Global Navigation Satellite System
GNSS
Global Navigation Satellite System (GNSS) technology originated with the development of the Global Positioning System (GPS) by the U.S. Department of Defense in the 1970s. Initially conceived as a military tool for precise global navigation, the first GPS satellite was launched in 1978, with the system becoming fully operational in 1995. Following the success of GPS, other nations developed their own GNSS systems. As GNSS technology has advanced, reliance on location-based services has grown significantly. Annual global shipments of GNSS devices are expected to continue rising over the next decade, reaching more than 2.2 billion units by 2033. Furthermore, services enabled by GNSS devices are projected to generate over 80% of total GNSS revenues by that time. In this blog, we will explore some of the key GNSS technologies that have become essential knowledge for design engineers.
GNSS Constellations
The constellation selection has increased significantly over the past decade, to include:
- • GPS (United States)
- • GLONASS (Russia)
- • BeiDou (China)
- • Galileo (Europe)
- • IRNSS (India)
- • QZSS (Japan)
Multi-Constellations and Multi-Frequencies
Using multiple GNSS constellations increases the number of satellites in the receiver’s field of view. Every GNSS constellation has multiple signals, each operating at its own frequency. This design enhances accuracy, as receivers can use two frequencies to reduce errors caused by the ionosphere. Additionally, using multiple frequencies improves the likelihood of signal availability when needed. The receiver needs to receive signals from as many satellites as possible for higher accuracy. For a deep dive into the GNSS constellations and navigating the L1, L2 and L5 Band Options for GNSS read our blog below.
Navigating the L1, L2 and L5 Band Options for GNSS
Read the blogGNSS Applications
Advancements in antenna and receiver technology make multi-band options appealing. However, the choice between single and dual-band depends on the application. An excellent way to gauge whether your application requires high precision is if the product needs to know where it is, then you need to look at a high-precision solution; if a person needs to know where it is, then you will need a standard solution. The table on the right is a helpful guide on the preferred GNSS bands used by application.
GNSS Antennas
A GNSS antenna receives signals from GNSS satellites, which provides data on the satellite’s geolocation and the time the signal was sent. This data allows the receiver to calculate its position on Earth accurately. The effectiveness of a GNSS antenna directly influences the accuracy and reliability of the positioning system. GNSS antennas come in many sizes and form factors from chip, flexible PCB, and patch to dipole and helical.
The type of antenna you choose for your device will depend on the commercial application of the device. Key considerations include (but aren’t limited to) the device’s application/use case, the type of enclosure you need, how much space is available, what kind of directionality is required, if the device is static or mobile and how you will connect the antenna. Selecting the right GNSS antenna is a critical decision that shapes the accuracy and efficiency of your entire system. The typical parameters you need to consider for your GNSS antenna’s performance are the Antenna Gain, Axial Ratio, Phase Centre Offset (PCO), Phase Centre Variation (PCV) and Group Delay. The graphic below further demonstrates these characteristics in detail.
GNSS Receivers
Selecting the correct radio module plays a crucial role in boosting the precision and reliability of your device. To maximize your GNSS receiver's capabilities, choose a device that offers access to a wide range of constellations and bands. This will ensure that your receiver can tap into the signals transmitted by multiple satellite systems, enabling you to benefit from a larger pool of measurements and achieve enhanced accuracy in your positioning calculations and improved positioning performance. The accuracy of a GNSS receiver is heavily dependent on the quality of its antenna. A poor-performing antenna can introduce errors in the positioning data, leading to reduced accuracy and sub-par performance.
What you need to know
Active or Passive Antennas?
Choosing the most suitable GNSS antenna is a complex decision that requires careful consideration and expert guidance. The antenna you choose can significantly impact the performance of your GNSS solution, making it essential to consult expert advice early in your integration journey. If you are still searching for your ideal GNSS antenna solution, consult expert advice from Taoglas' Engineering team. Our global engineering team can help you understand everything you should consider. Alternatively, take a deep dive into further reading on GNSS antennas below.
