NR402 GIS Applications in Natural Resources

Size: px
Start display at page:

Download "NR402 GIS Applications in Natural Resources"

Transcription

1 NR402 GIS Applications in Natural Resources Lesson 5 GPS/GIS integration Global Positioning System (GPS)..a global navigation system that everyone can use What is GPS? How does it work? How accurate is GPS? GPS/GIS integration? This module explains how GPS works, sources of error, and error correction using real time or post processing differential correction. Cost and accuracy of different grades of GPS units are also part of this module. 1

2 Global Positioning System (GPS) Installed and maintained by U.S. Dept. of Defense Worldwide radio navigation system w/ constellation of GPS satellites and their ground stations NAVSTAR satellites (NAVigation Satellite Timing and Ranging) First launch 1978 Can be used for any application that requires location information. The Global Positioning System (GPS) was first launched in 1978 by the Department of Defense. The system includes a constellation of satellites (NAVSTAR) and ground control stations. GPS can be used by anyone and for any application that requires location information. 2

3 Components of GPS NAVSTAR satellites GPS receiver Earth s surface GPS requires three components: Direct connection to at least 4 NAVSTAR satellites, a GPS receiver, and location on or near (airplanes) the earth s surface. 3

4 GPS Satellite Constellation GPS satellite constellation 4

5 GPS Satellites and Orbits NR402 - GIS Applications in Natural Resources GPS satellites and orbits 5

6 GPS ground control stations NR402 - GIS Applications in Natural Resources Locations of GPS ground monitoring stations. These stations controls and monitors the satellite orbits and function. 6

7 How GPS works? GPS receivers calculate their position by measuring the time it takes for the signal to travel from the satellites to the receiver Satellite signals require a direct line to the GPS receiver Signals can not go through water, soil, walls or others GPS receivers calculate their position by measuring the time it takes for the signal to travel from the satellites to the receiver. Satellite signals require a direct line to the GPS receiver. Signals can not go through water, soil, walls or others. 7

8 How GPS works - 5 steps 1. Accurate measure of time for signal to travel from satellite to receiver 2. Speed of light X travel time = distance 3. Distance measurements to 4 satellites is necessary to compute a 3-D position through triangulation 4. Knowledge of satellite positioning 5. Corrections due to atmospheric influences and other errors The time it takes from the GPS signal to travel from the satellite to the receiver is measured and then converted to distance by multiplying with the speed of light. Distance measurements form 4 satellites is necessary to compute a 3-d position (including a reasonably accurate measure of elevation). A lower accuracy 2-D position can be computed from distance measurements from three satellites. Differential correction can be applied to the signal to correct for atmospheric and other errors. We will talk more about differential correction later in this lecture. 8

9 Triangulation The basic concept behind GPS is very simple and is based on a process called triangulation. One distance measurement narrows down the position to the surface of a sphere. 9

10 The second measurement. NR402 - GIS Applications in Natural Resources The second measurement narrows down the position to the intersection of two spheres. 10

11 A third measurement NR402 - GIS Applications in Natural Resources A Fourth measurement is needed for correction of timing offset. A third measurement narrows down the position to only two points. A fourth measurement narrows down the location to only one location. You can get a reasonable (less accurate) estimate of location with only three satellite measurements, however four satellite measurements are necessary for computation of altitude. 11

12 Measuring travel time NR402 - GIS Applications in Natural Resources GPS receivers and the NAVSTAR satellites are generating a synchronized code at exactly the same time. The receiver can back-calculate the time it took for the signal to travel from the satellite to the receiver by comparing the signal generated by the receiver and the signal sent from the satellite. 12

13 Satellite Signals NR402 - GIS Applications in Natural Resources each satellite transmits two signals - L1 & L2 microwave frequencies/wavelengths (L1 = MHz and L2 = MHz) L1 - carries precision code (P-code) along with a coarse acquisition code (C/A-code) L2 - carries only the P-code P-code much higher frequency - generates a much more accurate position Satellites transmit two signals L1 and L2. L1 - carries precision code (P-code) along with a coarse acquisition code (C/A-code), L2 - carries only the P-code. The P-code at a much higher frequency (10.23 MHz) - generates a much more accurate position compared to the C/A-code at MHz. High end mapping units, survey units and military units can receive the more accurate P-code while recreational grade units only receives the C/A-code. 13

14 GPS errors Atmospheric effects Measurement noise Ephemeris errors Satellite clock drift Multi-path effects Satellite geometry Selective Availability (turned off May 2000) Many contributing factors add to the error associated with acquisition of a GPS location. In the next few slides you will explore the sources and influence of the different errors on the total GPS error. The last bullet in the slide addresses the error introduced by Selective Availability. Selective Availability was a ~100 m error introduced to the GPS signal by the Department of Defense. Selective Availability was turned off in May 2000, and is currently not affecting the accuracy of GPS receivers. 14

15 Atmospheric refraction The ionosphere and troposphere both refract the GPS signals. This causes the speed of the GPS signal in the ionosphere and troposphere to be different from the speed of the GPS signal in space. Therefore, the distance calculated from "Signal Speed x Time" will be different for the portion of the GPS signal path that passes through the ionosphere and troposphere and for the portion that passes through space. 15

16 Multipath A GPS signal bouncing off a reflective surface prior to reaching the GPS receiver antenna is referred to as multipath. Because it is difficult to completely correct multipath error, even in high precision GPS units, multipath error is a serious concern to the GPS user. 16

17 Satellite geometry NR402 - GIS Applications in Natural Resources PDOP - Position Dilution of Precision Good PDOP (< 6) Higher accuracy Poor PDOP Lower accuracy PDOP is an indicator of the quality of the geometry of the satellite constellation. Your computed position can vary depending on which satellites are used for the measurement. Different satellite geometries affect the errors. A greater angle between the satellites lowers the PDOP, and provides a better measurement. A higher DOP indicates poor satellite geometry, and an inferior measurement configuration. PDOP under good conditions is below 6. The accuracy specification for a high end GPS unit is only valid when the PDOP is below a specified value (usually 6). 17

18 GPS error budget Source Ionosphere Troposphere Measurement Noise Ephemeris Data Clock Drift Multipath Uncorrected Error Level 0-30 meters 0-30 meters 0-10 meters 1-5 meters meters 0-1 meter (Selective Availability 0-70 meters) removed in May 2000 The error levels for different sources of GPS error are listed in the table above. Selective Availability was an error introduced by the Department of Defense, however this error was turned off in May of year Ephemeris data refers to imperfections in the satellite orbits. 18

