USE OF GPS METHODOLOGY IN CELLPHONE Submitted to Dr. Ahmed El-Rabbany Professor of Geometrics Engineering Department of Civil Engineering Ryerson University Submitted by: Atique Ahmed ID # 989056528 Images courtesy of USDoD and writer
<ul><li>Overview GPS operations </li></ul><ul><li>How does receiver work ? </li></ul><ul><li>How does Cell Phone built-in GPS receiver work? </li></ul><ul><li>Cell Phones Methodology to use GPS </li></ul><ul><li>Features of Cell Phones using GPS </li></ul><ul><li>Conclusion </li></ul><ul><li>Case Study </li></ul>Objectives:
OVERVIEW GPS OPERATIONS What does GPS ? GPS was originally intended for military applications, but in the 1980s, the US DoD made the system available for civilian use. GPS works in any weather conditions, anywhere in the world, 24 hours a day. There are three Satellite Navigation systems; GPS, GLONASS and GALILEO. I would reflect GPS only. GPS was developed in the 1970s GPS is satellite navigation system used to know specific location and time almost anywhere on the globe.
<ul><li>There are unlimited applications to use GPS. But I would elaborate following extent only: </li></ul><ul><li>If you buy 4G cell phone; GPS receiver is inclusively built-in with it. </li></ul><ul><li>If you buy a new car since 2009, GPS navigation system also included with it. </li></ul><ul><li>Latest still cameras have a built-in GPS features. When you take a photo it tells you the latitude and longitude of where you were and stamps that information on the photo. </li></ul>APPLICATIONS OF GPS
<ul><li>Following are few features of GPS approach: </li></ul><ul><li>If radio frequency tag is attached to multi-story warehouse bin of items then its location can be precised using GPS system. </li></ul><ul><li>If employees card has radio frequency tag attached, he/she can be traced out during on or off duty. </li></ul><ul><li>In hospitals new born babies cannot be lost or abducted anymore due to GPS system. </li></ul>APPLICATION’S FEATURES
HOW RECEIVERS WORK? The GPS receiver and satellite generate the same pseudo-random code at exactly the same time. When the code arrives from the satellite, the time difference is compared to the same code generated by the receiver. This difference is multiplied by the speed of light 299,729,458 m/s (186,000 miles per second) to determine the distance to the satellite. (Note: Considering there is no GPS errors or biases interface)
HOW RECEIVERS WORK?.... Pseudo-random code generated by receiver Pseudo-random code generated by satellite Time difference Image courtesy to Nokia website
CALCULATION METHODOLGY Let suppose a driver travels from Toronto to Niagara Fall city, triangulation is a trigonometry function helps us to find the distance to a destination point using known angle and sides of a triangle. Measures distance using law of Cosine 20100 ? Calculate the distance from A to B ( C ) using Law of Cosine 19 0 20000 Suppose a satellite (S ) is from 20100 KM away from a point A (Toronto) and 20000 KM from point B (Niagara Fall City). B = Niagara falls A = Toronto S = Satellite
CALCULATION METHODOLGY By inserting the values in equation we find that C2 is equal to (20000)2 + (20100)2 – 2(20000)(20100) Cos(19deg). Measures distance using law of Cosine As Cellphone receiver does not measure angles, but they calculate the time in which signal took to reach Cellphone receiver. By simplifying, we calculated C 2 is equal about 1,000KM or C = 100KM This example helps us how to GPS on Cellphone determine the distance from one point to destination point.
USE OF TRILATERATION Trilateration is the method using measured distance from three satellites to cell phone receiver. When the distances from three different satellites are obtained in Cellphone receiver then using trilateration method, position of the receiver can be measured. HOW GPS RECEIVER WORKS?
Using Trilateration Mythology Intersection Point Providing location HOW GPS RECEIVER WORKS?
Understanding Errors and Biases Light Refraction: Sometimes the GPS signal from the satellite doesn’t follow a straight line. Refraction is the bending of light as it travels through one media to another. HOW GPS RECEIVER WORKS?
