design and develop gps system for applications use in positioning and navigation

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ĐẠI HỌC BÁCH KHOA HÀ NỘI

TRƯỜNG ĐIỆN - ĐIỆN TỬ

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LIST OF SIGNS AND ABBREVIATIONS

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LIST OF FIGURES

Figure 0.1 fg1 . . . . 1Figure 3.1 Maps produced from a GPS receiver . . . . 4Figure 3.2 System architecture of the GPS error sharing framework using

vehicular blockchain. . . . 5Figure 3.3 Types of GPS receiver . . . . 9Figure 3.4 QPS future in the US . . . . 10

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Febru-CHAPTER 1: INTRODUCTION

The U.S. Department of Defense created and maintains the satellite-based radionavigation system known as the Global Positioning System (GPS). Everyone is welcometo use the GPS satellites for no cost. Any number of land, sea, air, and space users whoare properly equipped can receive accurate position, velocity, and time (PVT) informa-tion through GPS. The way a GPS satellite operates is by sending signals to equipmenton the ground (Fig. 1). GPS receivers do not transmit; instead, they passively receivesatellite signals. Since GPS receivers must have a clear view of the sky to function prop-erly, they are only used outside and may not be as accurate in densely wooded areas orclose to towering structures (TomTom, 2015). Atomic clocks in the U.S. offer the highlyprecise time reference needed for GPS functioning. Military Observatory. There areatomic clocks on board each GPS satellite. Using a network of satellites, the Global Po-sitioning System (GPS) enables users of GPS receivers to determine their exact locationin any part of the globe.

Figure 0.1 Figure 1

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CHAPTER 2: SATELLITE SELECTION

Satellite Choice A typical satellite tracking sequence, according to Navstar (1996),starts with the receiver deciding which satellites are visible for it to monitor. The re-ceiver will target a satellite to track and start the acquisition procedure if it can quicklyidentify satellite visibility.The GPS satellite almanac, the initial receiver estimate of timeand position, or user input, are used to determine satellite visibility.

The receiver initiates a "search the sky" operation that repeatedly searches the PRNcodes until lock is established on one of the satellites in view if the receiver does not al-ready have the almanac and position information recorded.The receiver can demodulatethe navigation message data stream and obtain the current almanac as well as the condi-tion of every other satellite in the constellation after successfully tracking one satellite.A receiver either chooses the "best" subset of the visible satellites to track, dependingon its architecture, or employs every healthy satellite in view to calculate a "all-in-view"PVT solution. Even while an all-in-view system necessitates a more complicated re-ceiver and reception processing, it is typically more accurate than a four satellite ap-proach. The all-in-view method is also more reliable because PVT data continues toflow while the receiver tries to reacquire a lost satellite signal (for instance, if there isa physical blockage close to the receiver). In order to balance complexity, accuracy,and robustness, many receivers track more than four satellites but fewer than all-in-view.According to geometry, estimated accuracy, or integrity, receivers that choose a "best"subset do so (Navstar, 1996).

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CHAPTER 3: APPLICATION

GPS has developed into a widely used and practical instrument for business, ence, tracking, and spying. By enabling well-synchronized hand-off switching, it simpli-fies routine tasks like banking, using mobile devices, and even managing power grids.This technology can also be used to measure buildings, help resolve land ownershipdisputes, study the movements and feeding habits of deer, aid marine archaeologists intheir research, and in other fields (GPS data showed that Mt. Everest is growing taller)(Kaplan, 2011).