19 Differential GPS NR402 - GIS Applications in Natural Resources.is used to correct for errors 1) Real-time differential correction 2) Post-processing Differential GPS (DGPS) incorporates a series of techniques to account for some of the GPS errors. Differential GPS can be applied on the fly (real-time differential GPS) or post-processing differential correction (correction applied to the GPS data after it has been collected). 19

20 Differential GPS NR402 - GIS Applications in Natural Resources Involves use of two receivers - one that s stationary (reference) and another rover errors are a compounding of factors, but receivers within 100km usually have same errors stationary receiver sits on a known location and back calculates what the timing should be, compares with what they are and develops error correction factor corrections are transmitted to rovers or differential corrections are made after field data collection - post-processing differential correction Both real-time and post processing differential correction involves two receivers, one that is stationary and one that is roving. The stationary unit collects data continuously and the location for this unit is therefore very accurate. The roving unit is carried by the navigator (mapper, surveyer, recreationist.). As you learned in previous slides GPS errors are influenced by many factors, but receivers within 100 km usually have about the same errors. The stationary receiver ate a precisely known location compares the current reading with the known location and can tereby compute a correction factor. In real-time differential GPS this correction factor is transmitted to the roving unit. The user of the roving unit reads the corrected GPS coordinates directly on the GPS display. In post-processing differential correction the correction factors are posted in a database, many are available via the Internet. The GPS data from the roving unit is downloaded to a computer and corrected using the information from the stationary unit (base-station). Post-processing can currently not be applied to recreational grade units. 20

21 Control for DGPS operations Base station networks - Forest Service, BLM, USGS, DOT, US Coast Guard WAAS Wide Area Augmented System by FAA (Federal Aviation Administration ) Omnistar and Landstar - commercial systems with base stations and satellite transmitters many new GPS receivers can accept corrections and many now with built-in radio receivers can be achieved by post-processing collected data Base station are located all over the country, commonly managed by the Forest Service, Bureau of Land Management, US Geological Survey, Department of Transportation or the US Coast Guard. Base station data used in post-processing differential correction can accessed at: WAAS is a system of 2 satellites and 25 ground stations that transmit a real-time differential correction signal to GPS units that are WAAS enabled. There are also two commercial satellite differential service providers, Thales Survey LandStar (formerly Racal LandStar) and OmniSTAR Inc.. These companies use a control hub where reference station data is checked, formatted, and uploaded to a geostationary satellite for broadcasting to subscribers for an annual fee. A beacon can be attached to many GPS units for reception of the real-time differential signal. One example is the Beacon on a Belt from Trimble: If you cannot receive a real-time differential correction signal, post-processing is another way to achieve differentially corrected data for higher end mapping units (not available for recreational units). 21

22 How does WAAS work? WAAS is based on a network of approximately 25 ground reference stations Two geo-stationary satellites serving the WAAS area ( POR (Pacific Ocean Region) and AOR-W (Atlantic Ocean Region-West) The message is broadcast from the satellite on the same frequency as GPS (L1, MHz) The WAAS will improve basic GPS accuracy to approximately 7 meters vertically and horizontally WAAS is a network of 25 ground stations and 2 geostationary satellites put up by the Federal Aviation Administration. The system broadcasts a real-time differential correction signal at no annual fee or registration requirements all you need is a WAAS enabled GPS unit. WAAS is not received everywhere or all the time. For GPS you can expect an improved accuracy of ~7 meters during the times the GPS unit receives the WAAS signal. Read more about WAAS: 22

23 The WAAS system Two geo-stationary satellites are presently serving WAAS WAAS ground station coverage is approximately 200km around these stations The WAAS system includes two geostationary satellites, one over the Atlantic and one over the Pacific, and 25 ground control stations. 23

24 GPS Base Stations Web access Base station data for post-processing differential correction can be accessed at: Read more about differential correction at: 24

25 GPS system Sportsman unit (Garmin, Magellan.. Sportsman unit DGPS Pocket PC w. GPS card Sportsman DGPS Cost $100 - $300 $600 $700 - $1000 $600 Accuracy 5 25 m 2 5 m 5 25 m 2 5 m Codes C/A C/A C/A C/A Data base x Geoexplorer III $ C/A X Geoexplorer III DGPS $ C/A X Geo XM Geo XT DGPS $4000 $ < 1 m C/A L1 +C/A X X Trimble Pro-XRS DGPS $15, m L1 c/a+p X Survey grade GPS $50, m L1, L2 X The table gives a few examples of GPS systems, cost, and accuracy. Data storage capabilities is another important aspect of GPS data collection. Mapping grade and survey grade units (Trimble units for example) have data storage capabilities and gives the user the ability to create a custom made database form directly on the GPS unit. In the data dictionary the GPS user can store attribute information associated with the location recorded with GPS. The Pocket PC with a GPS card can also store extended attribute data. Recreational units can store waypoints, but are very limited when it comes to storing attribute data. 25

26 New GPS field mapping technology GPS Flash Card that works with a Pocket PC Trimble GeoXT IPAQ Pocket PC New GPS technology allows the user to load aerial photographs or topographic maps into the GPS unit for display during the GPS data collection. The current GPS locations is displayed on top of this backdrop of photo or map. Software also exists (for example ArcPad from ESRI) that allows the user to create features via onscreen digitizing on the GPS unit or Pocket PC. Read more at: 26

27 GPS in Natural Resources NR402 - GIS Applications in Natural Resources Forest inventory Weed mapping Wildlife habitat Vegetation monitoring Lake and stream boundaries Property corners In summary, GPS is commonly used in natural resource and land management applications. It is important to be aware of GPS accuracy, sources of GPS errors, options for differential correction and what unit to use for what application. 27

