logging in or signing up Global Positioning System Control aSGuest47261 Download Post to : URL : Related Presentations : Share Add to Flag Embed Email Send to Blogs and Networks Add to Channel Uploaded from authorPOINT lite Insert YouTube videos in PowerPont slides with aS Desktop Copy embed code: (To copy code, click on the text box) Embed: URL: Thumbnail: WordPress Embed Customize Embed The presentation is successfully added In Your Favorites. Views: 297 Category: Entertainment License: All Rights Reserved Like it (0) Dislike it (0) Added: June 04, 2010 This Presentation is Public Favorites: 0 Presentation Description No description available. Comments Posting comment... Premium member Presentation Transcript Introduction : Introduction Summary of Topics : Summary of Topics - GPS - DGPS/WAAS - Coordinate Systems - Datums How does GPS work? : How does GPS work? The Global Positioning System : The Global Positioning System Control Segment Space Segment User Segment Control Segment : Kwajalein Atoll US Space Command Control Segment Hawaii Ascension Is. Diego Garcia Cape Canaveral The Space Segment : The Space Segment 30+ satellites in Earth orbit that transmit: PRN code Ephemeris data Atmospheric data Clock information An almanac JTrack : JTrack Altitude 20,200 km 10,900 nm http://liftoff.msfc.nasa.gov/RealTime/JTrack/3D/JTrack3D.html Earth in a Cage of Satellites : Earth in a Cage of Satellites Current: Satellites 1 - 32 Max: 32 Satellites User 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 How to Calculate a Position : How to Calculate a Position Measure the Distance to the Satellites How to Calculate Distance : How to Calculate Distance Speed of Light x Travel Time Distance Time signal left satellite Time current Minimum # of Satellites Required-Algebra Problem : Minimum # of Satellites Required-Algebra Problem Unknown time latitude longitude elevation 4 Unknowns We Need 4 Satellites Equation satellite location Minimum # of Satellites Required-Trilateration : Minimum # of Satellites Required-Trilateration 1 satellite – somewhere on a sphere Minimum # of Satellites Required-Trilateration : Minimum # of Satellites Required-Trilateration 2 satellites – somewhere on a circle Minimum # of Satellites Required-Trilateration : Minimum # of Satellites Required-Trilateration 3 satellites – one of two points Minimum # of Satellites Required-Trilateration : Minimum # of Satellites Required-Trilateration Note: with 3 satellites, one point is on the earth’s surface and one is nowhere near. However, we still need the 4th satellite because receiver clocks are inaccurate. 4 satellites – one point 3D GPS Location When There are Only 3 Satellites(2d GPS Location) – Horizontal Error is Greater : When There are Only 3 Satellites(2d GPS Location) – Horizontal Error is Greater Elevation - last known 2-5 X Error Rule Garmin Estimated Accuracy : - Want tetrahedron as large as possible - Want index as low as possible Garmin Estimated Accuracy Relies on Dilution of Precision Ideal Satellite Geometry : Ideal Satellite Geometry N S W E Good Satellite Geometry : Good Satellite Geometry Poor Satellite Geometry : Poor Satellite Geometry Note: if poor satellite geometry, then on the receiver the Accuracy value will be higher Poor Satellite Geometry : Poor Satellite Geometry Note: if poor satellite geometry, then on the receiver the Accuracy value will be higher Poor Satellite Geometry : Poor Satellite Geometry Note: if poor satellite geometry, then on the receiver the Accuracy value will be higher Poor Satellite Geometry : Poor Satellite Geometry Positions Recorded by Stationary GPS Receiver : Positions Recorded by Stationary GPS Receiver Garmin GPSmap76S 1 position/second 10 minutes WAAS Disabled 3.6 meters 3.1 meters Errors : Errors Ionosphere Troposphere Satellite Clock Errors Satellite Ephemeris Errors Multipath Receiver Noise Real Time Ground-based Differential GPS : 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 Real Time Ground-based Differential GPS Slide 28: WAAS satellites GPS Constellation