The market for more accurate location capabilities has never been hotter. As companies dream of new applications for the Internet of Things (IoT) and other use cases, knowing the absolute location of an object or the relative location of an object in relation to another object, is becoming increasingly critical.
Imagine trying to quickly find a specific package in a pile of similar-looking boxes or delivering a pesticide to only certain plants in a vast field of plants. In cases like these and hundreds of others, including drone deliveries, supply-chain logistics, and the use of autonomous vehicles, accuracy is becoming a critical component that can dictate the success or failure of an initiative.
There’s a missing link, however, in many of today’s location technologies. A wealth of technologies can provide location accuracy to a dozen or so meters, and GPS within a few feet. But for a growing list of business cases, close isn’t close enough. Accuracy matters, and thus companies need a whole new approach for the accuracy conundrum, for both outdoor and indoor applications. Antennas are emerging as a key part of the equation in driving the market toward more precise location accuracy.
Outdoor Location: Multiband to the Rescue
Standard location capabilities have served the industry well over the past several decades, with the big beneficiary being vehicle navigation systems and smartphone mapping. Other applications like precision agriculture, precision construction, autonomous or assisted vehicles, and others demand much more accurate positioning, oftentimes within a few centimeters. Centimeter-level capabilities are being made possible through emerging technologies in GNSS receivers and high-quality antenna systems.
Current location solutions generally work in the GPS L1 band, in the 1500- to 1600-MHz range. To achieve high-precision absolute location accuracy requires the use of multiple RF frequencies. Location error comes from ever-changing signal delays in the atmosphere, and by listening to signals from the same satellite at more than one frequency, these errors can be removed. Such frequencies are commonly referred to in the GPS system as L1, L2, and L5.
Emerging solutions also utilize additional satellite constellations, including the Galileo, GLONASS, and BeiDou GNSS systems. By developing multi-constellation and multi-frequency receivers and combining them with high-performance, low-profile antennas that can cover multiple bands, location accuracy is reachable within a few centimeters. For GNSS antennas, key performance measures such as axial ratio, radiation pattern, and radiation efficiency need to be optimized to ensure this level of performance.