Table of Contents

• What is RTK? Why do you need a high-precision GNSS receiver

• 10-point checklist for selecting an RTK-compatible GNSS receiver - 1. Supported satellite systems (GPS, GLONASS, Galileo, QZSS) - 2. Supported frequency bands (L1/L2/L5, etc.) - 3. Correction data methods (RTK networks, Ntrip, etc.) - 4. Positioning accuracy (horizontal accuracy, vertical accuracy) - 5. Communication methods (radio, Bluetooth, SIM card support) - 6. Internal memory and data logging - 7. Environmental resistance (dustproof/waterproof, operating temperature range) - 8. Battery operating time - 9. Weight and size (portability) - 10. Software and app integration

• Simple surveying achievable with LRTK

• FAQ

What is RTK? Why do you need a high-precision GNSS receiver

In recent years, the importance of RTK-compatible GNSS receivers (high-precision GNSS positioning systems) has grown dramatically in construction, civil engineering, and infrastructure maintenance. Measuring position with the GPS built into car navigation systems or smartphones is indispensable for daily tasks, but the accuracy of typical standalone positioning (standalone GPS) remains on the order of several meters, and in some cases errors of about 10 m (32.8 ft) can occur. Construction management and surveying require millimeter-level accuracy, so such errors are insufficient. This is where the high-precision positioning method known as RTK positioning (Real-Time Kinematic) comes in. Using an RTK-capable GNSS receiver can reduce position errors to a few centimeters (cm level accuracy (half-inch accuracy)), delivering the high precision needed for surveying and construction.

RTK positioning operates two GNSS receivers simultaneously: a base station with a known, accurate coordinate, and a rover that observes while moving. Because the base station knows its exact position, it can calculate in real time the various error components contained in the signals received from GNSS satellites. It then sends that correction information to the rover via communication, and the rover applies the correction to its own positioning solution. This cancels errors that a single GPS cannot remove and achieves centimeter-level high accuracy.

Although RTK positioning requires dedicated equipment and procedures, it contributes significantly to productivity on construction and surveying sites. Introducing RTK technology can dramatically improve work efficiency compared with traditional methods such as total stations, and in some cases allows a single operator to complete wide-area surveying alone. Recently, many manufacturers offer a wide variety of RTK-capable GNSS receivers with varying functions and performance. Which device should you choose to avoid failure on site? Below is a summary of the 10 checkpoints for choosing an RTK receiver. Carefully check each point and select the model that best suits your company’s work.

10-point checklist for selecting an RTK-compatible GNSS receiver

1. Supported satellite systems (GPS, GLONASS, Galileo, QZSS)

The first thing to check is which satellite positioning systems the RTK receiver supports. GNSS satellites include the U.S. GPS, Russia’s GLONASS, Europe’s Galileo, China’s BeiDou, and Japan’s Quasi-Zenith Satellite System “QZSS” (Michibiki). The more types of satellites the receiver can use, the greater the number of satellites visible overhead, which helps stabilize positioning in urban canyons or mountainous areas. For use within Japan, support for QZSS (Michibiki) is a significant advantage. Michibiki satellites have orbits that remain over Japan for long periods, ensuring at least one satellite is generally overhead, which can improve accuracy in mountainous regions.

Modern high-precision GNSS receivers typically support multi-GNSS reception that includes GPS+GLONASS as well as Galileo and BeiDou. Considering future increases in signals and satellite counts, choose a unit that supports as many satellite systems as possible.

2. Supported frequency bands (L1/L2/L5, etc.)

GNSS signals from satellites are divided into multiple frequency bands (L-band). The representative band is L1 (around 1.5 GHz), but achieving higher-precision positioning requires multi-frequency reception such as L1 plus L2 or L5. Dual-frequency (L1+L2) receivers can cancel ionospheric errors, improving positioning accuracy over single-frequency reception and reducing the time required for initialization (resolving integer ambiguities).

