Home Blogs How GNSS works?

How GNSS works?

2 Minutes Read
Do you know how GNSS works? How the tiny flocks of satellite gives the exact navigation point? Here is all about the magic, the magic of navigation by GNSS.

how gnss works Globalย Navigationย Satellite System, popularly known as GNSS, isย aย satelliteย navigation or satnavย systemย that uses small satellitesย to pinpoint the geographic location of a user’s receiver on Earth.

The technology was initially developed by US Air Force as the Global Positioning System (GPS) and was restricted to only the countryโ€™s defense forces is now in everyoneโ€™s hands. The advent of smartphones has made the technology even more accessible, and with time other GNSS systems have also come up. As of now, Russiaโ€™s GLONASS and European Unionโ€™s Galileo are other two operational global navigational systems. Galileo will be fully operational by 2020.

And then there are regional navigational systems โ€“ Chinaโ€™s BeiDou, Indiaโ€™s Indian Regional Navigation Satellite Systemย or IRNSS (later renamed NaviC) and Japanโ€™s Quasi-Zenith Satellite System or QZSS. China is in the process of expanding BeiDou into the globalย BeiDou-2 GNSSย by 2020.

So how GNSS works?

While GNSS satellites vary in age and design, their principal operation remains the same. The satellites transmit two carrier waves in the L-Band referred to as L1 and L2. The carrier waves transmit information from the satellite to the earth.

Most GNSS receivers have two parts โ€” antenna and processing unit. The antenna receives satellite signals while the processing unit makes sense of it. To determine the position of the receiver it needs to collect information from a minimum of three satellites.

GNSS satellite orbits Earth once every 11 hours, 58 minutes and 2 seconds at a medium-orbit altitude. Each satellite transmits coded signals which contain the satelliteโ€™s precise orbit details and a very stable time stamp from an atomic clock.

Also Watch –ย Know all about navigation โ€“ The world of GNSS

The time information broadcast as codes by the satellite so that a receiver can continuously determine the time the signal was broadcast. The signal contains data that a receiver uses to compute the locations of the satellites and adjust for accurate positioning. The receiver uses the time difference between the time of signal reception and the broadcast time to compute the distance, or range, from the receiver to the satellite. When the receiver knows the precise position of itself with respect to each satellite, it translates its own position into an Earth-based coordinates system, thus gives the result in latitude, longitude and height.

Watch this descriptive video too, to know the working of GNSS.

Former Correspondent, Geospatial Media & Communications. A poet at heart, Mahashreveta is what it takes to be a new-age digital journalist. Be it tech-heavy conference coverage, quick blogs, or elaborate magazine stories, she always put her best foot forward. An M.Phil in Media Studies, Mahashreveta has wide experience in video production, and in her earlier stints, she has worked on notable documentaries on art and culture. In her free time, she loves to try her hands at photography.