Flashcards in this deck (119)

• GNSS stands for Global Navigation Satellite Systems and is a technology that uses satellites to provide accurate positioning and navigation anywhere in the world.
  gnss technology navigation
• The purpose of GNSS is to determine your exact location anywhere on Earth.
  gnss location earth
• Key GNSS systems include GPS (USA), GLONASS (Russia), Galileo (EU), and BeiDou (China).
  gnss systems satellites
• The GNSS system consists of three main components: space segment, control segment, and user segment.
  gnss components navigation
• The space segment of GNSS includes satellites orbiting the Earth that send signals to receivers.
  gnss space_segment satellites
• The control segment consists of ground stations that monitor and control satellites.
  gnss control_segment satellites
• The user segment includes devices like cars, drones, and smartphones that receive satellite signals for positioning and navigation.
  gnss user_segment devices
• GNSS satellites are in medium-altitude orbit (~20,000 km above Earth) and send signals for distance determination, orbit data, and clock data.
  gnss satellites orbit
• Global GNSS systems include GPS, GLONASS, Galileo, and BeiDou, while regional systems include QZSS (Japan) and IRNSS (India).
  gnss global_systems regional_systems
• Comparative statistics for GNSS systems: GPS has 6 orbital planes with 31 satellites, GLONASS has 3 planes with 25 satellites, BeiDou has 6 planes with 29 satellites, and Galileo has 3 planes with 28 satellites.
  gnss comparison satellites
• The inclination angles of the satellites are 55°, 64.8°, 55°, and 56°.
  satellites angles
• The altitudes of the satellites are 20,200 km, 19,100 km, 38,300 km, 21,500 km, and 23,616 km.
  satellites altitude
• BeiDou includes 20 geostationary satellites for regional coverage.
  beidou satellites
• Combining multiple satellite systems allows users to utilize up to 55 satellites simultaneously, improving precision and reliability.
  satellites precision
• Key benefits of using multiple satellite constellations include more accurate positions due to more satellites = better accuracy.
  benefits accuracy
• Using multiple systems ensures global coverage and strong signals worldwide.
  global_coverage signals
• Multi-frequency signals help eliminate ionospheric errors and provide easier fault detection.
  error_mitigation ionospheric_errors
• The GNSS control segment includes components like Master Control Stations, Data Upload Stations, and Monitoring Stations.
  gnss control_segment
• The functions of the control segment include tracking satellite orbits, sending corrected data to users, and adjusting orbital parameters.
  control_segment functions
• The GPS control network consists of 2 Control Stations, 4 Data Upload Stations, and 16 Monitoring Stations.
  gps control_network
• User devices equipped with GNSS antennas calculate position, velocity, and time from satellite data.
  user_devices gnss
• Types of GNSS receivers include Cell Phones, Portable Receivers, and Specialized Receivers.
  gnss receivers
• Single-frequency GNSS receivers typically receive signals from the L1 frequency band, suitable for basic positioning.
  single-frequency gnss
• Dual-frequency GNSS receivers utilize signals from two frequency bands (e.g., L1 and L2) for improved accuracy.
  dual-frequency gnss
• Triple-frequency GNSS receivers use signals from three frequency bands (e.g., L1, L2, and L5) for better accuracy.
  triple-frequency gnss
• Multi-constellation GNSS receivers support signals from multiple satellite constellations like GPS, GLONASS, Galileo, and BeiDou.
  multi-constellation gnss
• Embedded GNSS receivers are integrated into devices like smartphones and vehicle navigation systems.
  embedded_gnss devices
• GNSS signals are radio waves sent by satellites to user receivers, containing essential information for calculating position.
  gnss signals
• Components of GNSS signals include the Carrier Wave and PRN Code (Ranging Code).
  gnss signal_components
• The radio frequency signal (e.g., L1, L2) for GPS serves as the foundation for transmitting data.
  gnss signals gps
• The PRN Code is a unique identification code for each satellite that enables the receiver to determine signal travel time.
  gnss prn_code satellite
• The C/A Code is used for civilian applications, while the P Code is used for military or high-precision tasks.
  gnss codes applications
• The Navigation Message contains satellite health, status, time, and orbital information.
  gnss navigation_message data
• In the signal transmission phase, satellites broadcast signals containing their position and precise time.
  gnss signal_transmission satellites
• Receivers measure the time delay of incoming signals to calculate the distance to each satellite using the formula: Distance = Speed of Light Time Delay*.
  gnss position_calculation formula
• Trilateration is the process of measuring distances from at least four satellites to determine the receiver’s 3D position (latitude, longitude, altitude).
  gnss trilateration positioning
• GNSS provides precise time references critical for synchronization in various applications.
