Wireless Antenna Integration
Jul 27
Antenna selection makes or breaks small GNSS tracking devices. Even a minor lapse in functionality can be problematic for a tracking device, which needs to be able to reliably and consistently report on its precise location. Choosing the right antenna is the only way to ensure this smooth operation.
Today there are all sorts of antennas available, made of different materials and coming in different sizes, which each offer different advantages depending on the nature of the device they are a part of. In this guide we will look at the six crucial factors to keep in mind when selecting an antenna, to ensure you make the best possible decision for your purposes.
Perhaps it seems obvious, but your antenna needs to operate in an appropriate frequency range for GNSS signals. Different countries operate different satellite systems, such as the United States&#; Global Position System (GPS), China&#;s BeiDou Navigation Satellite System (BDS), and the EU&#;s Galileo. Each satellite system operates at different frequencies and across different bands. Make sure you know which satellite system your GNSS tracking device will make be using, and the associated frequency bands.
Antennas come in different sizes, with a different footprint on a circuit board. With a GNSS tracking device, you often want your antenna to be as small as possible. Antenova&#;s Intelligent Antenna Selector shows you how much space your GNSS antenna will take up, allowing you to easily see how it will relate to the final design of the device.
While the phrase &#;antennas&#; may bring to mind the silver metal rods that were once attached to TVs and radios, the range of materials available to engineers today is extensive. Ceramic, flexible, and various composite antennas are all viable options for GNSS trackers today.
Depending on the other components in your tracking device, different materials will make for more efficient or less efficient transmissions. The environments your device will be functioning in should also influence choice of the material your antenna is made of. For example, if your GNSS tracking device needs to be wearable, perhaps a flexible antenna capable of moving with the wearer would be your best option. Alternatively, If size is most important, perhaps a miniature antenna would be most suitable. For rugged devices incorporating metal surfaces, there is even an antenna which can be mounted directly onto the metal without de-tuning.
Think about the potential needs and applications of your tracking device and speak to Antenova&#;s wireless experts to discuss which materials would work best for your device.
Ground planes are an essential part of all antennas, but pose a conundrum for portable GNSS tracking devices. In short, ground planes are crucial if an antenna is going to reliably send and receive transmissions, but they require space, and space is precious on tracking devices.
Make sure you know how much space your antenna requires for an effective ground plane, and that you can incorporate that space into your designs. Some antennas are able to utilise others components as part of their ground plane, others will require clear space on a circuit board. To ensure your ultimate design isn&#;t compromised, consult with wireless engineers as soon as possible to see how best to ensure your choose an antenna with a ground plane that works for your tracking device.
Tracking devices are likely to be exposed to a range of environments, depending on where their wearer moves. This makes interference likely: glass, metallic objects, tall buildings, nearby wireless devices, and even the other components in a device itself can all potentially disrupt the signals from an antenna.
When selecting an antenna for a tracking device, it is useful to know whether your design suits an antenna that can isolate interference, or whether you will have to find other ways of minimising disruption to its signal. Ceramic antennas may be able to isolate interference, but their ground plane requirements may not suit your tracking device. Talk to an expert to make sure you select an antenna that works with your device to avoid potential interference.
Careful positioning of your antenna is one of the key ways to avoid potential interference. Engineers should carefully follow the design advice in the product datasheets but Antenova can also analyse your circuit board layout to address the impact of your components&#; materials and positioning.
Portable tracking devices need to be able to send and receive signal whatever their orientation: whether they are horizontal, vertical, or resting diagonally, they need to be able to say where they are. As a result, it is essential that you choose an omnidirectional as opposed to dipole antenna. This will in turn impact upon component selection and positioning, as your antenna needs to send and receive signal from all around with no disruption from nearby parts. Be sure to choose an antenna that will function with whatever other components make up your tracking device.
Choosing the right antenna is essential if your GNSS tracking device is going to work. The need for a tracking device to be easily portable, compact, functional, and robust put particular constraints on your choice of antenna. The variety of antennas now available makes it possible to find a wireless solution whatever your parameters. Get in touch with Antenova to ensure you have the expertise to guide you towards the right decision for your device: in the meantime take a look at the Intelligent Antenna Selector App.
As GNSS technology continues to advance, a new reality is emerging. Our world increasingly relies on location-based services for daily activities, and this trend is set to continue. According to research by Markets and Markets, the global GNSS chip market is projected to grow to $4.9 billion by , representing a remarkable 48% growth over the next five years. The rise of autonomous vehicles, advanced robotic applications, precision agriculture, and many other use cases is spurring this demand. As a result, we are witnessing GNSS technology become a more integral part of our daily lives, cities, and industries.