Recently, triple-frequency receivers that include GPS’s new civil signal L5 have become available. L5 signals have stronger power and wider bandwidth than previous signals, making them more resistant to multipath (reflections from buildings or the ground) and radio interference, thereby improving positioning reliability. For example, the latest receivers can simultaneously receive GPS L1/L2/L5, GLONASS G1/G2, Galileo E1/E5, and BeiDou B1/B2. Considering the future full deployment of GPS L5 signals, it is reassuring to choose a model that supports L5 if possible.

3. Correction data methods (RTK networks, Ntrip, etc.)

In RTK positioning, a communication method to send correction data from the base station to the rover is indispensable. The correction data exchange method is an important selection criterion. Broadly speaking, you can either set up your own base station and communicate via radio, or use an internet-based network RTK (such as VRS). Recently, the Geospatial Information Authority of Japan’s reference station network and private correction services have been established, and many sites commonly obtain correction data over the Internet using the Ntrip protocol. Therefore, verify that the receiver has Ntrip client functionality and can receive correction data in real time via mobile data.

On the other hand, for tunnel work or surveying deep in the mountains where Internet connectivity is unstable or unavailable, a traditional RTK method that links your own base station and rover directly by radio can be effective. Some receivers include an internal UHF radio modem to communicate directly between base and rover, while others support external radios. Choose according to your operating environment: whether the receiver supports network RTK, direct radio communication with your own radio, or both. Also confirm that correction data formats such as RTCM3 or CMR, matching your use case, are supported. Note that in some countries or regions, subscription fees may be required for correction services, so consider that in your budget.

4. Positioning accuracy (horizontal accuracy, vertical accuracy)

Always check the positioning accuracy specs listed in catalogs to ensure they meet your requirements. RTK receiver accuracy is usually stated separately for horizontal (planimetric) and vertical (height) components in formats like “error = X mm + Y ppm.” For example, a high-performance RTK receiver might specify “Fixed solution (RTK Fix) accuracy: horizontal 8 mm + 1 ppm, vertical 15 mm + 1 ppm (RMS).” ppm (parts per million) is a distance-proportional error term that increases with separation from the base station. In this example, even at a distance of 10 km, the horizontal error would be approximately 8 mm (0.31 in) + 10 km × 1 ppm = about 18 mm (0.71 in).

Manufacturers may express these error specifications as RMS (one standard deviation) or 2-sigma (95% confidence), but in any case, the devices are capable of producing sub-centimeter to centimeter-level accuracy. Note, however, that vertical accuracy is generally about 1.5 times worse than horizontal accuracy. Initialization time (time to resolve integer ambiguities) and the time required to regain a fixed solution after loss can vary between models. Even if catalog specs claim similar accuracy, actual on-site stability may differ—especially in high-multipath urban areas or under tree cover. If possible, consult evaluation data from actual devices or user reviews for reassurance.

5. Communication methods (radio, Bluetooth, SIM card support)

Communication between base and rover is critical for RTK. Confirm the supported communication methods. As mentioned, base–rover communication may use dedicated radio (UHF) or the Internet. Many survey-oriented RTK receivers include built-in UHF radio modems so that, where mobile networks are unavailable, real-time corrections can be received provided you obtain the necessary radio licensing (in Japan, operating a UHF designated station requires application for digital simple radio license or notification for specified low-power radio).

For network RTK, the rover needs mobile Internet access. Increasingly, receivers include SIM card slots or built-in LTE modules. A receiver with built-in SIM support can connect to correction services on its own; non-SIM receivers can share a tablet/PC’s connection via Bluetooth or Wi‑Fi.

Bluetooth is standard on almost all receivers, allowing wireless connection to smartphones or dedicated data collectors for receiver control. Some models include Wi‑Fi access point functionality so you can configure settings or transfer data from a browser on a phone. Imagine how you will use the device on site and choose a receiver with the necessary communication interfaces (built-in radio, SIM support, Bluetooth version, etc.).

6. Internal memory and data logging

While RTK is primarily for obtaining coordinates in real time, the ability to record observation data can be important. Many RTK receivers have internal memory to log raw data (e.g., RINEX) for static surveying (long-duration static observations) or post-processing (PPK: Post Processed Kinematic). Internal storage capacities vary from a few MB to several GB or more (32 GB+). If you plan to log large amounts of high-frequency data for long periods, choose a model with ample memory.