WAAS Control Station(Position known) GPS receiver(Position with errors) Real Time Space-based Differential Correction 25 Reference Stations (Position known) WAAS : WAAS Wide Area Augmentation System WAAS Satellite Errors Reduced by WAAS Correction : Errors Reduced by WAAS Correction Ionosphere Troposphere Satellite Clock Errors Satellite Ephemeris Errors Multipath Receiver Noise Receiving WAAS Correction : Receiving WAAS Correction If WAAS signal intermittent- WAAS correction for SV 19 No WAAS correction for SV 11 Signal Disruption : Signal Disruption Ionosphere Solid Structures Metal Electro-magnetic Fields Good Data Collection Techniques : Good Data Collection Techniques Hold Upright & High External Antenna Sleeve Mounts Vehicle Brackets Map Projections & Coordinate Systems : Map Projections & Coordinate Systems Projecting a Sphere Onto a Plane : Projecting a Sphere Onto a Plane Three-dimensional sphere to two-dimensional flat map. Examples of Several Projections : Examples of Several Projections Depending on the projection, a certain amount of distortion occurs when portraying the earth on paper. Coordinate Systems (Projections) : Coordinate Systems (Projections) We Use – 2 Coordinate Systems Latitude / Longitude Universal Transverse Mercator (UTM) Garmin - 29 Location Formats Latitude & Longitude : Latitude & Longitude Parallels of Latitude : Parallels of Latitude 10º 10º 10º 690 miles 690 miles 690 miles 10º S 0º N 10º N 20º N Meridians of Longitude : Meridians of Longitude 10º 10º 110º W 120º W 690 miles 460 miles 240 mi 10º Equator To North Pole To South Pole Three Ways To Express Latitude / Longitudeon a Garmin : Three Ways To Express Latitude / Longitudeon a Garmin Three Ways To Express Latitude / Longitude(for the Same Location) : Three Ways To Express Latitude / Longitude(for the Same Location) hddd° mm’ ss.s” Degrees-Minutes-Seconds (Decimal Seconds)N 43° 40’ 55.8”, W 116° 17’ 14.1” hddd° mm.mmm’ Degrees-Minutes (Decimal Minutes)N 43° 40.930’, W 116° 17.235’ hddd.ddddd° Degrees (Decimal Degrees) N 43.68216°, W 116.28725° Slide 43: Lat/Long Format Conversion hddd0 mm’ ss.s”: N 430 40’ 55.8” X W 1160 17’ 14.1” (55.8” / 60 = .93’) Different coordinates representing the same location: UTM/UPS: 11T 0557442m E 4836621m N Example: Error in Latitude : Example: Error in Latitude 35° 24´ 45˝ N 35° 24.450’ N 1/3 of a mile Lat / Long Shortcomings : Lat / Long Shortcomings 1 minute ? ? + + + ? Universal Transverse Mercator : Universal Transverse Mercator measured in meters located in zones (1 - 60) include northing and easting are positive Coordinates Zone Easting Northing Latitude Band UTM Zones in the Lower 48 : UTM Zones in the Lower 48 UTM Grid Overlay : 1 60 UTM Grid Overlay 60 Zones, and 20 Latitude Bands Zones Equator UTM Latitude Band : Garmin Uses – UTM bands Bands C - M, southern hemisphere Bands N - X, northern hemisphere UTM Latitude Band Latitude Band We Use – 2 GIS choices UTM Zone _ North UTM Zone _ South no “I” no “O” If You Don’t Know Zone, Latitude Band… : If You Don’t Know Zone, Latitude Band… Entering Waypoints Zone – look up Band – enter any letter N-X for northern hemisphere, receiver will display correct one Collecting Waypoints Receiver figures it out! UTM Location Format on a Garmin : UTM Location Format on a Garmin What is a datum? : What is a datum? Datums : Datums WGS 84 NAD 83 NAD 27 Garmin - >100 Map Datums We Use – 3 Datums 1 meter 10 – 120+ meters Example: Datum Shift in Arizona : Example: Datum Shift in Arizona NAD83 N34.555o, W111.195o NAD27 N34.555o, W111.195o 210 meters Slide 55: With a Garmin GPS Receiver you always collect in the right coordinate system and datum! Lat, Long WGS-84 UTC Always Correct When Collecting! Lat, Long NAD27 -8 GMT UTM NAD83 UTC Lat, Long WGS84 -9 GMT Lat, Long NAD27 -8 GMT UTM NAD83 GMT Lat, Long WGS84 UTC Display doesn’t matter Slide 56: Always Ask When Transferring! Coordinate System? Datum? Review of Topics : Review of Topics - GPS - WAAS - Coordinate Systems - Datums You do not have the permission to view this presentation. In order to view it, please contact the author of the presentation.