  gnss time_synchronization applications
• The trilateration principle is a mathematical technique used in GNSS to determine a position based on distances from three or more satellites.
  gnss trilateration mathematics
• In trilateration, each satellite's distance defines a sphere around it, and the receiver's location is at the intersection of three or more spheres.
  gnss trilateration spheres
• Adding a fourth satellite improves accuracy and resolves time errors in the receiver’s clock.
  gnss accuracy satellites
• Factors affecting signal strength include satellite factors, atmospheric factors, and user factors.
  gnss signal_strength factors
• Satellite-related errors include clock errors and orbital errors (Ephemeris Errors) that affect accuracy.
  gnss errors accuracy
• Atmospheric delays can be caused by ionospheric delays and tropospheric delays, affecting signal travel time.
  gnss atmospheric_delays signal
• Dilution of Precision (DOP) occurs when satellites are too close together, decreasing positioning accuracy.
  gnss dop accuracy
• Multipath effects occur when signals reflect off buildings or terrain, leading to errors as the receiver processes both direct and reflected signals.
  gnss multipath_effects errors
• Receiver noise can affect signal processing and accuracy due to imperfections in the GNSS receiver hardware or environmental interference.
  gnss receiver_noise accuracy
• GNSS surveying requires a clear line of sight between receivers and satellites.
  gnss surveying principles
• A GNSS receiver determines the distance using code measurements and/or carrier phase measurements on the GNSS signals.
  gnss receiver measurements
• To calculate its position, a GNSS receiver needs distances to at least four satellites.
  gnss positioning satellites
• Sources of errors that affect GNSS surveying include atmospheric delays and multipath.
  gnss errors surveying
• GNSS surveying can be carried out with one or more GNSS receivers.
  gnss surveying receivers
• Absolute positioning uses signals directly from GNSS satellites without external corrections.
  gnss positioning absolute
• Time measurements in GNSS determine how long signals take to reach the receiver from multiple satellites.
  gnss time_measurements satellites
• Pseudorange calculation converts time measurements into distances (pseudoranges) to the satellites.
  gnss pseudorange calculations
• Trilateration uses known positions of satellites and measured distances to compute the receiver's position.
  gnss trilateration positioning
• Relative positioning determines the position of a GNSS receiver (rover) relative to another receiver (base) by processing simultaneous observations.
  gnss relative_positioning observations
• Differencing techniques in relative positioning eliminate common errors like satellite clock errors and atmospheric delays.
  gnss differencing errors
• The base station in GNSS surveying is installed at a precisely known, surveyed point.
  gnss base_station surveying
• The base station continuously collects GNSS signals to compare its derived position with its known location.
  gnss base_station positioning
• Correction data from the base station is transmitted to rover stations in real-time or for post-processing.
  gnss corrections rover
• The rover station moves to various survey points with unknown positions and collects raw measurements.
  gnss rover surveying
• Real-time corrections are transmitted from the base station to the rover via radio, cellular, or internet connections.
  gnss real-time corrections
• Post-processing involves the rover storing data for later correction application during data processing.
  gnss post-processing data
• The rover stores data for later correction application during data processing.
  rovers data_processing
• Permanent Base Stations are fixed stations that are always set up in one place.
  base_stations permanent
• Temporary Base Stations are portable stations set up for specific, short-term tasks.
  base_stations temporary
• Virtual Base Stations (VBS) use data from multiple permanent stations to create a virtual reference.
  base_stations virtual
• Local/Custom Base Stations can be permanent or temporary and are tailored for specific needs.
  base_stations custom
• Mobile Base Stations are mounted on vehicles or movable platforms and provide continuous corrections.
  base_stations mobile
• The SATREF system is Norway’s national system for precise positioning, managed by Kartverket.
  satref positioning
• SATREF consists of a network of geodetic stations spread across Norway.
  satref geodetic
• The SATREF system provides real-time satellite data for creating positioning services.
  satref services
• SATREF enables high-accuracy positioning without the need for users to set up their own base stations.
  satref base_stations
• The SATREF system is monitored from the Norwegian Mapping Authority's control center in Hønefoss.
  satref control_center
• SATREF-based positioning can achieve horizontal accuracy in EUREF89 of 8-14 mm.
  satref accuracy
• Vertical accuracy in EUREF89 for SATREF is 17-30 mm for ellipsoidal height.
  satref accuracy
• Norway offers several positioning services through SATREF, including DPOS and CPOS.
  satref services
• DPOS uses single-frequency code & phase from GPS and GLONASS and offers decimeter-level accuracy.
  dpos gnss
• CPOS provides centimeter-level accuracy using dual-frequency code & phase from GPS and GLONASS.