28 Geographic coordinates NR402 - GIS Applications in Natural Resources Coordinates are expressed as Latitude and Longitude in Degrees, Minutes, Seconds. If you are going to import your collected GPS data to a GIS it is advantageous to record the GPS locations in the same coordinate system as your GIS layers are in. The default setting on most GPS units is to collect in Geographic coordinates (Degrees, Minutes and Seconds) and the WGS84 datum. If you want to record GPS locations in a different coordinate system and datum you can adjust the settings under SETUP on the GPS unit. It is important to coordinate data collection within a field crew such that all members of the crew records data in the same coordinate system and datum. As we learned in the Map Projection section of this course the map projection tools in ArcToolbox can be applied to convert data from one coordinate system and datum to another. This is however contingent upon the fact that the original coordinate system and datum for the collected data is known!! Units can be set to collect in Degrees, Minutes, Seconds or degrees and decimal minutes or in decimal degrees along with other coordinate systems such as UTM (Universal Transverse Mercator). Format for degrees, minutes and seconds: DD MM SS.ss Format for degrees and decimal minutes: DD MM.mmm Format for decimal degrees: DD.ddddddd If data is collected in decimal degrees it is important to record at least 6 decimals. 28

29 Map coordinates on USGS map Degrees, minutes UTM Map coordinates are present on most maps. This 7.5 minute USGS quadrangle map shows coordinates in both degrees&minutes and in the UTM coordinate system. The map datum is also available in the map information. 29

30 GPS references on the Internet ial2of2.html A few GPS references on the Internet. 30

Line and polygon features can be created via on-screen digitizing.

Line and polygon features can be created via on-screen digitizing. This module explains how GPS works, sources of error, and error correction using real time or post processing differential correction. Cost and accuracy of different grades of GPS units are also part of

More information

What is a GPS How does GPS work? GPS Segments GPS P osition Position Position Accuracy Accuracy Accuracy GPS A pplications Applications Applications

What is a GPS How does GPS work? GPS Segments GPS P osition Position Position Accuracy Accuracy Accuracy GPS A pplications Applications Applications What is GPS? What is a GPS How does GPS work? GPS Segments GPS Position Accuracy GPS Applications What is GPS? The Global Positioning System (GPS) is a precise worldwide radio-navigation system, and consists

More information

Global Positioning Systems (GPS) Trails: the achilles heel of mapping from the air / satellites

Global Positioning Systems (GPS) Trails: the achilles heel of mapping from the air / satellites Global Positioning Systems (GPS) Trails: the achilles heel of mapping from the air / satellites Google maps updated regularly by local users using GPS Also: http://openstreetmaps.org GPS applications

More information

GPS Errors. Figure 1. Four satellites are required to determine a GPS position.

GPS Errors. Figure 1. Four satellites are required to determine a GPS position. Expl ai ni nggps:thegl obalposi t i oni ngsyst em since a minimum of four satellites is required to calculate a position (Fig 1). However, many newer GPS receivers are equipped to receive up to 12 satellite

More information

36. Global Positioning System

36. Global Positioning System 36. Introduction to the Global Positioning System (GPS) Why do we need GPS? Position: a basic need safe sea travel, crowed skies, resource management, legal questions Positioning: a challenging job local

More information

The Global Positioning System

The Global Positioning System The Global Positioning System 5-1 US GPS Facts of Note DoD navigation system First launch on 22 Feb 1978, fully operational in 1994 ~$15 billion (?) invested to date 24 (+/-) Earth-orbiting satellites

More information

GPS Milestones, cont. GPS Milestones. The Global Positioning Sytem, Part 1 10/10/2017. M. Helper, GEO 327G/386G, UT Austin 1. US GPS Facts of Note

GPS Milestones, cont. GPS Milestones. The Global Positioning Sytem, Part 1 10/10/2017. M. Helper, GEO 327G/386G, UT Austin 1. US GPS Facts of Note The Global Positioning System US GPS Facts of Note DoD navigation system First launch on 22 Feb 1978, fully operational in 1994 ~$15 billion (?) invested to date 24 (+/-) Earth-orbiting satellites (SVs)

More information

Introduction to the Global Positioning System

Introduction to the Global Positioning System GPS for Fire Management - 2004 Introduction to the Global Positioning System Pre-Work Pre-Work Objectives Describe at least three sources of GPS signal error, and identify ways to mitigate or reduce those

More information

FieldGenius Technical Notes GPS Terminology

FieldGenius Technical Notes GPS Terminology FieldGenius Technical Notes GPS Terminology Almanac A set of Keplerian orbital parameters which allow the satellite positions to be predicted into the future. Ambiguity An integer value of the number of

More information

GLOBAL POSITIONING SYSTEMS. Knowing where and when

GLOBAL POSITIONING SYSTEMS. Knowing where and when GLOBAL POSITIONING SYSTEMS Knowing where and when Overview Continuous position fixes Worldwide coverage Latitude/Longitude/Height Centimeter accuracy Accurate time Feasibility studies begun in 1960 s.

More information

Introduction to Geographic Information Science. Last Lecture. Today s Outline. Geography 4103 / GNSS/GPS Technology

Introduction to Geographic Information Science. Last Lecture. Today s Outline. Geography 4103 / GNSS/GPS Technology Geography 4103 / 5103 Introduction to Geographic Information Science GNSS/GPS Technology Last Lecture Geoids Ellipsoid Datum Projection Basics Today s Outline GNSS technology How satellite based navigation

More information

Introduction to NAVSTAR GPS

Introduction to NAVSTAR GPS Introduction to NAVSTAR GPS Charlie Leonard, 1999 (revised 2001, 2002) The History of GPS Feasibility studies begun in 1960 s. Pentagon appropriates funding in 1973. First satellite launched in 1978. System

More information

GLOBAL POSITIONING SYSTEMS

GLOBAL POSITIONING SYSTEMS GLOBAL POSITIONING SYSTEMS GPS & GIS Fall 2017 Global Positioning Systems GPS is a general term for the navigation system consisting of 24-32 satellites orbiting the Earth, broadcasting data that allows

More information

GPS: The Basics. Darrell R. Dean, Jr. Civil and Environmental Engineering West Virginia University. Expected Learning Outcomes for GPS

GPS: The Basics. Darrell R. Dean, Jr. Civil and Environmental Engineering West Virginia University. Expected Learning Outcomes for GPS GPS: The Basics Darrell R. Dean, Jr. Civil and Environmental Engineering West Virginia University Expected Learning Outcomes for GPS Explain the acronym GPS Name 3 important tdt dates in history of GPS

More information

What is it? History. Other systems. How does it work? Trilateration GEOG 201 4/28/2010. Instructor: Pesses 1. {06} The Global Positioning System

