau-c-11/62)

2. Contents
• Introduction
• Working
• Mathematics behind GPS
• NMEA Format
• Various components used in the project
• Block Diagram
• Circuit Diagram
• Circuit description
• Results and discussions
• Reason for error
• Conclusion and future scope
• Utilities
• Reference

3. Introduction
Global Positioning System shortly known as GPS is one
of the advanced addition in the field of modern
inventions. It has a wide application in navigation
systems, construction sites, military equipments and
so on. With the new efforts GPS systems are being more
accurate and precise day by day. The forming of GPS system was started
in 1973and it became fully operational in 1995.
The Global Positioning System (GPS) network we all use is called
Navstar. It is paid for and operated by the US Department of Defense
(DoD). This Global Navigation Satellite System (GNSS) is currently the
only fully operational system. Other countries like Russia has GLONASS,
China has COMPASS and the EU has GALILEO each at varying stages
of development or testing. India is working on IRNSS(Indian Regional
Navigation Satellite System).

4. Working
A GPS receiver knows the location of the satellites
because that information is included in the
transmitted data. By estimating how far away a
satellite is, the receiver also knows it is located
somewhere on the surface of an imaginary sphere
centered at the satellite. It then determines the
sizes of several spheres, one for each satellite
and therefore knows the receiver is located where
these spheres intersect.
There are 24 satellites divided in 6 orbital. Each orbital is separated by 60 and
has 4 satellites equally spaced. The satellites revolve at an altitude of 20,000
kms above the earth surface with a speed of 14,000km/hr.

5. Working continued…
The timing and position are two main factors for working of GPS systems.
For accurate time GPS satellites are equipped with the most possible
precise timing device atomic clock. While positions are monitored by a
ground based control unit.
The GPS satellites also suffer the relativity effect. There are two kinds
relativity-
Special relativity
General Relativity.
Special Relativity deals with space, time and motion while the General
Relativity with gravity and time. As mentioned above GPS satellites move
with a speed of 14,000 km/hr so they delay a time duration of 7usec/day.
The GPS satellites also revolves at an altitude of 20,000 km where the
gravity is weaker than on the earth surface. So they advances a time
duration of 45usec/day.

6. Working continued…
So combining the both effects we can see that a GPS satellite advances a time
period of 38usec/day. This may not seem much but it can lead up to an error
of 11km/day. So the GPS satellites’ time is reduced by 38usec/day to
overcome this problem.

7. MATHEMATICS BEHIND GPS
As we can see in the first figure for specifying a point on a straight line two
fixed points are required and for 2 dimension three points are required.
Similarly in case of three dimension fours points will be required.
FIGURE One-dimensional user position
FIGURE Two-dimensional user position

8. As we can see in the above image three known points(GPS satellites) and an
unknown point(user) are there. Now the distance from the three different
satellites to the user are as follows
Figure: Use three known positions to find one
unknown position.

9. Equation for user position
The above equation can be written as
Measurement of pseudorange
Now we can see that the above equations are second order equations. So
these are difficult to solve using normal calculations. So we liniarise these
equations for simplicity.
2
3
2
3
2
33
2
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2
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22
2
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10. The equations after linearization
Equations in matrix form
The solutions of the above equations
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11. Relation between Cartesian coordinates and longitude latitude
Latitude,
Longitude,
Altitude,
The above relations shows the relation between Cartesian solutions and
latitude and longitude value. We can calculate that for kokrajhar with a
location of
Latitude=26.4N
Longitude=90.27E
X=26.89 km
Y=5706.51 km
Z=2832.77 km
e
U
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222

12. NMEA FORMAT
The message from the GPS receiver is obtained in NMEA( National
Marine Electronics Association). It is transmitted in a string fashion which
contains typically 17 different units within it. Each unit specifies different
parameter.
Message Structure:
$GPGGA,hhmmss.ss,Latitude,N,Longitude,E,FS,NoSV,HDOP,msl,m,Altre
f,m,DiffAge,DiffStation*cs<CR><LF>
Example:
$GPGGA,092725.00,4717.11399,N,00833.91590,E,1,8,1.01,499.6,M,48.0,
M,,0*5B

