Verified by RTK-GNSS Comparison! LRTK Smartphone Surveying Achieves Centimeter-Level Accuracy

Table of Contents

• Basic principles and types of RTK-GNSS

• Comparison between general RTK-GNSS receivers and LRTK smartphone surveying

• Technologies that enable LRTK to achieve centimeter-level accuracy

• Comparative verification under various environments and positioning conditions

• Differences in peripheral functions and UX such as point cloud measurement, photos, and AR guidance

• Cloud integration and operational advantages of LRTK

• Simple centimeter-accuracy surveying to start with LRTK

• FAQ

Basic principles and types of RTK-GNSS

For high-precision surveying, technologies that correct satellite positioning errors to achieve centimeter-level accuracy are indispensable. With ordinary standalone positioning, various errors—such as satellite orbit and clock errors, ionospheric and tropospheric signal delays, and multipath (reflections) from buildings and terrain—are not corrected and accumulate, so the practical accuracy remains around about 3–10 m. Typical smartphone or car-navigation GPS often deviates by several meters and cannot approach the few-centimeter accuracy required for construction management or surveying work.

RTK (Real Time Kinematic) positioning was developed to solve this problem. In RTK, both a base station (reference station) and a rover receive GNSS satellite signals simultaneously and compute the differential in real time to cancel common error components. This enables high accuracy that cannot be achieved by standalone positioning; depending on conditions, RTK positioning can confine errors to the order of a few centimeters horizontally and vertically. In actual field work, for example, positions can often be determined with horizontal errors of about 2–3 cm and vertical errors of about 3–5 cm, a dramatic improvement over standalone positioning.

RTK is broadly classified into two types by operational mode. One is the base station method (single-reference RTK), in which you install your own reference receiver near the site and transmit the error relative to its known coordinates to the rover via radio or wireless. The other is the network RTK method, which uses correction information combined from multiple fixed stations such as the Geospatial Information Authority of Japan’s Continuously Operating Reference Stations (CORS) delivered over communication lines (commonly distributed via a protocol called Ntrip; representative methods include VRS^※). With network RTK, you do not need to set up a dedicated base station; the rover’s GNSS receiver simply receives correction data via mobile communication. Because nationwide reference-station networks are established in Japan, surveying using network RTK is becoming mainstream.

There is also a high-precision positioning technique other than RTK called PPP (Precise Point Positioning). PPP improves standalone positioning accuracy using global-scale satellite orbit and clock error models and augmentation information broadcast by satellites, and it has the advantage of not requiring base stations. However, real-time PPP requires time for initial convergence and can take several minutes to tens of minutes to reach centimeter-level accuracy. Therefore, for surveying while moving or applications that require immediate high precision, RTK—which provides instantaneous error correction—has the edge (PPP is useful where deploying base stations over wide areas is difficult, so choosing the appropriate method is important). Japan’s Quasi-Zenith Satellite System “Michibiki” offers CLAS (described later), a PPP-RTK style satellite augmentation service that is notable as a correction means usable even outside communication coverage.

Comparison between general RTK-GNSS receivers and LRTK smartphone surveying

What are the differences between conventional fixed RTK-GNSS equipment and the new LRTK smartphone surveying solution? Here we compare both from the perspectives of accuracy, initialization speed, antenna performance, operability, and cost.

Positioning accuracy: Both dedicated survey-grade RTK-GNSS receivers and LRTK devices can fundamentally achieve centimeter-level high-precision positioning in real time. High-quality GNSS receivers can obtain RTK FIX solutions (integer solutions) and keep errors within a few centimeters; LRTK similarly uses correction information to achieve positional accuracy on the order of about 2–3 cm horizontally. Field validation shows that LRTK RTK positioning is stable and meets the accuracy required for general surveying tasks (errors on the order of a few centimeters), producing results comparable to conventional equipment. As long as satellite signals are not severely blocked, both can record measured point coordinates with errors in the order of a few centimeters, making them suitable for applications that demand high precision.

