How to Achieve Solo Surveying as Fast as Possible? LRTK Implementation Checklist [Definitive Edition]

Background: Why Solo Surveying Is Required

On construction and civil engineering sites, surveying work has traditionally required multiple people. For example, one person would operate the surveying instrument (total station, etc.), while another would hold a staff (rod) at a distant point to mark locations. Such two-person operations take significant time and effort from setup to cleanup, and for wide-area surveys or surveys with many points it is not unusual to spend an entire day. Manual measurements also carry the risk of human error (misreading or recording mistakes), and if errors occur the work must be remeasured later, which is inefficient.

In recent years the construction industry has faced severe labor shortages and an aging workforce, prompting demands for labor-saving and efficiency improvements so that sites can be operated with limited personnel. [Note: The Ministry of Land, Infrastructure, Transport and Tourism’s i-Construction initiative also aims to improve productivity through labor reduction.] The number of veteran surveying technicians is declining, making it difficult to continue “person-dependent surveying.” For this reason, expectations for solo surveying (one-person surveying) are rising. By leveraging the latest digital technologies, high-precision surveying can be performed with few people, accelerating DX (digital transformation) on site.

Challenges of Solo Surveying (Accuracy, Safety, Operational Burden)

When conducting surveying alone, several challenges must be considered. First is ensuring accuracy. Standalone GPS positioning typically yields errors on the order of several meters, raising concerns that accuracy may be inferior to traditional methods. Beginner surveyors may feel uneasy without someone to double-check whether positioning is correct.

There are also safety issues. Traditionally two or more people could perform surrounding safety checks while working, but with solo surveying you must operate the equipment and monitor the surroundings at the same time. When working alone on construction sites with operating heavy machinery or in areas with heavy traffic, thorough safety measures are required so that attention to the surroundings is not neglected.

Operational burden is another challenge. One person must carry, set up, measure, and record all equipment. Conventional surveying instruments are heavy and complex to set up, posing a high barrier for novices. If equipment trouble or communication errors occur during surveying, you must handle them yourself, requiring specialist knowledge. A method that resolves these issues and enables one person to survey comfortably while maintaining accuracy and safety has been needed.

What Is LRTK (Mechanism and Differences from RTK)

A revolutionary surveying system that combines a smartphone with a compact GNSS receiver—LRTK—has emerged to meet these needs. First, some background on GNSS (global navigation satellite systems), represented by GPS. The technology that measures your position (latitude, longitude, altitude) from GNSS satellite signals is familiar from car navigation and smartphone maps, but standalone positioning accuracy is typically on the order of several meters. Construction surveying and boundary confirmation require centimeter-level accuracy, so ordinary GNSS alone is insufficient.

The high-precision technique that addresses this is RTK (real-time kinematic). RTK uses a base station receiver and a rover (mobile receiver), and by correcting errors from the differences between data received by both, RTK improves real-time positioning accuracy to centimeter levels. Since the 1990s RTK has spread into surveying, and today network RTK using the Geospatial Information Authority of Japan’s permanent GNSS station network (Ntrip method) and commercial correction services are available. However, traditional RTK surveying equipment was expensive and bulky, and operation required expertise. Dedicated base stations and communication devices had to be prepared and correction services contracted, making introduction costly and cumbersome. Also, transporting a full set of equipment often required multiple people, so “even with high precision you still needed manpower.”

LRTK is a new RTK solution that changes this. LRTK is an ultracompact RTK-GNSS receiver that attaches to a smartphone (currently mainly iPhone/iPad), integrating an antenna and battery in a smartphone-sized housing weighing approximately 150–170 g and with a thickness of around 1 cm (0.4 in). By attaching to the back of a smartphone and connecting via Bluetooth or Lightning, your smartphone instantly becomes a high-precision GNSS surveying device. Surveying instruments that once weighed several kilograms and were fixed in place now fit in a pocket, eliminating the need to carry a tripod. A major feature of LRTK is that it supports both network RTK and satellite-delivered RTK. In Japan, you can receive correction data from the permanent GNSS station network (Ntrip) via mobile communication where cellular coverage is available, or if outside coverage you can directly receive the free high-precision augmentation signal (CLAS) from the Quasi-Zenith Satellite System “Michibiki.” In other words, real-time correction of positioning errors to within a few centimeters is possible nationwide, making LRTK a revolutionary portable device. Its ease of use—just attach to a smartphone and launch an app to start high-precision positioning without specialist knowledge—is also a major difference from conventional RTK.

