Fundamental of GNSS

Cards (18)

  • GNSS Consists of

    • GPS
    • Glonass
    • Galileo
    • Beidou
    • SBAS
  • SBAS
    • Function is to enhance the Basic systems above and the primary objective is for navigation safety
    • WAAS
    • EGNOS
    • MASAS
    • GAGAN
  • GPS-Glonass
    Outcome of differences of capabilities and outcome for precision but Glonass so far has 9 Satellites operational
  • Galileo
    • Truely a system of innovations that their objective is more with the safety of public in navigation and transport systems –benefit of Institutions and Organisations
  • Common Attributes

    • Satellite Components
    • Ground and Geosystem Control Stations
    • User Segment
  • GPS Signal Frequencies

    • L1 on 1575.42 Mhz
    • L2 on 1227.6 MHz
    • L5 on 1176.45 MHz
  • GPS has L3 and for Atomic Bomb detection and also adding the L5 for safety in the modernisation program
  • Galileo is almost like GPS but compared to GPS is the implementation of global/regional segments for integrity monitoring
  • Galileo Objective

    • To assist the Safety critical aircraft navigation, locate and guide railway trains operations
  • ECEF (Earth Centred, Earth Fixed) Geocentric System

    Relationship with the Geographic System Lat, Long and Height
  • Galileo Refers to Galelio Terrestrial Reference Frame (GTRF) similar to ITRF
  • GTRF and WGS84 differ by few cm
  • Glonass- PZ90 Coordinate System ITRF of WGS84 System and on ECEF system
  • IERS does the transformation of the system
  • Observation Techniques

    Measure the difference of time travel from the satellite to the receiver to compute location and time
  • Signal Frequencies

    • Code Pseudorang Measurments for very basic Receivers- Standalone
    • Phase Pseudorange for High Precision Receivers
  • System Observable Errors

    • Satellite Clock Errors
    • Orbit Errors (Satellite Drift)
    • Ionospheric
    • Tropospheric
    • Receiver Clock
    • Multipath
  • GNSS Positioning Techniques

    • Single Point Positioning
    • Differential Positioning