Introduction to the Global Positioning System Introduction to the Global Positioning System Pre-Work GPS for ICS - 2003.

Slides:



Advertisements
Similar presentations
 Global  Positioning  System  Department of Defense developed for navigation  Standard positioning service (public uses)  Precise positioning service.
Advertisements

Introduction Introduction. Summary of Topics - GPS - WAAS - Coordinate Systems - Datums.
Data Collection and Management with GPS & GIS Quentin Rund for the High Desert ESD.
Presenter- Dan Carey August 11 and 12, 2009.
Introduction to NAVSTAR GPS Introduction to NAVSTAR GPS.
GLOBAL POSITIONING SYSTEM FOR ENVIRONMENTAL MANAGEMENT.
Background Accessibility Popularity of GPS and INS –Cell phones Apple iPhone, Blackberry, Android platform –Nintendo Wii Wii Remote, MotionPlus.
Basic Principles of GPS Mathias Lemmens EU GIS/Mapping Advisor Abuja 4 th August 2005.
Introduction.
Surveying with the Global Positioning System Code Pseudo-Ranges
Global Positioning System. The History of GPS Feasibility studies begun in 1960’s. Pentagon appropriates funding in First satellite launched in.
What is GPS? GPS, which stands for Global Positioning System, is the only system today able to show you your exact position on the Earth anytime, in any.
PRESENTATION BASED ON GPS. Introduction To GPS Introduction To GPS.
GPS Receivers: Basics and Selection T.S. Stombaugh, J.D. Luck and S.A. Shearer Biosystems and Agricultural Engineering University of Kentucky.
Patrick Caldwell Chris Kellar. Overview  Basic Concepts  History  Structure  Applications  Communication  Typical Sources of Error.
Field Methods in Geospatial Science I: GPS and GIS tools (BOT 4810/5810, Section 200)
GPS Global Positioning System Lecture 11. What is GPS?  The Global Positioning System.  A system designed to accurately determining positions on the.
GLOBAL POSITIONING SYSTEM
ESSC Lecture 1/14/05 1 Global Positioning System (GPS)
GPS Concepts June 21, Control Segment 1- Satellite/Space Segment 3- User Segment 3 Main Segments to any GNSS Monitor Stations Ground Antennas.
Geographic Information Systems
How Global Positioning Devices (GPS) work
Global Positioning System Applications in Agriculture.
INTERNATIONAL INSTITUTE FOR GEO-INFORMATION SCIENCE AND EARTH OBSERVATION The Global Positioning System Bart Krol / Jeroen Verplanke.
Intro. To GIS Lecture 4 Where does spatial data come from? February 20 th, 2013.
Global Positioning Systems GPS
Introduction to the Global Positioning System Introduction to the Global Positioning System Pre-Work GPS for Fire Management
Dr.B.R.AMBEDKAR NATIONAL INSTITUTE OF TECHNOLOGY, JALANDHAR Department of Electronics and Communication Introduction to Global Positioning System By- ANKIT.
GLOBAL POSITIONING SYSTEMS. Introduction Geographic Positioning Systems have in many ways taken taken over the need to know where you are going. You.
Global Positioning System
Intro to GIS Spring  GPS = Global Positioning System  GNSS = Global Navigation Satellite Systems  Satellite based technologies that give location.
GPS: Global Positioning System  The Geographer’s best friend!  You can say with confidence… “I’m not lost!, I’m never lost!”* *Of course, where everybody.
Precision Agriculture: GPS and Differential Corrections.
Global Positioning Systems Glen T. Huettl Agricultural Education Garrison High School.
Networked Systems Practicum Lecture 8 – Localization 1.
Global Positioning System
West Hills College Farm of the Future. West Hills College Farm of the Future GLONASS Russia’s global satellite navigation system 24 satellites in three.
By Andrew Y.T. Kudowor, Ph.D. Lecture Presented at San Jacinto College.
What is GPS?. GPS  Global Positioning System  Network of 24 satellites (with spares)  Developed by Department of Defense  Operational 24 hours/day.
NAVSTAR GPS Mike Mickelson KD8DZ 08 Dec GPS BASICS.
Introduction to the Global Positioning System Introduction to the Global Positioning System GPS.
CRGIS Global Positioning Systems The Basics CRGIS National Park Service.
Introduction to GPS/GNSS Introduction to Tidal and Geodetic Vertical Datums Corbin Training Center January 7, 2009 Jeff Little Guest Speaker ,
Introduction To Localization Techniques (GPS)
GPS NAVSTAR (Navigation System with Timing And Ranging), known as GPS (Global Positioning System), launched by U.S. Department of Defense for military.
GPS Global Positioning System. What is GPS?  The Global Positioning System.  A system designed to accurately determining positions on the earth  The.
Lecture 11: Global Positioning System (GPS) Lecture 11: Global Positioning System (GPS)
Global Positioning System
Precision Agriculture: GPS and Differential Corrections.
Flight Planning and Navigation GPS Navigation © 2011 Project Lead The Way, Inc.Aerospace Engineering.
West Hills College Farm of the Future. West Hills College Farm of the Future Precision Agriculture – Lesson 2 What is GPS? Global Positioning System Operated.
Chapter 2 GPS Crop Science 6 Fall 2004 October 22, 2004.
 Fully-functional satellite navigation system  Orbiting navigational satellites › Transmit position and time data  Handheld receivers calculate ›
GPS Receivers University of Manitoba University of Manitoba Recreation Services GPS Workshop. Recreation Services GPS Workshop.
Introduction to NAVSTAR GPS Introduction to NAVSTAR GPS Charlie Leonard, 1999 (revised 2001, 2002)
Where am I?. Each satellite constantly sends out the current time as a message contained within radio waves Speed of light = 3X10 8 meters/second.
Yacht Navigation Support Systems Communications and Networking Systems Prof. Igor Bisio DITEN Via Opera Pia 13, 16145, Genoa Tel Fax
Introduction to the Global Positioning System Introduction to the Global Positioning System.
SURVEYING Subject Code : Presented By : Topic : GPS ( ) ( ) ( )
Revised 10/30/20061 Overview of GPS FORT 130 Forest Mapping Systems.
… Presented By DEEPAK KUMAR-10/ECE/54 Index INTRODUCTION HISTORY HOW IT WORKS? APPLICATION CONCLUSION.
A GADGET WHICH CHANGED THE WAY THE WORLD OPERATES Global Positioning System Seminar by: B V Aparna ECE CMR College of Engg. And Tech.
The Global Positioning System
Global Positioning System
GPS: Global Positioning System
Global Positioning System
Global Positioning System Supplemental from JD Text
Introduction To GPS.
Global Positioning System
Presentation transcript:

