What is RTK technology in GNSS and how does it work? Uses and advantages

GNSS (Global Navigation Satellite System) technology has revolutionized the way we perceive geolocation and navigation, impacting sectors such as agriculture, construction, surveying and drones, among others. In this area, signal correction to improve accuracy is essential, and this is where RTK (Real-Time Kinematic) technology comes into play. In this article, we will explore what RTK is, how it works, and its most relevant applications.

What is RTK?

RTK is an advanced technique that significantly improves the accuracy of GNSS systems. While standard GNSS devices can offer accuracy up to a few meters, RTK reduces this margin of error to a few centimeters or even millimeters in some cases. This is achieved through the use of base stations and mobile receivers that communicate in real time.

The basic principle of RTK is the correction of the GNSS signal in real time using a base station that has a fixed and known location. This station compares the signals received from the satellites with their exact position and sends corrections to the mobile receiver, eliminating errors caused by the atmosphere, satellite clock errors, among other factors.

How does RTK technology work?

To understand how RTK works, it is important to break down the process into two main components:

1. Base station: This is a fixed antenna located at a known location with millimeter precision. The base station receives the signals from the GNSS satellites and compares them with its own position, calculating differences or errors in real time.

2. Rover or mobile receiver: It is the mobile device that needs to be positioned with high precision. This receiver also receives signals from the GNSS satellites and, at the same time, the corrections emitted by the base station. Using these two sets of data, the rover can calculate its exact position, reducing the error to centimeters.

This communication between the base station and the mobile receiver is typically carried out via radio frequency or mobile networks, allowing users to obtain high-precision data in real time.

Advantages of RTK technology

The main advantages of RTK over other GNSS methods are clear:

• Centimeter Accuracy: RTK is capable of delivering accuracy down to 1 or 2 centimeters, making it a very valuable tool for applications that require a high level of accuracy.

• Real-time correction: Unlike other techniques that require post-processing, RTK provides instantaneous corrections, allowing users to obtain accurate data in the moment.

• Versatile Applications: From precision agriculture to construction and drones, RTK enables a level of control not possible with conventional GNSS technologies.

Uses and applications of RTK technology

RTK technology has proven to be of great relevance in several sectors that depend on geospatial precision. Here we mention some of the most notable applications:

1. Precision agriculture: Agricultural machines equipped with RTK receivers can perform tasks such as sowing, fertilizing and harvesting with centimeter precision. This reduces unnecessary use of inputs and optimizes crop yields, increasing efficiency and sustainability.

2. Surveying and Mapping: Surveyors and cartographers have embraced RTK technology due to its ability to provide extremely accurate location data, eliminating the need for physical reference points in many cases. This speeds up work times and reduces operating costs.

3. Drones and UAVs: The combination of drones and RTK has enabled extraordinary advances in geospatial data collection. RTK-equipped drones can map large areas with unprecedented accuracy, improving both the efficiency and quality of surveys.

4. Construction and civil works: The accuracy that RTK offers in real time facilitates the planning and execution of construction projects, allowing heavy machines to work with levels of precision that were not possible before. This ensures that structures are erected in exact locations, minimizing errors.

5. Mining and geological exploration: In areas such as mining, where operations are complex and margins of error can have large implications, RTK is essential to ensure that extractions and drilling are carried out accurately.

Limitations of RTK technology

Despite all its advantages, RTK also has some limitations:

• Base station dependence: To obtain centimeter accuracy, it is essential to have a nearby base station (usually within a range of 10 to 20 kilometers). If the base station is too far away, the accuracy decreases.

• Coverage and communication: RTK technology requires a constant and stable connection between the rover and the base station. In rural or mountainous areas, where radio frequency or mobile network coverage is limited, it may be more difficult to maintain signal accuracy.

• Costs: Although RTK technology has come down in price in recent years, it is still more expensive compared to traditional GNSS systems. However, the added value in terms of precision and efficiency justifies the investment in most cases.

The future of RTK technology

RTK technology continues to evolve as GNSS systems and telecommunications infrastructures advance. One of the most interesting developments is network-based RTK (NRTK), which allows users to access corrections from multiple base stations over a network, rather than relying on a single station. This expands the coverage range and improves accuracy over larger areas.

Additionally, the integration of RTK with emerging technologies such as 5G and low-orbit satellite networks promises greater real-time availability and accuracy, even in remote areas.