What is it? History. Other systems. How does it work? Trilateration GEOG 201 4/28/2010. Instructor: Pesses 1. {06} The Global Positioning System What is it? {06} The Global Positioning System G.P.S. = Global Positioning System Different from G.I.S. (Geographic Information Systems) Map Interpretation & GPS Spring 2010 M. Pesses History Conceived

More information

Introduction to the Global Positioning System

Introduction to the Global Positioning System GPS for ICS - 2003 Introduction to the Global Positioning System Pre-Work Pre-Work Objectives Describe at least three sources of GPS signal error, and ways to mitigate or reduce those errors. Identify

More information

What is GPS? GPS Position Accuracy. GPS Applications. What is a GPS. How does GPS work? GPS Segments

What is GPS? GPS Position Accuracy. GPS Applications. What is a GPS. How does GPS work? GPS Segments What is GPS? What is a GPS How does GPS work? GPS Segments GPS Position Accuracy GPS Applications 1 What is GPS? The Global Positioning System (GPS) is a precise worldwide radio-navigation system, and

More information

Sources of Geographic Information

Sources of Geographic Information Sources of Geographic Information Data properties: Spatial data, i.e. data that are associated with geographic locations Data format: digital (analog data for traditional paper maps) Data Inputs: sampled

More information

PRINCIPLES AND FUNCTIONING OF GPS/ DGPS /ETS ER A. K. ATABUDHI, ORSAC

PRINCIPLES AND FUNCTIONING OF GPS/ DGPS /ETS ER A. K. ATABUDHI, ORSAC PRINCIPLES AND FUNCTIONING OF GPS/ DGPS /ETS ER A. K. ATABUDHI, ORSAC GPS GPS, which stands for Global Positioning System, is the only system today able to show you your exact position on the Earth anytime,

More information

UNITED NATIONS UNIVERSITY Institute for Environment & Human Security (UNU-EHS) Bonn, Germany

UNITED NATIONS UNIVERSITY Institute for Environment & Human Security (UNU-EHS) Bonn, Germany UNITED NATIONS UNIVERSITY Institute for Environment & Human Security (UNU-EHS) Bonn, Germany Introduction to GPS technology Prof. Dr. Jörg Szarzynski Education Programme Director Head of Section EduSphere

More information

Appendix D Brief GPS Overview

Appendix D Brief GPS Overview Appendix D Brief GPS Overview Global Positioning System (GPS) Theory What is GPS? The Global Positioning System (GPS) is a satellite-based navigation system, providing position information, accurate to

More information

GPS: What do I need to collect Application Appropriate location data?

GPS: What do I need to collect Application Appropriate location data? GPS: What do I need to collect Application Appropriate location data? Bob Goodwin, GISP GIS/Remote Sensing Analyst Remote Sensing & GIS Research and Outreach Services, MSU http://www.rsgis.msu.edu 2005

More information

ENGI 3703 Surveying and Geomatics

ENGI 3703 Surveying and Geomatics Satellite Geometry: Satellites well spread out in the sky have a much stronger solution to the resection type problem (aka trilateration) then satellite that are grouped together. Since the position of

More information

How is GPS Used in Farming? Equipment Guidance Systems

How is GPS Used in Farming? Equipment Guidance Systems GPS Applications in Crop Production John Nowatzki, Extension Geospatial Specialist, Vern Hofman, Extension Ag Engineer Lowell Disrud, Assistant Professor, Kraig Nelson, Graduate Student Introduction The

More information

GNSS & Coordinate Systems

GNSS & Coordinate Systems GNSS & Coordinate Systems Matthew McAdam, Marcelo Santos University of New Brunswick, Department of Geodesy and Geomatics Engineering, Fredericton, NB May 29, 2012 Santos, 2004 msantos@unb.ca 1 GNSS GNSS

More information

GPS 101. An Introduction to Using a GPS Receiver

GPS 101. An Introduction to Using a GPS Receiver GPS 101 An Introduction to Using a GPS Receiver The goal of this presentation if to provide a basic understanding of what is GPS, how it works, provide some basic terminology and to provide ideas on how

More information

LAB 1 METHODS FOR LOCATING YOUR FIELD DATA IN GEOGRAPHIC SPACE. Geog 315 / ENSP 428

LAB 1 METHODS FOR LOCATING YOUR FIELD DATA IN GEOGRAPHIC SPACE. Geog 315 / ENSP 428 LAB 1 METHODS FOR LOCATING YOUR FIELD DATA IN GEOGRAPHIC SPACE Geog 315 / ENSP 428 Lab 1 Schedule Introduction to bio-physical field data collection (8:00-8:20am) Locating your data on the earth: NAVSTAR

More information

METIS Second Master Training & Seminar. Augmentation Systems Available in Egypt

METIS Second Master Training & Seminar. Augmentation Systems Available in Egypt METIS Second Master Training & Seminar Augmentation Systems Available in Egypt By Eng. Ramadan Salem M. Sc. Surveying and Geodesy Email: ramadan_salem@link.net Page 1 Augmentation Systems Available in

More information

GPS and Recent Alternatives for Localisation. Dr. Thierry Peynot Australian Centre for Field Robotics The University of Sydney

GPS and Recent Alternatives for Localisation. Dr. Thierry Peynot Australian Centre for Field Robotics The University of Sydney GPS and Recent Alternatives for Localisation Dr. Thierry Peynot Australian Centre for Field Robotics The University of Sydney Global Positioning System (GPS) All-weather and continuous signal system designed

More information

GNSS 101 Bringing It Down To Earth

GNSS 101 Bringing It Down To Earth GNSS 101 Bringing It Down To Earth Steve Richter Frontier Precision, Inc. UTM County Coordinates NGVD 29 State Plane Datums Scale Factors Projections Session Agenda GNSS History & Basic Theory Coordinate

More information

GPS Technical Overview N5TWP NOV08. How Can GPS Mislead

GPS Technical Overview N5TWP NOV08. How Can GPS Mislead GPS Technical Overview How Can GPS Mislead 1 Objectives Components of GPS Satellite Acquisition Process Position Determination How can GPS Mislead 2 Components of GPS Control Segment Series of monitoring

More information

NJDEP GPS Data Collection Standards for GIS Data Development

NJDEP GPS Data Collection Standards for GIS Data Development NJDEP GPS Data Collection Standards for GIS Data Development Bureau of Geographic Information Systems Office of Information Resource Management April 24 th, 2017 Table of Contents 1.0 Introduction... 3