Initialization time: The time from starting RTK positioning to obtaining an RTK FIX solution (Time To First Fix, TTFF) is generally short for both conventional receivers and LRTK. With network RTK, initialization typically completes in a few seconds to a few tens of seconds, enabling use of centimeter-accurate position information. There is little difference between the two because both apply correction information by the same principle; in open environments, high-precision positioning starts almost immediately. However, when using satellite augmentation services (PPP-RTK) outside communication coverage, initial convergence may take several minutes. LRTK supports satellite augmentation signals (CLAS), but in such cases accuracy is somewhat lower immediately after start and stabilizes after a few minutes of static observation. When using network RTK, like conventional equipment, FIX solutions are obtained instantaneously, so for tasks performed while moving it is efficient to use network RTK where mobile communication is available.

Antenna performance and positioning stability: Typical survey-grade GNSS receivers have large, high-sensitivity antennas and ground planes that reduce multipath and receive weak satellite signals well. LRTK, on the other hand, integrates a small antenna that mounts on a smartphone, but because it supports multi-GNSS, it can use many satellites simultaneously and achieve stable positioning in practice. Owing to its smaller antenna diameter compared to conventional units, LRTK may be somewhat more affected in urban canyons or under trees; however, by receiving signals not only from GPS but also GLONASS, Galileo, and Michibiki (QZSS), LRTK secures satellite numbers to minimize accuracy degradation. As a result, LRTK can maintain a certain level of stability even in obstructed environments, and in many cases continue to hold FIX solutions under some shielding (in extreme cases, any device will struggle to maintain a fixed solution, but given the same conditions, LRTK and conventional devices exhibit similar stability). Operational countermeasures such as optimizing antenna placement or temporarily moving to an open spot to reinitialize are commonly effective.

Operability and manageability: Conventional RTK-GNSS systems required transporting and setting up multiple devices—an antenna-integrated positioning terminal, a data collector (field controller), a communication modem, and sometimes a tripod or pole. Skilled surveyors carried heavy equipment to the site, set up and configured base stations, and connected devices, which involved complicated procedures. LRTK, by contrast, completes everything with a smartphone and a small receiver, and operation is extremely simple—just operate the smartphone screen. Dedicated apps are designed with intuitive UIs, and coordinate measurement and recording are executed by following on-screen prompts and tapping buttons. There is no need for multiple people to carry a set of equipment; the pocket-sized LRTK can be taken out on site and used immediately, which is a major advantage. Tasks that traditionally required two people, like setting out batter boards (datum lines), can be performed by one person with LRTK, greatly improving field efficiency. Minimal complex settings or specialized knowledge are required, making LRTK easy to adopt even for first-time RTK users.

Introduction cost: Survey-grade GNSS equipment commands a premium due to high-performance antennas, receiver circuits, and rugged housings. A conventional RTK kit (rover + controller, and sometimes a base station system) can cost on the order of several million yen depending on the manufacturer. This makes it difficult for small businesses or local governments to procure multiple sets. LRTK, however, can significantly reduce costs because it leverages users’ existing smartphones. The dedicated devices themselves are ultra-compact and cheaper to manufacture, enabling pricing that is a fraction of conventional systems. Low initial costs and the ease of assigning one device per person make it possible for anyone to access centimeter-accuracy positioning when needed. Lower barriers to entry have contributed to wider adoption of high-precision positioning across many sites.

Technologies that enable LRTK to achieve centimeter-level accuracy

LRTK smartphone surveying achieves high accuracy despite small size by combining the following advanced technologies.

• CLAS support (use of satellite augmentation services): LRTK supports Japan’s Quasi-Zenith Satellite System “Michibiki” Centimeter Level Augmentation Service (CLAS). CLAS is a PPP-RTK correction service that distributes orbit and clock corrections and observations from CORS via L6-band signals from satellites. If a dedicated antenna is attached to the LRTK device, it can directly receive CLAS signals and apply real-time corrections. This means centimeter-level positioning is possible using only satellite-broadcast correction information even in mountainous areas or remote islands where mobile signals do not reach (positioning accuracy improves gradually after several minutes of reception at startup). The ability to fully utilize free satellite augmentation is a major strength of LRTK.

