Real-time kinematic (RTK) positioning is a technique that has been designed to counteract signal errors in global navigation satellite system (GNSS) positioning and to enable IoT and other devices to achieve far greater positioning accuracy than other means allow. RTK is necessary because standard GNSS positioning identifies a device’s position by measuring the time of flight of signals from satellites to the receiver. Accuracy can be impacted by atmospheric delays, satellite clock errors and the effects of multipath errors. Multipath errors occur when a satellite signal reaches the receiver from two or more paths. One path might be direct from the satellite while others are reflected off buildings, for example. This has the potential to distort the time of flight measurement, resulting in inaccurate positioning information.

As use cases from lawnmowers to logistics and from ride-sharing vehicles to shipping containers depend ever more on accurate positioning, RTK provides a way to support precise location demands. While for many use cases such as navigation, tracking and location-based services, GNSS positioning is adequate, for an emerging range of uses, it is no longer fit for purpose. Use cases in unmanned aviation, land surveying, construction, agriculture, robotics and some logistics services can need highly precise positioning that is accurate down to just a few centimeters.

Combine RTK and dead reckoning to maximize GNSS precision

RTK in contrast to GNSS uses the known positions of fixed reference stations to compute corrections for these issues and applies them in real-time to achieve enhanced positional accuracy. Positioning capability is further strengthened by adding dead reckoning (DR) technology in situations when GNSS is unstable or unusable. By adopting multi-band GNSS, RTK and DR technologies, businesses can achieve unprecedented levels of accuracy and reliability in positioning.

The benefits include improved operational efficiency, enhanced safety and expanded possibilities for IoT deployments. As the IoT market continues to grow, accurate positioning will play a pivotal role in unlocking its full potential and RTK, allied to DR, provide foundational technologies for a rapidly growing marketplace of applications that relies on accurate and robust location. By combining RTK and DR with GNSS, robust and granular positioning can be achieved at a cost and power consumption that mainstream intelligent devices can sustain.

Importantly, mastery of these techniques is no longer confined to just a few people and companies and costs are coming down. The availability of the technologies means precise positioning of this type is no longer the preserve of high-end equipment such as vehicles and access to centimeter-level accuracy can now be supported for lower value devices and services.

The value that RTK can add to enable accurate positioning was detailed in recent Quectel Masterclass titled ‘Introduction to RTK and dead reckoning for GNSS devices – APAC’. The Masterclass was presented by Jonghyun Won, an FAE at Quectel. Won has more than 16 years of experience with a deep understanding of BSP software development. His field test experience covers control planes and user planes in A-GNSS (assisted GNSS). In the Masterclass he introduced both RTK and dead reckoning and reported on field tests for both technologies in Korea.