RTK GNSS vs GPS: Accuracy Differences That Change Field Efficiency – LRTK Makes Centimeter Precision Easy and Cost-Effective

Table of Contents

• Differences between RTK GNSS and GPS

• How accuracy differences affect field efficiency

• Benefits of using RTK GNSS

• Easy centimeter-level positioning with LRTK

• FAQ

Have you ever been puzzled when a map app on your smartphone shows your current location a few meters off from where you actually are? That few-meter offset might not be a big issue in everyday life, but on construction or surveying sites it can cause critical losses. In construction and surveying, slight differences in position information can greatly affect work efficiency and outcome quality. General GPS can tell you your position, but its lack of precision often becomes a limitation in the field. This is where RTK GNSS, which offers accuracy beyond GPS, comes into play. This article explains the differences between RTK GNSS and GPS, and how those accuracy differences translate into efficiency differences on site. At the end, we also introduce LRTK, a solution that brings high-precision positioning within easy reach.

Differences between RTK GNSS and GPS

Modern positioning technology can be broadly divided into conventional GPS (Global Positioning System) positioning and RTK GNSS positioning. First, GPS is a system that receives signals from satellites to calculate your position. The GPS used in our smartphones and car navigation systems makes it easy to know your location, but its accuracy generally has an error of several meters (about 5–10 m (16.4–32.8 ft)). That is sufficient to know roughly where you are on a map, but not suitable for precise positioning. These errors arise from delays as satellite signals propagate through the atmosphere, satellite orbit and clock errors, and other factors.

On the other hand, RTK GNSS stands for Real Time Kinematic Global Navigation Satellite System and refers to techniques for achieving high-precision satellite positioning. RTK corrects errors through simultaneous observations between a base station (a receiver with a known accurate position) and a rover (the receiver whose position you want to determine), enabling centimeter-level positioning. In short, instead of using a standalone GPS, RTK combines “relative positioning with respect to another point” to cancel out error sources. Therefore, using RTK GNSS yields dramatically higher real-time accuracy—horizontal positions on the order of ±1–2 cm (±0.4–0.8 in) and vertical positions within several centimeters.

Below are the main differences between conventional GPS and RTK GNSS.

• Positioning accuracy: Conventional GPS has errors on the order of 5–10 m (16.4–32.8 ft), whereas RTK GNSS improves accuracy to about 1–2 cm (0.4–0.8 in) (vertical around 3 cm (1.2 in)).

• Vertical measurement: Standalone GPS has large vertical errors and struggles to obtain accurate elevations, but RTK GNSS can measure elevation with high accuracy.

• Positioning mechanism: GPS calculates position by capturing signals from satellites with a single receiver. RTK GNSS uses correction data from a base station (or enhancement signals from compatible satellites) to correct error sources in real time.

• Required equipment: Conventional GPS can be done with a single receiver like a smartphone. RTK GNSS requires a high-precision GNSS receiver and a way to receive correction information (mobile data connection or augmentation signals from satellites). However, correction services can now be obtained directly from satellites, and receivers have become smaller and lower cost.

• Real-time capability: Traditional centimeter-level surveying methods (static positioning or long-term averaging) took time to obtain results. RTK GNSS performs corrections in real time, so high-precision positions are available immediately on site.

Note: GNSS (Global Navigation Satellite System) is a collective term for all satellite positioning systems, such as GPS, Russia’s GLONASS, Europe’s Galileo, and Japan’s QZSS (Michibiki). RTK-capable receivers can use multiple satellite constellations simultaneously, which helps maintain accuracy and stability even when satellite availability is low.

How accuracy differences affect field efficiency

Hearing “a few meters” versus “a few centimeters” may sound like a small difference, but in actual fieldwork it produces a decisive gap. If positioning accuracy remains low, the field will need extra work and manpower to compensate, significantly reducing efficiency.

For example, consider driving stakes at coordinates from a design plan on a construction site. A smartphone GPS has large errors, and the actual location can be off by several meters from the design coordinates. Traditionally, surveyors would use total stations to conduct separate surveys and determine stake positions—work that requires effort and labor cost. With RTK GNSS equipment, however, a worker holding the receiver can be guided to the design coordinates and perform accurate staking alone. There is no need to wait for surveying specialists or to stretch long measuring tapes.

