Worldwide Situating Frameworks (GPS) for Exactness Cultivating.


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The Global Positioning System (GPS) is an overall radio-route framework shaped from a group of stars of 24 satellites and their ground stations ...
Transcripts
Slide 1

´╗┐Worldwide Positioning Systems (GPS) for Precision Farming An Introduction

Slide 2

The arrangement Introduction to GPS What is GPS How GPS functions Differential Correction Integration and use of GPS into PF frameworks

Slide 3

Introduction to GPS What is GPS The Global Positioning System (GPS) is an overall radio-route framework shaped from a group of stars of 24 satellites and their ground stations GPS beneficiaries utilize these satellites as reference focuses to figure positions and time Originally known as NAVigation System with Timing And Ranging (NAVSTAR)

Slide 4

How GPS Works (Six Steps) 1. Triangulation 2. Separation 3. Timekeepers 4. Satellite Position 5. Coordinate framework 6. Mistakes

Slide 5

Triangulation Number of Satellites One separation = circle Two separations = circle Three separations = two focuses Four separations = one point Three separations + earths surface = one point Locking 1,2 satellites - No lock, course time 3 Satellites - 2D situating (Earth\'s surface expected) 4 Satellites - 3D situating (Lat/Lon/Alt)

Slide 6

Triangulation - basic focuses Position is figured from separation estimations (extents) to satellites. Numerically we require four satellite reaches to decide definite position. Three territories are sufficient on the off chance that we dismiss absurd answers or utilize different traps. Another reach is required for count of time.

Slide 7

Distance = Speed x Time ? 180 miles = 60 miles for each hour x 3 hours Speed of radio waves ? 186 kmps Time 0.06 second Distance = 186000 mps x 0.06 s D = 11,160 miles (11Hr 58 Min period) Accuracy (+/ - 0.000,000,001 sec) = +/ - 1 ns

Slide 8

Distance How does a beneficiary time the sign travel? Satellites send a pseudo-arbitrary code (each sends its own melody of 1\'s and 0\'s) Receiver coordinates its figured arrangement with the got signal by deferring pretty much it\'s flag The measure of postponement = the travel time! How does the collector isolate the signs of each of the satellites? Every satellite has it\'s own particular succession (tune) figured through an equation Formula is passed on in information from the satellites

Slide 9

Distance - basic focuses Distance to satellites is dictated by measuring signal travel time. Accept satellite and GPS collector create same pseudo-arbitrary codes in the meantime. By synchronizing the pseudo-arbitrary codes, the deferral in accepting the code can be found. Increase delay time by the pace of light to get separation

Slide 10

Synchronization Satellites timing is to a great degree exact. exact nuclear tickers on board. Every single satellite clock are synchronized and they send their codes at a known time Ground GPS unit synchronizes its clock with the satellites Four satellites with same time = one and only right answer for 1. time and 3. separations (4 Equations, 4 questions)

Slide 11

Synchronization - basic focuses Accurate planning permits separation to satellites to be measured Satellites accomplish precise planning with on-load up nuclear tickers. Collector timekeepers can be precise on the grounds that an additional satellite extent estimation can expel blunders.

Slide 12

Where are the satellites? (ephemeris) Satellites are propelled into exact circles GPS recipients utilize a chronicle to ascertain precise positions for the satellites (ephemeris) Almanac is sent from satellites US Airforce measures mistake in ephemeris (satellite position and speed) when they fly over C. Springs Corrected ephemeris data is sent up to the satellite

Slide 13

ephemeris - basic focuses Satellite position (ephemeris) must be known as a kind of perspective for extent estimations. GPS satellite circles are extremely unsurprising. Minor varieties in their circles are measured by the Department of Defense. The ephemeris blunder data is sent to the satellites, to be transmitted alongside the planning signals.

Slide 14

Coordinate Systems ECEF Coordinates Latitude/Longitude/Altitude Degrees Minutes Seconds (Ag Hall, OSU USA) Latitude 36 0 07\' 29" N Longitude 97 0 04\' 21" W Latitude = degrees from equator N or S Longitude = degrees from Greenwitch E or W Altitude = Meters above reference geoid GPS utilizes WGS84 Ellipsoid (ECEF) Can be changed to others: NAD27, NAD83 See: Peter Dana\'s Web website

Slide 15

Coordinate Systems UTM Cartesian situating in meters Abbreviation for " Universal Transverse Mercator" Divided into cartesian zones 6 0 wide, 84 0 North to 80 0 south Reference Specifies a beginning stage for estimation eg.: (NAD 1927) Important to represent mistake between review reference and genuine lat/lon

Slide 16

Computation of separation along Longitude South

Slide 17

Computation of separation along Latitude South

Slide 18

Error Budget Trimble Navigation Limited

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