Introduction to the Global Positioning System Introduction to the Global Positioning System Pre-Work GPS for ICS

 Describe at least three sources of GPS signal error, and ways to mitigate or reduce those errors.  Identify the three segments of the Global Positioning System and describe the purpose of each.  Describe two technologies that enhance the accuracy of GPS positioning and collected position data.  Describe the process a GPS receiver uses to triangulate its position.  Identify the four main functions of the GPS.  Successfully complete the Pre-Work Test. Pre-Work Objectives

 A very brief history of navigation  A brief history of the Global Positioning System  Segments of the GPS  A primer on how the GPS works  Problems with the GPS  Advancements in the GPS Unit A Lesson 1 Pre-Work Outline

The History of GPS

How the GPS Works

Control Segment Space Segment User Segment Three Segments of the GPS Monitor Stations Ground Antennas Master Station

Kwajalein Atoll US Space Command Control Segment Hawaii Ascension Is. Diego Garcia Cape Canaveral Ground Antenna Master Control Station Monitor Station

Space Segment

 Military.  Search and rescue.  Disaster relief.  Surveying.  Marine, aeronautical and terrestrial navigation.  Remote controlled vehicle and robot guidance.  Satellite positioning and tracking.  Shipping.  Geographic Information Systems (GIS).  Recreation. User Segment

 Position and coordinates.  The distance and direction between any two waypoints, or a position and a waypoint.  Travel progress reports.  Accurate time measurement. Four Primary Functions of GPS

Position is Based on Time T + 3 Distance between satellite and receiver = “3 times the speed of light” T Signal leaves satellite at time “T” Signal is picked up by the receiver at time “T + 3”

Pseudo Random Noise Code Receiver PRN Satellite PRN Time Difference

What Time is it Anyway? Zulu Time Military Time (local time on a 24 hour clock) Universal Coordinated Time Greenwich Mean Time Local Time: AM and PM (adjusted for local time zone) GPS Time - 13* * GPS Time is currently ahead of UTC by 13 seconds.

Signal From One Satellite The receiver is somewhere on this sphere.

Signals From Two Satellites

Three Satellites (2D Positioning)

Triangulating Correct Position

Three Dimensional (3D) Positioning

Selective Availability (S/A)  The Defense Department dithered the satellite time message, reducing position accuracy to some GPS users.  S/A was designed to prevent America’s enemies from using GPS against us and our allies.  In May 2000 the Pentagon reduced S/A to zero meters error.  S/A could be reactivated at any time by the Pentagon.

