DOC PREVIEW
Rutgers University MS 552 - Orbits and Measurement Geometry

This preview shows page 1-2-17-18-19-35-36 out of 36 pages.

Save
View full document
View full document
Premium Document
Do you want full access? Go Premium and unlock all 36 pages.
Access to all documents
Download any document
Ad free experience
View full document
Premium Document
Do you want full access? Go Premium and unlock all 36 pages.
Access to all documents
Download any document
Ad free experience
View full document
Premium Document
Do you want full access? Go Premium and unlock all 36 pages.
Access to all documents
Download any document
Ad free experience
View full document
Premium Document
Do you want full access? Go Premium and unlock all 36 pages.
Access to all documents
Download any document
Ad free experience
View full document
Premium Document
Do you want full access? Go Premium and unlock all 36 pages.
Access to all documents
Download any document
Ad free experience
View full document
Premium Document
Do you want full access? Go Premium and unlock all 36 pages.
Access to all documents
Download any document
Ad free experience
View full document
Premium Document
Do you want full access? Go Premium and unlock all 36 pages.
Access to all documents
Download any document
Ad free experience
Premium Document
Do you want full access? Go Premium and unlock all 36 pages.
Access to all documents
Download any document
Ad free experience

Unformatted text preview:

Slide 1Slide 2Slide 3Slide 4Slide 5Slide 6Slide 7Slide 8Slide 9Slide 10Slide 11Slide 12Slide 13Slide 14Slide 15Slide 16Slide 17Slide 18Slide 19Slide 20Slide 21Slide 22Slide 23Slide 24Slide 25Slide 26Slide 27Slide 28Slide 29Slide 30Slide 31Slide 32Slide 33Slide 34Slide 35Internet resources on orbits and satellitesRemote Sensing of the Oceanand Atmosphere: John L. WilkinOrbits and Measurement Geometry (1)[email protected] Building Room 214C609-630-0559 (g-voice)The flow of information from land or sea surface to satellite to user depends on features of the land/ocean phenomena, the observing system, and the intervening atmosphere. (1) Ocean phenomena: color, temperature, roughness, height (2) Water leaving signal: WLR can depend on relative position of sun and satellite, time of day, emissivity, reflectance (3) Sensor: the data is a measurement or image (4) resolution: FOV, aperture, scan geometry can depend on satellite trajectory and altitude (orbit), pointing (5) Geolocation: position, time, pointing. Orbit affects repeat sample interval (6) Position of the satellite, or range to target may be the actual data.1. Planets move in elliptical orbits with the sun as one focus2. the radius vector from the sun to the planet sweeps out equals areas in equal times3. T2 : R3 ratio is constant for all planets, where T is orbital period and R is semi-major axis of the orbitJohannes Kepler (1571 – 1630) German mathematician, astronomer and astrologer1. Newton discovered the laws of gravitation and explained planetary and satellite orbits in terms of the balance of forces:2. Centripetal acceleration3. Gravity Isaac Newton (1643 - 1727) English physicist, mathematician, astronomer, theologian)F =ma =mdvdtFgravity=GMmr2Galileo Galilei (1564 - 1642)Italian physicist, mathematician, astronomer, and philosopher Galileo's pupil Vincenzo Viviani stated that Galileo had dropped balls of the same material, but different masses, from the Leaning Tower of Pisa to demonstrate that their time of descent was independent of their mass. This was contrary to what Aristotle had taught: that heavy objects fall faster than lighter ones, in direct proportion to weight.There is no account by Galileo himself of such an experiment, and it is generally accepted that it was at most a thought experiment which did not actually take place.v1-v1Δvv2v2ΔθΔθΔs = rΔθchange in velocity (acceleration) is perpendicular to the direction of travel v =ΔsΔt=rΔθΔt=rdθdt⇒dθdt=vrNov 5, 2007 view from Space ShuttleEpoch (UTC): 10:07:53 AM, Monday, January 28, 2008Eccentricity: 0.0005362Inclination: 51.6418°Perigee Height: 334 kmApogee Height: 341 kmRight Ascension of Ascending Node: 22.2238°Orbit Number at Epoch: 52631Revolutions per Day: 15.77540422John L. WilkinOrbits and Measurement Geometry (2)[email protected] Building Room 214C609-630-0559 (g-voice)Remote Sensing of the Ocean and Atmosphere:Stewart, R. H., 1985, Methods of Satellite Oceanography, University of California Press, 360 pp. x-axisRight ascension - declination coordinate systemFirst Point of Aries: One of the two points on the Celestial Sphere where the Ecliptic and the Celestial Equator cross one another. Ecliptic: An imaginary line in the sky that approximates the plane in which the planets orbit the Sun. From the perspective of an observer on Earth, the planets and the Sun will always remain close to this line. When the Sun reaches the First Point of Aries, as it does once each year, the Northern hemisphere Vernal Equinox occurs.The First Point of Aries, which is actually in Pisces, defines the zero-point for Right Ascension.Right ascension: the celestial equivalent of longitude (starting at the First Point of Aries)Declination: the celestial equivalent of latitudeThe celestial north pole is at declination +90http://spaceflight.nasa.gov/realdata/elements See graphics of orbital elements and data for ISSOSTM / Jason-2 Boost ProfileSpace craft separation:http://www.youtube.com/watch?v=1aBpcCVljt4Jason-1 launch from Vandenburg Air Force Base, CaliforniaLaunch: ** http://www.youtube.com/watch?v=Z4WHOSF2Ktg Pegasus vehicle aircraft launch http://www.youtube.com/watch?v=QRHiTvRHHd8 Other launches:Delta-II (Themis):http://www.youtube.com/watch?v=p_pAhPecto0Ariane launch failure:http://www.youtube.com/watch?v=kYUrqdUyEpI Jason-2 OSTMhttp://www.youtube.com/watch?v=cf0loVEs_lo Space craft separation:http://www.youtube.com/watch?v=1aBpcCVljt4On Jan 11, 2007, China tested anantisatellite rocket. The initial collisionadded 800 to 1000 pieces of space junkto the current total of “detectable” objects. Kessler, D. J., and Burton G. Cour-Palais. "Collision frequency of artificial satellites – The creation of a debris belt." Journal of Geophysical Research Vol. 83 (June 1978): 2637-2646. Collisions between existing debrisgenerate additional pieces of debris.There is concern that eventually a chainreaction will ensue (the Kesslersyndrome) littering the low earth orbit(LEO) with debris making it almostimpenetrable to new satellite launches forfear of collision. How many detectable objects (> 4inches) are in orbit?http://www.nytimes.com/2007/02/06/science/space/06orbi.html?emc=eta1http://www.nytimes.com/2007/02/06/science/20070206_ORBIT_GRAPHIC.htmlostm-topex-5days-orbit animationSeaWiFS daily coverageseawifs_daily_coverage animationIs this orbit prograde or retrograde?Terra satellite, MODIS instrument, coverage of all instrument swaths during a single day ( 01/28/2006 )Jason altimeter satelliteEquatorial separation of Jason groundtracks is 315 kmENVISAT 35-day repeatSidereal day = time it takes for Earth to rotate through 360o This is slightly shorter than a solar day (24 hours)There are 365.25 solar days in a year but 366.25 sidereal daysSidereal day = 365.25/366.25*24 = 23.93 hourssiderealsolarhttp://en.wikipedia.org/wiki/Sidereal_timehttp://en.wikipedia.org/wiki/Hohmann_transfer Maneuver to different inclination Hohmann TransferScan geometry• zenith angle w.r.t. satellite nadir• look angle and solar zenith angle w.r.t local vertical• Fixed solid angle Field of View (FOV) such as for an optical lens, gives elliptical footprint off-nadir and varying spatial resolution in the scanPanoramic distortionNOAA AVHRRPixels 2.89 times bigger if earth flatPanoramic distortionNOAA AVHRRPixels 2.89 times bigger if earth flatPixels 4.94 times bigger if earth roundRotating mirror continuous scan e.g.


View Full Document

Rutgers University MS 552 - Orbits and Measurement Geometry

Download Orbits and Measurement Geometry
Our administrator received your request to download this document. We will send you the file to your email shortly.
Loading Unlocking...
Login

Join to view Orbits and Measurement Geometry and access 3M+ class-specific study document.

or
We will never post anything without your permission.
Don't have an account?
Sign Up

Join to view Orbits and Measurement Geometry 2 2 and access 3M+ class-specific study document.

or

By creating an account you agree to our Privacy Policy and Terms Of Use

Already a member?