More information

UNIT 1 - introduction to GPS

UNIT 1 - introduction to GPS UNIT 1 - introduction to GPS 1. GPS SIGNAL Each GPS satellite transmit two signal for positioning purposes: L1 signal (carrier frequency of 1,575.42 MHz). Modulated onto the L1 carrier are two pseudorandom

More information

ENGRG Introduction to GIS

ENGRG Introduction to GIS ENGRG 59910 Introduction to GIS Michael Piasecki December 01, 2017 Lecture 12: GPS Systems Lecture 7: Introduction To GPS November 27, 2017 ENGRG 59910 Intro to GIS 2 November 27, 2017 ENGRG 59910 Intro

More information

GPS Performance in Southern Hardwood Forests

GPS Performance in Southern Hardwood Forests GPS Performance in Southern Hardwood Forests Pete Bettinger Warnell School of Forestry and Natural Resources University of Georgia In forests, vegetation plays a significant role in obstructing signals

More information

Errors in GPS. Errors in GPS. Geodetic Co-ordinate system. R. Khosla Fall Semester

Errors in GPS. Errors in GPS. Geodetic Co-ordinate system. R. Khosla Fall Semester Errors in GPS Errors in GPS GPS is currently the most accurate positioning system available globally. Although we are talking about extreme precision and measuring distances by speed of light, yet there

More information

GPS Accuracy Comparison. Tom Biernacki Florida Department of Environmental Protection

GPS Accuracy Comparison. Tom Biernacki Florida Department of Environmental Protection GPS Accuracy Comparison Tom Biernacki Florida Department of Environmental Protection What Effects the accuracy of GPS? Atmospheric delay Multipath bounce Weak receiver algorithms Atmospheric Delay Signal

More information

GPS Performance in Southern Hardwood Forests Pete Bettinger Warnell School of Forestry and Natural Resources University of Georgia

GPS Performance in Southern Hardwood Forests Pete Bettinger Warnell School of Forestry and Natural Resources University of Georgia GPS Performance in Southern Hardwood Forests Pete Bettinger Warnell School of Forestry and Natural Resources University of Georgia Introduction In forests, vegetation plays a significant role in obstructing

More information

GEOGRAPHIC INFORMATION SYSTEMS Lecture 22: Field Mapping with GPS

GEOGRAPHIC INFORMATION SYSTEMS Lecture 22: Field Mapping with GPS GEOGRAPHIC INFORMATION SYSTEMS Lecture 22: Field Mapping with GPS GPS Receivers - there are many GPS receivers on the market today - some receivers are relatively inexpensive (recreational grade receivers)

More information

Global Navigation Satellite Systems II

Global Navigation Satellite Systems II Global Navigation Satellite Systems II AERO4701 Space Engineering 3 Week 4 Last Week Examined the problem of satellite coverage and constellation design Looked at the GPS satellite constellation Overview

More information

Global Positioning Systems -GPS

Global Positioning Systems -GPS Global Positioning Systems -GPS GPS Why? What is it? How does it work? Differential GPS How can it help me? GPS Why?? Where am I? How do I get there? Where are you, and how do I get to You? WHO CARES???

More information

Entity Tracking and Surveillance using the Modified Biometric System, GPS-3

Entity Tracking and Surveillance using the Modified Biometric System, GPS-3 Advance in Electronic and Electric Engineering. ISSN 2231-1297, Volume 3, Number 9 (2013), pp. 1115-1120 Research India Publications http://www.ripublication.com/aeee.htm Entity Tracking and Surveillance

More information

Principal Investigator Co-Principal Investigator Co-Principal Investigator Prof. Talat Ahmad Vice-Chancellor Jamia Millia Islamia Delhi

Principal Investigator Co-Principal Investigator Co-Principal Investigator Prof. Talat Ahmad Vice-Chancellor Jamia Millia Islamia Delhi Subject Paper No and Title Module No and Title Module Tag Geology Remote Sensing and GIS Concepts of Global Navigation Satellite RS & GIS XXXIII Principal Investigator Co-Principal Investigator Co-Principal

More information

Global Positioning Systems - GPS

Global Positioning Systems - GPS Global Positioning Systems - GPS GPS Why? What is it? How does it work? Differential GPS How can it help me? GPS Why?? Where am I? How do I get there? Where are you, and how do I get to You? WHO CARES???

More information

GEO 428: DEMs from GPS, Imagery, & Lidar Tuesday, September 11

GEO 428: DEMs from GPS, Imagery, & Lidar Tuesday, September 11 GEO 428: DEMs from GPS, Imagery, & Lidar Tuesday, September 11 Global Positioning Systems GPS is a technology that provides Location coordinates Elevation For any location with a decent view of the sky

More information

Primer on GPS Operations

Primer on GPS Operations MP Rugged Wireless Modem Primer on GPS Operations 2130313 Rev 1.0 Cover illustration by Emma Jantz-Lee (age 11). An Introduction to GPS This primer is intended to provide the foundation for understanding

More information

MOBILE COMPUTING 1/28/18. Location, Location, Location. Overview. CSE 40814/60814 Spring 2018

MOBILE COMPUTING 1/28/18. Location, Location, Location. Overview. CSE 40814/60814 Spring 2018 MOBILE COMPUTING CSE 40814/60814 Spring 018 Location, Location, Location Location information adds context to activity: location of sensed events in the physical world location-aware services location

More information

Introduction. Global Positioning System. GPS - Intro. Space Segment. GPS - Intro. Space Segment - Contd..