Why LRTK Makes Solo Surveying Possible

The main reason LRTK enables solo surveying is the dramatic improvement in positioning accuracy and real-time performance. If you start satellite reception in the dedicated app, RTK centimeter-level positioning information can be obtained in tens of seconds. Once positioning stabilizes and you achieve a “FIX solution” (a resolved solution with errors of a few centimeters or less), you can walk around the site and conduct surveying alone. For example, move to the point you want to measure and simply tap the “Position” button on the smartphone screen to immediately record the coordinates (latitude, longitude, height) of that location. There is no need for someone else to hold a staff. Using the averaging positioning function for several seconds as needed allows you to obtain stable high-precision coordinates by averaging multiple measurements.

LRTK’s ability to link with the smartphone camera and LiDAR to perform continuous positioning and point-cloud scanning while walking is also revolutionary. When efficiently surveying a large site alone, you can simply walk with the smartphone in hand and automatically scan the surroundings to acquire 3D point-cloud data. All acquired point clouds are tagged with absolute coordinates (global geodetic system coordinates) by LRTK, making it easy to later compare with drawings or BIM models or perform volume calculations. High-density 3D surveying that previously required specialized laser scanners and multiple people can be done solo with LRTK.

Real-time performance and cloud sharing are also key supports for solo surveying. Data acquired with the LRTK app (coordinate lists, point-cloud models, photos, etc.) are automatically recorded on the smartphone and can be uploaded to the cloud with one tap. Because data can be shared from the field, supervisors, colleagues, and clients can receive results by the time you return to the office. The LRTK Web service plots measured points and photos on a map and allows point clouds to be previewed in a 3D viewer. Stakeholders can view data from a browser without dedicated software, enabling real-time coordination with remote site managers or government officials. Even when surveying alone, cloud sharing ensures the whole team has the latest data so you’re not “the only one holding the information.” Faster data sharing also helps early detection of omitted or erroneous measurements, contributing to overall site quality improvement.

As described above, LRTK provides a solution that did not exist previously in terms of high precision, real-time operation, and data sharing, making solo surveying practical and usable.

LRTK Implementation Checklist

To successfully perform solo surveying, it is important to thoroughly prepare for the introduction of the LRTK system. Below is an implementation checklist. Use it as a definitive reference.

• Satellite positioning and communications environment check: Confirm in advance whether stable GNSS positioning is possible at the site. If cellular coverage is available, use network RTK over the internet; if in mountainous or out-of-coverage areas, operate by receiving Michibiki (CLAS). Identify site environmental conditions such as securing open-sky positioning points in mountainous areas and considering satellite occlusion and multipath (reflections) from high-rise buildings in urban areas.

• Preparation of GNSS receiver (LRTK device): Prepare the RTK-GNSS receiver that will serve as the LRTK unit. Choose a model that can be attached to the intended smartphone (e.g., *LRTK Phone*). Before purchase, check supported frequencies (Michibiki CLAS compatibility), accuracy specifications, continuous operating time (battery life), etc. Update the device firmware to the latest version.

• Smartphone and dedicated app setup: Install the dedicated LRTK app on the smartphone or tablet (iPhone/iPad recommended). For Bluetooth connections, pair in advance; for Lightning connections, physically attach and verify operation. Also check the smartphone’s OS version and specs, and ensure sufficient battery capacity and free storage for long surveying sessions.

• Cloud service setup: To share and store surveying data in the cloud, register for the LRTK cloud service (create an account). Complete login and project setup on first use and, if possible, verify operation with a test upload. Decide on your company’s data management rules in the cloud (folder structure and naming conventions) so usage across multiple projects is smooth.

• On-site safety measures: Enforce safety management when working alone. On construction sites, follow basics such as wearing a helmet and reflective vest and placing cones around the work area. Avoid focusing on the smartphone screen to the detriment of surroundings; perform periodic checks and breaks. Share the work schedule and location with your organization beforehand, and ensure periodic check-ins and emergency contact methods are in place.

• Operational training: Conduct LRTK operation training before actual surveying. Practice basic app operations (how to use the positioning button, save photos with coordinates, perform point-cloud scans, etc.). Try measuring several points on familiar grounds to verify data accuracy and sharing procedures. For those new to RTK surveying, it is reassuring to experience how long it takes to obtain a FIX solution and the effect of averaged positioning.