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sci-CHAPTER 4: DEVELOPMENT

The American military developed GPS. The first satellite was launched in ary 1978 after development began in the 1960s. The Magellan Corp. unveiled the firstportable GPS receiver in 1989. President Ronald Reagan approved the unrestricted civil-ian use of GPS in 1996 (America.gov, 2006). The US Federal Government is dedicatedto giving GPS technology away for free to benevolent organizations all around the world.Since its introduction, the United States has made a number of improvements to the GPSservice, including adding new signals for civil use and enhancing its accuracy and in-tegrity for all users while still maintaining backward compatibility with earlier GPSdevices. The U.S. Department of Defense has been working on modernizing the satellitesystem through a number of satellite purchases to satisfy the expanding requirementsof the military, civilian population, and commercial market. Although several factors,including receiver quality and atmospheric difficulties, can affect this accuracy, high-quality, FAA grade Standard Positioning Service (SPS) GPS receivers offer horizontalaccuracy of greater than 3.5 meters as of early 2015 (GPS Accuracy, 2015). The Amer-ican government owns and manages GPS as a national asset.

Febru-Figure 3.1 Maps produced from a GPS receiver

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CHAPTER 5: SYSTEM MODEL1. Positioning Scenarios and System Architecture

Generally speaking, there are two types of vehicles,i.e.,common vehicles and rich vehicles, driving on the road. Among them, common vehicles can only obtain po-sition information through GPS. In addition to GPS, sensor-rich vehicles can also beassisted by other on-board sensors, such as camera and Lidar. Assume that the GPS re-ceivers of the two types of vehicles are the same. All vehicles can access the MECNs torequest service within the communication range.The MECNs have enough storage spaceand computing power,which store accurate location information of the infrastructure inthe area (e.g.,landmark), as shown in:

sensor-Figure 3.2 System architecture of the GPS error sharing framework using vehicularblockchain.

When a sensor-rich vehicle approaches the landmark,the distance and angle between self and the landmark can be obtained by on-board sensors. And the position of thelandmark can be used to calculate the current position of the vehicle. For vehicle ,ithe GPS position is expressed as Pi=< pe

l+ dil∗ cos θil

p′ni = pn

where Pl=< pel, pn

l>is the position of landmark l, diland θilare the distance and anglebetween vehicle i and landmark l, respectively. Currently, on-board sensors have relative

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where Esand Erare the systematic errors and random error, respectively. Particularly,the systematic error mainly includes satellite orbit error, satellite clock error, ionosphericdelay,tropospheric delay,receiver clock error and receiver position error, providing thesame error magnitude and direction for each GPS receiver within a certain range, about50200km.The random error mainly includes multi-path effect error and receiver noise.Usually, random error Eris much smaller than the systematic error Es[43], [44].For vehicles i and j that are driving on the same road at similar times, their relative error||∆Ei j|| is satisfied:

||∆Ei j|| = (P|| i− Pj)|| − || P( ′i)|| <= || P( i− Pj) − (P′ i− P′j|| <= ||Ei− Ej|| (3.4)where Pi, Pj, P′i, P′j, Eiand Ejare the GPS position, accurate position and GPS posi-tioning error of vehicle i and vehicle j, respectively. According to (3) and (4), we can get:

||∆Ei j|| <= (E|| si+ Eri) − (Es j+ Er j)|| <= E|| si− Es j|| + E|| ri− Er j|| (3.5)where E Esi, s jand Er jare systematic errors and random error of GPS positioning ofvehicle i and vehicle j, respectively. For the same type of GPS receiver, the positioningerror radius is fixed. In addition, at similar moments, the satellite combinations that canbe observed by each vehicle are basically the same. Therefore, when using the samesatellite combination for positioning, the satellite position deviation caused by satellite

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clock difference, atmospheric delay, etc.,is almost the same. Moreover, for two vehicleswith similar positions, the difference in position between vehicles is negligible relativeto the distance from the vehicle to the satellite.In this paper, vehicles for cooperativepositioning and common vehicles are considered to be on the same road segment, thatis, between two intersections, and generally less than 2 km. Therefore, in this case, thesystematic error can be considered to be almost the same, that is, Esi≈ Es j. Bring it into(5) to get:

||∆Ei j|| <= E|| ri− Er j|| (3.6)Since random errors Erare quite small compared to sys-tematic errorsE Es, iEjcanbe considered in this case.

