How to ensure high-precision GNSS performance from antennas
A large and still 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. The Global Navigation Satellite System (GNSS) is a constellation of satellites that offers coverage in every location, over land and sea, on the Earth. This is essential for the uninterrupted connectivity of things that are deployed across the globe. GNSS often provides the only alternative in locations where there is no cellular or low power wide area network (LPWAN) network coverage.
Often these areas are in hard-to-reach areas of low population – typically where industries such as mining or forestry are located. However, there are increasing challenges with cellular coverage in locations such as dense urban canyons that high-precision GNSS can address. 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 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 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 their device should utilize.
High-precision GNSS with real-time kinematic positioning
Real-time kinematic positioning (RTK) is one option, and it involves the application of surveying to correct for common errors in GNSS systems by measuring the phase of signal’s carrier wave in addition to the information content of the signal. By doing so, it can provide up to centimetre level accuracy. An alternative is dead reckoning, a method by which the current position is determined by incrementally integration the distance travelled and the direction of travel relative to a known start location.
With even more emphasis now being placed on accuracy and high performance it is essential that IoT device developers and designers know how to test and validate the performance of antennas to ensure they can support the specific needs of their deployments. These issues were explored in a Quectel Masterclass titled ‘High-precision GNSS antenna selection and integration’. To access the Masterclass, visit: https://www.quectel.com/masterclass-library/high-precision-gnss-antenna