Implementation Steps (Preparation → Communication Test → Operation Training)

Confirm the broad steps from introducing LRTK to starting field use as follows.

• Preparation: As pre-work, attach the LRTK device to the smartphone and ensure the dedicated app can be launched. Complete account and device registration if required. Fully charge batteries and prepare backup power (mobile battery). Also set the coordinate system and surveying references to be used at the site (for example, a specific plane rectangular coordinate system) in the app settings if available.

• Setup: Upon arrival at the site, start the LRTK system in a safe, unobtrusive location. Securely attach the device to the smartphone and power it on (some attached models receive power from the phone and power on automatically). Open the app and begin acquiring GNSS satellites in an outdoor location with good visibility. Initial satellite acquisition and position initialization may take time at a first site, so wait in an open-sky area for a while.

• Communication test: Once GNSS signals are being received, confirm reception of correction data. If a mobile network is available, start Ntrip connection within the app and enter RTK mode. If out of coverage, ensure it switches automatically to Michibiki CLAS reception mode or set CLAS mode in the settings. Confirm whether the solution reaches “FIX” status within tens of seconds. A FIX solution indicates centimeter accuracy is available. If FIX is not obtained quickly, check for objects blocking satellite view and relocate if necessary. Also check the smartphone’s communication status and Bluetooth connection.

• Operation training: When positioning is stable, measure a few points. If known points (control points) are available, verify correct coordinates are output at those locations. Try measuring features and also use coordinate navigation (guiding to a coordinate) to test the workflow. Test saving photos with location information and the point-cloud scanning function if time allows. Finally, upload data to the cloud and confirm the office can access the data as a communication test. If these steps work correctly, fieldwork can begin in earnest.

With the above flow of preparation and setup, even sites introducing LRTK for the first time can be started smoothly.

Notes and Operational Points for Successful Solo Surveying

To safely and reliably conduct one-person surveying with LRTK, pay attention to the following points.

• Strict accuracy management: Always monitor positioning status in the app and confirm a FIX solution before recording. If the accuracy indicator (estimated error) is large, do not record immediately; wait a bit or use the averaging function to stabilize. If necessary, remeasure multiple times per point to check for obvious outliers. GNSS accuracy also fluctuates depending on satellite constellation. If the app displays satellite count or DOP (dilution of precision) values, use them as a reference and plan to survey at times with better accuracy.

• Consider the positioning environment: Avoid factors that obstruct satellite signals as much as possible. Positioning is likely to be unstable under overpasses, directly under trees, or in urban canyons between buildings. If you must survey locations where GPS signals do not reach, consider using LRTK’s indoor positioning mode or remote target positioning features if available. If still difficult, do not force the measurement—have a survey assistant perform those points using conventional methods.

• Safety-first behavior: When working alone you are responsible for your own safety management. Avoid becoming so absorbed in surveying that you miss hazards underfoot or traffic around you; make frequent surrounding checks. For roadworks, consider placing traffic guides at the shoulder or otherwise avoid solitary work. Heatstroke prevention is also important—take appropriate hydration and rest breaks in summer. Efficiency is meaningless without safety.

• Handling and maintenance of equipment: LRTK devices and smartphones are precision instruments—avoid drops and shocks. Use straps at the site and store devices in zippered pockets to prevent loss or damage. In rain use waterproof cases or plastic bags and do not overestimate dust/water resistance. After use, clean mud and dust from device contacts and regularly update firmware and apps to keep them current.

• Data management and backup: Although survey data stored in the cloud is generally safe, confirm the data is also saved on the smartphone offline. After uploading to the cloud, export CSV or PDF reports as needed to keep local copies. This prepares for cases such as forgetting to send a cloud share link or incompatibility with the recipient’s data format. Always organize and back up the day’s data before the day ends so you do not leave it for the next day.

Common Failures and Countermeasures

Here are common mistakes when introducing a new surveying system and countermeasures.

• Communication errors: There are cases where correction information cannot be received at the site and RTK positioning does not start. Causes include Ntrip connection setting mistakes (wrong ID/password, incorrect mount point) or lack of mobile coverage. A countermeasure is to perform a connection test in the office or an area with good reception beforehand. If out-of-coverage is expected, switch to CLAS reception mode and move to an open-sky location where Michibiki can be received. If correction cannot be obtained at all, avoid forcing a single-receiver measurement on site and plan to remeasure later.