• Support for network RTK corrections: In areas with mobile coverage, LRTK can perform centimeter-level positioning using standard network RTK corrections. The smartphone connects to an Ntrip-compatible reference-station network service over the internet and receives high-precision correction data in real time. LRTK supports public CORS networks and private high-precision correction services, so users do not need to prepare their own base stations. In stable communication environments, fixed solutions can be obtained within seconds, enabling smooth handling of dynamic surveying tasks. All LRTK models support major domestic correction services (for example, high-precision positioning services provided by large mobile carriers), making it easy to integrate into existing operations.

• Multi-GNSS and triple-frequency support: LRTK receivers support multiple satellite navigation systems and multiple frequency bands. Specifically, they can simultaneously receive signals from GPS, GLONASS, Galileo, and Michibiki (QZSS), and fully utilize triple-frequency signals such as L1/L2 plus L5 or L6 bands. This dramatically increases the number of tracked satellites, making it easier to secure enough satellites even in urban canyons or under trees. Using three frequencies also improves ionospheric delay correction accuracy and speeds up the determination of RTK integer ambiguities. While dual-frequency (L1+L2) was common previously, LRTK’s triple-frequency capability accelerates initialization and enhances positioning stability. These advanced multi-GNSS and multi-frequency specifications are the secret behind compact devices achieving performance comparable to conventional units.

• RTK computation on the smartphone app: In LRTK, much of the positioning computation is handled by a dedicated app on the smartphone. Raw data acquired by the GNSS receiver are sent to the phone via Bluetooth or Lightning, and RTK processing (differential calculations and filtering) is performed within the app. Leveraging high-performance smartphone CPUs and memory reduces processing load on the small device and lowers power consumption while enabling application of advanced algorithms. This approach allows the hardware to be compact and low-cost while enabling continuous improvement through software updates. Because the smartphone is internet-connected, acquisition of correction information and cloud integration occur seamlessly. In other words, LRTK is designed around the concept of "running the GNSS engine on the smartphone," which is the driving force behind pocket-sized centimeter-level positioning.

Comparative verification under various environments and positioning conditions

RTK performance is influenced by environmental conditions; here we explain the expected differences when comparing LRTK and conventional equipment in real environments—looking at accuracy trends by environment (urban, mountainous, etc.) and differences between static and kinematic measurements.

Open environments: In open sites with no tall buildings or obstructions, both conventional units and LRTK can receive satellite signals well and maintain stable fixed solutions. With sufficient satellite count and geometry, horizontal and vertical errors remain within a few centimeters, yielding ideal accuracy. For example, tests in suburban open fields comparing known points showed average errors for LRTK RTK positioning around 2–3 cm horizontally and 3–5 cm vertically, with maximum deviations only a few centimeters. This is accuracy comparable to conventional survey-grade RTK equipment; in open environments, small LRTK units perform on par with conventional equipment. Initialization also completes in seconds, and measurements show little fluctuation, enabling reliable real-time positioning.

Urban areas (building canyons): In urban areas surrounded by high-rise buildings, part of the satellite signals are blocked or reflected, creating a multipath environment. Even conventional RTK receivers with high-performance antennas can experience some degradation and unstable solutions in city centers. LRTK likewise may see temporary increases in error due to reduced satellite visibility and reflections; experiments in city areas showed average errors remaining in the centimeter range but occasional deviations exceeding 10 cm were observed. This phenomenon can happen with conventional equipment as well, meaning RTK errors can worsen to tens of centimeters under certain environmental factors. If the antenna is completely shadowed by a building, sufficient satellites cannot be tracked and the solution may lose FIX status (switching to FLOAT or NG). In such cases, LRTK users can check status on the smartphone and move to a slightly more open location to regain FIX. In urban areas, keeping sky visibility in mind and avoiding obstruction above the antenna—just as with conventional systems—is important. The small size of the LRTK antenna makes it easy to handle and find a better reception position even between buildings.

