It’s Time to Pay Attention to Antennas for Precise GNSS Positioning

GNSS provides the ability to accurately locate devices down to the centimeter level anywhere on the planet’s surface provided that connectivity isn’t interrupted by obstructions or interference. To avoid these issues, GNSS antenna performance has become a fundamental requirement for precise GNSS-enabled positioning.

With annual shipments of global navigation satellite system (GNSS) devices predicted to increase from 1.6 billion units in 2023 to 2.2 billion units in 2033, according to research from The European Union Agency for the Space Programme (EUSPA), it’s clear the benefits of utilizing the technology are now well-understood. The organization predicts the value of GNSS device sales will grow from approximately €70 billion (US$78.2bn) in 2023 to almost €120 billion (US$134bn) in 2033. While the market continues to mature, the stock of GNSS devices installed worldwide will continue to grow accompanied by greater growth of ancillary components such as antennas.

The EUSPA research estimates the installed base of GNSS devices will hit almost 9 billion units by 2033. Mass market segments will dominate revenues while professional markets will make a significant contribution to the value of the GNSS sector, with applications such as smart agriculture, urban development, infrastructure and cultural heritage all helping to drive growth.

Analysis by ABI Research supports EUSPA’s projections. The firm has explored how the antenna market is evolving to address challenges specific to IoT and finds that growing competition and technology complexity will drive 7.2 billion IoT antenna shipments in 2025. With billions of connected devices comes the need for billions of antennas but antennas are often overlooked in the design phase of IoT devices and this can lead to significant delays in time-to-market as re-engineering work is needed. If this is overlooked, it can result in devices that perform sub-optimally in the form of increased power consumption, lack of connectivity or poor connectivity performance. It’s therefore important that antenna considerations are taken into account early on in and properly integrated into the overall device design.

Antenna selection

As deployments increase in scale, mistakes are magnified so it’s essential to assess carefully which types of GNSS antenna to use, where antennas should be positioned, whether to accommodate multiple antennas to aid resilience and location accuracy and whether to look to vendors who can provide pre-integrated antenna and module solutions.

Broadly speaking, there are three they different types of GNSS antennae: embedded, external and combo. Embedded antennas, which are integrated within IoT devices, are more complex to design for than external antennas, which are mounted to the outside of devices and are easier to add retrospectively with fewer integration issues.

External antennas for GNSS are typically patch or helix (quad-helix) antennas which are capable of achieving high-precision positioning. Mounting antennas externally to the product’s electronics means there is less risk of interference, electromagnetic compatibility (EMC) issues and fewer size constraints. Combination antennas are externally mounted and combine multiple technologies in a single product. It’s not uncommon to see 8-in-1 combo antennas that accommodate several cellular variants, multiple satellite bands and other low-power wireless technologies in a single unit.

Unlike external antennas, embedded antennas require experienced engineers and specialized equipment to test and tune the antenna to its unique RF environment. Without these inputs, external antennas will not work as per the datasheet. The ideal position for a directional GNSS antenna is above all other components, directly facing the sky. When this is not possible there are options to use an external antenna or a larger more complex embedded antenna. Further options include changing the mechanicals of the device to improve the antenna position or selecting a better receiver to achieve the desired accuracy. This highlights the need for antenna planning early in the design phase.

Within these categories there are huge variables from the mounting location and method to how the GNSS antenna is packaged, connected and supplied. Vendors with comprehensive ranges offer the greatest flexibility and can help to ensure developers can select the optimal antenna for their use case. The use cases themselves are becoming increasingly diverse and demanding, with positioning emerging as a critical technology in several industries and for multiple use cases.

Achieve accurate location information

GNSS is now utilized to achieve precise positioning of everything from robot lawnmowers to heavy equipment and ride-sharing vehicles but the technology, in spite of offering ubiquitous coverage of the entire surface of the planet, does suffer from coverage interruptions that need to be mitigated. These are caused by obstructions such as clouds, rain and vegetation, signal issues in dense urban canyons and the multi-path effect. This occurs when a device antenna receives signals via two or more paths and significantly impacts geolocation accuracy and direction finding. These obstructions combine to make uninterrupted positioning via GNSS unrealistic and prevent precise device location information from being shared effectively.