Introduction. Global Positioning System. GPS - Intro. Space Segment. GPS - Intro. Space Segment - Contd.. Introduction Global Positioning System Prof. D. Nagesh Kumar Dept. of Civil Engg., IISc, Bangalore 560 012, India URL: http://www.civil.iisc.ernet.in/~nagesh GPS is funded and controlled by U. S. Department

More information

GPS (GLOBAL POSITIONING SYSTEM)

GPS (GLOBAL POSITIONING SYSTEM) GPS (GLOBAL POSITIONING SYSTEM) What is GPS? GPS, standing for Global Positioning System, is becoming common nowadays. Following is a brief introduction. The American Defense Department developed GPS originally

More information

The GLOBAL POSITIONING SYSTEM James R. Clynch February 2006

The GLOBAL POSITIONING SYSTEM James R. Clynch February 2006 The GLOBAL POSITIONING SYSTEM James R. Clynch February 2006 I. Introduction What is GPS The Global Positioning System, or GPS, is a satellite based navigation system developed by the United States Defense

More information

Resection. We can measure direction in the real world! Lecture 10: Position Determination. Resection Example: Isola, Slovenia. Professor Keith Clarke

Resection. We can measure direction in the real world! Lecture 10: Position Determination. Resection Example: Isola, Slovenia. Professor Keith Clarke Geography 12: Maps and Spatial Reasoning Lecture 10: Position Determination We can measure direction in the real world! Professor Keith Clarke Resection Resection Example: Isola, Slovenia Back azimuth

More information

Hitchhiker s s Guide Global Position System. Global Position System

Hitchhiker s s Guide Global Position System. Global Position System Hitchhiker s s Guide Global Position System Myles Sutherland Craig Greenwald Mike Shaw John Rogers Hitchhiker s s Guide Global Position System (GPS) Myles Sutherland - ESRI Craig Greenwald ESRI John Rogers

More information

Addressing Issues with GPS Data Accuracy and Position Update Rate for Field Traffic Studies

Addressing Issues with GPS Data Accuracy and Position Update Rate for Field Traffic Studies Addressing Issues with GPS Data Accuracy and Position Update Rate for Field Traffic Studies THIS FEATURE VALIDATES INTRODUCTION Global positioning system (GPS) technologies have provided promising tools

More information

GPS Global Positioning System

GPS Global Positioning System GPS Global Positioning System 10.04.2012 1 Agenda What is GPS? Basic consept History GPS receivers How they work Comunication Message format Satellite frequencies Sources of GPS signal errors 10.04.2012

More information

Differential Global Positioning ~ System Techniques For Surveying/ Mapping within Forested Wetlands

Differential Global Positioning ~ System Techniques For Surveying/ Mapping within Forested Wetlands WRP Technical Note WG-SW-2.2 ~- Differential Global Positioning ~ System Techniques For Surveying/ Mapping within Forested Wetlands PURPOSE: This technical note describes the use of Differential Global

More information

GPS Glossary Written by Carl Carter SiRF Technology 2005

GPS Glossary Written by Carl Carter SiRF Technology 2005 GPS Glossary Written by Carl Carter SiRF Technology 2005 This glossary provides supplementary information for students of GPS Fundamentals. While many of the terms can have other definitions from those

More information

CARRIER PHASE VS. CODE PHASE

CARRIER PHASE VS. CODE PHASE DIFFERENTIAL CORRECTION Code phase processing- GPS measurements based on the pseudo random code (C/A or P) as opposed to the carrier of that code. (1-5 meter accuracy) Carrier phase processing- GPS measurements

More information

GE 113 REMOTE SENSING

GE 113 REMOTE SENSING GE 113 REMOTE SENSING Topic 9. Introduction to Global Positioning Systems (GPS) and Other GNSS Technologies Lecturer: Engr. Jojene R. Santillan jrsantillan@carsu.edu.ph Division of Geodetic Engineering

More information

Introduction to Total Station and GPS

Introduction to Total Station and GPS Introduction to Total Station and GPS Dr. P. NANJUNDASWAMY Professor of Civil Engineering J S S Science and Technology University S J College of Engineering Mysuru 570 006 Introduction History GPS Overview

More information

The Global Positioning System II Field Experiments. 10/10/2013 GEO327G/386G, UT Austin 5-1

The Global Positioning System II Field Experiments. 10/10/2013 GEO327G/386G, UT Austin 5-1 The Global Positioning System II Field Experiments 10/10/2013 GEO327G/386G, UT Austin 5-1 Mexico DGPS Field Campaign Cenotes in Tamaulipas, MX, near Aldama 10/10/2013 GEO327G/386G, UT Austin 5-2 Are Cenote

More information

Global Positioning System (GPS)

Global Positioning System (GPS) Global Positioning System (GPS) GPS enables users to easily record the location of natural and man-made features on the land. It allows users to identify where a photo or video is taken, revisit previously

More information

BGRI Stem Rust Survey Protocol. Overview of Field Survey Procedure

BGRI Stem Rust Survey Protocol. Overview of Field Survey Procedure Overview of Field Survey Procedure 1. Ensure survey team have all items on check-list before departure 2. Travel to 1 st survey location 3. At survey location switch on GPS 4. Wait until GPS receives satellite

More information

Challenges and Solutions for GPS Receiver Test

Challenges and Solutions for GPS Receiver Test Challenges and Solutions for GPS Receiver Test Presenter: Mirin Lew January 28, 2010 Agenda GPS technology concepts GPS and GNSS overview Assisted GPS (A-GPS) Basic tests required for GPS receiver verification

More information

The Global Positioning Sytem II 10/19/2017

The Global Positioning Sytem II 10/19/2017 The Global Positioning System II Field Experiments 10/19/2017 5-1 Mexico DGPS Field Campaign Cenotes in Tamaulipas, MX, near Aldama 10/19/2017 5-2 Are Cenote Water Levels Related? 10/19/2017 5-3 M. Helper,

More information

Fundamentals of GPS Navigation

Fundamentals of GPS Navigation Fundamentals of GPS Navigation Kiril Alexiev 1 /76 2 /76 At the traditional January media briefing in Paris (January 18, 2017), European Space Agency (ESA) General Director Jan Woerner explained the knowns

More information

Swath Guidance Technology. Ron C. Johnson

Swath Guidance Technology. Ron C. Johnson Swath Guidance Technology by Ron C. Johnson Widespread acceptance of new information technologies in agriculture may still be a long way off. But some producers and custom applicators are beginning to

More information

Lecture 8: GIS Data Error & GPS Technology

Lecture 8: GIS Data Error & GPS Technology Lecture 8: GIS Data Error & GPS Technology A. Introduction We have spent the beginning of this class discussing some basic information regarding GIS technology. Now that you have a grasp of the basic terminology

More information

FieldGenius Technical Notes GPS Differential Corrections

FieldGenius Technical Notes GPS Differential Corrections FieldGenius Technical tes GPS Differential Corrections Introduction The accuracy requirement of survey grade or mapping grade GPS applications for real time positioning requires the use of differential