Mountainous areas and forests: In valleys and near forests, satellite visibility is partially blocked by surrounding terrain and trees. Even in these environments, LRTK’s multi-GNSS support allows it to capture signals from many satellites and secure surprisingly many satellites overhead. In forest-adjacent RTK tests, average horizontal errors were about 3–4 cm and vertical errors around 6–7 cm, maintaining practically acceptable accuracy. However, directly under dense tree cover where the sky is barely visible, FIX solutions can drop to FLOAT. In such cases it is better to stop trying to measure and move to an open spot to reinitialize (static for several tens of seconds). Conventional receivers also struggle in mountainous areas, but LRTK’s advantage is that it can use satellite augmentation CLAS even outside communication coverage. With a coverage-capable LRTK antenna, you can receive corrections directly from Michibiki, offering more stable accuracy than single-base-line RTK over long baselines—though if trees block the sky entirely, augmentation signals themselves may not be received. Overall, errors in forested environments may increase to several to a dozen centimeters, but LRTK can perform comparably to conventional equipment.

Static vs. kinematic measurements: RTK positioning shows subtle differences in accuracy when the device is static versus when it is moving. When static, continuous observations of the same point stabilize the data and produce more reliable solutions. The LRTK app includes an averaging function for static points; for example, it can output an averaged coordinate over several seconds of continuous observation to reduce per-point variability to the millimeter level. In tests where a point was measured 60 times and averaged, horizontal and vertical variations were both under 1 cm—extremely stable values comparable to or exceeding static surveying with conventional instruments, and sufficient for reference-point surveying. Conversely, kinematic measurements—such as walking surveys or mounting on a moving platform—record coordinates every second while the position changes. As long as FIX status is maintained, LRTK can provide centimeter-accurate coordinates during motion, but brief signal interruptions can momentarily degrade accuracy. For instance, if the antenna is momentarily blocked by the operator or an obstacle on rough footing, the solution can switch to FLOAT and position may deviate by tens of centimeters. However, in many cases FIX is restored within a few seconds once visibility returns, so kinematic surveys can still obtain practically continuous centimeter-level trajectories. LRTK is optimized for continuous kinematic positioning and displays the current solution state (Fix/Float/NG) color-coded on the smartphone, allowing users to monitor accuracy status. With proper operation, LRTK can deliver results in the same accuracy range as conventional equipment whether static or moving.

Differences in peripheral functions and UX such as point cloud measurement, photos, and AR guidance

While RTK-GNSS devices mainly measure positions, LRTK smartphone surveying provides value beyond mere positioning through enriched peripheral functions. In particular, point cloud measurement (3D scanning), geotagged photos, and AR-guided visual features deliver capabilities that conventional surveying equipment did not have—implemented with smartphone-native user experience (UX).

First, differences in point cloud measurement (3D scanning). Traditionally, obtaining detailed 3D shapes of terrain or structures required expensive laser scanners or combining drone photogrammetry with ground surveying to generate point clouds. Operation of specialized equipment and multi-person workflows were required, and assigning absolute coordinates to processed point clouds required separate RTK-based control points, which was time-consuming. LRTK integrates these workflows: by simply walking while holding a smartphone, you can scan surrounding point clouds. Images and depth information from the smartphone camera or LiDAR sensor combined with LRTK’s high-precision position data attach real-time absolute coordinates (latitude, longitude, altitude) to each point. For example, you can quickly acquire point clouds of slopes or roads on-site and immediately use them for progress management. The ability to perform dense 3D surveys single-handedly without specialized equipment is a major LRTK innovation.

Geotagged photos are another LRTK-unique feature. Site photos taken with the smartphone can be automatically tagged with the precise coordinates and camera orientation (azimuth). Previously, after shooting with a digital camera, positions had to be plotted on a map manually or a GPS-enabled camera had to be used; with LRTK this is done with one tap. Photos, timestamps, and notes are managed together, so you can reliably retain accurate location information for infrastructure inspections or attach photos to drawings as-built records. Smartphones capture high-resolution images and make cloud sharing easy, freeing you from manually writing coordinates in paper photo logs.