Global Positioning System Control aSGuest47261 Download Post to : URL : Related Presentations : Share Add to Flag Embed Email Send to Blogs and Networks Add to Channel Uploaded from authorPOINT lite Insert YouTube videos in PowerPont slides with aS Desktop Copy embed code: (To copy code, click on the text box) Embed: URL: Thumbnail: WordPress Embed Customize Embed The presentation is successfully added In Your Favorites. Views: 297 Category: Entertainment License: All Rights Reserved Like it (0) Dislike it (0) Added: June 04, 2010 This Presentation is Public Favorites: 0 Presentation Description No description available. Comments Posting comment... Premium member Presentation Transcript Introduction : Introduction Summary of Topics : Summary of Topics - GPS - DGPS/WAAS - Coordinate Systems - Datums How does GPS work? : How does GPS work? The Global Positioning System : The Global Positioning System Control Segment Space Segment User Segment Control Segment : Kwajalein Atoll US Space Command Control Segment Hawaii Ascension Is. Diego Garcia Cape Canaveral The Space Segment : The Space Segment 30+ satellites in Earth orbit that transmit: PRN code Ephemeris data Atmospheric data Clock information An almanac JTrack : JTrack Altitude 20,200 km 10,900 nm http://liftoff.msfc.nasa.gov/RealTime/JTrack/3D/JTrack3D.html Earth in a Cage of Satellites : Earth in a Cage of Satellites Current: Satellites 1 - 32 Max: 32 Satellites User 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 How to Calculate a Position : How to Calculate a Position Measure the Distance to the Satellites How to Calculate Distance : How to Calculate Distance Speed of Light x Travel Time Distance Time signal left satellite Time current Minimum # of Satellites Required-Algebra Problem : Minimum # of Satellites Required-Algebra Problem Unknown time latitude longitude elevation 4 Unknowns We Need 4 Satellites Equation satellite location Minimum # of Satellites Required-Trilateration : Minimum # of Satellites Required-Trilateration 1 satellite – somewhere on a sphere Minimum # of Satellites Required-Trilateration : Minimum # of Satellites Required-Trilateration 2 satellites – somewhere on a circle Minimum # of Satellites Required-Trilateration : Minimum # of Satellites Required-Trilateration 3 satellites – one of two points Minimum # of Satellites Required-Trilateration : Minimum # of Satellites Required-Trilateration Note: with 3 satellites, one point is on the earth’s surface and one is nowhere near. However, we still need the 4th satellite because receiver clocks are inaccurate. 4 satellites – one point 3D GPS Location When There are Only 3 Satellites(2d GPS Location) – Horizontal Error is Greater : When There are Only 3 Satellites(2d GPS Location) – Horizontal Error is Greater Elevation - last known 2-5 X Error Rule Garmin Estimated Accuracy : - Want tetrahedron as large as possible - Want index as low as possible Garmin Estimated Accuracy Relies on Dilution of Precision Ideal Satellite Geometry : Ideal Satellite Geometry N S W E Good Satellite Geometry : Good Satellite Geometry Poor Satellite Geometry : Poor Satellite Geometry Note: if poor satellite geometry, then on the receiver the Accuracy value will be higher Poor Satellite Geometry : Poor Satellite Geometry Note: if poor satellite geometry, then on the receiver the Accuracy value will be higher Poor Satellite Geometry : Poor Satellite Geometry Note: if poor satellite geometry, then on the receiver the Accuracy value will be higher Poor Satellite Geometry : Poor Satellite Geometry Positions Recorded by Stationary GPS Receiver : Positions Recorded by Stationary GPS Receiver Garmin GPSmap76S 1 position/second 10 minutes WAAS Disabled 3.6 meters 3.1 meters Errors : Errors Ionosphere Troposphere Satellite Clock Errors Satellite Ephemeris Errors Multipath Receiver Noise Real Time Ground-based Differential GPS : 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 Real Time Ground-based Differential