More information

GLOBAL POSITIONING SYSTEMS

GLOBAL POSITIONING SYSTEMS GLOBAL POSITIONING SYSTEMS Maps & Geospatial Concepts Fall 2015 Before GPS Historical look at navigation Giant concrete arrows that point your way across America What are these giant arrows? Some kind

More information

Modern Navigation. Thomas Herring

Modern Navigation. Thomas Herring 12.215 Modern Navigation Thomas Herring Summary of Last class Satellite Orbits Treat the basic description and dynamics of satellite orbits Major perturbations on GPS satellite orbits Sources of orbit

More information

GPS for GIS Data Collection - 101

GPS for GIS Data Collection - 101 GPS for GIS Data Collection - 101 Speaker: Eric Gakstatter, Editor of GPS World s Survey Scene Newsletter & Geospatial Solutions Guest Commentator: Craig Greenwald, Technical Director, GeoMobile Innovations,

More information

Unguided Transmission Media

Unguided Transmission Media CS311 Data Communication Unguided Transmission Media by Dr. Manas Khatua Assistant Professor Dept. of CSE IIT Jodhpur E-mail: manaskhatua@iitj.ac.in Web: http://home.iitj.ac.in/~manaskhatua http://manaskhatua.github.io/

More information

The Global Positioning System II Field Experiments

The Global Positioning System II Field Experiments The Global Positioning System II Field Experiments 5-1 Mexico DGPS Field Campaign Cenotes in Tamaulipas, MX, near Aldama 5-2 Are Cenote Water Levels Related? 5-3 DGPS Static Survey of Cenote Water Levels

More information

Lab Assignment #3 ASE 272N/172G Satellite Navigation Prof. G. Lightsey Assigned: October 28, 2003 Due: November 11, 2003 in class

Lab Assignment #3 ASE 272N/172G Satellite Navigation Prof. G. Lightsey Assigned: October 28, 2003 Due: November 11, 2003 in class The University of Texas at Austin Department of Aerospace Engineering and Engineering Mechanics Lab Assignment #3 ASE 272N/172G Satellite Navigation Prof. G. Lightsey Assigned: October 28, 2003 Due: November

More information

The topic we are going to see in this unit, the global positioning system, is not directly related with the computer networks we use everyday, but it

The topic we are going to see in this unit, the global positioning system, is not directly related with the computer networks we use everyday, but it The topic we are going to see in this unit, the global positioning system, is not directly related with the computer networks we use everyday, but it is indeed a kind of computer network, as the specialised

More information

The global positioning system

The global positioning system PHYSICS UPDATE The global positioning system Alan J Walton and Richard J Black University of Cambridge, Department of Physics, Cavendish Laboratory, Madingley Road, Cambridge CB3 0HE, UK University of

More information

GPS (Introduction) References. Terms

GPS (Introduction) References. Terms GPS (Introduction) WCOM2, GPS, 1 Terms NAVSTAR GPS ( Navigational Satellite Timing and Ranging - Global Positioning System) is a GNSS (Global Navigation Satellite System), developed by the US-DoD in 197x

More information

ACCURACIES OF VARIOUS GPS ANTENNAS UNDER FORESTED CONDITIONS

ACCURACIES OF VARIOUS GPS ANTENNAS UNDER FORESTED CONDITIONS ACCURACIES OF VARIOUS GPS ANTENNAS UNDER FORESTED CONDITIONS Brian H. Holley and Michael D. Yawn LandMark Systems, 122 Byrd Way Warner Robins, GA 31088 ABSTRACT GPS accuracy is much more variable in forested

More information

GPS for. Land Surveyors. Jan Van Sickle. Fourth Edition. CRC Press. Taylor & Francis Group. Taylor & Francis Croup, an Informa business

GPS for. Land Surveyors. Jan Van Sickle. Fourth Edition. CRC Press. Taylor & Francis Group. Taylor & Francis Croup, an Informa business GPS for Land Surveyors Fourth Edition Jan Van Sickle CRC Press Taylor & Francis Group Boca Raton London New York CRC Press is an imprint of the Taylor & Francis Croup, an Informa business Contents Preface

More information

GNSS Surveying & Processing (A Surveyors Peek Behind the Curtain) Presented by Jeff Clark, PLS

GNSS Surveying & Processing (A Surveyors Peek Behind the Curtain) Presented by Jeff Clark, PLS GNSS Surveying & Processing (A Surveyors Peek Behind the Curtain) Presented by Jeff Clark, PLS Global Positioning System (GPS) (GNSS) GPS is considered a passive system Passive in the sense that only the

More information

GPS POSITIONING GUIDE

GPS POSITIONING GUIDE GPS POSITIONING GUIDE (July 1993) Third printing July 1995 This product is available from: Natural Resources Canada* Geomatics Canada Geodetic Survey Division Information Services 615 Booth Street Ottawa,

More information

GPS Tutorial Trimble Home > GPS Tutorial > How GPS works? > Triangulating

GPS Tutorial Trimble Home > GPS Tutorial > How GPS works? > Triangulating http://www.trimble.com/gps/howgps-triangulating.shtml Page 1 of 3 Trimble Worldwide Popula PRODUCTS & SOLUTIONS SUPPORT & TRAINING ABOUT TRIMBLE INVESTORS GPS Tutorial Trimble Home > GPS Tutorial > How

More information

GPS Accuracies in the Field

GPS Accuracies in the Field GPS Accuracies in the Field A short and informative talk by A. Richard Vannozzi, PLS Assistant Professor of Civil Technology/Surveying and Mapping Thompson School of Applied Science University of New Hampshire

More information

ORBITAL NAVIGATION SYSTEMS PRESENT AND FUTURE TENDS

ORBITAL NAVIGATION SYSTEMS PRESENT AND FUTURE TENDS ORBITAL NAVIGATION SYSTEMS PRESENT AND FUTURE TENDS CONTENT WHAT IS COVERED A BRIEF HISTORY OF SYSTEMS PRESENT SYSTEMS IN USE PROBLEMS WITH SATELLITE SYSTEMS PLANNED IMPROVEMENTS CONCLUSION CONTENT WHAT