AR (augmented reality) guidance and visualization are also noteworthy features of LRTK smartphone surveying. By overlaying design positions or target points on the live camera view of a smartphone or tablet, you can intuitively perform on-site layout work and as-built checks. For example, when locating a stake position provided by a client, LRTK’s AR guidance can display arrows or markers on the screen to guide the operator to the stake location. It feels like the smartphone is a magical window showing invisible reference points or buried utilities. Traditionally, surveyors had to input coordinates into a device and locate stakes by distance and bearing; AR displays enable even novices to find points accurately without getting lost. Because LRTK provides high-precision positioning, AR objects remain stable and do not drift even after walking several meters. This enables on-site confirmation of as-built heat maps (color distributions of deviations), and advanced uses such as previsualizing underground utilities in AR to avoid them during excavation.

In terms of usability, LRTK’s smartphone-based approach brings many advantages. As noted, operations are completed within a smartphone app with a polished GUI that anyone can intuitively use. Positioning data is plotted on maps in real time, making it easier to understand than a string of numbers from traditional survey terminals. There is no need to keep paper field notes; everything is recorded digitally to prevent mistakes and omissions. The smartphone + small device configuration also means LRTK can be an all-in-one site ICT tool: with just an LRTK-equipped smartphone you can handle surveying, photo records, point cloud scanning, drawing reference, and AR—eliminating the need to swap multiple devices on site. The richness of peripheral functions is a differentiator from conventional equipment and overall improves usability for surveyors and technicians.

Cloud integration and operational advantages of LRTK

LRTK smartphone surveying offers excellent benefits in labor-saving and data utilization on-site. Here we summarize LRTK’s features related to cloud integration, mobility, and operational efficiency.

• Efficiency and labor reduction in surveying tasks: LRTK enables many surveying tasks that used to require two people to be performed by a single person. For example, when establishing reference points, measuring boundary points, or setting batter boards, conventionally one person would operate the instrument while another held a staff. With LRTK, a single operator can attach the receiver to a pole or monopod and walk around acquiring high-precision coordinates sequentially, drastically reducing personnel needs. This is a major innovation in the construction and surveying industries facing severe labor shortages and declines in experienced technicians. Reducing personnel also improves site safety by lessening the burden of mutual monitoring and reducing communication-related mistakes that can cause accidents. The small, lightweight LRTK (about 150 g and roughly 1 cm thick) is easy on the operator and can be kept in a pocket for immediate use, dramatically improving work efficiency.

• Real-time data sharing (cloud integration): LRTK systems can immediately upload and share acquired positioning data to the cloud. When measurements are saved in the LRTK smartphone app, they can be synced to the cloud with a single tap so results can be shared before returning to the office. Authorized stakeholders can view measured points, photos, and generated point cloud models on a web service without dedicated software; for example, remote site supervisors or clients can monitor measurement status in real time. Rapid data sharing helps quickly detect missed or incorrect measurements, preventing rework and improving overall quality.

• Lightweight, compact & long runtime: LRTK devices integrate antenna and battery in a very compact form yet offer sufficient toughness and battery life for field use. Devices weigh about 125–170 g and are light enough for all-day carry. They are designed with water- and dust-resistance for site use and have a case-like housing that can be wiped clean. Internal batteries provide about 10–12 hours of continuous operation on a full charge—enough for a typical working day—so you usually do not need spare batteries. The low-power design allows around 10 hours of operation even while connected via Bluetooth, enabling stable all-day use when paired with a smartphone (it is advisable to use a mobile battery for the smartphone itself during long operations). LRTK’s combination of low power consumption and robustness makes it practical for tough field conditions.

