GPS Receivers <ul><li>University of Manitoba   </li></ul><ul><li>Recreation Services  GPS Workshop.  </li></ul>
What is GPS? <ul><li>GPS is the acronym for  </li></ul><ul><li>Global Positioning System.  </li></ul><ul><li>GPS consists ...
The Short Story! <ul><li>GPS Receiver (Hand Held Unit) </li></ul><ul><li>Triangulation with at least 3 satellites  & a goo...
Where You Are -  Triangulation <ul><li>1 satellite </li></ul><ul><li>2 satellites </li></ul><ul><li>3 satellites (Lat/Long...
Enhancements to Accuracy (WAAS) <ul><li>Wide Area Augmentation System </li></ul><ul><ul><li>Geo-stationary Satellites </li...
Enhancements to Accuracy (DGPS) <ul><li>Differential GPS involves the cooperation of two receivers,  one that's stationary...
 
DGPS Accuracy <ul><li>1-3 meter with U.S. Coast Guard signal </li></ul><ul><li>0.5 cm with local base station (used extens...
Limitations for Hiking <ul><li>Need to see the sky! </li></ul><ul><ul><li>Trees, buildings, mountains, some car windshield...
Sources of Error (~10m) <ul><li>Measures  (some receivers display) </li></ul><ul><ul><li>DOP  (dilution of precision)  </l...
Of Datums and Coordinates <ul><li>Datum </li></ul><ul><ul><li>NAD27 (Canada), NAD83,  WGS84 </li></ul></ul><ul><li>Co-ordi...
 
Some Terms <ul><li>WayPoint </li></ul><ul><li>Bearing </li></ul><ul><li>Track (log) </li></ul><ul><li>Route </li></ul>
Cost: $100-50,000 <ul><li>Based mostly on the need for accuracy </li></ul>
GPS Applications in Agriculture <ul><li>Determine field boundaries </li></ul><ul><li>Crop scouting (maturation, weeds, pes...
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Gps Introduction

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  • Gps Introduction

    1. 1. GPS Receivers <ul><li>University of Manitoba </li></ul><ul><li>Recreation Services GPS Workshop. </li></ul>
    2. 2. What is GPS? <ul><li>GPS is the acronym for </li></ul><ul><li>Global Positioning System. </li></ul><ul><li>GPS consists of a series of </li></ul><ul><li>satellites (24+) that transmit data that allow receivers on Earth to determine their location with great accuracy. Also included in this system are ground stations (5) that are used for detecting and updating errors. Generally we only think about the receivers and call those a GPS or GPS units. </li></ul>
    3. 3. The Short Story! <ul><li>GPS Receiver (Hand Held Unit) </li></ul><ul><li>Triangulation with at least 3 satellites & a good view of the sky (4 satellites needed for X, Y and Z coordinates) </li></ul><ul><li>How accurate? </li></ul><ul><ul><li>± 10-20m (elevation ~ ± 2x horizontal error) </li></ul></ul><ul><ul><li>0.5cm with additional equipment </li></ul></ul>
    4. 4. Where You Are - Triangulation <ul><li>1 satellite </li></ul><ul><li>2 satellites </li></ul><ul><li>3 satellites (Lat/Long 2D) </li></ul><ul><li>4 satellites gives altitude </li></ul>
    5. 5. Enhancements to Accuracy (WAAS) <ul><li>Wide Area Augmentation System </li></ul><ul><ul><li>Geo-stationary Satellites </li></ul></ul><ul><ul><li>~25 ground stations of known location (North America) </li></ul></ul><ul><ul><li>corrects for GPS signal errors caused by ionospheric disturbances, timing and satellite orbit errors </li></ul></ul><ul><ul><li>Improves accuracy to 3-5m </li></ul></ul><ul><ul><li>Limits </li></ul></ul><ul><ul><ul><li>Must have good view of sky </li></ul></ul></ul><ul><ul><ul><li>Antenna/receiver must be powered all of the time. </li></ul></ul></ul>
    6. 6. Enhancements to Accuracy (DGPS) <ul><li>Differential GPS involves the cooperation of two receivers, one that's stationary and another that's roving around making position measurements. The stationary receiver is the key.  It ties all the satellite measurements into a true known position. </li></ul>
    7. 8. DGPS Accuracy <ul><li>1-3 meter with U.S. Coast Guard signal </li></ul><ul><li>0.5 cm with local base station (used extensively in Westside farming) </li></ul>
    8. 9. Limitations for Hiking <ul><li>Need to see the sky! </li></ul><ul><ul><li>Trees, buildings, mountains, some car windshields, etc... </li></ul></ul><ul><li>Only indicates place not movement or direction </li></ul><ul><ul><li>So how does it measure speed and direction? </li></ul></ul><ul><ul><li>Minimum speed ~1.5km/hour (some up to 4km/hour) </li></ul></ul><ul><li>Power </li></ul><ul><ul><li>Bring extra batteries </li></ul></ul><ul><li>Cold/Winter Temperatures </li></ul><ul><ul><li>Power </li></ul></ul><ul><ul><li>LCD Screen </li></ul></ul>
    9. 10. Sources of Error (~10m) <ul><li>Measures (some receivers display) </li></ul><ul><ul><li>DOP (dilution of precision) </li></ul></ul><ul><ul><li>EPE (Estimate Position Error) </li></ul></ul><ul><li>Minimize Error </li></ul><ul><ul><li>Averaging </li></ul></ul><ul><ul><li>Better Satellite Config </li></ul></ul><ul><ul><li>Move to get better sky view </li></ul></ul><ul><ul><li>Re-orient receiver (patch/helix) </li></ul></ul><ul><ul><li>Wait  </li></ul></ul>10.4 meters Total 1.0 meter Multipath 0.5 meters Receiver 0.7 meters Troposphere 2.1 meters Ephemeris 2.1 meters Clock 4.0 meters Ionosphere Value Error
    10. 11. Of Datums and Coordinates <ul><li>Datum </li></ul><ul><ul><li>NAD27 (Canada), NAD83, WGS84 </li></ul></ul><ul><li>Co-ordinate </li></ul><ul><ul><li>Lat/Long (dd.dddd, dd ° hh’mm.ss”) N49°52'10.11&quot; W097°13'45.95&quot; </li></ul></ul><ul><ul><li>UTM/UPS (Zone Easting Northing) 14U 627231 5525622 </li></ul></ul><ul><ul><li>MGRS (Zone GridRef Easting Northing) 14U PA 27231 25622 </li></ul></ul>
    11. 13. Some Terms <ul><li>WayPoint </li></ul><ul><li>Bearing </li></ul><ul><li>Track (log) </li></ul><ul><li>Route </li></ul>
    12. 14. Cost: $100-50,000 <ul><li>Based mostly on the need for accuracy </li></ul>
    13. 15. GPS Applications in Agriculture <ul><li>Determine field boundaries </li></ul><ul><li>Crop scouting (maturation, weeds, pests) </li></ul><ul><li>Soil testing </li></ul><ul><li>Tillage </li></ul><ul><li>Spraying (pesticides, herbicides, fertilizers) </li></ul><ul><li>Yield monitoring </li></ul>
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