13. Field
No.
Example Format Name Unit Description
0 $GPGGA String $GPGGA - Message ID,
GGA
protocol
header
1 092725.00 hhmmss.sss hhmmss.
ss
- UTC Time,
Current time
2 4717.11399 ddmm.mm
mm
Latitude - Latitude
3 N Character N - N/S
4 00833.91590 dddmm.
mmmm
Longitude - Longitude,
5 E character E - E/W
6 1 Digit FS Position Fix
Status
Indicator
7 8 Numeric NoSV - Satellites
Used, Range
0 to 12

14. Field No. Example Format Name Unit Description
8 1.01 Numeric HDOP - HDOP
9 499.6 Numeric Msl M MSl altitude
10 M Character uMSL - Units,
Meters
11 48.0 Numeric Altref M Geoid
Separation
12 M Character uSep - Units,
Meters
13 - Numeric DiffAge S Age of
Differential
Corrections,
Blank (Null)
fields
when DGPS
is not used
14 0 Numeric DiffStation - Diff.
Reference
Station ID

15. Table of Fix Status
Filed No. Example Format Name Unit Description
15 *5B hexadecimal cs - Checksum
16 - Character <CR><LF> - Carriage
Fix Status Description
0 No Fix / Invalid
1 Standard GPS(2D/3D)
2 Differential GPS
6 Estimated (DR) Fix

16. Various components used in the project
The various components used in the
project are mentioned below
• U-Blox NEO-6M GPS Module
• RF Trans-receiver
• ILX232N IC
• RS232 Connector
• PC
• U-Center v8.10

17. U-Blox NEO-6M GPS Module
The GPS module receives signal
from the GPS satellites and
provides data in NMEA format. The
baud rate of the GPS module is
normally 9600.

18. RF Trans-receiver
This module is basically used for wireless communication purpose. It works
on frequency of 433MHz. It uses ASK and FSK for modulation purpose. The
module has two sections receiver and transmitter. The transmitter transmits
the data in form signal while the receives the transmitted data.

19. ILX232N IC
The ILX232N IC used for the shifting of voltage level from 0-3V to 0-5V
voltage level. It is necessary for interfacing the data with computer.

20. RS232 Connector
The RS232 is a 9 pin communication port. In our project we have connected
this connector for sending data from the receiver section to the PC for further
data processing. Here only three pins are used those are Rx, Tx and GND pin.
The other pins are left free as those are not required.

21. PC
The PC stands here for Personal Computer or simply computer. The PC is
an essential part in our project. The received from the GPS module is
finally interfaced with Google Map in PC itself. Apart from this the GPS
module can be configured for various functions using the u-center software
in PC. The computer we are using for our project does not have a 9 pin
RS232 COM PORT. So one USB to RS232 9 pin converter cable is also
used in the connection.

22. U-Center Software
• Export data files to Google Earth and Google Maps.
• Supports (Multiple GNSS) AssistNow Online and AssistNow Offline.
• Data recording and playback function.
• Structural and graphical data visualization in real-time.
• Export functionality to standard PC applications.
• Docking views (real-time cockpit instruments): Satellite constellation,
compass, clock, altimeter, speedometer, GNSS and satellite information
views.
• Download firmware updates to GNSS positioning modules.

23. Block diagram
The block diagram of the project is shown blow. It shows a
simplified representation of the project work. In the project the GPS
data is transmitted and received through the RF trans-receiver for
wireless communication. The data is then fetched in the computer
through the interfacing with ILX232N IC. For interfacing RS232
protocol is also used. Finally in the PC u-center software is used for
interfacing with Google Map.