• Initial setup mistakes: Mismatches in coordinate output may be caused by app setting errors. For example, confusing world geodetic coordinates with local coordinate systems, or forgetting to enter antenna height or measurement reference offsets. Countermeasure: check configuration items against a checklist before work. For first-time introductions, double-check with a colleague and resolve questions using manufacturer support or the manual.

• Data transfer omissions: After surveying, you may think you shared data internally but some items may not have been uploaded. This can happen if you close the app before uploads finish or if photo files are large and take a long time. The remedy is simple: make it a habit to confirm upload completion and check the cloud data list. Before returning to the office, visually confirm on the cloud that all data are present and, if something is missing, send it before leaving the site. If necessary, supplement mobile connection speed with a mobile router or tethering.

• Battery exhaustion: Long continuous surveying can drain smartphone or LRTK device batteries. If the devices shut down before data are saved, you may need to remeasure. Always bring spare batteries and charge devices at appropriate intervals. In cold regions batteries degrade more quickly, so take measures to keep backup batteries warm.

• Other human errors: Beginners may make mistakes in point naming or memo input, forget to take photos, or miss points. These are often discovered too late to correct, so establish on-site routines to prevent them. For example, make “measure point → take photo → upload” a single set to complete each time, and cover important points with a checklist. When working alone, cultivate a mindset to double-check your own work.

Future Prospects (Use by Municipalities and Private Sector, BIM/GIS Integration, Disaster Response)

The potential for solo surveying using LRTK is expected to expand further. Pilot implementations by municipalities and construction companies have already begun. For instance, Fukui City early adopted iPhone + LRTK in 2023 for disaster prevention, using it to quickly record damage from earthquakes and heavy rains. Processes that previously required staff to travel between field and office to produce drawings were greatly streamlined by sharing field-collected data to the cloud immediately, shortening lead times to recovery. As such, low-cost LRTK adoption in the public sector is attracting attention as a DX tool for disaster response and infrastructure inspection.

In the private construction and civil engineering industries, the labor-saving benefits of solo surveying are immense. Using LRTK for as-built management allows rapid, high-density confirmation of post-construction results, preventing rework and improving quality. Piling and control point setting can be performed quickly and accurately with coordinate navigation, improving productivity in construction management tasks. For infrastructure maintenance, high-precision photos and 3D point clouds acquired with LRTK during routine inspections enable easy cloud-based comparative analysis of deterioration at the next inspection. This can shift inspections from manpower-dependent patrol checks to efficient digital-recorded maintenance.

Technologically, further developments are also exciting. High-precision data acquired with LRTK can readily integrate with other digital technologies. Combining with drone aerial photography and 360-degree camera footage to record sites, and linking with machine control for heavy equipment to automate construction, are already being trialed. There are also prospects for loading BIM/CIM models created during design into the LRTK cloud to perform as-built checks with AR display on site. LRTK itself is continuously receiving new features through firmware and app updates reflecting user feedback. Improvements in indoor positioning and non-contact positioning accuracy and support for new satellites will further expand the range of tasks that can be handled by solo surveying.

At the industry level, solo surveying may become a standard method that aligns with the Ministry of Land, Infrastructure, Transport and Tourism’s i-Construction and infrastructure DX initiatives. With goals such as a 30% labor reduction (1.5× productivity) in construction sites by 2040 [reference: MLIT *i-Construction 2.0* plan], tools like LRTK could become a trump card. In the future, smartphone-based solo surveying may spread nationwide among municipalities and companies, creating a new norm: “surveying is something you do quickly by yourself.”

Finally: Smart Solo Surveying Realized by LRTK

Surveying work that once required manpower and time can become astonishingly simple and fast by introducing LRTK. The benefits of solo surveying go beyond reducing personnel—they enable real-time data sharing and reduce mistakes, improving overall site productivity and quality. Lightweight and easy-to-handle LRTK can be used by veterans and newcomers alike, contributing to organization-wide DX promotion.

The world of surveying is undeniably changing. Why not realize this fastest and easiest form of solo surveying at your site? Adopt smart surveying with LRTK to achieve both efficiency and accuracy improvements and lead the future of construction and civil engineering sites. You’ll be surprised at the results and may never return to traditional methods. Use the LRTK implementation checklist as a reference and start the next-generation surveying style today. The future of the field begins with each individual’s step.