More information

Utilizing A GNSS Network Solution for Utility Applications

Utilizing A GNSS Network Solution for Utility Applications Utilizing A GNSS Network Solution for Utility Applications David Newcomer, PE, PLS GPServ, Inc. newcomer@ (407) 601-5816 AGENDA Types and accuracies of data collection o Autonomous o Meter + o Sub-meter

More information

King AbdulAziz University. Faculty of Environmental Design. Geomatics Department. Mobile GIS GEOM 427. Lecture 3

King AbdulAziz University. Faculty of Environmental Design. Geomatics Department. Mobile GIS GEOM 427. Lecture 3 King AbdulAziz University Faculty of Environmental Design Geomatics Department Mobile GIS GEOM 427 Lecture 3 Ahmed Baik, Ph.D. Email: abaik@kau.edu.sa Eng. Fisal Basheeh Email: fbasaheeh@kau.edu.sa GNSS

More information

ESTIMATION OF IONOSPHERIC DELAY FOR SINGLE AND DUAL FREQUENCY GPS RECEIVERS: A COMPARISON

ESTIMATION OF IONOSPHERIC DELAY FOR SINGLE AND DUAL FREQUENCY GPS RECEIVERS: A COMPARISON ESTMATON OF ONOSPHERC DELAY FOR SNGLE AND DUAL FREQUENCY GPS RECEVERS: A COMPARSON K. Durga Rao, Dr. V B S Srilatha ndira Dutt Dept. of ECE, GTAM UNVERSTY Abstract: Global Positioning System is the emerging

More information

Global Correction Services for GNSS

Global Correction Services for GNSS Global Correction Services for GNSS Hemisphere GNSS Whitepaper September 5, 2015 Overview Since the early days of GPS, new industries emerged while existing industries evolved to use position data in real-time.

More information

An Introduction to GPS

An Introduction to GPS An Introduction to GPS You are here The GPS system: what is GPS Principles of GPS: how does it work Processing of GPS: getting precise results Yellowstone deformation: an example What is GPS? System to

More information

GLOBAL NAVIGATION SATELLITE SYSTEMS (GNSS) ECE 2526E Tuesday, 24 April 2018

GLOBAL NAVIGATION SATELLITE SYSTEMS (GNSS) ECE 2526E Tuesday, 24 April 2018 GLOBAL NAVIGATION SATELLITE SYSTEMS (GNSS) ECE 2526E Tuesday, 24 April 2018 MAJOR GLOBAL NAVIGATION SATELLITE SYSTEMS (GNSS) Global Navigation Satellite System (GNSS) includes: 1. Global Position System

More information

t =1 Transmitter #2 Figure 1-1 One Way Ranging Schematic

t =1 Transmitter #2 Figure 1-1 One Way Ranging Schematic 1.0 Introduction OpenSource GPS is open source software that runs a GPS receiver based on the Zarlink GP2015 / GP2021 front end and digital processing chipset. It is a fully functional GPS receiver which

More information

Lecture-1 CHAPTER 2 INTRODUCTION TO GPS

Lecture-1 CHAPTER 2 INTRODUCTION TO GPS Lecture-1 CHAPTER 2 INTRODUCTION TO GPS 2.1 History of GPS GPS is a global navigation satellite system (GNSS). It is the commonly used acronym of NAVSTAR (NAVigation System with Time And Ranging) GPS (Global

More information

GIS and Remote Sensing BIO8014. Data acquisition

GIS and Remote Sensing BIO8014. Data acquisition GIS and Remote Sensing BIO8014 Data acquisition Introduction Data can be manually created Data can be obtained from a wide range of providers both free and at cost Acquisition is key and must be accounted

More information

ELEMENTS OF THE NATIONAL SPATIAL REFERENCE SYSTEM

ELEMENTS OF THE NATIONAL SPATIAL REFERENCE SYSTEM Dave Doyle NGS Chief Geodetic Surveyor dave.doyle@noaa.gov 301-713-3178 ELEMENTS OF THE NATIONAL SPATIAL REFERENCE SYSTEM ESRI SURVEY SUMMIT San Diego, CA June 17, 2007 ftp://ftp.ngs.noaa.gov/dist/daved/esri

More information

Proceedings of Al-Azhar Engineering 7 th International Conference Cairo, April 7-10, 2003.

Proceedings of Al-Azhar Engineering 7 th International Conference Cairo, April 7-10, 2003. Proceedings of Al-Azhar Engineering 7 th International Conference Cairo, April 7-10, 2003. MODERNIZATION PLAN OF GPS IN 21 st CENTURY AND ITS IMPACTS ON SURVEYING APPLICATIONS G. M. Dawod Survey Research

More information

Channel Modeling ETIN10. Wireless Positioning

Channel Modeling ETIN10. Wireless Positioning Channel Modeling ETIN10 Lecture no: 10 Wireless Positioning Fredrik Tufvesson Department of Electrical and Information Technology 2014-03-03 Fredrik Tufvesson - ETIN10 1 Overview Motivation: why wireless

More information

GPS based data acquisition system for mobile applications

GPS based data acquisition system for mobile applications GPS based data acquisition system for mobile applications D. Covaciu, I. Preda, Gh. Ciolan Transilvania University of Brasov, Romania e-mail: dinu.covaciu@unitbv.ro, pion@unitbv.ro, cgicu@unitbv.ro Abstract:

More information

GPS Basics. Introduction to GPS (Global Positioning System) Version 1.0 English

GPS Basics. Introduction to GPS (Global Positioning System) Version 1.0 English 20 30 40 50 GPS Basics Introduction to GPS (Global Positioning System) Version 1.0 English Contents Preface... 4 1. What is GPS and what does it do?... 5 2. System Overview... 6 2.1 The Space Segment...

More information

TSC1 - Asset Surveyor Operation

TSC1 - Asset Surveyor Operation TSC1 - Asset Surveyor Operation Menu Icons (current choice is highlighted) Data collection File manager Main menu Navigation GPS Position Battery Status PC Card (if used) Real-Time Status Number of Satellites

More information

Opportunities and Limitations of Automatic Steering Technologies. Nyle Wollenhaupt Advanced Technology Solutions Agronomist

Opportunities and Limitations of Automatic Steering Technologies. Nyle Wollenhaupt Advanced Technology Solutions Agronomist Opportunities and Limitations of Automatic Steering Technologies Nyle Wollenhaupt Advanced Technology Solutions Agronomist So where do we start? We start at the beginning. When we didn t have GPS-assisted

More information