24. Circuit Diagram

25. Circuit Description
The GPS receiver is basically a three terminal module. The two terminals
are for power supply with 3V and ground connection. The other terminal is
for data transmission purpose. In the module used in the project a receiver
terminal is also there. This plays a role when the configuration of the GPS
module is required. By default the module transmits data with 9600 baud
rate in NMEA format. Now from the power supply it is obvious that the
voltage level of the transmitted data is in between 0V to 3V. Now this data
is transmitted through the RF transmitter. The RF transmitter we are using
here is R433A module.
In the receiver section the data transmitted by the transmitter is received.
Since the voltage level is in the 0-3V range we use another IC ILX232N.
The connections are made as per the circuit diagram and thus we receive a
compatible voltage level to connect with the computer. Finally in the
computer u-center software is used for evaluation and various processing.
The data is interfaced with Google Map to show the GPS receiver location.

26. Results and Discussions
The following diagram shows the signal received from GPS receiver. The
signal that is generated by the GPS receiver is monitored by the
Oscilloscope and its frequency is found to be around 5 KHz. The mean
voltage is 1.64V with a peak to peak voltage of 4.44V.

27. Signal from RF receiver
The transmitted signal is effectively received by the RF receiver. The
received signal has a frequency of around 3 KHz with a mean voltage of
3.36V. The peak to peak voltage is 5.20V.The following is the output of the
test signal that is transmitted from RF Tx.

28. Signal from the IC
The signal received in the receiver section is fed to the ILX232N IC. The
IC changes the voltage level of the signal to make it suitable for interfacing
with PC. The signal has frequency of around 3KHz with mean voltage 0.
The peak to peak voltage is 14.88V.

29. Final output from the PC
Finally the data is received in the computer. Here the GPS data is
interfaced with Google Map using the u-center software. The following
image shows the result

30. Another work is done in the interfacing aspect. A local map image is taken
and it is calibrated using the software according to the specific longitude
and latitude value and the result is obtained as follows.

31. Reasons for error
• Ionosphere and troposphere delays
• Signal multi path
• Receiver clock errors
• Orbital errors
• Number of satellites visible
• Intentional degradation of the satellite

32. Conclusion and Future Scope
Conclusion
In this project we have firstly tested the GPS module by monitoring the
data in oscilloscope. Then we have connected the GPS module with the PC
through a USB to TTL converter module. The data is seen on the u-center
software in message view and other view. The data is in the NMEA format.
Then we have successfully used the RF trans-receiver for wireless
communication. This is a 433MHz RF module. The module uses ASK for
data transmission. Then we have implemented ILX232N IC for voltage
level shifting to make it compatible for interfacing with PC. For connecting
with PC RS232 communication port is used. Finally in the PC we have
successfully made the interfacing with the Google Map through u-center
software. A local map is also calibrated for showing the location.
5.2 Future Scope
In our project we have used RF trans-receiver for the wireless
communication purpose. It restricts the range of the system within 50- 100
m range. This can be improvised by using a GSM module to increase the
range of the system. The current system can be cascaded with other system
for automatic motion control in sophisticated areas.

33. Utilities
The current system can be independently used for location tracing in a
small area under observation. This can be beneficiary in sophisticated areas
like various industries and high security places. The system can also be
cascaded with any moving vehicle for automatic movement in a small
region of interest. This can be helpful in various industries for automatic
vehicle movement purpose.

34. REFERENCE
References
Books:
[1] James Bao Yen Tsui, “Fundamentals of Global Positioning System
Receivers: A Software Approach”, a wiley interscience publication john
wiley & sons, inc. 2000.
Journals:
[1] Hayward R, Marchick A, Powell J.D., “Single baseline GPS based attitude
heading reference system (AHRS) for aircraft applications”, American
Control Conference, volume 5, IEEE, 1999
[2] Pochmara J, Palasiewicz J, Szablata P, “Expandable GSM and GPS
systems simulator”, Mixed Design of Integrated Circuits and Systems
(MIXDES), IEEE, 2010
[3] Tae Hee Kim, Cehon Sig Sin, Sanguk Lee, Jae Hoon Kim, “Analysis of
performance of GPS L1 signal generator in GPS L1 signal”, IEEE, 2014
Websites:
[1] http://www.bms.by/eng/spec/PDF/ILX232_e.pdf
[2]http://www.u-blox.com/en/evaluation-tools-a-software/u-center/u-
center.html

35. Thank you