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Ask the Quexperts: What is RTK positioning in GNSS IoT?

Real-time kinematic (RTK) positioning is a technique designed to counteract signal errors in global navigation satellite system (GNSS) calculations and that enables far greater accuracy as a result. It utilizes a nearby reference station with known coordinates or a network of reference stations, also known as NRTK, to provide correction data in real-time via a cellular, broadcast radio or satellite carrier.

The basic principle behind RTK is that it utilizes the carrier-phase measurements instead of code phase measurements and differential techniques to compensate for common errors experienced in satellite bias, orbit, and clock along with delays due to ionospheric and tropospheric delays. This approach significantly improves the GNSS accuracy to the centimetre or decimetre level in open or semi-open environments. The corrections shared by the base station can then be used by the mobile receiver commonly referred to as a rover (delivery robot or autonomous vehicle etc.) which can use these corrections to calculate its own precise position relative to the fixed stations.

Why RTK is needed

RTK is necessary because standard GNSS positioning is only able to provide position updates with an accuracy limited to around 2.5m for L1 single band receivers or 1m for dual band receivers. Accuracy can be impacted by atmospheric delays, satellite clock errors and the effects of multipath errors. While multipath errors are better addressed by good antenna design and dead reckoning (DR) using on board IMUs, the errors common to both rover and base station can be reduced by using RTK.

For many use cases such as navigation, tracking and location-based services, single receiver positioning is adequate. For example, knowing the approximate position of a ship on the ocean or tracking a delivery van on its route. However, more demanding applications require far greater precision. Use cases in land surveying, construction, precision agriculture, robotics and logistics services can demand highly precise positioning that is accurate down to just a few centimetres.

How RTK positioning works

RTK provides high accuracy measurements but requires strong signals. Positioning reliability and resiliency is further strengthened by adding 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, has essential capabilities for a rapidly growing marketplace of applications that relies on accurate and robust location.

Relevant products

GNSS LC29H series

GNSS LC29H series

AGNSSDRIntegrated LNAsRTK
Read more: GNSS LC29H series
GNSS LG69T series

GNSS LG69T series

AutomotiveDRRTKTESEO V chip
Read more: GNSS LG69T series
GNSS LG290P

GNSS LG290P

AGNSSQuad-bandRTKSBAS
Read more: GNSS LG290P

By combining RTK and DR with GNSS, robust and accurate positioning can be achieved at a cost and power consumption that mainstream intelligent devices can sustain. Mass market applications for RTK range from e-scooters and lawn mowers to agricultural drones, metal detectors and delivery robots. Precise positioning of this type is no longer limited to high-end equipment at prohibitive costs.

Location data is an essential enabler of a growing range of consumer and prosumer use cases and the improved accuracy RTK delivers is now available for many use cases. Quectel is simplifying and creating further cost savings and performance gains with its innovative LC29H and LG69T series of GNSS modules that can include RTK and DR and the comprehensive Quectel range of pre-integrated antennas.

Combined with Quectel’s recently launched RTK Correction Services, these modules and antennas provide precision for all at affordable prices.

Relevant resources