In recent years, there has been a trend towards combined technologies (sensor fusion, PPP, RTK etc.) in GNSS systems, resulting in productivity gains and devices that are increasingly accurate and versatile. However, this adds further complexities and challenges for antenna design.
Selecting the correct GNSS antenna performance is crucial to deliver a high level of accuracy and to justify the GNSS receiver's cost. GNSS signals are extremely weak; with that, you need a high-performing antenna and receiver, but most importantly, the optimal integration for the antenna, which many underestimate. Poor antenna integration will result in poor system performance, low accuracy, delays in device development, and commercial costs, ultimately leading to unhappy customers. So always consider which antenna best suits your application and the required receiver, and ensure you integrate them properly inside your device.
Choosing the most suitable GNSS antenna for your device can be daunting, especially with many available options. In this article, we will determine the necessary considerations for selecting your device's GNSS antenna.
Multi-Constellations GNSS Systems
While GPS-based positioning served us well in the past for applications such as navigation and logistics, today's use cases demand higher precision. In particular, mission-critical applications such as emergency services and autonomous driving require cm-level accuracy.
New technologies such as Real-Time Kinematic (RTK), which uses a reference ground station to provide real-time corrections to GNSS signals, can correct errors in GNSS signals and other positioning systems. Additionally, a multi-constellation, multi band approach helps to minimize the influence of obstructions caused by cityscapes or foliage and enables more precise location information. These receivers can improve accuracy and reliability by combining signals from multiple systems, such as GPS, GLONASS, and Galileo. Consumer chipset manufacturers have recognized the benefits of multi-constellation, with more than 30% of all chipsets supporting four constellations.
Figure 1:GNSS Constellation Types and Spectrum Bands
Figure 1 shows the bands that each constellation uses. The most common band used for GNSS is the L1 band, as it's been available for several years. But in the last few years, bands L2, L5 and L6 were made available to the public sector, and they are allowing greater access to many more satellites. The introduction of the L2 band, the increasing availability and utilization of L1+L5, and the development of dual-band receivers have all contributed to improved positional accuracy and reduced impact from ionospheric errors and interference in GNSS systems.
Multiband GNSS Receivers
When it comes to multiband GNSS receivers, selecting the correct radio module plays a crucial role in boosting the precision and reliability of your device, as it determines the constellations and bands accessible to you. To maximize the capabilities of your GNSS receiver, choose a device that offers access to a wide range of constellations and bands. By doing so, you ensure that your receiver can tap into the signals transmitted by multiple satellite systems, enabling you to benefit from a larger pool of measurements, achieve enhanced accuracy in your positioning calculations and open a world of capabilities for improved performance in positioning.
The accuracy of a GNSS receiver is also 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. To simplify selecting the appropriate antenna, Taoglas provides reference guides for leading module providers including u-blox, Nordic, and Sierra Wireless, making it easier to filter and choose the most suitable antenna for the module. By selecting the right radio module and antenna combination, device manufacturers can optimize their products' performance and improve the user experience.
GNSS Antenna Form Factors and Environment
mide contains other products and information you need, so please check it out.
GNSS antennas come in many different sizes and form factors from chip, flexible PCB, and patch to dipole and helical. Figure 2 summarizes the major types and characteristics.
Figure 2: GNSS Antenna Types, Characteristics and Form Factors
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.
Motorsport Telemetry solutions can help us understand some of the challenges and considerations when choosing an antenna. In Motorsport, accuracy is everything. The margins are impossibly slim, and the difference between winning and losing can come down to a few thousandths of a second. The harsh environment of racing vehicles also presents unique challenges, such as heat and vibration, so when developing a telemetry solution, you're straddling the boundaries of what is both technically and physically possible. Every gram counts - the antenna needs to be highly compact and lightweight, so it doesn't affect the vehicle's overall weight. In addition, it needs to work across several frequencies seamlessly. Lastly, it is essential that the antenna solution can withstand harsh conditions for long periods without its performance being affected.
In this case, choosing a high-performing, multi-band GNSS antenna such as Taoglas' ADFGP.60A is an example of considering these challenges. It is made from Terrablast, a material used instead of traditional ceramic antennas when impact resistance and weight are key considerations for the devices use case. Terrablast antennas are 30% lighter than ceramic antennas and highly durable, making them the perfect solution for a mobile environment. Additionally, it performs well on all worldwide GNSS bands, including the L-bands.