GPS Slide 28: WAAS satellites GPS Constellation WAAS Control Station(Position known) GPS receiver(Position with errors) Real Time Space-based Differential Correction 25 Reference Stations (Position known) WAAS : WAAS Wide Area Augmentation System WAAS Satellite Errors Reduced by WAAS Correction : Errors Reduced by WAAS Correction Ionosphere Troposphere Satellite Clock Errors Satellite Ephemeris Errors Multipath Receiver Noise Receiving WAAS Correction : Receiving WAAS Correction If WAAS signal intermittent- WAAS correction for SV 19 No WAAS correction for SV 11 Signal Disruption : Signal Disruption Ionosphere Solid Structures Metal Electro-magnetic Fields Good Data Collection Techniques : Good Data Collection Techniques Hold Upright & High External Antenna Sleeve Mounts Vehicle Brackets Map Projections & Coordinate Systems : Map Projections & Coordinate Systems Projecting a Sphere Onto a Plane : Projecting a Sphere Onto a Plane Three-dimensional sphere to two-dimensional flat map. Examples of Several Projections : Examples of Several Projections Depending on the projection, a certain amount of distortion occurs when portraying the earth on paper. Coordinate Systems (Projections) : Coordinate Systems (Projections) We Use – 2 Coordinate Systems Latitude / Longitude Universal Transverse Mercator (UTM) Garmin - 29 Location Formats Latitude & Longitude : Latitude & Longitude Parallels of Latitude : Parallels of Latitude 10º 10º 10º 690 miles 690 miles 690 miles 10º S 0º N 10º N 20º N Meridians of Longitude : Meridians of Longitude 10º 10º 110º W 120º W 690 miles 460 miles 240 mi 10º Equator To North Pole To South Pole Three Ways To Express Latitude / Longitudeon a Garmin : Three Ways To Express Latitude / Longitudeon a Garmin Three Ways To Express Latitude / Longitude(for the Same Location) : Three Ways To Express Latitude / Longitude(for the Same Location) hddd° mm’ ss.s” Degrees-Minutes-Seconds (Decimal Seconds)N 43° 40’ 55.8”, W 116° 17’ 14.1” hddd° mm.mmm’ Degrees-Minutes (Decimal Minutes)N 43° 40.930’, W 116° 17.235’ hddd.ddddd° Degrees (Decimal Degrees) N 43.68216°, W 116.28725° Slide 43: Lat/Long Format Conversion hddd0 mm’ ss.s”: N 430 40’ 55.8” X W 1160 17’ 14.1” (55.8” / 60 = .93’) Different coordinates representing the same location: UTM/UPS: 11T 0557442m E 4836621m N Example: Error in Latitude : Example: Error in Latitude 35° 24´ 45˝ N 35° 24.450’ N 1/3 of a mile Lat / Long Shortcomings : Lat / Long Shortcomings 1 minute ? ? + + + ? Universal Transverse Mercator : Universal Transverse Mercator measured in meters located in zones (1 - 60) include northing and easting are positive Coordinates Zone Easting Northing Latitude Band UTM Zones in the Lower 48 : UTM Zones in the Lower 48 UTM Grid Overlay : 1 60 UTM Grid Overlay 60 Zones, and 20 Latitude Bands Zones Equator UTM Latitude Band : Garmin Uses – UTM bands Bands C - M, southern hemisphere Bands N - X, northern hemisphere UTM Latitude Band Latitude Band We Use – 2 GIS choices UTM Zone _ North UTM Zone _ South no “I” no “O” If You Don’t Know Zone, Latitude Band… : If You Don’t Know Zone, Latitude Band… Entering Waypoints Zone – look up Band – enter any letter N-X for northern hemisphere, receiver will display correct one Collecting Waypoints Receiver figures it out! UTM Location Format on a Garmin : UTM Location Format on a Garmin What is a datum? : What is a datum? Datums : Datums WGS 84 NAD 83 NAD 27 Garmin - >100 Map Datums We Use – 3 Datums 1 meter 10 – 120+ meters Example: Datum Shift in Arizona : Example: Datum Shift in Arizona NAD83 N34.555o, W111.195o NAD27 N34.555o, W111.195o 210 meters Slide 55: With a Garmin GPS Receiver you always collect in the right coordinate system and datum! Lat, Long WGS-84 UTC Always Correct When Collecting! Lat, Long NAD27 -8 GMT UTM NAD83 UTC Lat, Long WGS84 -9 GMT Lat, Long NAD27 -8 GMT UTM NAD83 GMT Lat, Long WGS84 UTC Display doesn’t matter Slide 56: Always Ask When Transferring! Coordinate System? Datum? Review of Topics : Review of Topics - GPS - WAAS - Coordinate Systems - Datums