Some models support USB memory sticks or SD cards for easy data export. Recently, products with cloud integration have also appeared: recorded positioning data or point cloud data can be uploaded directly to the cloud for immediate sharing with the office. For example, our LRTK automatically saves acquired coordinate data to a cloud database, allowing office PCs to view lists over the Internet. Choose a receiver with recording functions that match your data management workflow and post-processing needs.

7. Environmental resistance (dustproof/waterproof, operating temperature range)

Construction and surveying sites can be harsh. Check the device’s environmental resistance for use in rain, dusty conditions, muddy scaffolding, and steep terrain. Many surveying instruments indicate protection level using the IP dust/water ingress standard. For instance, a receiver rated IP67 means “no ingress of dust and can withstand temporary immersion,” and most major manufacturers provide IP65–IP67 level dust and water protection.

Shock resistance is also important. Rugged models are tested to survive drops from a height of 2 m (6.6 ft) (mounted on a pole) onto concrete. Also verify the operating temperature range—typically around -20 ℃ to +60 ℃ (-20°C to +60°C), but if you plan to operate in extreme cold or hot conditions, ensure the device specs cover those temperatures. Devices with internal batteries may have their performance limited by temperature range. Because these units are intended for long-term field use, consider the housing material (magnesium alloy vs reinforced plastic) and overall ruggedness to ensure reliable durability.

8. Battery operating time

Battery life is critical for outdoor surveying. RTK receivers perform continuous high-precision computations and radio communications, so power consumption is significant and runtime varies by model. Typical receivers offer about 5–10 hours of continuous operation on a full charge, while some power-optimized designs can run close to 20 hours.

For example, Emlid’s “Reach RS2” claims more than 18 hours of RTK operation due to a large-capacity battery. In contrast, ultra-compact smartphone-linked devices may only last a few hours because of small internal batteries. For long surveying days, a model with swappable batteries or a hot-swap dual-battery system is reassuring. Devices that accept external power can run while being charged from a power bank or vehicle power. Always check the catalog “continuous operating time” to ensure it meets your field needs, and consider whether you can carry spare batteries and how long charging takes.

9. Weight and size (portability)

The weight and size of an RTK receiver matter for field handling. Traditional fixed receivers that integrate antenna, battery, and radio internally are robust but often weigh around 1 kg. For example, antenna-integrated receivers from major manufacturers typically weigh about 1.0–1.5 kg. On the other hand, modern mobile RTK devices that pair with smartphones or tablets, and wearable GNSS receivers, can weigh only a few hundred grams.

Our LRTK is a representative example—it is far more compact and lightweight compared with conventional fixed GNSS survey gear or total stations. Tasks that previously required two people carrying equipment into the mountains have been reported to be completed by a single person using LRTK.

A portable receiver makes it easy to access narrow paths or survey points reachable only on foot. However, miniaturization often trades off battery capacity and antenna performance, so choose based on the required positioning accuracy. If the device will be mounted on a vehicle, larger size may be acceptable; for long-distance foot surveys, opt for the lightest model possible.

10. Software and app integration

Beyond hardware performance, the supported software environment is important. To fully utilize an RTK receiver on site, integration with field survey apps and data processing software is essential. Major manufacturers provide dedicated data controllers (rugged tablets) and software—examples include Trimble’s “Access,” Topcon’s “MAGNET Field,” and Leica’s “Captivate”—enabling end-to-end workflow from observation to design verification on site.

Newer RTK products from emerging vendors increasingly adopt a smartphone/tablet operation model. For instance, Emlid’s receivers can be configured and managed via dedicated Android/iOS apps, and our LRTK integrates with a smartphone app to instantly share acquired position data to the cloud for stakeholder viewing. Compatibility with surveying CAD and GIS software (e.g., DXF, LandXML, Shapefile) directly affects field workflows. Confirm whether the receiver you plan to buy can smoothly integrate with your current or planned systems, what data formats are supported, and whether an SDK is available. Usability and expandability on the software side are major factors influencing actual work efficiency.