• Wide range of applications: LRTK smartphone surveying is expected to be applied across many industries beyond construction and civil engineering. For example, railway companies that routinely measure track deformation or settlement can have workers wearing LRTK-equipped helmets walk along tracks to record high-precision displacements. In highway maintenance, inspectors can record the locations of pavement cracks or equipment while patrolling, aiding repair planning. LRTK can also be combined with UAVs for aerial survey accuracy control or synchronized with 360-degree cameras to virtually reproduce job sites. The centimeter-level position information from LRTK is a key enabler of new DX solutions, and its smartphone usability encourages creative field applications.

• Ease of introduction: Despite containing cutting-edge positioning technology, LRTK is designed to be easy for general technicians to handle. Menus are in Japanese on the smartphone screen and positioning results are displayed on maps for intuitive understanding. Complex settings and adjustments typical of conventional survey instruments are largely unnecessary—just launch the app and a few taps start high-precision positioning. If trouble occurs, the app shows error messages and guidance so users can respond calmly. Manufacturer support and manuals are well developed, and free trial plans are often available. Even companies new to RTK can try devices hands-on and build familiarity before purchase, making LRTK a facilitator of site DX by lowering cost and skill barriers.

Simple centimeter-accuracy surveying to start with LRTK

As shown above, LRTK smartphone surveying achieves centimeter-level accuracy comparable to conventional RTK-GNSS equipment while offering many benefits in portability, ease of use, and extensibility. From the RTK-GNSS comparison perspective, the conventional approach’s cultivated accuracy and reliability are realized by LRTK in a compact smartphone device—an innovation that has democratized RTK surveying that was once considered expensive and specialist-only.

Japan’s Ministry of Land, Infrastructure, Transport and Tourism promotes i-Construction, which emphasizes labor-saving and accuracy through ICT. LRTK smartphone surveying aligns with this philosophy and is expected to accelerate on-site DX as a trump card. Sites that introduced LRTK report significant reductions in survey time for as-built management, reductions in personnel, and improved safety. The ability to record and share positional information digitally in a pocket-sized surveying device leads to unprecedented changes in site work styles.

If you want to introduce high-precision surveying more easily or manage sites efficiently with fewer people, LRTK is a compelling option. With LRTK you can start centimeter-accuracy surveying with just a smartphone—even those without specialist knowledge can try centimeter-level surveying from tomorrow. Free trials are often available so you can experience performance before committing, and support systems are in place to ease adoption. With barriers lowered by the latest technologies, now is an ideal time to bring LRTK smartphone surveying to your site. Let the simple, smart centimeter-accuracy positioning take your operations to the next level.

FAQ

Q. Why is LRTK necessary instead of using a smartphone’s GPS alone? A. Built-in smartphone GPS (GNSS) alone has errors of several meters to tens of meters and cannot meet the few-centimeter accuracy required for surveying and construction management. LRTK attaches a dedicated high-sensitivity GNSS receiver to the smartphone and corrects positioning errors using RTK methods, dramatically improving accuracy. Differential correction mitigates orbit and atmospheric errors that standalone positioning cannot handle, reducing real-time position offsets to within a few centimeters—this is the key difference from a smartphone alone. In short, LRTK transforms an ordinary smartphone into a centimeter-accuracy surveying instrument, removing the need for traditional specialized surveying equipment.

Q. Do I need a base station or special equipment to use LRTK? A. No—you do not need to prepare your own base station. LRTK supports network RTK, so it receives correction data via mobile communication from public CORS networks or private correction services that are Ntrip-compatible. No separate radio equipment or large antennas are required; the smartphone and LRTK receiver are sufficient. However, to achieve centimeter-level accuracy you must use a correction information service. In communication-covered areas you connect to a contracted Ntrip correction service (public or private). In communication-outage sites, LRTK can use satellite augmentation information (Michibiki CLAS) to achieve high-precision positioning without a base station. In either case, no special hardware beyond the LRTK unit and smartphone is required; the needed correction information is obtained via communication or satellite.