Differential Correction Differential correction is a technique that greatly increases the accuracy of the cellular collected GPS data. It involves correlation of Cell Phone receiver with base station - like Fido, Bell, or TELUS. Satellite signals use L1 and L2 to communicate with cellular while Base Stations use CDMA - Code Division Multiple Access at 1900 MHz. CELL PHONE METHODOLOGY USING GPS
Differential GPS System Photo courtesy to Google Base Station-Tower CELL PHONE USING GPS…. Differential Global Positioning System (DGPS) is an improvement to Global Positioning System data received by cellular receiver. The Cellular Receiver correct their pseudoranges by synchronizing with base stations. The correction signal is typically broadcast over UHF radio modem.
Differential Correction Cell phones & Service Provider: User + Service Provider + Satellite Link Images courtesy to Clip Art & iPhone CELL PHONE USING GPS….
4G Cell phones converts RF to digital signals User + Service Provider + Satellite Link Digital Signals Service Provider Processor RF Images courtesy to clip art & iPhone CELL PHONE USING GPS….
Cellular system is very attractive to use in: 911 For emergency calls AVL Automatic Vehicle Location RTK GPS Real Time Kinematic Real Time Kinematic (RTK) is a technique used to measure carrier phase for GPS satellite navigation. GPS and Cellular Integration FEATURES OF CELL PHONE USING GPS
Methodology How GSP Traced Phones <ul><li>There are limitations where Satellite signals are not available for Cellular Phones. </li></ul><ul><li>RFID tags attached to every single phone facilitate to remain in contact with their B.S. </li></ul><ul><li>Using this technology, wireless network base station can locate precisely phones location always if its power is on. </li></ul><ul><li>The caller’s location can be further précised if the signal is received by minimum of three surrounding base stations. </li></ul>FEATURES OF PHONE USING GPS….
CONCLUSION A reference station (base station and tower) calculates differential corrections for its own location and time. Phones would remain in contact with their respective base stations up to 370 km (200 miles) from the station. However, some atmospheric errors and biases vary this space: specifically, satellite ephemeris errors and those introduced by ionospheric and tropospheric distortions. For this reason, the accuracy of DGPS may decreases with distance from the reference station.
Case Study How does iPhone work with GPS Developer: Apple Inc. Manufacturer: Foxcom & Pegatron Model 3G or 4G Built in GPS Receiver CDMA Mode enable UMTS/OSM enable Network 2.4 GHz at 802.11 b/g/n GPS enable with A-GPS support Simcard: MicroSIM card support CPU – A4 (ARM cortex-A8) dual core RAM 512 KB Storage memory: 8-32 GB Frequency response: 20Hz to 20KHz Power Li-ion battery 3.7V Software iOS 4.3.1 CDMA Application: Google Maps and Digital compass
Useful Acronyms using iPhone CDMA = Code Division Multiple Access UMTS = Universal Mobile Telecommunication System (Terrestrial Radio Access Network) GSM = Global System for Mobile-communication iOS = iPhone Operating System CPU = Central Processing Unit (ARM-Cortex – A8) RAM = Random Access Memory
iOS- iPhone Operating System <ul><li>iOS is derived from Mac OS X, with which it </li></ul><ul><li>shares the Darwin foundation, and is therefore </li></ul><ul><li>a Unix-like operating system by nature. </li></ul><ul><li>iOS front panel has 18 gestures ready to use </li></ul><ul><li>iOS capable to run 300,000 Applications </li></ul><ul><ul><li>Can be download using iTunes </li></ul></ul><ul><li>GPS point of view </li></ul><ul><li>iOS is compatible with: </li></ul><ul><li>Google Mapping </li></ul><ul><li>Google search </li></ul><ul><li>Radio Frequency – 850 – 1900 MHz </li></ul><ul><ul><li>Can Synchronize L1, L2 and L5 </li></ul></ul><ul><ul><li>L1 (1575.42 MHz) </li></ul></ul><ul><ul><li>L2 (1275.50 MHz) </li></ul></ul><ul><ul><li>L5 (1176.45 MHz) </li></ul></ul><ul><li>Networking: 2.4 GHz </li></ul><ul><li>SMS: Compatible with MSOS </li></ul><ul><li>Quad-band = UMTS/HSDPA/HSUPA/CDMA </li></ul>Image courtesy to iPhone