What Is an RTK Module

What Is an RTK Module: Design, Accuracy and Applications

An RTK module is a navigation device that picks up signals from GNSS satellites while also receiving correction data from a base station. Thanks to this combination, coordinates are determined to within a few centimeters instead of the meters typical of standard GPS.

Essentially it's the same kind of receiver. Just with a separate channel for correction data working in real time. That's exactly why the module works where an error of even half a meter means the job fails - whether that's a tractor in a field or a surveying instrument.

What an RTK Module Is Made Of

Let's break down what a typical RTK module for farm equipment or a drone consists of. Based on our research, there are four main components:

• a GNSS receiver - works with several constellations at once: GPS, GLONASS, Galileo, BeiDou;
• an antenna - picks up both the satellite signal and the network corrections;
• a communication module - GSM, GPRS or a radio channel that carries the correction data;
• a phase-measurement processing board - this is what turns the raw signal into centimeter-level accuracy.

For drones these modules are made quite light, just a few dozen grams. A tractor, on the other hand, gets an industrial version - in a rugged housing with its own power supply, since field conditions are far tougher.

How an RTK Module Works

It all comes down to two data streams. The first is the regular signal from satellites. The second comes from a base station or a network of stations that already knows its own exact position, so it can calculate the difference between what the satellite shows and the real coordinates.

The key point is that the module processes phase measurements rather than code measurements - that's what produces such a jump in accuracy compared with standard GPS. In our experience, the practical side matters more to a farmer than the physics behind it: initialization takes a few seconds, after which the receiver enters a fixed solution mode (fix) and holds centimeter-level accuracy for the entire work session.

RTK Module Accuracy Compared to Other Systems

The numbers speak for themselves, so take a look at the table below.

According to farmers who have already switched to network correction, it's not just about the error figure itself. What matters more is that it stays stable day after day - the seams between equipment passes don't drift apart even after a week of work, and there's no need to adjust by eye each time.

RTK Station Range and Network Coverage

A single base station can cover roughly 30 to 50 kilometers around it, and under favorable conditions even up to 70 km. But the farther you get from the reference point, the harder it is to keep that same centimeter-level accuracy, which is why 50 km is treated as a reasonable practical limit.

Building your own base station doesn't make sense for most farms. That's why in Ukraine it's common to connect to networks of reference stations through a paid subscription - and, based on our research, this works out cheaper than owning and maintaining equipment yourself.

Applications of RTK Modules

Agriculture is where RTK is talked about most, and for good reason. But that's far from the only field - the range of applications is much wider than it might seem at first.

Essentially the task is the same everywhere - take the human eye out of determining coordinates. The operator is left simply overseeing the overall situation, without manual adjustment.