Q. Can I survey in places without mobile phone reception? A. Yes. LRTK series devices are designed to work even outside mobile coverage by supporting Michibiki’s CLAS satellite augmentation signals. With a coverage-capable LRTK antenna, you can receive real-time correction information directly from Michibiki satellites in mountainous areas or other sites without mobile networks, enabling centimeter-level base-station-less positioning nationwide. Note that PPP-RTK via satellite augmentation can require several minutes of convergence at startup. Allowing sufficient time in open sky to receive satellites before operation is recommended. In any case, the ability to continue surveying without communications is a significant reassurance.

Q. Which smartphones and tablets are supported by LRTK? A. Currently, iPhone and iPad (iOS) are the primary supported devices, with Android support for the latest LRTK devices being rolled out (some Android models are already supported). In particular, iPhone “Pro” models from iPhone 12 Pro onward (which include LiDAR scanners) can use all LRTK functions such as point cloud scanning and object positioning. The recommended device is the latest iPhone 15 Pro for optimal processing performance and sensor accuracy. Standard iPhone and iPad models can perform RTK positioning itself, but some advanced AR or scanning functions may not be available. Please check the LRTK official site for the latest supported device information before introduction.

Q. How long does the battery last? A. The LRTK receiver has an internal battery and runs for about 10–12 hours on a single charge (actual time varies with use and communication conditions). This typically covers a full workday. With a full charge in the morning, you usually do not need to worry about battery depletion during daytime surveying. Bluetooth-connected operation with a smartphone also typically lasts around 10 hours. Charging is done via the supplied USB cable and takes about 2.5 hours to full. Note that the smartphone’s battery will also be consumed during long surveying sessions; the LRTK device does not supply power to the smartphone. For long operations, carrying a mobile battery for the smartphone is recommended. Overall, LRTK offers enough endurance for day-long use without worrying about power.

Q. Is the positioning accuracy really a few centimeters? A. Yes—actual measurements have confirmed accuracy on the order of a few centimeters. LRTK RTK positioning often yields horizontal errors of about 2–3 cm and vertical errors of about 3–5 cm in favorable conditions, satisfying typical surveying task requirements. Field tests in open areas showed measurement errors mostly within 2–3 cm and negligible differences from design coordinates. In challenging environments such as urban canyons or forests, temporary deviations around 10 cm can occur, but on average errors remain within a few to a dozen centimeters—acceptable for construction management. In short, LRTK delivers accuracy comparable to high-end GNSS receivers. However, accuracy depends on satellite visibility and environment; like conventional equipment, the more open the sky, the higher and more stable the accuracy.

Q. Can LRTK be used for deliverables in public works such as i-Construction? A. Yes. Coordinate and point cloud data obtained with LRTK can be output and processed in formats that meet official standards. The app supports coordinate systems including geodetic latitude/longitude and conversion to the Geospatial Information Authority of Japan’s plane rectangular coordinate systems (zone-based), and can compute geoid heights—making the data usable as formal survey deliverables. Point cloud data can be validated per the Ministry of Land, Infrastructure, Transport and Tourism’s as-built management guidelines, and error adjustments using control points can be performed. There are cases where as-built reports were prepared and submitted based on point clouds acquired with LRTK. The LRTK series is designed as an *i-Construction*-compatible solution, so it can play an active role in ICT-enabled construction and public surveying. Final applicability depends on the client’s standards, but LRTK’s centimeter accuracy and data-sharing features make it a viable tool for the public sector.

Q. Is specialized knowledge required for introduction or operation? A. No—specialist skills are not required. LRTK is designed to be usable by general field personnel, and those familiar with smartphones can learn operation quickly. The dedicated app is in Japanese and guides the user from positioning start to recording, so even RTK novices can use it with confidence. Mode selection and coordinate system settings are simple selection menus, so deep GNSS theory is not necessary to achieve high-precision positioning. In addition, free trials and thorough support are available to help with initial setup and on-site usage; manufacturers and dealers provide follow-up. If questions arise, inquiry support is available, so even first-time RTK users can adopt LRTK smoothly. LRTK was designed to meet needs for people who want to conduct surveying themselves without relying on experts.