test Answer

• GPS receiver


  Needs 4 satellites in view from a point in time to do measurements
• GPS system


  • Has 24 satellites in orbit
• Ionospheric error


  Contributes to errors in GPS system by estimate of ± 0.5
• L1 frequency


  Carries CA code, P-code and Navigation message
• WAAS


  An SBAS built by USA
• GNSS


  • Comprises 4 systems
• Satellite Based Augmentation


  • There are 4 to improve the Navigation safety in GNSS
• Geographic coordinate system


  Formats are Latitude, Longitude and Height
• Geodesy


  Has 1 surface
• Geodetic surface that GPS/GNSS measurements are done

  Reference Ellipsoid
• Datum


  Point of reference where all the measurements are tied to
• SBAS


  Satellite Based Augmentation system
• Geodesy


  The science which determines the size and shape of the Earth, The precise positions and elevations of points, lengths and direction of lines on the earth's surface, and the Terrestrial Gravity and its variation
• Reference Ellipsoid


  Usually defined by semi major (equatorial radius) and flattening (the relationship between equatorial and polar radii). It is the mathematical surface that best fits the physical Earth
• UTM


  Universal Transverse Mercator
• GPS


  Has 24 satellites in orbit that makes up the system and has multiple errors
• GNSS


  GPS plus other Satellite based systems which all help in improving the accuracy and precision of point positioning on earth Surface and supports safety of navigation
• Pseudo-random code strings used by GPS

  • Coarse Acquisition Code (C/A-code), sometimes called the "Civilian Code"
  • Precise, or Protected Code (P-Code)
• Augmentation Systems to improve and correct the errors on Satellite positioning

  • WAAS
  • EGNOS
  • MASAS
  • GAGAN
• WGS84


  Derived its positioning from Earth Centered, Earth Fixed X, Y, and Z