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CHAPTER 6: INVIRONMENT

GPS data collection systems complemented with GIS packages provides a meansfor comprehensive analysis of environmental concerns. Environmental patterns andtrends can be efficiently recognized with GPS/GIS data collection systems, and thematicmaps can be easily created. GPS data can be quickly analyzed without the preliminaryrequirement for field data transcription into a digitized form. Accurate tracking of envi-ronmental disasters such as fires and oil spills can be conducted more efficiently. Precisepositional data from GPS can assist scientists in crustal and seismic monitoring. Mon-itoring and preservation of endangered species can be facilitated through GPS trackingand mapping.

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CHAPTER 7: TYPES OF GPS RECEIVERS

Numerous receivers are produced by various businesses. Depending on the ware at their disposal, they carry out various tasks. The right software can be purchasedor downloaded from the internet. When the proper software is used, a receiver like theone in Figure 2 can scan maps and, if a GPS is connected, it can directly draw trails onthe map and send them to the GPS.Photos look exactly where they are taken. In anothertypical example, a receiver can combine CAD, GIS and GPS data over a map. Distance,area, location can be measured and calculated.

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soft-CHAPTER 8: FUTURE OF GPS

The US modernization initiative is ongoing, and significant effort is being made toupgrade the GPS space and control segments with new features in order to increase itsperformance

Figure 3.4 QPS future in the US

Modern technologies are being introduced to the space and control segments aspart of the modernization, which will improve overall performance. A network-centricarchitecture is replacing antiquated computers and communications infrastructure to en-able more frequent and accurate satellite commands that will increase accuracy for all.A succession of subsequent satellite acquisitions, including GPS IIR(M), GPS IIF, andGPS III, are part of the GPS modernisation effort. The Next Generation OperationalControl System (OCX) and the Architecture Evolution Plan (AEP) are two more GPScontrol segment enhancements. Below is a timeline for the modifications to the controlsegment and parallel space. There are a couple of things that will emerge over the nextcouple of years. All mobile devices will be able to integrate GPS very cost-efficiently.Cell phones will be the most important driver of GPS adoption over the next couple ofyears. As the carriers roll out services and provide information based on location therewill be a major new segment that is opening up (Rojas, 2015). A GPS device will beused to track lost ones. In tax related issues, GPS devices will be used on every carand figure how many miles one traveled and when one get gas they can tax that person

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by miles driven. In a report by Fiedler (2015), the AllSport GPS route and mappingprogram allows you to track and map your bike rides, runs and other outdoor activities,including distance travelled, average speed, calories burned, etc. When an additionalsubscription application is used for cellphone, route can be automatically mapped viaGPS and uploaded to one the computer. Routes once covered or by other person can alsobe downloaded on the phone. This can be effectively used in determining the days’ runor ride.

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I’d want to thank Dr. Nguyen Tien Hoa and Ms. Bui Van Anh for their assistancewith latex and with helping me finish my report on "Technical writing and presentation."I also want to express my gratitude to the group 3 friends who gave these useful resourcesto me. I sincerely appreciate it.

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3. GPS.gov. (2015). GPS Accuracy. GPS.gov. Retrieved 4 May 2015.

4. Hoffman-Wellenhof, B., H. Lichtenegger and J. Collins. Global positioning system:theory and practice. New York, Springer-Verlag, c2001. 382 p. Kaplan (1996).Understanding GPS: principles and applications. Edited by Elliott D.

5. Kaplan. Boston, Artech House, c1996. 554 p. Navstar (1996).6. Navstar GPS user equipment instruction. Public release version.

7. Rojas Peter (2015). The Engadget Interview: Christian Bubenheim, general ager, Magellan Consumer Products. Engadget. AOL Inc.

man-8. The Library of Congress (2011). What is a GPS? How does it work? EverydayMysteries.

9. TomTom (2015). What is GPS? TomTom International BV

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