Advantages of GNSS | Disadvantages of GNSS
This page covers advantages and disadvantages of GNSS (Global Navigation Satellite System). It mentions benefits or advantages of GNSS and drawbacks or disadvantages of GNSS.
What is GNSS?
The GNSS stands for Global Navigation Satellite System. It consists of global systems and regional systems. Global GNSS systems include GPS (operational in US), GLONASS (in Russia), BeiDou (in China) and Galileo (in Europe). The regional GNSS systems are QZSS (in Japan) and IRNSS (in INDIA). Global systems are further assisted by augmentation systems to deliver better accuracy. These augmentation systems include WAAS, EGNOS, GAGAN and MSAS. GNSS uses concept of Time of Arrival ranging.
The figure depicts GNSS system architecture. As shown, there are three segments in GNSS viz. space segment, control segment and user segment. Space segment for GPS, GLONASS, BeiDou and Galileo are different in terms of number of satellites and their location coverage. Control segment consists of monitoring stations and master control station. Control segment keeps all the information about satellites and helps to keep them in their respective orbits. User segment consists of devices with GNSS receivers to help find their own locations with the help of radio signals received from the GNSS satellites.
• GPS : It uses about 32 satellites across six planes. It is used in United States.
• GLONASS : It uses about 24 satellites across three planes. It is used in Russia.
• BeiDou : It uses about 22 satellites. It is used in China.
• Galileo : It uses about 14 satellites. It is used in Europe. It offers more accurate positioning at high altitudes.
Benefits or advantages of GNSS
Following are the benefits or advantages of GNSS:
➨All the global navigation systems are available at the same time. GNSS leverages benefits of all these systems. It provides more access and availability of signals to operators.
➨GNSS provides accurate timing information which is utilized to develop high precision IoT network.
➨Multiple GNSS constellations improve availability of navigation solution. This improves TTFF(Time to First Fix).
➨It saves time and money by delivering increased location accuracy at enhanced performance.
➨Multiple GNSS systems offer uninterrupted connectivity in all the locations such as dense and vast forest, densely populated city etc.
➨GNSS receivers remove any failed satellite from its list of navigation solution automatically.
Drawbacks or disadvantages of GNSS
Following are the drawbacks or disadvantages of GNSS:
➨It can not support requirements of all phases of flight with stringent precision approaches. Hence augmentation systems are needed along with GNSS systems.
➨Accuracy is not sufficient i.e. vertical accuracy is greater than 10 meters.
➨Availability, integrity, accuracy and continuity requirements are not met and hence augmentation systems (ABAS, GBAS, SBAS) are deployed.
➨GNSS affects aircraft operators, air traffic services, pilots and regulatory personnel.
➨The safety of GNSS navigation depends on accuracy of navigation databases.