Similarly, when recording coordinates of a location, downstream processes are affected by whether the data are high-precision. If a point recorded with conventional GPS is off by 5–10 m (16.4–32.8 ft), it becomes unusable when reflected on maps or drawings, often necessitating remeasurement or additional checks. With RTK GNSS, coordinates obtained on site can be used directly in design drawings or GIS maps, reducing rework and verification tasks.

Furthermore, RTK GNSS reduces labor in surveying operations. Traditional precision surveying instruments (e.g., total stations) are heavy, require tripod setup, and usually need two or more people to operate. High-precision GNSS allows you to carry a compact receiver around the site and quickly obtain positions, enabling one person to measure many more points in a short time. Reducing dedicated staff also lowers personnel costs. Equipment transport and setup time are reduced, and overall site efficiency improves significantly. Of course, satellite positioning cannot be used in tunnels or indoors where satellite signals cannot reach, but RTK GNSS is highly effective for many outdoor tasks.

Benefits of using RTK GNSS

Centimeter-level position information enabled by RTK GNSS not only improves efficiency but also has the potential to transform onsite workflows. With improved accuracy and easy access to position data, digital methods that were previously impractical due to time or effort constraints become feasible on site.

Here are several specific applications.

• Advanced 3D surveying: If you attach RTK absolute coordinates to data from drone photogrammetry or ground laser scanners, creating survey maps and calculating earthwork volumes becomes smooth. Large-area topographic surveys are also more efficient.

• Automation of construction machinery: Equipping bulldozers and tractors with RTK-compatible GNSS for automatic control and machine guidance dramatically increases work efficiency and precision.

• AR-based construction management: When overlaying design data on site using a tablet or smartphone, RTK GNSS accuracy allows 3D models to be placed without offset. You can intuitively check discrepancies between drawings and the field with AR, preventing rework.

• 3D point-cloud scanning: By combining smartphone-integrated LiDAR or photogrammetry with RTK, you can obtain high-precision 3D point-cloud data. This can be used for as-built management and displacement measurement, enabling one person to document complex terrain.

• Sharing and remote collaboration: High-precision positioning data and site photos can be instantly shared via the cloud. Office staff can understand site conditions remotely and issue instructions easily.

Local governments have also used smartphones plus RTK GNSS to quickly grasp disaster-site conditions. Sharing photos and measurement data with high-precision location tags to the cloud allows all stakeholders to act on the same information, shortening the lead time to recovery. In this way, RTK GNSS use goes beyond surveying and is becoming a driving force for field DX (digital transformation). This aligns with the Ministry of Land, Infrastructure, Transport and Tourism’s i-Construction initiative (productivity improvement through ICT), and its importance will likely grow.

Easy centimeter-level positioning with LRTK

Even if you understand the benefits of RTK GNSS, you might think “implementation seems difficult” or “aren’t the devices expensive?” That’s where LRTK comes in. LRTK is a solution that pairs with familiar smartphones like the iPhone and uses an ultra-compact GNSS receiver so anyone can easily achieve centimeter-level positioning.

The LRTK receiver (commonly called the LRTK Phone) is pocket-sized yet high-performance, weighing only about 165 g and with a thickness of about 1 cm (0.4 in), while providing RTK GNSS positioning capabilities. It connects to a smartphone via Bluetooth and uses a dedicated app for positioning and data logging, requiring no complicated setup. With accuracy comparable to first-class surveying instruments yet lower equipment cost, it is easy even for first-time users of high-precision positioning to adopt.

Key features of the LRTK receiver include:

• Pocket-size design weighing about 165 g and about 1 cm (0.4 in) thick.

• Bluetooth connection to a smartphone with intuitive operation via a dedicated app.

• Positioning accuracy of horizontal ±1–2 cm (±0.4–0.8 in) and vertical ±3 cm (±1.2 in) (comparable to first-class GNSS surveying instruments).

• Built-in battery providing about 6 hours of operation (USB Type-C charging).

• Compatibility with Japan’s QZSS Michibiki CLAS, enabling reception of correction information even in mountainous areas outside mobile coverage.

• Positioning data automatically synchronized to the cloud for immediate viewing and sharing from office PCs.

• Multiple functions in one device, such as point-cloud scanning, AR-guided staking, and photogrammetry.

The LRTK receiver can be attached directly to a smartphone for one-handed use or mounted on a dedicated pole (monopod) for stable positioning, allowing flexible use according to field conditions.

