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How Does RTK GPS Work?


One of the most fascinating parts of construction projects often receives the least amount of attention. Of course, we are talking about the preparation phase of a project. Here you see such a wide array of industries in action, such as draftspeople, estimators, and of course, surveyors. It may surprise you that these activities do not receive as much attention as they deserve because their actions often pave the way for the success of the rest of the project.

For instance, surveying equipment will provide useful information about how to design the project, the constraints of the land, and other essential data. In order to get the most out of their surveying equipment, surveyors use real-time kinematic (RTK) GPS measurements. This system utilizes satellite and terrestrial positioning and is actually quite fascinating. Find out more below:

RTK GPS Base Stations & Rovers

The first thing you must understand about RTK GPS is that precise measurement is difficult. 

People without a surveying background may assume that locating coordinates is simple. As simple, perhaps, as using a tape measure to measure the distance between two points. That is a vast understatement. However, the concept of measuring distance is a part of RTK GPS, through the implementation of base stations and rover.

First, the base station is set up in a location free from interference or overhead obstructions, as the location allows. Ideal places are tall hills without much tree cover, with limiting barriers being the critical requirement. The base station serves the purpose of measuring timing biases from the satellites and relaying that information to the rover.

Conversely, the rover’s job will vary depending on the survey equipment in use. Regardless of application though, the rover will listen to the information relayed by the base station, and use it to correct its own position relative to the base station.


The Satellite’s Role in RTK GPS

One of the reasons accurate measurements are not so simple is the movement of the Earth. Of course, this is a little broad, but the core concept is that when the Earth is rotating, the base station must take into account the delay in transmissions. There are several variables this applies to, such as satellite clock bias, satellite orbital error, ionospheric delay, tropospheric delay, and more. Therefore, accurate measurements made by RTK GPS surveying incorporate a fair amount of mathematical calculations to get, in some cases, accuracy down to the millimeter.

In conclusion, RTK GPS works through a combination of land-based measurements reinforced through measurements recorded by satellites. This data is combined and run through software designed to strengthen the information, and as a result, accurate measurements are possible. 

Bench Mark Equipment & Supplies is your team to trust with all your surveying equipment. We have been providing high-quality surveying equipment to land surveyors, engineers, construction, airborne and resources professionals since 2002. This helps establish ourselves as the go-to team in Calgary, Canada, and the USA. Plus, we provide a wide selection of equipment, including global navigation satellite systems, RTK GPS equipment, GNSS receivers, and more. We strive to provide the highest level of customer care and service for everyone. To speak to one of our team today, call us on 403-286-0333 or email us [email protected]

About the Author

Nolan has been working in the surveying field since 2017, starting as a part-time student at Bench-Mark while attending the University of Calgary. He now works in technical support and sales helping customers find the right product for them.

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