Sources of GPS Error Standard Positioning Service (SPS ): Civilian Users SourceAmount of Error  Satellite clocks:1.5 to 3.6 meters  Orbital errors:< 1 meter  Ionosphere:5.0 to 7.0 meters  Troposphere:0.5 to 0.7 meters  Receiver noise:0.3 to 1.5 meters  Multipath:0.6 to 1.2 meters  Selective Availability(see notes)  User error:Up to a kilometer or more Errors are cumulative and increased by PDOP.

Sources of Signal Interference Earth’s Atmosphere Solid Structures Metal Electro-magnetic Fields

Receiver Errors are Cumulative! User error = +- 1 km System and other flaws = < 9 meters

Using GPS Receivers for Positioning and Navigation

XTE (CDI) N (000 0 ) (0 0 ) N Desired Track (DTK) (x º ) Active Leg Distance to Waypoint Bearing (X 0 ) Present Location Speed Over Ground (SOG) Tracking (TRK) (x º ) Active GOTO Waypoint GPS Navigation Terminology Course Made Good (CMG) (CMG) (x º ) Active From Waypoint

Active GOTO Waypoint Bearing = Course Over Ground (COG) = Cross Track Error (XTE) = Location Where GOTO Was Executed Bearing = 65 0 COG = 5 0 XTE = 1/2 mi. Bearing = 78 0 COG = XTE = 1/3 mi. Bearing = 40 0 COG = XTE = 1/4 mi. Active Leg N GPS Navigation: On the Ground

Position Fix  A position is based on real-time satellite tracking.  It’s defined by a set of coordinates.  It has no name.  A position represents only an approximation of the receiver’s true location.  A position is not static. It changes constantly as the GPS receiver moves (or wanders due to random errors).  A receiver must be in 2D or 3D mode (at least 3 or 4 satellites acquired) in order to provide a position fix.  3D mode dramatically improves position accuracy.

Waypoint  A waypoint is based on coordinates entered into a GPS receiver’s memory.  It can be either a saved position fix, or user entered coordinates.  It can be created for any remote point on earth.  It must have a receiver designated code or number, or a user supplied name.  Once entered and saved, a waypoint remains unchanged in the receiver’s memory until edited or deleted.

Planning a Navigation Route Start = Waypoints

How A Receiver “Sees” Your Route Yellow stars: where you want to go. Green stars: where the GPS receiver may take you. Blue circles: the potential circle of GPS error at each waypoint.

GPS Waypoint Circle of Error X

GPS Dilution of Precision and Its Affects On GPS Accuracy

GPS Satellite Geometry  Satellite geometry can affect the quality of GPS signals and accuracy of receiver trilateration.  Dilution of Precision (DOP) reflects each satellite’s position relative to the other satellites being accessed by a receiver.  There are five distinct kinds of DOP.  Position Dilution of Precision (PDOP) is the DOP value used most commonly in GPS to determine the quality of a receiver’s position.  It’s usually up to the GPS receiver to pick satellites which provide the best position triangulation.  More advanced GPS receivers can filter out poor DOP values.

Ideal Satellite Geometry N S W E

Good Satellite Geometry

Poor Satellite Geometry N S W E

Differential GPS  Realtime  Post process

DGPS Site x+30, y+60 x+5, y-3 True coordinates = x+0, y+0 Correction = x-5, y+3 DGPS correction = x+(30-5) and y+(60+3) True coordinates = x+25, y+63 x-5, y+3 Real Time Differential GPS DGPS Receiver Receiver

USCG NDGPS Ground Stations National Differential Global Positioning System Yellow areas show overlap between NDGPS stations. Green areas are little to no coverage. Topography may also limit some areas of coverage depicted here.

USCG NDGPS Ground Stations National Differential Global Positioning System Yellow areas show overlap between NDGPS stations. Green areas are little to no coverage. Topography may also limit some areas of coverage depicted here.

Wide Area Augmentation System Geostationary WAAS satellites GPS Constellation WAAS Control Station (West Coast) Local Area System (LAAS) WAAS Control Station (East Coast)

How good is WAAS? meters +-15 meters With Selective Availability set to zero, and under ideal conditions, a GPS receiver without WAAS can achieve fifteen meter accuracy most of the time.* Under ideal conditions a WAAS equipped GPS receiver can achieve three meter accuracy 95% of the time.* * Precision depends on good satellite geometry, open sky view, and no user induced errors.