Simple surveying achievable with LRTK

By following the checklist above and selecting an RTK-compatible GNSS receiver that suits your company, on-site positioning tasks can be significantly more efficient. Finally, as a simple surveying solution usable even by beginners or on sites without specialist surveyors, we introduce our product, LRTK.

LRTK is a compact handheld GNSS receiver that, when paired with a smartphone, allows anyone to easily obtain centimeter-level position information using RTK. Complex operations are handled by a dedicated app, and processes from starting positioning to data logging and cloud upload are intuitive, making it easy for non-specialists to use. For example, local government staff taking geotagged photos during road or river inspections, or construction personnel performing simple as-built checks, can use LRTK to obtain high-precision positions on site without large-scale equipment or contracting specialist surveyors.

LRTK supports not only network RTK but also Japan’s QZSS-provided free centimeter-level positioning augmentation service (CLAS), enabling continued high-precision positioning even in locations without cellular coverage by receiving correction data directly from satellites overhead. This allows surveying without dependence on terrestrial radio infrastructure. Combining ease of use and reliable accuracy, LRTK is gaining attention as a tool to drive DX (digital transformation) in construction and surveying. Consider LRTK for a simpler, smarter approach to on-site positioning.

FAQ

Q1. What is RTK? How does it differ from normal GPS positioning? A1. RTK stands for “Real-Time Kinematic,” a technique that corrects GNSS positioning errors to produce high-precision positions in real time. Standalone GPS typically has meter-level errors, but RTK uses corrections from a base station to reduce errors to below centimeter levels. Therefore, RTK is widely used where millimeter-level accuracy is required, such as civil surveying and precision construction management.

Q2. What equipment and preparations are needed for RTK positioning? A2. Fundamentally, RTK requires a base GNSS receiver with a known accurate coordinate and a rover GNSS receiver for mobile measurements. In addition, a communication method (radio or Internet) to send correction data from the base to the rover is required. Nowadays, it is also common to obtain correction data via national reference station services or private correction services over the Internet without installing your own base station. In any case, RTK-capable high-precision GNSS receivers, a communications environment, and, if needed, tablets or PCs to control them are required.

Q3. What should I prioritize when choosing an RTK receiver? A3. It depends on the application, but first clarify “how much accuracy is needed” and “in what field environment it will be used.” That will reveal the required features. For example, if high accuracy is required, choose multi-GNSS and multi-frequency support. If you will operate in mountainous areas without network coverage, radio communication capability is essential. For urban-centered use, a compact network-RTK-capable device may be more convenient. In short, compare and evaluate factors such as number of satellite systems supported, frequency bands, communication methods, and positioning accuracy to choose the model matching your field conditions.

Q4. Is RTK surveying possible in areas with poor radio conditions or in forests? A4. In dense forests or urban areas with tall buildings, satellite signals can be blocked or affected by multipath reflections, making RTK positioning unstable. However, modern GNSS receivers support multiple satellite systems and frequencies, making it easier to acquire satellites than before. Additionally, augmentation signals from QZSS (Michibiki) and techniques such as bridging multiple rovers are emerging to complement positioning under difficult conditions. If the sky is completely occluded, GNSS positioning itself becomes infeasible, so you may need to adapt surveying methods or temporarily move to an open area for positioning.

Q5. Are licenses or qualifications required to use RTK receivers? A5. No special qualification is required to operate a GNSS receiver itself, but regulations apply to radio equipment used for communications. If you communicate directly between base and rover via UHF radio, qualifications such as the Land Radio Special Technician and radio station licensing may be required in Japan. Network RTK using cellular networks does not require radio licensing. However, public surveying (official surveying for public works) may require national qualifications such as assistant surveyor or higher, so be aware of legal qualification requirements depending on the work.

Q6. Are there RTK systems that are easy for beginners to use? A6. Recently, beginner-friendly RTK systems with excellent usability have increased. Devices that can be intuitively operated from smartphone or tablet apps, or products that automate setup steps to reduce initial configuration time, are now available. For example, our LRTK starts positioning simply by following prompts in the dedicated app, and acquired data is saved to the cloud for easy data management. Manufacturers also provide training support and user manuals, so even first-time RTK users can introduce the technology with confidence.