GNSS Antenna Performance
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. Figure 2 further demonstrates these characteristics in detail.
Figure 3: GNSS Antenna Characteristics
GNSS System
From the perspective of RF Engineers, when analyzing the GNSS system or subsystem within a product or device, we perceive it as comprising multiple distinct parts rather than a single subsystem. Additionally, we recognize that the GNSS system cannot be considered in isolation; it is essential to assess the entire product and understand that external factors may impact device performance or introduce issues. Figure 4 illustrates a comprehensive GNSS system encompassing the receiver, RF front end (which integrates the antenna and receiver module within the subsystem), and the antenna.
It is crucial to recognize that the GNSS system cannot be evaluated independently, as other factors can potentially cause problems. These include other radios and potential sources of noise and interference, even if they operate outside the GNSS system bands. Failure to account for these factors may result in jamming and interference with the GNSS system. While 3G GPRS radios posed challenges a decade ago, the concern today is typically LTE, and we anticipate 5G to present future issues.
Figure 4: GNSS System
GNSS Antenna Location and PCB Size
Ceramic Patch Antennas
Ceramic patch antennas are typically the primary form factor considered for a standard GNSS antenna. It is essential to determine the optimal placement of the patch antenna, whether on a PCB or a ground plane.
We recommend using a PCB with dimensions of ideally 70x70mm; however, that does not mean you cannot make this area larger or smaller. Increasing the size results in higher gain and a more directive antenna. Conversely, reducing the size of the ground plane leads to decreased gain and efficiency. Figure 5 demonstrates examples of GNSS ceramic antenna placement, illustrating that moving it towards the corner will necessitate tuning. Additionally, bandwidth and gain may also be affected. For applications requiring high precision, it is advisable to position the antenna in the middle. If you need to fine-tune the antenna you should reach out to an RF Engineer for assistance.
Figure 5: Examples of GNSS Ceramic Antenna Placement
Flex Antennas
Flex antennas offer an ideal solution for device designs where flexibility and space limitations are important considerations. These antennas can be easily mounted on nonmetal surfaces like plastic, glass, and screens using a simple "peel and stick" method, eliminating the need for drilling holes. When integrating the antenna, keeping it at least 1cm away from metal is essential to ensure optimal performance.
Chip Antennas
Chip antennas are tiny and compact. They can be tightly integrated into assemblies and PCBs. When working with chip antennas, it is important to consider a few key factors. Like most surface mount antennas, the visible portion of the chip antenna utilizes the PCB's ground plane as an integral component of the antenna. Consequently, both the PCB's size and the antenna's placement on the PCB can significantly impact its performance.
The width of the PCB, especially when it reaches 80mm, becomes a critical dimension that must be maintained. If this area is reduced, it will noticeably degrade the antenna's performance. However, the length of the PCB has a different level of criticality. When placing the chip antenna, we recommend mounting it in the centre of the longest edge of the PCB. Remember that during the device development process, you may need to modify the values of the matching circuit to optimize the antenna's performance. Adjustments to these values are to be expected at some stage in the development of your device.
Figure 6: Example of Internal Chip Antenna Placement
External Antennas
External antennas are often considered plug-and-play. However, a key consideration includes a good sky view. Additionally, the ground plane can often be helpful (for example, the vehicle roof) as some antennas expect the ground plane to be there and having a ground plane in place can help negate the multipath.
Commercial Considerations
The most accurate and sensitive antennas and receivers tend to cost more. Therefore, weighing the cost against the benefits is essential to determine whether your application requires the investment. Additionally, consider whether an augmented service from Wi-Fi or cellular could be a viable alternative. The decision depends on your commercial application and what you hope to achieve with your device. By choosing a module and antenna that can support multiple constellations and has a higher performance, a device could give its product a competitive edge, futureproofing the design and gaining added value for your customers.
Seek Expert Advice on Integration
If you are still deciding which GNSS antenna to choose, consult expert advice from an antenna manufacturer, such as Taoglas, who can provide guidance and recommendations based on your specific application. Device OEMs often need more in-house RF resources to integrate the correct module and antenna into their design to ensure reliable performance. Choosing an antenna manufacturer that can help design and optimize RF and antenna performance can significantly benefit device OEMs time to market. Such manufacturers offer design support that allows customers to achieve even greater positional accuracy (down to the cm level) by testing their high-precision GNSS antennas in anechoic chambers and in an open sky view environment to simulate the expected values that an end-user may expect in a field test. These engineering services can significantly improve product performance and reduce the likelihood of design flaws.