  cpos gnss
• ETPOS uses RINEX files from all stations for post-processing and can achieve millimeter-level accuracy.
  etpos post-processing
• Web Services offer access to visualization tools and information, such as seSolstorm service for monitoring ionospheric activity.
  web_services visualization
• The EUREF Permanent Network is a network of permanent GNSS stations across Europe providing high-quality GNSS data. There are more than 4,000 GNSS stations in this network.
  gnss euref network
• Data from the EUREF Permanent Network is freely available to the public and can be accessed through sources like the European GNSS Agency (GSA) and the International GNSS Service (IGS).
  gnss data access
• GNSS surveying methods are categorized into two main types: Static Surveys and Kinematic Surveys.
  gnss surveying methods
• Static Surveys involve keeping the GNSS receiver stationary at a point for an extended period, providing the highest accuracy but taking longer to complete.
  gnss static accuracy
• Types of static surveys include: - Static: receiver remains for 1 hour or more - Rapid Static: shorter occupation times of about 15-20 minutes per point.
  gnss static types
• Kinematic Surveys involve a moving receiver, allowing for faster data collection. Types include: - Real-Time Kinematic (RTK): provides real-time corrected positions - Post-Processed Kinematic (PPK): data is processed after the survey.
  gnss kinematic types
• Examples of Static Method applications include: - Mapping and surveying large areas - Monitoring tectonic plate movements - Determining the location and height of static points.
  gnss static applications
• Examples of Kinematic Method applications include: - Navigation of vehicles and aircraft - Surveying difficult areas - Monitoring structural deformation - Agriculture applications.
  gnss kinematic applications
• The Real-Time Kinematic (RTK) Method is used for: - Surveying and construction applications - Precision agriculture - Navigation and mapping - Monitoring land and building deformation in real-time.
  gnss rtk applications
• In Consumer Navigation, GNSS is used for: - Vehicles: GPS for driving directions - Walking: Route guidance on foot - Mobile Devices: Navigation apps on smartphones.
  gnss navigation consumer
• In Aviation, aircraft use GNSS for navigation, planning routes, and making precise landing approaches.
  gnss aviation navigation
• In Maritime applications, ships rely on GNSS for navigation, route optimization, and avoiding collisions.
  gnss maritime navigation
• In Surveying and Mapping, GNSS is used for accurate land surveying, mapping, and cartography positioning.
  gnss surveying mapping
• In Timing and Synchronization, GNSS is used for precise timekeeping in telecommunications networks and for timestamping transactions in financial institutions.
  gnss timing synchronization
• In Precision Agriculture, GNSS aids in precise tractor guidance, yield mapping, and variable rate application of fertilizers.
  gnss agriculture precision
• Institutions use precise timing for timestamping transactions.
  technology transactions
• In Precision Agriculture, GNSS aids in precise tractor guidance, yield mapping, and variable rate application of fertilizers and pesticides.
  agriculture gnss
• In Search and Rescue, GNSS helps locate distressed individuals, especially in remote areas or during natural disasters.
  disaster emergency gnss
• Accurate positioning is crucial for coordinating emergency response efforts.
  emergency response
• Military operations rely on GNSS for accurate navigation and target tracking.
  military navigation
• GNSS is used for precision-guided munitions in missile guidance.
  military missiles
• GNSS data assists in atmospheric sensing, contributing to more accurate weather predictions.
  weather forecasting
• In Earth Science, GNSS helps monitor tectonic plate movements, earthquakes, and changes in the Earth's atmosphere.
  science earth
• GNSS contributes data to monitor sea-level changes and polar ice melting in climate studies.
  climate studies
• In Fleet Management, GNSS tracks and manages vehicles in logistics and transportation companies.
  transportation fleet
• GNSS aids in route planning and tracking for trains and public transportation.
  transportation public
• Tracking valuable assets using GNSS is crucial for logistics and inventory control.
  asset management
• Wearable devices and smartphones use GNSS for location-based services and fitness tracking.
  personal tracking
• Indoor usage of GNSS is still a challenge, though it is improving.
  gnss limitations
• Accuracy of GNSS can be limited due to various factors.
  gnss limitations
• Multipath issues, such as the urban canyon effect, impact GNSS accuracy.
  gnss multipath
• Using GNSS can lead to a drain on power for devices.
  gnss power
• Additional resources include Textbook: Grunnleggende Landmåling and Websites: Satellite navigation – Wikipedia.
  resources education
• For more information, visit Wikipedia or NovAtel's website about GNSS.
  resources gnss
• The guide to CPOS can be found on the Kartverket.no website.
  resources cpos
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