Because of its ease of use and cost performance, many companies and local governments are already adopting LRTK. LRTK challenges the conventional wisdom that high-precision surveying must be left to specialists or requires prohibitively expensive equipment. The LRTK system continues to evolve through software updates that add new features and improve accuracy, making it a platform that keeps getting better after purchase. If you are considering introducing RTK GNSS to improve site efficiency or drive DX, LRTK is an excellent, cost-effective choice.

FAQ

Q: What is RTK GNSS? How is it different from ordinary GPS? A: RTK GNSS is a satellite positioning technology that provides high-precision positioning. Ordinary GPS processes satellite signals on a single receiver, but RTK uses correction information from a base station to compute more accurate positions in real time. As a result, where standalone GPS typically has errors of several meters, RTK GNSS can reduce errors to the scale of several centimeters.

Q: How accurate is RTK GNSS? A: It depends on the environment, but typically horizontal accuracy is about ±1–2 cm (±0.4–0.8 in) and vertical (height) accuracy is about ±3 cm (±1.2 in). This is orders of magnitude more precise than standalone GPS (errors of several meters). For example, a 5 m (16.4 ft) offset is about the width of a passenger car, while a 2 cm (0.8 in) offset is only a fingertip’s difference. Therefore, for most civil engineering and construction surveying and construction management tasks, RTK GNSS provides practically sufficient accuracy.

Q: What do I need to use RTK GNSS? A: You need a GNSS receiver that supports high-precision positioning and a method to receive correction information. Traditionally, this meant installing your own base station or obtaining correction data via a communications line. Nowadays, services like Japan’s Michibiki CLAS provide augmentation signals directly from satellites. Network RTK (VRS) services using the Geospatial Information Authority of Japan’s electronic reference station network are also widely used. Products like LRTK let you start high-precision positioning immediately with just a small dedicated receiver and a smartphone, without the complicated base-station setup.

Q: In what sites or applications is RTK GNSS useful? A: RTK GNSS is powerful in a wide range of situations where position information is used: surveying and construction management in civil and building works, land boundary confirmation, infrastructure equipment inspection, precision agriculture (autonomous driving and application control), disaster-site surveys, and more. Its benefits are greatest where accuracy is required—for example, precise staking on construction sites prevents rework. In agriculture, RTK-enabled autosteering tractors dramatically improve efficiency and application accuracy. For municipal disaster response, rapid surveying and shared information among stakeholders speeds decision-making. RTK GNSS can often maintain stable high precision even in environments where conventional GPS has large errors, such as mountainous forest surveys.

Q: I’ve heard high-precision GNSS is expensive. Should I be concerned about costs? A: It’s true that, until recently, centimeter-level surveying equipment often cost several million yen. But advances in technology and wider adoption have reduced prices. Especially products like LRTK that leverage existing smartphones significantly lower initial costs compared to dedicated equipment. Maintenance overhead is also smaller, and cloud services can often be used without additional fees, so long-term total cost performance is excellent. You can expect substantial efficiency improvements with relatively small investment, making RTK GNSS adoption cost-effective.

Q: Does operating RTK GNSS require specialized knowledge? A: No. Modern RTK GNSS systems are user-friendly. In the past, setup and positioning required expertise, but contemporary systems like LRTK allow positioning by following smartphone app guidance. Intuitive interfaces make it easy for first-time users to master the system quickly (basic surveying knowledge is helpful but not essential).

Q: In which reference frame are the measured coordinates obtained? A: GNSS positioning results are generally obtained in the World Geodetic System (WGS84), but LRTK can instantly transform positions to Japan’s geodetic systems (JGD2011/2024) or plane rectangular coordinate systems on site. This allows measured positions to be displayed directly on maps aligned with the Geospatial Information Authority of Japan’s coordinate system without post-processing. LRTK also supports localization to arbitrary local coordinate systems, making management in site-specific local coordinates easier than before.

Q: What is the future outlook for RTK GNSS? A: High-precision GNSS positioning is expected to become more widespread, and RTK GNSS utilization will likely become standard infrastructure in the construction industry. The i-Construction initiative encourages GNSS use in ICT-enabled construction, making it a pillar of site DX. Demand for centimeter-level position information is also rising outside construction—in autonomous vehicles and drone logistics—so RTK GNSS technology will become increasingly important. As receivers continue to shrink and drop in price, smartphones themselves may eventually support RTK natively. Combining satellite positioning with image sensors and high-precision map information could also produce technologies that provide accurate positioning even where satellite signals cannot reach. RTK GNSS is at a turning point, and it will become an indispensable foundational technology for future fieldwork.