Geography 2122A/B Chapter Notes - Chapter 14: Geostationary Orbit, Medium Earth Orbit, Glonass
26 Nov 2014
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Document Summary
Space segment- constellation of gps" positioned in medium earth orbit @ alt. 20. 2km, below geostationary orbit, used for weather satellites. Control segment- satellites as references for position finding. Ephemeris- describes each of the satellites positions at all times. User segment- the receiver of the gps- radio freq. selective availability. Dod- intended errors of up to 100m to through of enemies -discontinued the future of gps. Sidereal day- the period it takes for the earth to complete one rotation about it"s axis with respect to the stars. Ranging- finding distance from one place to another. Geoid- gravity surface relative to mean sea level. Multipath error- reflection of signal off other objects. Ephemeris bias- relates to error in the position of the satellite due to earth"s pull. Dop- dilution of precision (geometric, position, time, horizontal, vertical) Carrier phase enhancements- use higher frequency satellites (real time kinematic navigation) Gps augmentation- gps used alongside peripherals/external info for better accuracy.
