5 types of GNSS that you need to know.
What is GNSS?
GNSS is an umbrella term that refers to various satellite navigation systems used for positioning, navigation, and timing services. This permits users to accurately determine their geographic location, track their movements, and access location-based services and applications.
The GNSS works by receiving and processing signals from these satellite constellations. The GNSS receiver chip within the smartphone calculates the device's position by measuring the time it takes for the signals to travel from multiple satellites to the receiver. This process, known as trilateration, enables the determination of precise latitude, longitude, and altitude coordinates.
The GNSS hardware components in smartphones including the GNSS receiver chip, antennas, and supporting circuitry designed and manufactured by specialized semiconductor companies such as Qualcomm, Broadcom, MediaTek, and others.
GPS (Global Positioning System)
Developed and operated by the United States. GPS is the most widely used GNSS worldwide.
It consists of a constellation of 24 satellites orbiting the Earth transmitting precise time and position data.
Smartphones receive signals from multiple GPS satellites to triangulate their location with remarkable accuracy.
GALILEO
GALILEO is the European Union's global navigation satellite system designed to provide an alternative to GPS.
It currently has 28 operational satellites in orbit with plans to expand to a total of 30 satellites.
GALILEO offers improved positioning accuracy and reliability compared to GPS, especially in urban environments.
GLONASS (Global Navigation Satellite System)
Developed and operated by Russia, GLONASS is another GNSS that complements GPS and GALILEO.
It currently has 24 operational satellites in orbit providing global coverage.
GLONASS enhances positioning accuracy by providing additional satellite signals for triangulation.
QZSS (Quasi-Zenith Satellite System)
Developed by Japan, QZSS is a regional navigation satellite system designed to augment GPS coverage in Asia-Oceania regions.
It consists of four satellites in highly inclined orbits providing superior coverage in urban areas and mountainous regions.
QZSS improves positioning accuracy and availability in areas where GPS signals may be obstructed.
BDS (BeiDou Navigation Satellite System)
Developed and operated by China, BDS is a GNSS that provides global coverage with a constellation of 35 satellites.
It offers an alternative to GPS, GALILEO, and GLONASS, providing independent positioning capabilities.
BDS enhances positioning accuracy and reliability, especially in Asia-Pacific regions.
Main features of GNSS
Positioning and Navigation: The primary function of GNSS is to provide accurate position and navigation information. Smartphones can determine their latitude, longitude, altitude, and speed for various location-based services and navigation applications.
Assisted GPS (A-GPS): Most modern smartphones use A-GPS technology. This enhances the speed and accuracy of the initial position fix. A-GPS combines satellite data with additional information from cellular networks or internet sources reducing the time required to acquire satellite signals.
Sensor Fusion: GNSS receivers in smartphones often work in conjunction with other sensors such as accelerometers and gyroscopes to improve positioning accuracy and provide a navigation experience.
Augmentation Systems: Smartphones can leverage augmentation systems like WAAS (Wide Area Augmentation System), EGNOS (European Geostationary Navigation Overlay Service), and MSAS (Multi-functional Satellite Augmentation System) to improve the accuracy and reliability of GNSS signals.
Location-based Services: GNSS helps a wide range of location-based applications and services including real-time traffic updates, geo-fencing, location-based advertising, and location sharing.
Emergency Services: GNSS plays a crucial role in emergency services by providing accurate location information for emergency calls, faster response times, and improving public safety.
Time Synchronization: GNSS signals provide precise time information for synchronization of network systems, financial transactions, and other time-critical applications.
Real-Time Kinematics (RTK): Some high-end smartphones incorporate RTK technology, which uses carrier phase measurements from GNSS signals to achieve centimeter-level positioning accuracy. This feature is particularly useful for applications like precise surveying, construction, and agriculture.
Geofencing: GNSS in smartphones helps geofencing capabilities, which permit applications to trigger actions or notifications when the device enters or exits a predefined geographic area. This feature is widely used in location-based services, asset tracking, and security applications.
Augmented Reality (AR) and Mixed Reality (MR): The GNSS feature combined with other sensors like cameras and inertial measurement units (IMUs) for augmented reality and mixed reality applications in smartphones for the integration of digital content with the real-world environment.