For some applications, such as tracking the approximate position of a ship on an ocean, this is simply an inconvenience and the ship can connect again quickly enough for the service to appear uninterrupted. However, for others, it’s a mission-critical, service-affecting issue. A ride-sharing vehicle such as an e-scooter, for example, might rely on GNSS to ensure it cannot enter a geofenced area such as a highway or a pedestrian area. Being unaware of the precise location hinders this essential performance characteristic. Similarly, if a customer is unable to locate the scooter, they can’t start their ride and revenue is potentially lost.

High-precision GNSS antennas

A large and still rapidly growing range of IoT applications relies on high-precision GNSS to track everything from micro-mobility vehicles to mining equipment, with shipping containers, trucks and other high-value items routinely connected. For these reasons, uptake is accelerating with research firm IoT Analytics reporting that the number of global IoT satellite subscribers reached five million in 2021. The firm expects the market to grow by US$1bn by 2026 on the back of three key developments: the rise of low earth orbit (LEO) satellite networks, the adoption of hybrid satellite-terrestrial connectivity, and the entry of tech giants as operators of satellite networks.

With capacity and coverage coming to market and costs becoming attractive for even lower-value use cases, the final frontier is enabling devices with satellite connectivity and ensuring high-performance connectivity can be maintained. The importance of antenna selection and of correctly integrating the antenna has therefore risen in importance as the antenna can make a deployment succeed or fail. Antennas need to be selected to enable devices to connect to multi-constellation or multi-band systems in order to provide optimized performance and a choice of GNSS provider.

In addition, networks need to be integrated and configured so they minimize power consumption and take up a small amount of device space while still being positioned for the greatest performance. Achieving an optimal deployment has many moving parts and several complex technological challenges to overcome. For example, device developers and designers must carefully assess the relative merits of different types of antennas and then identify what performance characteristics should be prioritized. They will also need to consider what correction services – implementations of techniques such as real-time kinematic (RTK) correction or dead reckoning (DR) which can be provided as-a-service by a provider – their device should utilize.

Better by design

The antenna, alongside connectivity and power, is a third area that needs to be given equal attention during the IoT concept development and device design process because of the fundamental impact it has on device performance. The antenna is the means by which an IoT device receives and sends signals to the outside world and therefore is a mission critical element of an IoT device. In GNSS, the antenna is the essential enabler of centimeter-level accurate positioning.

In addition to the precise GNSS positioning functionality enabled by antennas, satellite communication can also be supported. For example, devices can enable the transmission of short messages for communication. This feature can be particularly useful for SOS alerts or specific scenarios when alerts or urgent information need to be communicated.

GNSS has enabled a new wave of precise positioning to support the latest and forthcoming generations of IoT applications. By knowing with great accuracy the location of a device whether it’s a soil probe in agriculture or heavy equipment deployed at a remote mine, immense value can be generated by enterprises, service providers and IoT operations. The advantages all rely on robust antenna performance to ensure not only that communication can be supported but also that positioning data can be transmitted in real time so performance-impacting decisions can be made.

In spite of this growing importance, GNSS antenna decisions are often neglected until the end of the development process, resulting in unnecessary compromises and sub-optimal siting of antennas that could have been avoided with better planning and design. Quectel provides a complete range of antennas with embedded, external and combo products offered alongside antenna design and customization services. Antenna offerings address cellular, GNSS, GPS and Wi-Fi and Bluetooth connectivity, with mounting options including terminal, screw, magnetic, bracket, adhesive, pin and SMD. 

Depending on the use case, GNSS antennas need to be custom-designed for specific use cases. Automotive OEMs, for example, embed antennas in their vehicles and customization of antennas is required to address issues such as interference. Signal reception and propagation need to be considered with antenna solutions requiring specific development for installation in assets such as heavy equipment, two-wheelers, robots, drones and many others.

Quectel’s antenna services extend from initial analysis, with initial services that include the electrical path from the antenna to the receiver and beyond, as well as mechanical and RF design support for devices with limited space. The service portfolio includes technical requirement analysis and device overview, antenna selection and antenna integration recommendation. With precision now a priority for GNSS-reliant deployments, it’s time to pay greater attention to antennas, beginning at the concept development phase.